Spline alignment

[[Ja...]]

Hello all. We are measuring some splines on some solid shafts using a Prismo Navigator with a rotary table and GearPro. Every now and then we get some helix results that dont seem to make sense, and I am wondering if this is affected by the alignment we are doing. At the moment, we are doing a manual alignment with 4 points on the outside of the spline on the same Z plane, then 4 points on top, and then one point midway down the spline at 6 o'clock. When the program runs, it runs the 4 points around the spline, then 4 points on top, then rotates 180 and does both again, then rotates back to the original and does both again, finishes up with the 1 point at 6 o'clock before actually switching over to the spline probe. Should we be doing this differently? Some of our helix angles will be + and - on the same side of the tooth which seems a bit odd.

When you have helix angles where one tooth can be fine or angled over spec and then another tooth on the same side being under spec, its hard to explain. My guess is it could be the tooling that rolls the spline is not consistent, or possibly loose? I want to make absolutely sure that we are measuring this the right way and are not contributing to the results being out of spec. Please let me know your thoughts. Thank you.

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[[Ky...]]

Hello Jason,

If the profile looks good, but the lead looks like this, than my guess is that it's a rotation of the primary axis of the gear (the Z axis I think from the explanation you gave) relative to your alignment. In short, yes I'm questioning the alignment.

It's a bit hard to say exactly what I would hear since I don't have the part in my hands, but I probably wouldn't take individual points on the top plane, especially if that is my spatial feature.

The description of the base alignment seemed a bit vague I'm afraid. What is your spatial feature? Is it that plane you mentioned?

[[Ün...]]

Some suggestions for spline alignment

[[Ed...]]

Hi,
Try to prepare the alignment for spline measurement like in this file.

Clocking the Gap of a spline and creating a datum from the pitch circle.pdf