gagalabs

Laser-Cut "Frabjous"

Thu, 06 Oct 2011 10:18:00 -0700

"Frabjous" is a scupture by Georg Hart. It's made of 30 identical S-shaped pieces. Some time ago I did a paper version of it, but always wanted to do a laser cut wooden one.

Finally I got around doing it. Contrary to the original, my pieces are self-interlocking, so no glue is needed.

See the full gallery on Posterous

You can get the design files here on thingiverse.

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Create 3D models from photos: A quick test of Autodesk Labs' Photofly

Thu, 07 Jul 2011 05:29:00 -0700

Project Photofly is a program and a web service, which lets you convert a series of photos of an object into a 3D mesh.

I gave it a quick test.

I made around 50 photos of a small double headed figure (around 20 cm high) and used the tool to create a 3D mesh from it.

This is the result:

Here is one of the photos:

I'm really surprised how easy it was. After reviewing the photos (and rejecting a couple of them becouse they were too dark) I just imported them into the Autodesk tool. The photos get uploaded into the cloud and after a short while the result can be downloaded. And the result was great! I didn't do any manual editing in Photofly whatsoever, the photo/camera positions where all calculated correctly. After exporting the mesh (it contains textures too, but for 3D printing I'm not interested in them) I loaded it into netfabb Studio. The mesh was pretty much complete, only one bigger hole under the chin where I didn't provide enough info with the photos it seems. Besides that there were only smaller holes, all of which could be automatically fixed by netfabb. I just had to cut off the base and now I have a great watertight 3D model.

Really promising, given that was my very first try.

Here's a video showing how you should take the photos:

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Stencil Painting with the Help of a Laser Cutter

Fri, 24 Jun 2011 10:14:00 -0700

A small experiment to use stencils created with a laser cutter to create a painting with acrylics.

First I took a photograph and fiddled around with the color curves:

Then I ran some filters (median etc) to get rid of noisy areas. After that I created 2 layers (one for each the darker blue tones). More filtering and some manual painting made sure the stencils can be made out of them (all parts of the stencils need to be connected with no "islands" left).

The 2 layers look like this:

Then I loaded the frames into Inkscape, where I traced them to have vector outlines, which are needed for the laser cutter:

As you can see, I also added registration marks to the top corners, so that I could align the stencils correctly.

The cut stencils look like this:

I taped the stencil on a canvas and applied the first color using a small foam roller. After drying I did the same with the second stencil/color

After some manual finishing touched (e.g. white dots in the eyes) the result is this:

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Look what I have found in the Ars Electronica Center: my ellipical gears!

Fri, 11 Mar 2011 11:18:00 -0800

Visited the Ars Electronica Center in Linz today. And what do I see in their FabLab? My ellipical gears!

They found it on thingiverse and printed it on their 3D printer.

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Printed a Penrose Triangle. Optical illusion + 3D printed = double awesomeness!

Thu, 24 Feb 2011 23:40:59 -0800

Printed the fantastic Penrose Triangle Illusion by chylld
The illusion works even better on video:

http://www.thingiverse.com/thing:6513

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First results from our CNC mill

Wed, 13 Oct 2010 01:22:00 -0700

Over at the FabLab Munich we are currently building our own CNC mill. Almost finished now.

Here is one of the first pieces done with it:

The mill is not perfect yet, but we are getting somewhere!

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Modified Z Switch for the RapMan

Wed, 25 Aug 2010 15:45:00 -0700

I have upgraded my RapMan with a heated print-bed and needed a modified z switch holder (the z switch normally is mounted directly on the print bed, which is not a good idea if it is heated). I tried Laszlo's one, it works, but I had problems with it. It is attached to one of the 3 screws the print bed is hold by. These 3 screws are equipped with a spring mechanism, allowing the print bed to back down if the print head by error tries to go down below the print bed surface.
When attaching Laszlo's z switch holder, this spring has no effect any more. Laszlo says he doesn't have the problem and I think the reason is that I have a RapMan version 3.1 while he has a previous version. My RapMan z stage platform has threaded holes for the 3 screws I was talking about which seem to be the reason for problem.

Anyway, I designed a different solution, where the z switch is not attached to the print-bed but to the z stage platform instead. This also makes fine-tuning the print-bed/extruder distance easier. You can do that with the 3 screws now and you get direct feedback about the new distance. Before you had to turn the distance screw at the print head and run a home sequence to get the new adjusted distance.

With this new mechanism the z switch is not pressed directly, but there is a arm which presses it. The arm reaches up where the distance regulation screw comes down during the home sequence.

Here you see my RapMan with the heated print-bed and the new z switch mechanism in the left back corner:

Here a couple of close-up photos. In case you wonder, I added a bit of duct tape because I needed a M3 screw to hold the arm and the only one I had left was a bit too short, so the duct tape holds it in place :-)

See the full gallery on Posterous

The OpenSCAD and STL files for the 2 printed parts can be found on thingiverse.

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My new heated print-bed

Sat, 21 Aug 2010 16:01:00 -0700

It is already a couple of weeks since my heated print-bed from László arrived. I was busy so I didn't find time yet to update the blog, but finally here is my experience with building and installing it.

The print-bed is made of aluminium. It's heated from the bottom side using power resistors. The print is done on a Kapton-covered steel sheet which lies on to the of the aluminium bed and which is hold in place by powerful magents.

The bottom side has threads to attach 9 power resistors and pits where the magnets will find it place. First I covered it with Kapton tape, cut out holes for the resistors (I only used 5 in the beginning) and the magnets:

Then I added the magnets.
U/D stands for up/down for the orientation of the magnets.

László recommends to add iron bars on top of the magnets. This makes the magnetic force stronger. Neodym magents don't stand heat that well, but short-cutting them with the iron bars also seems to improve this.
I decided to mount all 9 resistors I ordered at that point, so I added the remaining ones too:

Then I wired the resistors. For a start I was only using 6 of them, this is why the middle 3 are not conencted. Here the 3 mounting screws an the z-switch holder are already added as well.

I tested the bed in this configuration, but it was not getting hot enough. Even with all 9 resistors it hardly reached the temperature where ABS sticks to the steel sheet, which should be at about 100-110°C.

So the next step was to add heat insulation. To prepare that I added the heat-resistant insulation for the connecting wires. I chose not to wire all the resistors together but have two groups with 6 and 3 resistors to have more possibilities later.

Then I covered the bottom side with the rock wool. I also attached a thermistor to the bottom side of the bed, so there are now 5 wires coming out there.
Shouldn't have done this in our living room really, it's quite a mess. I'm lucky I have an understanding wife.

OK, now the bed was ready to be installed. Removed old bed, replaced it with the new one, attached the power transformer, covered the steel sheet with Kapton.
I wasn't happy with the z-switch holder, so I replaced it with a newly designed one (more in an extra post later).

See the full gallery on Posterous

Turned out that the temperature now was ideal for printing ABS. I now always switch the print-bed on about 5 minutes before the print and leave it on for the whole print. With all 9 resistors connected (all parallel) the power transformer which comes with the kit is a bit too weak by specification. It gets a bit hot, but it works fine. I'll probably add a fan for it later.
I didn't measure the temperature, but the ABS sticks very well on the Kapton. I didn't have to do anything (like sanding) to improve the adhesion.

See the full gallery on Posterous

Here's a finshed print (lots of strings, but that's not the fault of the print bed). I'm using the scraper which came with my RapMan to remove the steel sheet (it's not that easy, the magnets are really strong). I added small pieces of card-board on both sides of the scraper so that I do not burn my fingers.
When the print is cooled down a bit you can remove it from the sheet.

Right now am really happy with the print bed. Its a bit costly, but it is nicely made and very flat. And it probably cannot be made cheaper really. You would have to go for a different approach like a circuit board, but I haven't seen one which covers the full RapMan print area.

I do not sand the Kapton, so the bottom faces of my prints are really nice, flat and shiny. I did not have any warping issues any more when using it.
I didn't print really big objects yet, this is one of the next things I will test, but I do not expect problems.

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My heated print bed kit arrived

Fri, 16 Jul 2010 07:26:00 -0700

I ordered a heated print bed for my RapMan from László which arrived today.
Here are some unboxing pics. Looks promising!

See the full gallery on Posterous

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Now experienced that evil head dive bug too. The "naked lady" doesn't look too good... #rapman #3dprinting

Wed, 14 Jul 2010 07:14:33 -0700

Time to upgrade my RepMan firmware. Version 3.0.0 should be out soon.

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The 10$ Heated Printbed

Wed, 07 Jul 2010 06:56:00 -0700

I had a couple of objects where I wanted a really flat, clean bottom side, which is hard to archive when printing on a raft with your RepRap/RepMan. So I wanted to have one of these heated printbeds where you do not need a raft - the objects stick to it directly and due to the heat they do not shrink while printing avoiding the warping problem ABS has which would cause the edges to come off the printing surface otherwise.

But I did not like spending lots of money in a machined metal table. I'll probably will get one now, but for trying it out and playing around I looked for something cheaper.

So here is my (roughly) 10$ heated printbed design. You need:

flat piece of wood board
a proto-board with stripes (something like this)
Kapton tape
old PC power supply

I soldered bridges onto the protoboard so that the whole board is covered by one long zig-zag ciruit. With my board size of 160x100mm (Euro card size) this resulted in about 2.5 Ohms. Attaching that to 5V resulted in about 60°C which is is not enough, but with 12V it was at about 90°C, which proved to be enough.

I covered the board with Kapton so that the holes are covered and ABS sticks much better to it. I mounted the proto-board on the wooden board using little wooden pieces as spacers which I covered with a few layers of Kaption tape for insulation. I wrapped some Kapton all around the proto-board and the wooden board which proved to be enough to hold it in place. I glued the wooden board onto the print bed mount of the RepMan using double-sided take. Pay attention to what take you use, mine was really hard to get off again.

See the full gallery on Posterous

In case you wonder, my proto-board was broken, so I soldered it together again. Made a bit of trouble, because it was not flat any more.

So does this work? Yes, I was able to print a couple of nice objects with it.
However, there are a couple of cons:

The prints stick really well. This is good, but you have to wait for the printbed to cool down before attempting to get the print off, otherwise the object will get bent. Once I was ripping the proto-board off the wooden board while trying to get the print off. Also the Kapton tape came off easily.
I had problems to get the printbed flat. Mostly because of the broken proto-board so that probably a problem that could be avoided easily.
100x160mm is enough for many objects, but if you have a RepMan you could do much larger prints. When using larger proto-boards the resistance will be different, so you need either a higher voltage or you need a different way to connect the stripes on the board. Either way you probably need a higher rated power supply.
The proto-board started smelling funny. I think it was a really cheap one (don't know, I used one I had lying around) so this could be avoided by using a better, more heat-resistant one.

It was a fun experiment and useful for smaller prints. But I guess I get something better now.

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Modeled the FIFA World Cup Trophy for my 3d printer. Just need some gold paint now...

Wed, 07 Jul 2010 01:23:00 -0700

For the Germany-Spain game tonight I printed this. I just need some
gold paint now...
You can download the STL file at http://www.thingiverse.com/thing:3494

See the full gallery on Posterous

Update: after painting it with gold spray paint and adding the dark green stripes, it looks like this:

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Finally a successful print of my Tie Interceptor #reprap #3dprinting #starwars

Tue, 25 May 2010 08:17:08 -0700

Print quality still could be better, I had lots of "strings" to remove. While doing this, one wing broke off (I glued it back on).
The thing was printed in 2 parts. Gluing them together did not work as well as I hoped as the pieces had quite some warping.
Maybe it would print better in PLA instead of ABS.
But hey, the kids like it! :-)

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Cool! @bre likes my Star Wars Tie Interceptor on Thingiverse!

Sat, 22 May 2010 06:07:26 -0700

http://www.thingiverse.com/bre
http://www.thingiverse.com/thing:3006

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Finally printed: the telescope-webcam adapter

Thu, 20 May 2010 00:17:00 -0700

The STL and the OpenSCAD files are now on thingiverse: http://www.thingiverse.com/thing:3177

See the full gallery on Posterous

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Switched from skeinforge to netfabb. Great tool, no fiddling with params anymore

Tue, 18 May 2010 05:19:00 -0700

After playing around with skeinforge for some days I had enough of fiddling around with its loads of parameters. It eventually printed my test objects fine with 0.5mm layers, but other objects were not that good. And my 0.3mm layer setup would have needed more work too.

So I bought "netfabb Engine for Rapman Basic",a 99€ (+VAT) software from Germany based netfabb GmbH (http://netfabb.com/). They have a free software called Studio Basic, which is great for examining and fixing STL files, but I does not have any gcode generation functionality.
There's no eval version of "netfabb Engine for Rapman Basic", so you cannot judge the gcode quality before buying, but I did not get disappointed. Calibration is easy, you simply print a test object, take measurement and enter the values back into the software. After that (and probably adjusting the printing temperature) you are ready to go. Awesome! The quality is better then what I was able to do with skeinforge. I'll post some printed examples the next days.

The software uses a unusual "pillar" raft (watch it get printed), it's a bit hard to get off the print bed, but works nicely. But you still can choose to use a "traditional raft" if you want.

What I find a bit strange is that it does not use the "no string function" implemented in the latest RapMan firmware (version 1.0.8 and later). Using it the prints probably would have less strings you have to remove.

The downside of hiding away all the complexity of generating gcode for you is that you have less influence over the result. There are "expert settings", which lets you adjust a few more things, but being a commercial closed-source tool, netfabb is not a tool for users who want to be able to change anything.

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RepMan build recap

Wed, 12 May 2010 14:34:00 -0700

Some quick notes to summarize my experience of assembling a RepMan 3.1 kit:

It took me about 30 working hours until the first print
The documentation is good, but not perfect. Sometimes a photo does not match the text or the part list for a certain step misses something. Nothing serious, you can figure it out. But still, if these glitches were ironed out one could build it faster and with more confidence. Now you keep asking yourself: Is this right? Am I missing something or is the docu wrong? Also the docu is split up: there is a text with photos to follow along, there are videos (for certain build steps), there is a 3D view for each build step and there's an animation. And there's a wiki. All is great, but I still wished I had exactly one document I just could have followed along.
The acrylic parts are laser cut, and therefore have high precision. No need for filing away bits for exact fit or something. Also they look great. Downside: they break pretty easily. The kit includes training parts where you can test how much you can tighten screws on them before they break. This is really needed. Still I now have some small cracks in some (luckily rather unimportant) parts.
My kit arrived with the large extruder acrylic part broken. I contacted BitsFromBytes and they immediately sent me a replacement part. No questions asked, no extra costs. Nice!
Depending on where you live, some of the tools need might be hard to get. I live in Germany, which is in the "metric part" of the world. A 1/16" Allen key is not something I had at home. In fact, I still have none and that's why my pulleys come loose from time to time. I ordered one on ebay, but still waiting for it to arrive. If you are in the US you might have a 1/16" Allen key, but note that you also need a 1.5mm and 2mm Allen key (among other tools). So it still might be worth checking what tools you have before starting the assembly.
As reported in an earlier post, I did not use fire cement for my extruder. My fire cement was dry and hard by the time I wanted to use it. I didn't bother getting new one, but instead tried attaching the heating wire and the thermistor to the hot end using Kapton tape. Didn't work on the first try (thermistor lost contact thus the hot end was heating up too much) but now works well. I wound some wire around the hot end to hold the thermistor in place. The thermistor is wrapped in Kapton too for electrical insulation.
After I finished the assembly I printed countless test objects to get my skeinforge setting right. This really is not easy. The BfB wiki explains most of the parameters but not all. There are helpful hints on the net, but there are different approaches to reach a good combination of parameters and most of them are for older versions of skeinforge, where the parameters where different.

In the photo above there are some of my better test objects. To get a feeling for the size, the square (it actually a cube where I stopped printing after a couple of slices) is 2cm wide.
None of them is perfect, but they get better every time.

Overall I'm pretty pleased with the RepMan. It's more expensive than a Makerbot, but it offers a larger printing area. I also like the electronics which allow printing without a PC attached. Compared to building a Mendel it is just nice to have a kit that includes everything. Building a Mendel probably would take much longer.

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RapMan first prints: (partial) success

Fri, 07 May 2010 23:48:00 -0700

Completed the first prints. I used (of course!) the mini-mug model.
The very first print had a hole in it and it was not round. I had a problem with the y-direction, too much play, a pulley was not fixed properly.
With the second print the geometry was good, but it was printed too hot it seems, the print dissolved itself at higher layers (I aborted it).
I looks like the thermistor lost its direct connection to the extruder, so it was heated up more than it should. I rebuild the extruder - again using the Kapton tape technique instead with fire cement - and this time the print looked much better (I also switched to black ABS).
The geometry still is not perfect, it has a slight skew in x-direction. I have to check what causes this. The print has some "hair" inside, nothing serious, easy to clean up, but maybe the print temperature was a bit too high.

See the full gallery on Posterous

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RapMan day 10: Assembly finished, test raft looks great!

Thu, 06 May 2010 16:17:00 -0700

Yes! Assembly finally finished. All looks good (after fixing a wiring mistake with the extruder), the "test raft" pattern printed fine.
First real print tomorrow!

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Modeling with Blender 2.5: Tie Interceptor

Thu, 06 May 2010 08:37:00 -0700

I tried using Blender a long time ago, but I found the GUI really combersome. Even after reading a tutorial I wasn't able to create something useful.

Now Blender 2.5 (alpha 2) is available and as they have promised to have a more intuitive user interface, I gave it another try. My goal was to create a 3d-printable model of a Star Wars Tie Interceptor. There are a couple of nice (but short! :-))) Blender tutorials for newbies on thingiverse (http://blog.thingiverse.com/2010/05/05/assembled-blender-tutorials/). They are for previous versions of Blender, but they are easy to adopt and the keyboard shortcuts are the same.

So this is what I did:

I'm really pleased with it. No textures, as they cannot be used it for printing.

Blender 2.5 is really nice! Very stable already, and taken account that I hardly did any 3d modeling before it allowed me to do this pretty fast (a few hours). Bravo!

The printable STL file can be found on thingiverse: http://www.thingiverse.com/thing:3006

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