vcarve width varies???

[fredtoo]

So the set up is: PRS Alpha, spindle, 90 degree v-bit (Onsrud 37-87)

Material is sign foam

Project is a simple oval, 24" across the long way

V-groove designed in Aspire, .25" wide, 1" in from outside edge of the oval

Problem is the cut v-groove at one end of the oval is .25" wide and the other end is .35" wide. When this first occurred I re-zeroed my Z at either end of the oval with the same results. Thinking the material wasn't the same thickness across the oval, or not secured down the same across the oval, I put my planer bit in and planed off the earlier v-groove. That in theory should have compensated for any leveling discrepancies. Run the v-groove file again and I get the same thing????

What am I missing?

[curtiss]

Something is a bit out of level somewhere.

Without material / Can you measure the z clearance in the two locations to see if the tip of the bit is the same off table ??

What happens if you flip the linework 180 and create a second toolpath, does the error flip to the other side ?

Maybe a shallow follow up with a small endmill would true up the edges so you don't waste the material.

[tmerrill]

Have you verfied in Aspire the two ovals are the correct size and have the same center point? Possibly one got shifted a little bit.

Tim

[cabnet636]

are you profiling with a v bit on a single vector or are you vcarving between two vectors

[fredtoo]

Saving the piece was relatively easy. I just rotated the oval 180 degrees so both ends were then cut to .35". That should rule out a variation in the thickness of the material but then that should have been ruled out when I planed the piece.

I've checked and rechecked the file. The v-groove is created with parallel lines .25" apart created in Corel Draw and imported to Aspire as vectors. Something I've done many times with no problem.

I have some more money files to cut tomorrow but need to figure out what is awry before I tackle that oval on the full sheet of sign foam! Maybe some test cuts tomorrow with a file created in Aspire verses imported from Corel.

[gene]

What i would do is draw a single line between the two and v carve on it instead of between the two lines. measure the difference between the lines on one end then another . Use the scroll button on the mouse to zoom in when you are measuring them for more accuracy .let us know if this clears it up. it should.

[knight_toolworks]

to see if it is the code or the machine is either run the toolpath and see if the z changes or check the toolpath file. those will tell you machine or code. if it is code there is a problem with the file.