CMM fixture design help needed 1

[Taner41]

Hello,
I am a mechanical designer used to design welding fixtures and visual inspection fixtures but for the first time I am asked to design a fixture for a subframe part to be measured in a Coordinate Measurement Machine(CMM).The CMM is Wenzel brand bridge-type granite CMM using Metrosoft software. I am new in CMM subject and if someone experienced can answer my questions I will be glad.

Here are my questions:
-How can I fix my fixture to the CMM?
-Does it matter which features I use to align the part in the fixture? If I use some holes where machine needs to measure, how can it measure them?
-If I use two holes to align the part(one round pin, one diamond pin) must the pins pass the holes tight?
-Does the machine use its own coordinate system or does it zero itself by using RPS holes of the part which are mentioned in the part drawing? Or If something else, how?
-If the machine zeroes itself by using RPS points how we can measure if RPS points are at the correct place?

these are the questions in my mind now. Thanks in advance.

Regards,
Taner

 

[ajack1]

You can do that but once you go away from carline it does not relate to how it interacts with other parts. The part doesn't have to be in carline it can be whatever suits best for measuring or manufacturing.

Working from the fixture gives greater control than just working from the part, especially on parts that are pressed or moulded with lots of 3D form.