Mdk Measurement

[[Ed...]]

Hello everyone.

First thing, what you do if you have, for example, Mdk ball Ø2.487mm, but you use ball Ø1mm? How do you calculate contact diameter? And the new values of dimension?

Second thing, how to choose correctly measuring position?
My teacher give me one file, where I can calculate this position, but now I`m thinking that is not correct. Our customer is using "Reference diameter" all the time, I`m using "Manualy calculated"

Thank you in advice...

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[[Ün...]]

Hello edgars

I always use a reference diameter. The probe diameter you will use is proportional to the Module indicated by the drawing. The probe diameter shown in the training I received should not be larger than half the module.

After entering the Mdk diameter in the thread thickness parameters setting section, you can extract the desired measurements.

[[Ed...]]

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Thank you,
can you explain more about this - "After entering the Mdk diameter in the thread thickness parameters setting section, you can extract the desired measurements."

[[Ün...]]

I'm sharing a few pictures to help.

Just enter the desired values according to the information from the technical drawing.
In this picture, Module 1.00 mm and I use 0.5 mm probe.
Pin diameter 2,00 mm
mdR 40,588 mm
reference diameter 44.00 mm
The settings according to the drawing should be as follows.
I hope it helps. Good work

[[Ed...]]

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Great, now I understand what you mean...

Is there any place were I can read about measuring positions (Reference dia, v-circle, etc). Could not find anything in "Help"

Big thank you for helping 🙂

[[Ma...]]

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If you have access to it, there is a lot of current pertinent information in ISO 21771 - 2007
Gears — Cylindrical involute gears and gear pairs — Concepts and geometry

[[Wo...]]

The Measuring diameter varies from the sphere diameter in the drawing.
The different measurement like manual with the default diameter and a single point measurement in GEAR can cause different results.
Another option is selfcentering meausurement in GEAR. If you use this, it is recommended to set Shop Floor calculation. That meas no recalculating of GEAR to the involute curve. It takes the value like you measure in Calypso.

The tool to get the right probing diameter is in page of tolerances of runout. Here you can input the default value and the software is calculating the contact diameter. The diameter you can copy and paste to the measurement. This helps to get the same result between manual and cmm measurement.
Regards Wolfgang
You can use a standard involute gear for measuring MdK and runout.
I think the easiest way is to set the measuring position at the mean value between root and tip .
For avoiding collisions:
In Feed in you should take tooth thickness correction. This recalculates the tooth thickness to get the following measurement without collision.

[[Do...]]

@Wolfgang Haug I didn't find where we can input the default value for is calculating the contact diameter. Sorry about that 🙁
can show me where can set this value

if i change the "tooth thickness factor" (pictured below) can works????

thanks for help

regards

sprocket tooth data.jpgtooth thickness.jpg

[[Ri...]]

That isn't a gear. That looks like an inverted tooth sprocket. Those are not easy to measure with a gear software because the gear geometry typically doesn't make sense (the PD hangs off the tooth as an example).

You can see that they want you to measure Profiles of the teeth between different measurement zones. You would do this in Calypso (with Curve).

Feel free to reach out to me directly if you'd like further assistance with this. I have extensive experience with measuring IT sprockets (Borg Warner, IWIS, etc.).

[[Do...]]

@Richard Shoemaker thanks for help. Actually i use calypso curve, works very fine. But my only control process in production line is with MDK measuring with micromether gage. You can help me to find a better Gear Pro software set-up???

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[[Ri...]]

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For IT sprockets, I would just use Curve to calculate the Mdk. Unless you have a ball/pin size that you can get a stylus in (5mm or something like that).

You can use the Circle in Contour feature to drop the pin into the flanks with Curve.

There are some designers who will give you enough information to build the gear in GearPro, but unless you have GearPro 2019, and you want to do an unknown gear to build it, it's just much easier in Curve.

I once had a spreadsheet on how to build IT sprockets, but I seemed to have misplaced it.

[[Wo...]]

I ask you if you have a cmm with measuring head, which can do selvcentering?

Do you have the option bestfit circle in curve?

For a selvcentering pitch measurement you can use a similar involute gear.
Here you have to use a probe pin with the value in the drawing.In the tolerance of 2-flank pitch measurement of runout you select " floor shop evaluation"

With circle in curve bestfit you can use a curve-segment of gap and evaluate with the drawing sphere the center of the sphere.
Here you have to calculate MdK with formula.

I have done a measurement on a straigt gear with this 2 methodes and got with statistics a difference between the 2 measurements of 0.4 micrometer.