I'm measuring the material thickness on a casting with curved surfaces. I have points at the same co-ordinates on opposite sides of the material and am having issues getting the correct readings. The vectors on the opposing points are opposite, not sure if this is correct. Since these are points not along a datum so measuring parallel or perp. to them is not an option. Thanks.
The casting is somewhat round with bulges in varied places.
Since these are points not along a datum so measuring parallel or perp. to them is not an option. Thanks.
I have points at the same co-ordinates on opposite sides of the material and am having issues getting the correct readings.
If I understand all this correctly, having points "at the same coordinates" on both sides of material is the problem. If the surface isn't normal to your alignment, then none of the coordinates will be the same on both sides of material. The opposing points need to lie along the same vector (provided you're dealing with a constant thickness).
If this is the issue, your cmm results will be consistently thicker than your caliper results. Is this what you're seeing?
If you create a plane on one of the surfaces and align to it, then create a point on the other surface when you do a distance dimension you can make sure that the "line" is completely parallel to the 'Z' (or whatever) axis. That should give you a "caliper" result. Also check you are in the correct workplane when doing distance dimensions.
I would also say to check your caliper is reading correct, it has happened to me and a few other people on this forum where you start chasing problems with the CMM and your program when in fact the problem lies with the manual equipment.
Thanks for all the responses. The readings I was getting were lower than the caliper. I followed the advise given by creating a plane, alignment and everything matched up correctly.
I've been racking my brain on how to go about measuring the thickness of a part. we'll say it is a block and I want to know the thickness of it, top to bottom. I understand all of the methods of creating opposing features such as planes or points and using the distance dimension. Using planes for example, I could create a plane on the top face of the part but how would I create a feature on the bottom to get a distance? Is it possible to measure from the table of the machine? Or would I have to place my physical part on its side to get this measurement?
Yes. Just measure a plane on the granite around the outside of the part. Level to the granite and set your Z origin on it. Then take vector points on the top of the part.
thanks Rider. Our table has a glass top, not granite. I swear I was trying to create a plane on that table this morning and I couldn't ever get the machine to register a touch. I just noticed your comment and tried again and low and behold I was able to create a plane on the glass. With my Z level being on the top of my part, I was able to get my thickness. I'm not sure why it wasn't working for me this morning but it seems to be working fine now. Thanks for the help!
if the surfaces are not normal to the alignment, is there a way to get points opposite each other? e.g. if the surfaces are complex, how do you get points across from each other?
