In June 2009 we found this video created by Chris Warren from GAUGE AND FIXTURE and we thought it would be interesting to share it with you in this post. It is a simple gauge, but the video shows perfectly how it works.

A new module is now available on Metrolog XG12.003 version. The new Blade Inspection Module is an expert module fully integrated in Metrolog XG for the measurement of this type of parts.

It enables to calculate the main features for controlling blades.

Not only this new advanced module is easier and quicker to use, but it also spares you the task of doing many extra calculations, with the risk of mistakes this task implies.

The measurement process is completely automated, since this module can be entered as one of the instructions of the measurement programme.

2- HOW TO USE IT

To use it, it is necessary to measure a series of sections on the part that we want to control.

The sections can be named according to the drawing references, to make it easier to identify them.

Once they are measured, click on Modules => Blade analysis

You can choose between three levels of features to control, and tick the elements you want. This selection will be saved for the next calculation. Once you have finished your selection, just click on OK.

Level 1

In this level you can calculate:

• the mean line for the blade section
• the inscribed circles centered on the mean line points
• the Leading Edge (LE) and Trailing Edge (TE) points or circles

Level 2

In this level you can calculate :

• The largest diameter (thickness) within the section
• The minimum circumscribed diameter within the section
• The blade thickness at a certain distance from the Leading edge and Trailing edge points perpendicular to the mean line or to the tangent point

Level 3

In this level you can calculate:

• the lines tangent to the nearest section to the leading edge or trailing edge
• the lines perpendicular to the lower Chord line
• the stacking point
• the alignment optimization
• the circles inscribed in the nominal mean line
• the profile points of the suction and pressure zones
• the line crossing all the stacking points of the blade

You can see a video of the module in our YouTube account:

COMMENTS ON THIS OPTION

• It is necessary to have a relevant number of points on each section
• When the function is done in a recording programme, the following line will be added

3- HOW TO SET UP NEW OPTIONS IN YOUR KEY

To set up new options, you must receive a notification from Metrologic Group that your programming code is available.

Once your code has been added in Metrologic Webread, follow the following steps:

• If the computer where the key is located has an Internet connection
  Right click on the Metrolog access icon
  Click on Properties
  Click on Find a destination
  Execute the file Security.exe
  Click on Webread
  Fill in the user information
  Click on Programme
• If you do NOT Internet on the computer where the key is located
  From a computer with Internet, get connected to
  http://213.244.3.235
  As a username, enter your key number and your password (5 numbers)
  Fill in the user information
  Copy the programming code ( the longest one)
  Right click on the Metrolog access icon
  Click on Properties
  Click on Find a destination
  Execute the file Security.exe
  Copy the code on the main window
  Click on Programme

For more information, request the document “How to programme Metrolog codes” at infosp@metrologicgroup.es

The CMM machine works, but the problem is that it gives us non-repeatable values of more than 0.1mm. These values do not provide us with the guarantee we need. We have studied the possible causes of the problem with the CMM manufacturer but have not got neither clear conclusions nor solutions easy to implement in such a short period of time.

We know that we must change our CMM machine, so we will not spend too much time in trying to solve such a problem. Actually, we have already started to look for a CNC CMM machine of 3000×1500×1500 with Metrolog XG, but Murphy’s laws prevail once again…a few weeks before organising the replacement of our current CMM machine by a new one we had found, we have started to have problems with our CMM machine that could affect the delivery of the cubing. This could not have happened at a worst moment…

The positive part of this story is that with the market crisis you can find CMM machines in a good state and with very reasonable prices.

To come back to our story, we quickly started to think about possible solutions that would enable us to meet the deadline initially set. Our priority was to measure and adjust correctly the cubing in a company where, besides having measurement means available, there would be tools to rectify the parts with deviations, as well as a Catia license to check our design and do calculations. Where would we be better than in our own premises?

The first thing we did was to enter in contact with companies renting portable measurement arm in order to see if they could help Tecnomatrix. As the precision required had to be as close as possible of 0.05mm, we managed to get a 1.8mm FARO Platinum arm with a metrologist. This would be our first experience with such a device, as we had never had the opportunity to try it before.

Then, once we had made sure that this solution could provide us with guarantees of success for meeting the deadline, we have had to inform our customer (TIER1) of the situation and ask him if we could do the validation of the cubing with this FARO arm. This type of checking fixtures are usually validated by our customer together with the OEM (car manufacturer). Consequently, the customer asked the same question to the OEM. The answer was no. They could not accept to have the checking fixture validated with a portable measurement arm, only a CMM machine was acceptable as its precision is much higher than the arm’s.

The conclusion is clear: we have to find a CMM machine for the validation of the checking fixture.
As I am writing this article, we have already finished to adjust the checking fixture. It took us three days. Our current problem is to find a place where we could measure again the checking fixture to make sure that there are no differences with the values obtained with the FARO arm. Once we have found where we can do these measurements, we will have to take the checking fixture there very carefully to prevent anything from moving or varying and hope that the CMM results will not vary from the ones obtained with the portable arm. Once the fixture is there and before starting to measure it will have to let it temper at least during 24h to avoid bad surprises.

The simplest solution that we have thought about is using our customer’s CMM machine. This is the cheapest and the most effective option – even more so as we will deliver the checking fixture with its corresponding dimensional report and commit ourselves to do the relevant changes should the customer detect a deviation -. We will try to fix the problem that way…

In about one week we should be able to explain you how this project has finished.

I have found this video in YouTube and I would like to add a few nuances which, I think, are important when estimating the return on investment. There are data that cannot be given so coldly without being sure that they are true. Most of our readers know how things really are in this sector, and their first reaction when being confronted to uncorrect data may be the exact contrary of what this article wants: finding potential customers.

As far as standard checking fixtures are concerned:

• It is not true that they can only be used for one single part. In many occasions the same checking fixture can be used to check similar families of parts by moving or modifying a few elements.
• They only need a minimal maintenance depending on the way they are used and on the material used for their manufacturing; if the materials are the correct ones we should not have problems of wear-and-tear, broken parts, or short useful life.
• Due to the requirements of the market, manufacturing deadlines are getting shorter and shorter, since suppliers do not have other option but to adapt themselves. In all cases the deadlines range from a few days to a few weeks, with a general tendency to a decrease of about 10 to 15% per year of the design or manufacturing deadline.
• Prices for standard checking fixtures can range from 500€ to 50,000€ – for checking fixtures for large assemblies of parts, which are very complex -. As for the example of the checking fixture displayed in this video, I do not think that it cost more than 4,000€. The crisis the automotive sector has been going through over the past few years has made the prices plummet. The requirements and the complexity of the checking fixtures are still the same, but prices are reduced of about 15% from one year to another.
• Most of the parts or assemblies are not rigid enough to be measured completely free. Generally, parts have to be conformed in order to be measured in the same conditions as the vehicle environment. Some parts even need a simulation of their outlines or of fitting areas, to fulfill their function and be checked correctly.
• No car manufacturer will accept to work without cubing fixtures – simulating the part environment – to carry out a visual check of the gaps and flushes of the outline of most of the parts. In the end, they are the ones assuming the investment in checking fixtures and they set the requirements for these checking fixtures.
• The part fixations and RPS must be correctly reproduced. All the clamps or element applying a pressure must be only used if there is a solid holding point bellow. In that case the part should not be more deformed than when mounted on the real vehicle. Conforming the part with its RPS is a symbol of safety for measurement and repeatability.
• It is totally wrong that checking fixtures can only provide us with qualitative data (checks by attributes). Depending on how the design is made they can integrate variable measurement elements such as dial indicators or other means giving a precise information.
• The data provided by checking fixtures can also be stored automatically through electronic systems. There is an infinity of sensors available to extract the data and store them easily.

As far as CMM fixtures are concerned:

• They must be calibrated every time they are mounted, and once they have been adjusted it will not be easy to dismount them again, as it means to have to calibrate them again. Mounting and adjusting requires a long time which will make us let the CMM fixtures mounted for some time.
• Standard elements cannot be used to simulate the whole range of RPS we can usually find on parts. Many centring elements are positioned with inclinations, special shapes, threaded pins, etc., and they cannot be represented by standard elements.

With all this I do not want to say that Faro system is not interesting, but it is NOT as interesting as this presentation wants us to believe. Collecting data for a further process, and having a traceability is something that will go mainstream in all production systems, but we have to study very well the return on investment.

But a good one, as Measure Control is now available in your language as an independent blog! As you will see, Measure Control is now divided into three separate blogs: one in English, one in Spanish and one in French.

To switch from one language to another, just click on the corresponding language on the upper part of the blog window.

Now, you will not have any problems anymore to understand the toolbar, or the indications to get subscribed or leave a comment in an article, because everything is in English! We have decided to implement these changes to simplify the surfing of our readers on the blog, and be sure that it will get known by more people so… we are waiting for your visits and your comments, to be sure that it works!

First, you will see that we have improved the blog dictionary. From now on, you will have the possibility of reorganising the dictionary columns by clicking on the language of the word you are looking for. What is more, the dictionary new design is clearer, and more user-friendly, so you can use it more effectively.

Now, the blog search engine enables to search all the pages and in general all the blog contents, including the dictionary and glossary terms. We hope this improvement will enable you to search more effectively the information you need.

We hope that these modifications will suit you, feel free to leave us comments if you see other elements we could improve, your opinion is important for us!

We have considered, however, that this was not enough: even if this article has highlighted how important technical specifications are, we have decided to prepare you a handbook explaining how to write technical specifications for checking fixtures, gauges and CMM fixtures.

This handbook will detail why technical specifications are important , as much to estimate the costs necessary for the production of a checking tool, as to design and manufacture it.

Writing good technical specifications will be the guarantee that the fixture will be made according to the customer’s requirements, which will avoid losses of time – and consequently of money – when designing and manufacturing it; and most of all, it will prevent disagreements the checking fixtures manufacturer and his customer.

Moreover, this handbook will give you the list of all the points that should be included in good technical specifications , as well as a description of each and every one of these points with examples and pictures. You will also be shown the kind of documentation a good checking fixtures manufacturer should provide you with during the fixture production process.