Is this spline a form on top of another form, like a styling line on say a
plastic moulding or does it present a definite edge.
If it is the former, you will probably have to generate a number of sections
through a 3d scan. However if it presents a definite edge, why not drive the
cmm so that the shank of the probe actually contacts the face. You would
need to take either use a small stylus, smaller than the shank, and just
collect a series of points along the face.
Alternatively find somebody with something like a Renishaw Cyclone, and ask
them to generate a series of 2d profiles along the face. This would take a
cyclone a few minutes only - but make sure they output the data as points
We use this method very frequently when reverse engineering things like
mobile phones - we get very accurate profiles and then by matching in some
cross-sectional contours - it becomes a doddle (if you know what you are
You could always resort to a standard shadowgraph and plot the spline from
the cad system onto an overlay - but seeing as this is a bit low tech, and a
traditional toolroom technique not many people in our world use them.
Sometimes the old tools are the best ones. Just go to a local jig and
fixture shop - they should have one. It should take all of 5 mins to set up
Response Associates Limited
Tel: +44 01747 841 475
Fax: +44 01747 841 476
email : firstname.lastname@example.org
From: email@example.com [mailto:firstname.lastname@example.org]On Behalf Of
Impact - Doug Johnson
Sent: Tuesday, January 23, 2001 6:45 PM
To: RP Mailing List
Subject: Inspection of parts...
Here is what I am looking for help with:
I have a part that has a spline on it.
I need to check the profile of the spline to make sure it is within
We have been unable to do this with a standard CMM.
Is there a video inspection system that can use a visual go/no go gauge?
We don't have time to make a physical go/no go.
Doug Johnson – Prototyping Program Manager
IMPACT Engineering Solutions
3315 North 124th Street
Brookfield, WI 53005
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