offline programming error

[[jo...]]

Afternoon,

I am still fairly new to offline programming and currently have a program which measures two lines during the base alignment to create a symmetry line which is Datum A. my colleague tried running the program today and mentioned that the machine will measure the first line then move over to the second line and it treats the initial contact of the second line as a CNC collision, however it is measured via the same strategy as the first. I have tried deleting and remeasuring the feature just in case one of the X,Y or Z values wasn't correct but it still comes up with the same CNC Collision. is anybody able to give any suggestions to help fix this? I have attached a screenshot of the 2nd 2d line.

thanks in advance

Josh Baker

Zeiss.PNG

[[Ro...]]

Are you using that symmetry line as your Rotation in Space in your Base Alignment? If you are, don't. Use planes. If you use a line feature it doesn't have a spatial surface/plane to rotate to and will have trouble solving the alignment. Even better would be to use that the big flat surface as your spatial orientation.

If you aren't doing that I would look at the approach vectors of the feature. Is the CMM actually hitting the part and causing a collision or is it giving an error before it even measures the line?

[[jo...]]

I was initially using the symmetry line as my rotation in space however changed it to the big plane as was getting spatial errors like you mentioned. I've attached what my base alignment looks like. I believe the CMM is actually hitting the part when the error occurs

Zeiss.PNG

[[No...]]

How large is the dstance between the two scanned lines? Maybe the stylus is just trying to retract from the first line or to move to the clearance distance and already hits the opposite side. I remember that early versions of Planner (4.6 or so) were bad at detecting collisions durinng retract movements. I hope this is not the case anymore. 😕

[[jo...]]

The distance between the two lines is 9.85mm and the clearance distance is 10mm so I will try and lower that for this feature and get them to re run it.

[[To...]]

For the lines, just make the clearance distance 0, then take the narrowest width of slot minus the probe diameter, then divide by 2 and use this for your retract distance.

[[Ow...]]

Using the plane and ensuring the retract is correct should fix it.
When doing a manual base alignment, the operator takes two points for a line, if they take the points front to back and the line is made to where the points are supposed to be back to front, it will flip the alignment and a crash will happen.
On the CMM computer before doing the manual base alignment, you may have to go to resources and scroll all the way to the bottom and select "set base alignment to zero" to un-flip it. However , with a plane you shouldn't have to.