CAD Forum

We design gages and fixtures for the manufacturing of turbine blades. One of the challenges of designing these is finding the optimal place and orientation to clamp and hold the parts to keep them from moving off of their datum features. The parts are usually located in what is termed a 6 point nest with 3 primary locators on either the convex side or concave side of the airfoil, 2 secondary locators on the leading edge of the airfoil and a single tertiary locator on a shrouded surface. Does anyone have any programs or simulations that would be able to show what affect a clamp coming in at a certain direction would do to the blade to check if it would move off of those 6 fixed points. Thanks for any help.

are this fixtures to measure on CMM or for some machining ?
there are datums for this 6 points and you want to place points in different places ?

never understand why they love this points, maybe for making problems, there should be something stronger instead of pins.
saw some fixtures where whole aifroil is flooded in some kind of resin or easy heat up metal

Damianes wrote: ↑Sat Oct 28, 2023 2:03 pm are this fixtures to measure on CMM or for some machining ?
there are datums for this 6 points and you want to place points in different places ?

never understand why they love this points, maybe for making problems, there should be something stronger instead of pins.
saw some fixtures where whole aifoil is flooded in some kind of resin or easy heat up metal

These would be to both to machine features on the parts and to inspect them in gages afterwards. We've also done the encapsulation dies of the parts for machining as well but those normally use the same 6 point nest as the hard pointed fixtures to hold the part for encapsulating and clamping can be challenging on those as well. It always seems like the engineers that provide the datum points on the parts have never had to make them using their points and just throw darts to locate them on the drawings.
The basic simulation programs I've tried always seem to just show the deflection of the blade from clamping pressure and nothing about possible movement. May be asking too much for cad software to be able to do that but sure would be nice if it could

Problem is, the CAD model is perfect.
It won't move in CAD model as long as clamp and support line up perfectly.

To try:
Support use frictionless contact.
Clamp apply force with direction.

Also try Dynamic sim.

JD might be able to help if you can find him. Don't see him much on SW forum.

I've had casting drawings with datum inside and outside the part.
And of course non of the datum are on flat surface.