Buildin' Projects

Prusa MK3s+ & MMU3 Upgrade Review

2023-11-19T12:01:00.001-06:00

MMU2s --> MMU3 Upgrade Review

I had an early MMU2, which I later upgraded to a MMU2S. This meant I was using an old 2018 version of the MMU PCB and stepper motor set. The MMU3 upgrade kit doesn't include any of these - it is basically just a hardware kit (as in nuts and bolts), a new power supply board (which is probably the actual critical item of the MMU3), and a full set of redesigned and optimized printed parts (which you print yourself from supplied filament). All of this is well documented elsewhere, so I won't say anything here about the actual build other than it was fairly straightforward and easy to follow.

Ancient MMU control board- still being used!

Assembled MMU3 in action

Looks familiar but many improvements under the hood

Clownfish initial test print in eSUN PLA+. Model source HERE

The initial test prints were 'out of the box' better than the old MMU2s - but still not perfect. Interventions were still needed - but a large improvement from the MMU2s. The errors were also much easier to deal with as there is now some trouble-shooting text displayed on the printer's LCD.

Errors typically were of two types:

The FINDA or print head sensor wouldn't recognize the filament change had been successful and reached the head sensor
During filament retraction, the filament tip would back too far out of the selector, so the selector couldn't grab and load it during the next exchange

FINDA Tuning

To address the FINDA error described above, I adjusted FINDA sensor. The installation manual recommends setting this to to barely turn on when a filament is inserted - however didn't always recognize when a filament was inserted during changes. I adjusted this to barely turn off when a filament was removed - this seemed to increase reliability of filament changes, in particular with flexible filaments. The new method of tuning this sensor with a screw is a big improvement over the MMU2.

After adjusting the FINDA- the only failures seen was from filament retracting too far out of the MMU selector- probably due to the auto-rewind spool holder. I'm also printing TPU using the MMU, which seems to work better than expected as this isn't a supported filament type from PRUSA.

Too much auto-rewind action

I'm using gravity auto-rewind filament spools. These seem to cause intermittent problems by pulling too much filament out of the selector during filament change. I'm planning on switching to a simpler spool holder with no auto-rewind, and just a method to manage the slack created during filament unload. I haven't found an existing design yet that I like, I might just design and build one.

3D Printing FDM Multi-material adhesion experiment

2023-11-19T06:56:00.000-06:00

Background

Most multi-material prints I've seen on Thingiverse or Printables involve using multiple colors of the same material for cosmetic effects - printing characters, making art, etc.

While this is interesting, being able to print multiple types of filament in the same 3D print also enables using different materials for mechanical design reasons. Examples include adding a soft touch surface to a rigid mechanical part or flexible hinges to a rigid part.

For this to work, the different materials must adhere together during printing. If there is no bonding during printing, mechanical interlocks could also be used.

I'm planning on designing and making a part which good adhesion during printing is desired, so I conducted a quick experiment to test adhesion between various materials.

Method

I designed a small block- 25mm x 25mm with two solid bodies. Test block available on thingiverse here

I had 4 material combinations I wanted to test:

PLA to TPU
PETG to TPU
Nylon to TPU
PC to TPU

For this experiment, for all experiment trials conducted, the experiment material was the base, printed directly on the build plate, and the TPU was the top material.

Equipment

Prusa Research MK3S+ with MMU3
Prusa Research smooth PEI build plate

Prusa Slicer really didn't like using TPU as a material option to print with the MMU, so you need to manually select this material profile in the filament tab.

PLA / TPU test block

All Test blocks

Results Table

Base Material	Top Material	Adhesion
PLA eSUN PLA+, Blue	TPU ANYCUBIC A11795 TPU, red	Very Good
PETG Prusament, Orange	TPU ANYCUBIC A11795 TPU, red	Good
Nylon https://www.lay3rs.nl/ Nylon, Black	TPU ANYCUBIC A11795 TPU, red	Very Poor
PC Blend Prusament PC Blend, Black	TPU ANYCUBIC A11795 TPU, red	Poor

Conclusions

This TPU appears to adhere well to both PLA and PETG. Qualitatively, PLA may be slightly better, but both seemed firmly adhered with this test piece.

Adding Status LED lights to RE-ARM smoothieboard

2018-01-09T20:55:00.002-06:00

I've been the happy owner of a RE-ARM smoothieboard that I purchased through the kickstarter campaign. If you haven't heard of this board, it's a cost-effective way to upgrade your existing 3D printer that uses a Arduino Mega with Ramps 1.4. The RE-ARM replaces the old and creaky 8-bit Arduino Mega with a powerful ARM based Smoothieboard- and keeps your Ramps 1.4. It's basically a plug-and-play upgrade. The software configuration is fairly straightforward, and there are many example configuration files on the smoothieware website. In addition to the improved processing power, it also had a big advantage in configuration- you simply update a config file on the SDCARD and reboot- no recompiling each time you want to change a setting.

It was a great upgrade to my "snowstock" delta printer over it's original Arduino Mega. The old Mega didn't really have enough processing power to drive the delta, resulting in poor print quality and many pauses during print, particularly when it was trying to drive a LCD panel.

All was well until I did a firmware update last week, and something went wrong, apparently "bricking" the re-arm. It wouldn't even show up as an external USB drive when attached to my PC. I asked for help on the forums- and was asked for status lights on the smoothieboard. The re-arm only has one status light- power - so no help there. Another helpful person on the reprap forums described how to add status lights to the re-arm. I added status lights to my re-arm- which told me my firmware was locked up. I ended up downloading a fresh copy of the latest firmware from the smoothieware github site, and that did the trick. The version I downloaded that temporarily bricked the board must have been corrupted.

Example status LED example from Youtube:

Even though they were not helpful for this problem, the status lights do seem like a good thing to have available. I thought it might be helpful to post pictures of what I did. Also a note- the LED's are not in order of the smoothieboard- on this implimentation on the re-arm they are left to right, LED3-LED4-LED2-LED1.

I only have through hole components and supplies. The sample circuit shown on the youtube video linked in the reprap forums uses surface mount components. The build shown below only uses simple through hole components.

"Bricked" RE-ARM, power light illuminated- no other clues about what is going on

RAMPS 1.4. Note the unpopulated servo pins at the bottom center of the photo, immediately to the right of the reset button. This is where the status LED will be installed.

Step 1: Add female headers to the RAMPS 1.4 board to allow addition / removal of the status LEDs from the RAMPS board. Note we only need to add headers to the ground row and signal row of the servo pins.

Female header pins I had available

Trimming the headers to 4 pins wide

I used a 3x6 male header pin array to keep the proper spacing on the female header when I solder them to the RAMPS 1.4 board.

Another view of the female headers prepped for soldering

Female headers inserted into the RAMPS board

Female header soldered into place & excess pin length trimmed

Male header pin array removed. The male pin array kept the female headers nicely aligned during soldering onto the RAMPS board.

Supplies Needed

Step 2: Gather materials needed:

4x 1k ohm resistors
male header pins
LEDs
perf board (I used cheapo non-plated perfboard, but anything would work)
breadboard (used to keep pins aligned during soldering)

Step 3: Layout and solder

Cut 2 male header pin strips- 4 pins long, insert into breadboard as shown

Insert 4 1k ohn resistors into perf board

Flip over and place on top of male header pins in breadboard (see tips of male header pins slightly protruding through perf board)

Nicely lay out resistor leads

Solder resistor leads to first row of header pins

Trim & solder long LED lead (anode / +) to second row of header pins- right side of photo. Solder short LED lead (cathode / - ) to left resistor lead. Trim excess leads.

Completed "dead bug" build. Note the various LED leads have to be sided to space out the LEDs. Also make sure the various LEDs are not shorted to one another.

Completed board trimmed and ready to go. Ugly(!) but functional.

Side view

Step 4: Plug into RAMPs

New LED board plugged onto RAMPs. Note LED anode / + connect to the signal lead, and cathode to ground (through 1k resistor to control current) All LEDs lit- firmware crash!

Step 5: Check LEDs vs. reference

See Smoothieware wiki. Again, note that the LED order on the RAMPs board doesn't match the "real" smoothieboard: left to right, LED3-LED4-LED2-LED1.

Fixed- test print with Benchy

Arduino controlled 3D Printed Automatic Fish Feeder

2017-09-17T20:34:00.001-05:00

Recently I designed & put together a really simple small aquarium automatic fish feeder. The design files & simple build instructions are located on Thingiverse here.

And, since I didn't immediately see an easy way to park code on Thingiverse, the code is below:


/***********************************************************************************

Small fish feeder



code is set to have the feeder run 1x per day. It runs once immediatley upon startup,

then waits 24 hours for next run. For testing comment out the DAY (24*HOUR) line

and uncomment Day (2*SECOND) line

 *****************************************************************************************/



#define SECOND 1000L

#define MINUTE (60*SECOND)

#define HOUR (60*MINUTE)

#define DAY (24*HOUR) //uncomment for actual run

//#define DAY (2*SECOND) //test setup



const int SERVO_PIN = 3;      //pin number for the led pin - this is 'const' since it will not change during code, and saves Arduino memory

const int FILL_DEGREE=5;      //starting hole location, fill slider with fish food

const int DISPENSE_DEGREE=45; //dispensing hole location



Servo servo1;



//setup runs once when the Arduino is turned on

void setup()

{

  servo1.attach(SERVO_PIN); //attach the servo on pin SERVO_PIN



} //setup() is done, go to loop()



//loop runs forever once setup is complete

void loop()

{

  //******************************************************************************

  //NOTE: YOU WILL HAVE TO CHANGE THESE VALUES based on your servo horn alignment.

  //******************************************************************************



    servo1.write(FILL_DEGREE);              // tell servo to go to fill position

    delay(1000);                            // delay for 1 second

    servo1.write(DISPENSE_DEGREE);          // tell servo to go to dispense location

    delay(1000); 

    servo1.write(FILL_DEGREE);              // tell servo to go back to fill position  

    

    delay(DAY);                       // delay for 1 day

}

Fixing battery powered air mattress inflator with an Arduino Nano & Lipo batteries

2017-05-23T21:10:00.001-05:00

Our rarely used air mattress inflator bit the dust. It's a old Coleman rechargable Quickpump that used a 6 volt lead acid battery. It had two problems. One, the battery was toast and wouldn't accept a charge, even when directly attached to a nice charger. Two, I had lost the charger some time back so even buying a new battery would cause a charging hassle. Instead of buying a plug-in charger which would have been the easier move, I decided to fix it using parts on hand.

Be warned that any dealing with LIPO batteries is potentially risky. Try this at your own risk!

Proposed solution:

2s or 3s LIPO batteries- normally used for drone or RC airplanes. Great power source but a bit risky to use since they do not have any built-in over discharge protection.
MOSFET to handle power distribution
Arduino Nano- I thought it would be possible to use the Nano to control the system and safely run the pump off of the LIPO using the following strategy:

using a voltage divider, read the battery voltage and determine if it was a 2s or 3s battery (assuming the use of a LIPO pack)
determine if the battery is in a safe operating voltage, and if not, shut the system down
PWM the output to simulate a 6V power source for the motor

It's not well tested, and the code is messy, but it seems to work fine. I ended up not using the indicator lights as listed in the schematic and code. They really were not necessary, and they also seemed to make the circuit not work- perhaps I didn't have the pull down resistor sized properly on the MOSFET gate?

Schematic with calculation for voltage divider

There is a specific MOSFET listed, but any MOSFET that is N channel and can handle sufficient current should work.

I tested the circuit out on a breadboard first. After that seemed to work I soldered it on to a cheap 4x6cm protoboard and installed it in the pump shell. It was a bit of a tight fit on the protoboard.

Circuit installed in pump shell

The way it actually is wired is with the off/on switch controlling the + output- this way the Arduino will boot as soon as the battery is connected. The downside is that the Arduino will draw power the entire time the battery is connected- which would eventually destroy the LIPO.

Circuit detail

ready to rumble!

Ugly code- note there is a collection of serial print hooks to track what is going on with the code / circuit:

This software allows a 3s or 2s LIPO to power a 6V air mattress inflator

reads input voltage through voltage divider

determines if 2s or 3s battery is attached

if battery is in acceptable voltage range, allows pump to run and turns green LED on

if battery is too low, does not allow pump to run and turns red LED on

utilizes analog output (PWM) to simulate desired output voltage using MOSFET to control higher voltage and current from LIPO battery

void setup() {

// initialize serial communications at 9600 bps:

Serial.begin(9600);

}

void loop() {

// constants

int analogInPin = 0; // Analog input pin that the potentiometer is attached to

int GreenLEDPin = 5; // digital output pin that the green LED is attached to

int RedLEDPin=6; // digital output pin that the red LED is attached to

int MOSFETPin=3; //output pin for MOSFET, must be PWM capable pin

float R1=100; //R1 value of voltage divider (divided by 1000)

float R2=48; //R2 value of voltage divider (divided by 1000)

int Lipocell=0; // default lipo cell count

float mincellV=3.0; //standard low lipo cell voltage

float cell_cutoffV=3.2; // cutoff voltage

float maxcellV=4.2; //standard high lipo cell voltage

float batteryV=0; //battery voltage

float sensorValue=0;

float inputVoltage=0;

int outputV=6; //voltage desired for output

float outputValue; //value for analog output

//pinMode(MOSFETPin, OUTPUT); //set MOSFETPin as output

// read the analog in value:

sensorValue = analogRead(analogInPin);

inputVoltage=sensorValue * 0.0049; // 5 volts / 1024 resolution = 0.0049

batteryV=inputVoltage * (R1+R2) / R2 ;

// determine if battery is 2 cell or 3 cell battery or if no battery is connected

if(batteryV >= (mincellV*2) && batteryV <= (maxcellV*2)) Lipocell=2; //set cell count to 2

if(batteryV >= (mincellV*3) && batteryV <= (maxcellV*3)) Lipocell=3; //set cell count to 3

if(batteryV < (mincellV*2) ) Lipocell=0; //set cell count to 0 (no battery)

outputValue = map(outputV, 0, batteryV, 0, 255); // map desired output voltage to PWM & output

// determine if the battery voltage is within acceptable range and battery is present & act accordingly

if(batteryV > (Lipocell * cell_cutoffV) && Lipocell != 0)

{

analogWrite(MOSFETPin, outputValue); //start MOSFET using PWM value

Serial.println("turning on output pin");

digitalWrite(GreenLEDPin, HIGH); //green light on

digitalWrite(RedLEDPin, LOW); //red light off

}

else

{

analogWrite(MOSFETPin, 0); // if battery too low set output to zero

Serial.println("turning off output pin");

digitalWrite(GreenLEDPin, LOW); //green light off

digitalWrite(RedLEDPin, HIGH); //red light on

}

// print the results to the serial monitor:

Serial.print("input voltage = ");

Serial.println(inputVoltage);

Serial.print("battery voltage = ");

Serial.println(batteryV);

Serial.print("LIPO cell count = ");

Serial.println(Lipocell);

Serial.print("output value=");

Serial.println(outputValue);

Serial.println(); //blank line for clarity

// wait XX milliseconds before the next loop

delay(1000);

}

Shapeoko2 X-axis beam upgrade & Dinosaur Bookends

2017-01-08T14:52:00.002-06:00

The stock Shapeoko2 used two standard makerslide extrusions, separated by a small air gap, for the X-axis linear rail. This worked OK, but the assembly tended to twist and cause inaccuracy or cutting problems when driving the machine too hard. Some people stiffened their machines by bolting the two extrusions together or otherwise tying the two beams together and approximating a single beam.

Inventables recently released a new "Wide Makerslide" for their X-Carve CNC router. This new extrusion replaces both X-axis makerslides in their X-Carve product, and yields a much stiffer X-axis. This new part is a very easy and fast upgrade for older Shapeoko2 machines. They sell it in 500mm, 750mm, and 1000mm to fit most machines. My machine has the narrow X-axis so I needed the 500mm part.

Stock setup on the left, still assembled. New extrusion on the right.

Pay close attention to stepper motor wiring order when disconnecting Y axis steppers to disassemble unit

Together and ready for testing!

Cutting out parts for Dinosaur Bookend for Christmas present

The first project built with the upgraded Shapeoko2 were a set of these cool dinosaur bookends. They turned out great and were a hit at Christmas. The ~0.5" plywood was sourced from Menards- they had a super sale on Christmas Tree bases- pretty nice quality pseudo baltic birch 2' x 2' squares for $1.90. The bookend bases were cut from Ikea bamboo cutting boards.

Finished bookends

Shapeoko 2 Upgrades using XCarve parts

2017-01-08T14:27:00.001-06:00

This post is actually a little out of order- I actually did this before rebuilding the Z-axis.

After doing some initial aluminum cutting and also running into some size limitations with the stock Shapeoko2, I decided I need to upgrade the machine to make it both a) larger and b) stiffer.

Inventable's X-Carve has a number of parts that are bolt-on upgrades that are compatible with the Shapeoko 2. The first I purchased was the improved DC Spindle mount. This provided a much-improved interface between the DC spindle and the Z-axis slide- both improved rigidity and alignment. It's machined from a single aluminum extrusion and black anodized.

DC Spindle Mount

The second upgrade I purchased was the X-Carriage Extrusion. This was definitely a huge upgrade over the stock Shapeoko2 X-Carriage. The stock x-carriage is an assembly of plates bolted together with a ton of spacers and washers- it works, but the improved part is one massive extrusion. It should prove to be much stiffer in actual use.

X-Carriage Extrusion

Installation of the upgrades was pretty straightforward. The entire Shapeoko2 X axis needs to be disassembled. The wheels and stepper motor can be attached to the X-Carriage. Then, the X-carriage extrusion is slid over the X-axis Makerslide extrusions.

X-Carriage assembly in process.

Once the X-axis is re-assembled, the Z-axis with the new, improved DC Spindle mount can be bolted on and everything aligned.

I also took the opportunity to expand the stock build surface using new makerslide and some 8020 extrusions I purchased from an industrial salvage place.

Installing electrics on a board attached to the bottom of the frame

New, Super Beefy 8020 Frame, laid out but not yet squared

Just about ready to bolt together

Squared up and bolted together.

I used the stock 500mm x 500mm wasteboard, then added a new wasteboard I cut from 1/2" MDF. I did buy a set of 5mm threaded inserts to add hold downs to the new section.

New wasteboard cut from 1/2" MDF and hole locations marked

Holes cut and M5 threaded inserts added

New Wasteboard & Y axis makerslide braces in place

Assembled and ready for first part- a new faceplate from 1/8" MDF:

Cutting faceplate for E-stop and spindle RPM control

Faceplate cut & spray painted silver

Finished, assembled and ready to go

Shapeoko 2 Z-Axis upgrade to ACME screw thread

2017-01-08T14:04:00.003-06:00

After having my Shapeoko 2 for a few years, I decided it was time to give the Z-axis an upgrade to the ACME screw threaded rod, vs. the standard threaded rod it came with. This upgrade should improve Z-axis precision and speed, as well as clean up the mechanical "look" of the system.

I used parts from Inventables- I've always found them to be high quality with good service and speed.

www.inventables.com components used: (with P/N)

ACME Lead Screw Kit 30658-01 (includes M6 locknut)
Z-axis motor plate 30534-01
GT2 Belting 2" x 3" x 1/4" 30547-01
20T GT2 Pulley, 8mm Bore 26054-04
20T GT2 Pulley, 5mm Bore 26054-01

Additional hardware used:

2x M5 x 8mm button head screws
1x M3 x 12mm socket head cap screw (SHCS)
1x M3 washer

Inventables has a great step-by-step illustrated set of instructions for the newer X-Carve CNC. Their instructions are mostly appropriate for upgrading their older Shapeoko 2 as well.

Before I could start assembling the new Z-axis, I had to take apart the existing, stock Shapeoko2, Z-axis.

Stock ShapeOko 2 Z Axis - before disassembly

Z-axis apart and on the table

1) Use 2x M5 x 8mm button head screws (new screws to assembly) to retain the stock thrust bearing in the new Z-axis plate. I didn't have M5 x 8mm button head screws in my hardware collection, so I used the screws from the belt clips on the Shapeoko and used some M5 x 8mm SHCS on the belt clips.

Thrust bearing in Z-axis plate

Screws in place to retain the bearing

2) Use 2x M5 x 20mm button head screws to attach the Z-axis plate to the Z-axis makerslide. These screws were part of the original Z-axis assembly. I left the screws a little loose to allow for adjustment once everything was assembled.

3) Attach Z-axis makerslide to X-axis rail using original hardware. At this point it pays to take some time to get the Z-axis makerslide as square as possible with the rest of the machine. The recommended height is to leave just enough makerslide exposed below the X-axis slide to not expose any of the T-slot clips. Depending upon how you want to complete your assembly, you might also consider loading the Z-axis plate to the Z-axis makerslide before bolting it onto the machine.

Squaring Z-axis slide with the machine

Adjusted height to not expose the T-slot clips.

4) Took off Z-axis plate assembly, dropped Z-axis slide with ACME screw and block onto makerslide, then re-attached Z-axis plate assembly

Z-axis slide attached

5) Attach 20T GT2 Pulley (8mm bore) to top of ACME screw with setscrews, then tighten down M6 locknut)

ACME Screw 20T GT2 Pulley and locknut installed

6) Using 3x existing M3 x 12 SHCS & M3 washers, plus a new M3 x 12 SHCS & washer, attach stepper motor to Z-axis plate. Do not tighten screws though- you'll need the slop soon to tighten the belt.

Z-Axis motor installed

7) Attach the second GT2 pulley to the stepper motor shaft.

8) Load the GT2 Belt across the pulleys. You might have to loosen and remove the motor to get the belt in place. I actually had to completely detach the stepper motor to get the belt across the pulleys.

Belt in place, ready to test

9) check that everything is square and all screws are tight.

10) Use Universal G-Code sender or another G-code sender to update the Z-axis steps per mm:

Update Z-Axis setting to:

188.976 Steps/mm (for 12 threads per inch ACME screw thread)

with the following command in Universal G-Code Sender: $2=188.976

11) Check Z-axis direction - some help is here to adjust inverted Z direction

Enter $$ in the Universal G-Code sender command prompt to get a list of current GRBL settings. Take a look at the $6 setting- I had to subtract 128 from my current $6 value.

After getting everything set up, it was time to test by manually driving the tool head around using the Universal G-Code Sender's manual controls. Initially I had some binding and stepper motor skipping steps. I ended up having to do a few things to fix the step skipping:

loosened the screws attaching the Z-axis plate to the Z-axis makerslide, re-aligned the parts
added a little silicone grease to the ACME screw
increased the current to the Z-axis stepper by 1 increment on the adjustment pot

No test parts yet....

Solidworks to gcode for ShapeOko 2 using Autodesk Fusion 360 CAM

2016-01-19T19:49:00.002-06:00

I've been searching for a while to find the best (and cheap) way to go from Solidworks 3D CAD files to gcode to run my ShapeOko2. After reading through the forums and trying a couple different options, the software the worked the best for me was Autodesk Fusion 360's built-in CAM package. Fusion 360 is a full featured 3D CAD package- and the best part is that it is free to students / hobbyists. I think that's a great strategy to widen their user base, and it's beyond me why Solidworks doesn't adopt a similar model.

The first parts I wanted to cut were some 1/4" thick 6061 aluminum sections for a home-built adapter to put a Trail-A-Bike on my Yakima roof rack.

I could have modeled the parts in Fusion 360, but since I'm more familiar with Solidwork's interface, I created the .prt files in Solidworks then imported them into Fusion 360. Another option for model creation is Onshape's excellent CAD package- which is very similar to Solidworks, and also free for Home users.

So, the software toolchain I used was:

Model in Solidworks, save .prt file
Import into Fusion 360
Use Fusion 360's CAM module to create the toolpaths
export Gcode
use gcode sender to send to Shapeoko2

Creating a toolpath from a .prt file is much more involved than simply 3D printing a part- with a lot more pitfalls. It took me quite a few tries to get the process to work property. I cut out a complete set of parts from 1/4" plywood before I even tried cutting aluminum- it's a lot cheaper to scrap than aluminum!

I found a good tutorial video on Fusion 360's CAM:
https://www.youtube.com/watch?v=XYoovemQoiM

Initially I had some issues with Fusion 360's generic GRBL post processor (plug in to generate gcode optimized for the Shapeoko's software). After some searching I found and improved one to use:

Discussion:
https://camforum.autodesk.com/index.php?topic=6144.0

Link to post-processor:
https://camforum.autodesk.com/index.php?action=dlattach;topic=6144.0;attach=7615

I did find a couple settings to tweak on the post-processor:
set "retractheight" to 5mm
set output units to "mm" - definitely do not forget this, otherwise you'll have big problems.

Cutting aluminum with the Shapoko was also a trial and error process- lots of experimentation with feeds 'n' speeds and lubricant. I liked CRC True Tap coolant / lubricant I found on Amazon. WD-40 and 3-in-1 oil also seemed to work OK.

The final Trail-A-Bike rack adapter worked great- and kept the Trail-A-Bike safely secured during a 1,500 mile road trip.

I did learn some lessons about the Shapeoko2 cutting aluminum. I really want to do any modifications possible to stiffen the structure- stock it's pretty flexible to try and cut aluminum at anything but a very thin layer / stepdown.

Also, the plywood trial copy didn't exactly work- it was slightly thinner than 1/4", and was a little misleading about actual fit on the Trail-A-Bike. The plywood version fit exactly right, and the aluminum didn't. And, since I finished the aluminum version the night before the big road trip I didn't have time to re-design and re-cut all the parts- so I broke out the dremel and manually ground the parts down to make them fit. They were a bit ugly but still worked.

Cutting trial part from plywood

Completed trial part

Assembled Trial Rack Adapter

Getting Aluminum cut set up

Cutting Aluminum

Completed Aluminum Part

Completed Trail-A-Bike to Yakima Rack Adapter:

FPV Latency Measurement of GoPro 4 Silver & Quanum Complete FPV bundle

2015-10-04T21:16:00.001-05:00

One really critical performance attribute of any FPV system is it's latency- how much time elapses between when the FPV camera on your remote vehicle captures a frame of video and when it appears on your FPV goggles or groundstation monitor. If this latency is too great, it'll be really hard to control your FPV vehicle since you are watching what happened in the past rather than immediate feedback.

There is an easy way to measure latency with your system. Place a stopwatch (or stopwatch app on your phone) in view of your FPV camera. Start the stopwatch. Then, take a picture of both the stopwatch and your FPV display. Subtract the FPV display time from the stopwatch display and you'll have your latency. It can be a little tricky to get everything lined up to get a good photo, especially with the el-cheapo FPV goggles I have.

Human reaction time is ~ 0.1 seconds or 100ms. Hopefully your measured latency is less than that!

I measured the latency of my FPV system:

GoPro Silver 4, with video output cable (cable purchased from Amazon)
Quanum Complete FPV bundle transmitter, receiver, and DIY goggles

Test #1: Phone stopwatch on the left, FPV goggles on the right

Test#1: 26.10 - 26.03 = 0.07 seconds = 70 ms

Test#2

Test #2: 27.03 - 26.96 = 0.06 seconds = 60 ms

I'm pretty happy with the "measured" latency of the system- it seems like a GoPro4 with a real time video output cable, and the Quanum FPV bundle yields a latency of 60-70 ms.

Redneck Canoe Thwart Fix

2015-06-16T21:28:00.001-05:00

I have an ancient fiberglass canoe that I am "storing" for my brother. The Thwarts (or cross braces) were getting pretty rotten, and one had basically fallen off. The braces probably were not original equipment- they looked with 1/4's cut to length and screwed in. Since this canoe isn't a show piece and is only used occasionally, I thought I'd try something really cheap and easy for Thwart replacements.

Rotten Thwart! (cross-brace- not a yoke)

All ready for new Thwarts

I decided to try using EMT tubing- or galvanized steel conduit. It's super cheap- 5' long 1/2" diameter EMT tubing was less than $1.50 at the local Home Depot.

Step 1: Measure the stock Thwarts and cut the EMT to length with a hack saw

Step 2: Smash the ends flat- I used a combination of a big bench vise and a hammer. My bench vice has a built-in anvil. Everyone needs an anvil!

Getting ready to smash

Squishing with vice

Finishing the job with a hammer

Nice and flat

Step 3: Drill holes in the end for fastening hardware. I used M5 x 25mm stainless hardware, since I had some available.

Hole Drilled

Step 4: Install and go paddle!

Installed and ready to go!

Obviously these replacement EMT Thwarts are not strong enough to use as a portaging yoke, but they are certainly strong enough to hold the canoe sides in place.

Stratasys UPrint SE Plus material container

2015-06-11T21:34:00.001-05:00

Stratasys's Uprint SE PLUS is a great entry level "pro" 3D FDM printer. One minor annoyance is the printer comes with foil zip-lock bags for storing filament that isn't in use. When you have a team using the printer, and you've got a collection of colors, the foil bags make managing your filament inconvenient.Solutions that might work for hobby-level machines - such as putting the spools together into 5 gallon sealed buckets - won't work for the Stratasys as each spool has a keyed computer chip that must stay with the individual spool.

Sterilite makes a food container that works perfectly to store the filament spools. Sterilite's 03186606 food storage container seems almost custom-made to hold filament spools for the Uprint SE PLUS. The spool fits nice and snug in the container, and it has a rubber sealed top to seal out moisture.

These are sold at many retail outlets, and are also available at Amazon.com: Buy at Amazon here.

Q450 Quadcopter servo gimbal setup, Part 1

2015-04-10T21:06:00.004-05:00

Digging back into FPV / Aerial Photography with a new camera gimbal
I was inspired by recent articles in Make magazine about FPV racing and the local Minnesota Autonomous Vehicle meetup to do some more quadcopter flying and building. My main quadcopter is a Hobbyking Q450- which I originally bolted together a year or two ago with a crude FPV camera mount made from a Home Depot low voltage electrical box bandsawed and bent into something usable. These days there are many, many better options for mounting FPV cameras- ranging from simple servo stabilized mounts through very sophisticated 3-axis brushless gimbals that yield professional video smoothness.

I was looking for a cheap and simple solution, and I ended up buying the "ActionCam Inline Gimbal GOPRO and FPV" kit from Hobbyking. I'm planning on using it to mount and stabilize both a GoPro and my small FPV camera. It uses two standard servos, and the Hobbyking KK2.0 flight controller I have will be able to control the servos without any software updates or hardware.

Kit Assembly
The kit comes with decent hardware, although it doesn't include the screws that join the upper and lower plates together.

Kit Contents

"Instructions"

I used a larger, standard sized analog servo for the roll axis

I originally tried a smaller Hextronik HXT500 5g servo for the pitch axis, but it was a little too small.

A Turnigy TG9e 9g servo was a good fit for the pitch axis

Unpacked hardware kit. The camera mount pivot is pretty nice, it seems to have some rotary damping

I originally tried pressing the camera tray on to the servo directly. It wasn't quite the correct width- a tad too narrow.

So, I decided to bolt the camera tray on to a servo horn. I drilled the horn in two placed for 2/56 screws. I accidentally cracked the servo horn when I screwed in the outer screw. I didn't have a 2-56 tap so I drilled the holes to size then tapped the holes with a screw- mostly worked. I have since ordered a set of 2-56 taps off of e-bay- next time I'll use the right tool and avoid cracking the servo horn.

Servo mounted to the camera tray using 2x 2-56 SHCS + 4x washers. I used washers under both the nut and the screw head to allow for maximum clamping of components.

Second view of mounted pitch servo

Mounting the roll servo. My first try placed the servo horn on the "inside" of the frame, but there wasn't enough clearance for the mounting screws- they hit the servo. So I moved the servo horn on the "outside" of the frame.

Roll servo showing 2x 2-56 SHCS, washers and nuts

Upper mounting plate attached to servo. (note this is a photo of the first try with the kit's hardware which I ended up ditching) I decided to use my own 2-56 hardware because it seemed to fit better. I also decided to place the roll servo above the vibration damping plates, then attach the vibration damping plate to my Q450 frame. This arrangement seemed to make the most sense for my purposes.

Roll servo attached to the upper plate- first try with the kit hardware. The threaded ends of the screws extended too far past the upper plate and interfered with the lower plate.

. Now with the 2-56 screws attaching the servo to the upper plate. Vibration damping balls (blue) installed

Note the head of the screws securing the roll servo are under the upper plate, double-nutted on the top.

Bolting the lower plate onto the Q450 quadcopter frame

I had to dremmel the slots on the Q450 quad copter frame slightly wider to allow the lower mounting plate to fit.

Camera gimbal installed. I used 4x 4-40 x 0.75" SHCS to attach the upper mounting plate (with camera gimbal attached) to the lower mounting plate. I didn't have any 4-40 lock nuts, so I used a few drops of blue locktite threadlocker on the threads to keep the nuts from vibrating off during flight. I only used screws on the outside group of damping balls to save weight.

Ready for plugging in the servos and setting up the KK2.1 flight controller.

The setup that worked for me for plugging in the camera gimbal servos was the Roll servo in the KK2.1 output #7, and the Pitch servo in KK2.1 output #8.

KK2.1 Setup- first go to "Camera Stab Settings"

The "Gain" settings adjust how much the servo corrects. the "Offset" setting adjusts the neutral location of the gimbal. To check functioning- first take the props off the motors. Then throttle up slightly so the motors are spinning- only then will the gimbal react to motion of the quadcopter. If the gimbal moves the wrong way, change the gain to negative. The gains shown in the photo above is what I'm starting with that appears OK.

Next steps:

Adjust servo arm position on both servos to try and get the offset to zero. This will get a larger range of motion in one direction in both axis.
run servo cables
attach both gopro and FPV camera to gimbal
fly!

Magicshine mount for Giro Edit

2015-02-15T20:25:00.002-06:00

I just purchased a new helmet for winter riding- I was tired of getting a brain freeze from riding in 10 degree temps with my regular helmet and Gore balaclava underneath. Way back in the day I would have just duct-taped the helmet vents, but these days there are lots of great winter helmet options. The helmet is great by itself- and it has a nice bonus feature- a built-in GoPro mount. One of the nice things about this new helmet and printed mount is that no additional purchased hardware is needed to attach the light.

I designed a mount for the gopro adhesive mount I attached to my summer helmet, but the angles were not right for the new helmet. So, off to Solidworks to design a new mount. The first try seemed to work well. I might add a feature to clip on the wire, but other than that it's good to go. I might also try moving the light further back towards the helmet.

I placed the Solidworks .prt and .stl files on thingiverse if you want to print your own.

GoPro adapter printed

MagicShine bolted on

Magicshine LED mounted to the Giro EDIT

Raspberry Pi Time-Lapse, First Movie

2015-02-10T20:08:00.000-06:00

First shots taken- spaced one minute apart from 7am to 7pm on 2/10/15. Once the series of shots were taken, I used Microsoft Movie Maker to put together a video.

The process was very easy- basically import all the photos into Movie Maker and set the duration. I used a duration of 0.04 seconds per photo to yield about 24 frames / second. Unfortunately it was a snowy and overcast day, so it's a really boring video.

One issue that is noticeable right away is that the red camera on light shows in the photos. The Raspberry Pi camera light is very easy to turn off, see this link.

Following the link's instructions, open up the config.txt file for editing:

sudo nano /boot/config.txt

Then add this to the end of the file:

disable_camera_led=1

save, reboot your PI, and you are in business minus the annoying light.

Raspberry Pi Time-Lapse Camera : Go time!

2015-02-09T22:02:00.003-06:00

In the previous post I went though a few tries to get my Raspberry Pi set up to take time-laps photos. After a few false starts I had success using the instructions on the Pi foundation's website:

http://www.raspberrypi.org/learning/timelapse-setup/worksheet.md

I also found that my PI tended to pull the same IP every time it booted- even though I couldn't get it to successfully set it's network configuration to static.

I was successful, however, getting it to automatically log onto my wireless network every time it booted.

I used the instructions on the raspberrypi.org website listed above to set up a crontab scheduled job to take a photo every minute. Initially I used their instructions just to test the function and made sure it worked. Then, I combined those instructions with some info on a crontab tutorial (located here) to set up a job where it would take a photo every minute from 7am to 6pm, every day of the week. This roughly corresponds to daylight hours in Minnesota right now.

The line in crontab ended up to be:

* 07-18 * * * /home/pi/camera.sh 2>&1

The first position "*" indicates each minute

"07-18" indicates hours 0700 through 1800, every hour (24 hour clock)

The third position "*" is each day (# of days)

The fourth position "*" is every month

the Fifth position "*" is every day of the week

I'm not exactly sure what the "2>&1" does....

After I had that set up, I shut the PI down, disconnected the monitor, keyboard and mouse, and taped the PI's camera to my sun porch window, and plugged it in.

I was able to both SSH and sftp into the PI using the IP address I had written down earlier. I used the standard Nautilus file manager in Ubuntu 14.01 as the ftp client, and PuTTY as my SSH client.

Tomorrow night I'll sftp in to the PI, and hopefully have a folder full of pictures to put together a movie with.

Raspberry Pi Time-Lapse Photo initial setup

2015-02-08T22:03:00.001-06:00

I'm finally getting around to another project that's been on my list for a long time- putting together a self-contained time-laps camera using a Raspberry Pi and camera module. I'm planning on mounting it in some sort of waterproof container and placing it outside- I hope I can catch the melting and breakup of the lake ice later this spring.

If you haven't heard of the Raspberry Pi, it's a $35 linux computer the size of a deck of cards. Head to http://www.raspberrypi.org/ for more info.

Updating the Raspberry Pi
I'm using Raspberry Pi B model. It's been sitting in a box for quite a while so the first step is to update all of the software. Open up a terminal window and fetch available updates:

sudo apt-get update

then, apply the updates:

sudo apt-get upgrade

These two commands might take a while to complete- particularly if it hasn't been done in a while.

I'm planning on having the Pi close enough to my house so it should be able to connect to my wifi network- nice for transferring files and remoting in to adjust settings, checking alignment of the camera, etc.

Setting up the Pi to automatically connect to my home wifi network (successful)
I found some instructions on how to change the Pi's network configuration so that it'll automatically connect when it turns on:

http://weworkweplay.com/play/automatically-connect-a-raspberry-pi-to-a-wifi-network/

Attempting to set up a static IP address (not successful)
I also wanted to be able to SSH into the Pi to adjust settings, etc. So, to accommodate SSH the next step after configuring the wifi to automatically connect on boot was to change the Pi to a static IP. The previous link also had instructions on how to change from dynamically assigned to static IP. Here is another link with more detailed instructions on setting up a static IP on your raspberry pi:

https://www.modmypi.com/blog/tutorial-how-to-give-your-raspberry-pi-a-static-ip-address

However, when I was trying to comment out the old versions of lines in the network configuration files, I couldn't get # to work on the keyboard- some other character would appear instead. It turns out my PI didn't have it's keyboard configured properly.

Using:

sudo raspi-config

from the command line I was able to work through the menus to reconfigure the keyboard to a standard US 104 key layout. One note- some of the menus in the raspi-config program take a very long time to load- 10 seconds or longer. So have patience- it took me several times to realize this and not think the terminal window had crashed.

Then, back to trying to get a static IP setup.... And, no luck. I went through every tutorial I could find and it just didn't work. I'll have to postpone trying to set up SSH and just get the camera working on its own.

Back to the Camera setup
next step- installing Berrycam software on the PI so I can control it with my android phone.

see:
http://www.fotosyn.com/berrycam-support/

Installed- then installed the Pi Sight app on my Nexus 5- and no dice. The app would crash almost immediately every time I tried it. I immediately uninstalled it.

Then, after looking on the play store, I tried RaspiCam Remote. That worked right away- and without anything to install on the Raspberry Pi.

After trying and failing to use the Pi Sight app along with the berrycam script, I thought I'd go back to the basics and try using a tutorial that explains the process from scratch- and I found this:

http://www.raspberrypi.org/learning/timelapse-setup/worksheet.md

Great, step by step tutorial- and explanation about what each line does!

Tomorrow- to actually take some photos.

ShapeOko 2 Build: Part 1

2014-12-31T21:44:00.000-06:00

I've been watching the ShapeOko2 from Inventables for the last year. I've been interested in DIY CNC for the last several years, but the time wasn't right to jump in. When their kit went on sale for "small business Saturday" I decided the time to order the kit had arrived. I decided to spring for "the works" kit which includes the Quiet Cut spindle and a bunch of other upgrades.

The kit was very complete, down to including all the tools you'd need for mechanical assembly, and well packed. The basic instructions on their website were also very good. However, I was a bit underwhelmed with the documentation included for the extras in "the works" kit. The inventables website did have a page: ShapeOko 2 "The Works" kit instructions- not really instructions, but has at least a few more details.

So far, I have the mechanical assembly complete, and have started to wire up the system. The first challenge was to attach the drag chains / cable chains included in the expanded kit. Mounting brackets were not included. The Shapeoko2 wiki did reference these 3D printable drag chain mounts, they look nice but they don't fit the drag chains included in the shapeoko2 "the works" kit. I ended up designing a set of brackets (files posted here on thingiverse) since I couldn't find any ones on Thingiverse that seemed to do what I'd like.

A few of the brackets I designed, ready for trial mounting. (these were old versions, I ended up not using them)

X-axis carriage with drag chain mount. Wires not yet routed through chain

Outboard X-axis drag chain mount installed, again wires not yet routed through chain

It's getting closer to running....

As soon as I have the steppers all wired I'll start in on the Quiet Cut spindle. There are a few different sets of installation instructions- I have yet to choose one to follow:

Quiet Cut Spindle installation instructions:
http://blog.inventables.com/2014/08/quiet-cut-spindle-for-shapeoko-cnc.html
https://www.inventables.com/projects/quiet-cut-spindle-upgrade#instructions

Quiet Cut Spindle w/TinyG electronics instructions:
http://blog.inventables.com/2014/07/shapeoko-upgrade-quiet-cut-spindle-with.html
http://blog.inventables.com/2014/06/shapeoko-upgrade-quite-cut-spindle-with.html

45Nrth Vanhelga tubeless setup with Marge Lites

2014-12-02T21:10:00.002-06:00

It was time for some new, more aggressive tires for the fatbike. The Husker Du's I have are great on dirt and hard pack snow, but in looser conditions they really struggle. I'm planning on putting them back on next spring.

45Nrth has a new tubeless ready tire called the Vanhelga that has been getting great reviews- I decided to give it a try. It seems to be the widest, most aggressive tire I can fit in my old school 170mm 9:zero:7. New snowbike tires are not for the faint of heart- they certainly lighten the wallet. I've never paid this much per tire for even car tires!

Apply for a loan before you bring these to the counter

I decided to go with the more expensive 120TPI version- even with the additional cost, it's probably the cheapest way to knock some serious weight off of a fatbike.

As soon as I got home I tossed the tires on the scale:

120TPI 45Nrth Vanhelga: 1279g & 1298g each

Amazing that this aggressive of a tire is as light as it is.

Motorcross or Snowbike Tire?

"old" tires: 45Nrth Husker Du, 60TPI

As I took parts off the bike in preparation for changing out the tires (and attempting a tubeless conversion) I put everything on the gram scale.

Old Front Wheel setup: 3380g (all up inc. tire, tube, etc)

Bare Front Wheel: 1345g

MargeLite rim
907 135mm hub
160mm rotor
spokes, etc

Surly rimstrip: 60g
Bontrager 26x2.50-2.80 Tube: 280g

45Nrth Husker Du, 60TPI: 1650g

I'm going to attempt a tubeless conversion, but not the full "ghetto" tubeless conversion with split inner tubes, sill foam, etc. I'm going to first just try a solid rim tape setup and go from there.

Supplies, ready to go

Materials:

3M 8898 Tape, 72mm width
Reflective Tape, cut down to ~43mm width
Stan's valve stems
Stan's sealant
Tires

Plan:
1) remove tire, tube & rimstrip
2) true wheel
3) clean rim with rubbing alcohol
4) Cut down reflective tape & wrap around rim, securing at one end with small piece of tape, then stick to itself
5) apply 3M 8898, try to keep centered
6) carefully stick tape down to bead seat area of rim

Tire & rim strip removed, rim cleaned, truing it up.

Starting to wrap inner layer of reflective tape- sticky side "out", reflective side in (to show through rim cut-outs)

Full wrap of reflective tape

Getting the 72mm wide 3M 8898 wrapped down tightly was tough- it's nice and tight over bead seat area but not in the center.

1384g after reflective rim strip & 72mm 3M 8898

That's one beefy tread pattern

It looked good and I had high hopes for an easy tubeless setup, but no luck. I couldn't get the bead to seat even using the tie down strap method, with valve core removed and an air compressor. I tried putting a tube in, seating the beads, popping one bead, removing the tube, and trying again- but no luck. There is just too much room between the tire bead and the center of the rim. I think it'd work fine using the sill foam tape trick, but that'll be for another day.

So, I gave up tubeless for now- re-installed tube. Even with a tube there was substantial weight savings from the new tire:
2920g Front wheel, new rim strips, tube & new tire = 460g savings from the front wheel alone

I repeated the process with the rear tire, minus the tubeless attempt.

Old Rear Tire on wheel: 3920g (all up, tire, tube, etc)

Bare rear wheel: 1897g (no rimstrip)

MargeLite
907 170mm hub
160mm rotor
Cassette w/ 42T Giant Cog
spokes, etc

Bare rear wheel with 72mm 3M 8898 & reflective tape: 1962g
rear wheel with Vanhelga, Tube: 3470g = 450g savings

So, just changing out tires and rim strips to the new 120TPI Vanhelga's yields 910g weight savings, just a hair over 2 pounds. Pretty amazing, especially considering the new tires are both wider and have much, much more aggressive tread patterns.

Still plenty of chain clearance with a 1x10 setup. A 2x10 might be pretty tight.

A short ride around a frozen lake with 2-4" of snow shows the new tires function much better in loose snow- they tracked and gripped with authority. I'm hoping to ride some snow-covered singletrack this weekend!

I'm also going to search through Menard's and try to find some self adhesive foam tape for the tubeless conversion.

Canoe seat replacement using woven polypro webbing

2014-11-23T17:11:00.001-06:00

Our old wicker canoe seats were in terrible shape by the end of this summer. I was inspired by some nice woven seats I saw at the Minnesota State Fair, I decided to try replacing the original wicker / cane seats with something similar using a synthetic webbing.

reference canoe seat at the Fair

bottom of the reference canoe seat at the Fair

A quick search on Amazon.com brought up a bunch of choices for webbing- different materials, colors, and sizes. I did some research online, and it seemed as though Polypropylene webbing is a better choice than nylon webbing. The polypro webbing is supposed to be more weather / UV resistant, as well as less stretching when they get wet. I decided to go with 1" wide webbing since it would also be useful for belts, backpack straps, etc. I purchased a roll of the Country Brook Design 1" polypro black webbing via Amazon.com.

To fasten the webbing to the seat frame, I chose to use a staple gun and 1/2" x 1/4" crown 18 ga staples. These were the shortest staples I could find that would fit my Porter Cable pneumatic staple gun. Lowe's and Home Depot didn't have small boxes of this size staple- they only carried 3000+ staple cases. Menards turned out to carry a reasonable size box of staples.

After stripping the old woven cane seat off the canoe seat frames, I started cutting the webbing to length. I wanted a tight weave, so I laid out the webbing on the seat frame with no gaps between pieces. I cut the webbing with a heavy duty kitchen scissors and sealed the cut ends with a lighter to prevent fraying.

Starting webbing layout

I started attaching the webbing by stapling the end strand to the frame.

End webbing attached

Next, I lined up and stapled the webbing to the "side" and "bottom" of the frame.

After one end of each of the webbing segments was attached, I flipped the seat over and started weaving the strands, working my way out from the corner where the segments were attached.

Starting to weave the strands

During the weaving process, I'd stop occasionally and pull everything tight.

Nearly complete

After all segments were woven, and after I pulled out as much slack as possible, I started to staple down the loose ends. Before stapling each segment I'd grab the segment and pull it as tight as I could, and I also would slide it over to get it as close as possible to the adjacent segment.

Bottom stapled

Everything stapled!

Bottom of seat after stapling

Both seats, ready to go

Installed- ready for paddling!

This project was a lot easier and faster than I thought- and made the canoe seats much more comfortable.

Light-bicycle.com Carbon Wheels Initial Review

2014-06-27T10:53:00.001-05:00

The Light-Bicycle carbon hoops showed up about a month after ordering. They were packed really well in a surprisingly small box. They seemed to be very true and round, and spoke tension seemed even.

The box was a little beat up....

But the wheels seemed well protected.

I chose the new 29" "hookless" style rim, standard black bladed spokes, blue alloy nipples, and Hope Evo2 hubs. Customer service was great, they responded very quickly to e-mails. Make sure to send them a message and clarify exactly which rim you want- they seem to have once set of choices for rim only, and one set for pre-built wheels.

Check the hookless profile

Weights: (bare wheels, w/o tape)
686g front
813g rear

I applied Stan's tape, Stan's valve stem & sealant, and they seated just fine with a set of Maxis Ikon tires- using a floor pump. So far so good, although they've only been off road once because of all the wet weather.

Qualitatively they seem zippier and easier to accelerate.... I have yet to ride anything technical on them and I'm curious how they feel in rock gardens and hard corners.

Wide?

New bling!

Mounted and ready to ride!

MakerBot Replicator 2x: More Air Prints, custom heat sink

2014-06-22T22:00:00.000-05:00

I am increasingly frustrated with the MakerBot Replicator 2x we have at the office. It seems you need to spend twice the amount of time working on it as you get viable prints. After a streak of good luck and reliability, as of late it refuses to complete any kind of medium or large size print job. It'll get part of the way complete, and then stop feeding filament- a classic air print.

I am guessing the problem is because the aluminum block that holds the stainless steel feed throat for the hot ends in place isn't cooled sufficiently. If it gets too warm, the stainless steel feed throat will get too warm, and the filament will soften before it gets to the hot end nozzle and jam. I thought I would attack this problem by creating an improved heat sink and attempt to move more heat away from the aluminum block, and thus attempt to keep the stainless steel feed throat cooler. I also attempted to improve the insulation between the hot ends and the aluminum block.

First, I constructed a heat sink using 1/8" thick copper sheet purchased from Mcmastercarr. I thought the copper would create a improved heat flow path from the aluminum block to both of the fan-cooled heat sinks, as well as increase the total mass of the heat sink. It should also allow improved heat flow from the aluminum block near extruder #1 to extruder #2's heat sink.

Heat sink cut, drilled, and ready to go

Trial fit of stock heat sinks checking for hole alignment

Test fit on drive block

Next, I wanted to reduce the convective & radiant heat transfer from the hot ends to the drive block by adding some 1/32" thick silicone rubber, also sourced from www.mcmastercarr.com.

Covering all air gaps on the top of the extruder platform

Sheet of self-adhesive rubber cut to fit the bottom of the aluminum hot end block

Adhered to the bottom of the aluminum block

Extruder #2 Re-attached

During this assembly and dissemble, the thermistor / thermocouple for hot end #1 failed. The stock cables are very thin and fragile, so it wasn't much of a surprise. Makerbot actually sent a replacement thermocouple free of charge. The new thermocouple wire is much thicker and appears more durable than the stock cable.

New Makerbot Replicator 2x thermocouple on the left, original on the right. The stock cable used much smaller gage cable.

Since this is not the first time I've completely disassembled extruder #1's hot end, the stock ceramic / polyimide / insulation hot end insulation was cracked and looking pretty sad. Rather than tape it back together with some kapton tape I ordered a replacement insulation set off of amazon.com from VIRA design.

Mini-Review of the Vira Design Makerbot Replicator 2x upgrade kit, AKA: Upgrade Kit for the Hot End Insulation on Makerbot Replicator 2x-extruder-reprap

Shipping: Slow- took about two weeks- it appears as though they paid for shipping, then make the parts, then shipped them out.
Packaging: Poor- all the parts were tossed in a much-too large box- although since nothing it breakable it didn't matter
Instructions: Poor- zero instructions included with the kit, although if you are capable of installing it you'll be able to figure it out
Part quality: Good- cast silicone parts are serviceable, but required x-acto knife cleanup of all thru-holes
Value: Good - you'll have a hard time producing these parts yourself for much less, let alone the time required to design, create molds, and make the parts. If you need replacement insulation for your hot ends these are a good option. Plus they are completely non-fragile, unlike the stock ceramic insulation.

Vira Design upgrade kit for Hot End Insulation on Makerbot Replicator 2x Mini-instructions:

1) Use an X-acto knife to clean out all of the thru-holes in the silicone insulation parts.

New rubber insulation on the right., prior to trim

2) Cut the white insulation to size for the flat end of the aluminum hot end block.

Using aluminum hot end block as pattern to cut white insulation

3) Cut kapton / polyimide tape to hold the white insulation to the aluminum block

Cut tape using X-acto

4) Stick white insulation patch to kapton tape

Ready to go

5) Attach insulation patch to aluminum hot-end block

Attach tape / insulation patch to aluminum hot end block

Insulation in place

6) Insert hot-end assembly into silicone insulation

Ready to go!

Next up, loading new thermocouple into hot end block. I put a dab of thermal heat sink compound onto the threads to improve heat conduction and also to prevent the thermocouple threads from seizing in the aluminum block. When I threaded it in I rotated the aluminum block rather than the thermocouple to minimize any stress on the thermocouple wire. I also only tightened it finger tight- no tools used.

Thermal heat sink compound on thermocouple threads

Hot End #1 installed.

Next up, finish installation and fire it up.

Thermal compound on the interface between the new copper heat sink and the aluminum hot end block

Thermal compound on the back of the aluminum fan cooled heat sinks

Up and running!

So, after all this, you'd expect it runs perfectly..... And the answer is... NO! Very frustrating. It might work slightly better but I'm still getting air prints. So far I've only been trying authentic MakerBot brand natural ABS filament. I'll try using some generic colored ABS filament- I believe it has a higher melt temp, which might help.

MakerBot Replicator 2x upgrades from BC Technological Solutions

2014-05-12T22:00:00.002-05:00

Initial thoughts, review on Makerbot Replicator 2x upgrades from BC Technological Solutions:

After using a Replicator 2x for the past several months at my office, it was apparent that it desperately needed a glass build platform. The stock aluminum build platform wasn't flat, and it was time consuming and difficult to remove finished parts from the heated build platform. Plus, it required re-application of expensive Kapton / Polyimide film every dozen prints or so. I looked around for options, and the one I selected was from BC Technological Solutions. The impressions on the forums were decent, and the pictures looked pretty good. They seem to be perpetually backordered, so it took a few weeks for the parts to arrive. I ordered both the glass build platform / heated bed upgrade as well as the aluminum arm upgrade.

The parts arrived in two separate shipments, one for the heated bed and one for the upgraded arms. The aluminum arm upgrade required almost total dis-assembly of the Makerbot 2x. The glass bed upgrade was much less invasive, and would be pretty simple if done by itself.

Upgraded aluminum arm components. Bag 'o' hardware, nicely CNC'd arms, and a few printed parts

The replacement arms were nicely CNC'd from billet aluminum. The quality looked pretty good- not really top shelf, but all cuts were clean, burrs were removed, finish was good, and necessary holes were cleanly tapped. It did not appear that they were anodized though.

Bag 'o' hardware opened. Misc fasteners, recirculating ball bearings, printed spacers and printed bearing mounts

The printed parts of the kit looked like they were well done, and printed at about 0.1mm layer height. Fits on the printed parts were very good, they slid over the bearings and screws without any issues, and no sanding required. The creators of the kit obviously spent time optimizing their part design for printing.

The kits came with nice printed instructions. So, I won't provide instructions here, just some general photos showing the process. Overall it was an easy upgrade to install- but it did take time, and assembling the Z axis slide required some careful aligning of parts and patient work.

The patient, ready for surgery

Bottom of 2x, ready for electronics cover removal

Makerbot Mightyboard (Z-axis stepper on the bottom right)

Heated bed thermistor unplugged. Red and Black wires are the power leads for the heater. How do those come off?

Oh, you just press the buttons and the wires nicely pull out!

Stock heated bed removed

Back of the Makerbot 2x, back cover removed

Stock platform with plastic arms removed. Tape prevents nuts from falling out

Aluminum arms installed

Nuts in nut traps, screwed in place

Platform loaded onto Z axis rods

Z axis top plate in place

New heated bed in place (no glass)

Glass in place, powered up & ready

I only have a couple of prints on the new system. So far the glass bed seems like a great upgrade. Parts easily pop off the glass after it cools, and for rapid printing two glass beds can be exchanged between prints. It's more difficult to tell if the aluminum arms are worthwhile- only time will tell.

Delta Bot: First Motion!

2014-04-29T21:30:00.000-05:00

I've been fighting with the Arduino Mega and RAMPS 1.4 electronics for the last month or so on the RepRap Rostock clone I'm building. Every time I plug everything in - RAMPS into the 12v power supply, Arduino into the PC via USB cable - the 5V voltage regulator on the Arduino overheats. And not just a little- enough to get hot enough to smoke and eventually pop. I burned out the regulator on one Arduino by leaving it plugged in too long. I ordered a strip of replacement surface mount 5V regulators from ebay- hopefully replacement on the burned out Arduino isn't too hard.

Burned out Arduino Mega 2560 5v regulator- upper left next to the power plug. Note the big hole blown in it!

I tried searching the forums and general google searching to try and find the root cause. No luck- and forum responses were generally about making sure the power supply polarity was correct, etc. After finishing the searches and looking through reprap.org's RAMPS 1.4 page, I thought a possible cause might be some mismatch between the 12v power supply and the power supplied by the USB cable from the PC. The D1 diode on the RAMPS board allows the 12v power supply to also supply power to the Arduino. If the D1 is cut, the Arduino must be powered off the USB- but it wouldn't receive any potentially troublesome power from the RAMPS board. So, I decided to cut the D1 diode. Worst case I can solder in a new diode.

It was pretty tough to actually cut the D1- it's tucked way down next to the stepper driver sockets. (under the "x" and "y" stepper drivers) I ended up cutting it using the tip of an x-acto knife.

D1 is the small black / silver cylinder in the center left of the frame

I plugged everything back in- and no smoke! I left it plugged in with the 12V power supply and USB connected for five minutes, and monitored the 5F voltage regulator temperature with my finger. It seemed to stay cool- so I fired up Repetier Host and tried to make it go:

Delta Bot Build: cooling fan & magnetic bearings

2014-04-03T22:16:00.002-05:00

Finally- more progress on the "snowstock" delta bot 3D printer!

I've uploaded the files of all parts shown in this blog post to the "Snowstock" page on Thingiverse.

.STL and solidworks 2013 .prt files are located at: http://www.thingiverse.com/thing:214848

Cooling Shroud

One of the things I learned from using and modifying my MendelMax 1.5 is that a cooling fan really, really helps with part quality- particularly with bridging and small features. So, the snowstock will have a part cooling fan from the start.

Fan shroud wth 40mm fan mounted and ready to go

Mounted and ready to go

The assembly looks great, but the Traxxas rod ends introduced much more slop than I'd like. Ideally there should be zero backlash / slop in the print head. As assembled, it had at least a quarter inch of total play at the nozzle- unacceptable for a quality print. So, I decided to implement magnetic bearings right away and not as a future upgrade.

Assembling and installing the magnetic bearings

I chose to design and print ABS endcaps to epoxy onto carbon fiber rod to hold the M5x15 SHCS's. Other examples of magnetic bearings I've seen online have glued the 10mm spherical magnets to the ends of the carbon rods. That might work, but it seems less secure and messier than just using two screws per joint, one on each side of the ball magnet. Each screw is then threaded into the respective component.

Endcap ready for screw installation and epoxying

M5x15 SHCS installed- note head was dished out using a 10mm ball end mill for a higher strength joint with the 10mm rare earth magnets

The 10mm ball end mill was sourced from ebay- about $10 including shipping from China. The M5x15 SHCS were from McMaster Carr. One note- you'll want to use black oxide coated steel screws- not stainless steel. Stainless screws are not very magnetic, and you'll probably have problems getting your system to hold together if you try them. The cheap 10mm ball end mill was barely good for dishing the heads of the 24 screws, even with good lubrication.

Dishing out the M5x15mm SHCSs

All 6 rods, assembled and ready to go

Carriage mount installed

Joint detail shown- the silver ball is a 10mm spherical rare earth magnet from e-bay

There are plenty of sources for 10mm spherical magnets on ebay, just search for: "Nickel plated Neodymium Sphere Magnet 10mm N35 balls"

Magnetic arms assembled

I have yet to actually power up and run the printer- I still need to design, print and install the extrusion mechanism. But, even so, I think the magnetic bearing upgrade was worth while. The Traxxas rod ends had far too much slop, I'm sure it would have been very difficult to achieve a decent print quality. The magnetic bearings have zero slop, and also very securely hold the mechanism together. As long as there isn't any sort of long term wear issues I'm sure they will work great.