PDA

View Full Version : Offset questions?



tim_mcknight
01-12-2010, 10:49 PM
I am cutting some male inlay pieces and female pockets but they don't fit. Either the male inlay is too large or the female pocket is too small or the 1/16" diameter bit is flexing causing the errors? I am cutting a .3 IPS, .060" deep per pass, 90% step over at a total depth of .060".

I noticed in PW toolpaths under profile tab there is an option under Machine Vectors called "Allowable offset" 0.0 inches. I tried to use .005", then .010" and finally .015" and saw no difference in the width of the cut. I have three tool paths:
1) Profile inner
2) Profile outer
3) Pocket

I have the male pieces cut so I am trying to gradually enlarge the female pocket to fit the male parts. The male pieces are basically just two circular vectors or a single ring. Its not that there is a lot of detail in the parts. I am stumped so any suggestions or ideas would be greatly appreciated. Thanks,

eaglesplsh
01-12-2010, 11:25 PM
If you're using a positive value, the Allowance Offset moves the cut away from your vector. For your inside profile cut it would move the cut line toward the center of your shape, which is why you aren't seeing a difference in the fit.

To enlarge your female pocket you should use a negative value for the allowance offset.

For most work I don't recommend going above 40% step over. This isn't related to your fit problem, so if you're satisfied with your cut quality don't worry about it.

cnc_works
01-13-2010, 12:42 PM
Rather than messing with the vectors then retoolpathing, I will often just lie to the machine when I cut the pocket. For instance if I were using a .125" bit, I will tell it that I am using a .123" bit, automatically giving me a .002" offset. If that is not enough, tell it .122" on the next cut, adjusting until your inlay fits.

Donn

bcondon
01-13-2010, 05:00 PM
Tim,
Did you use the inlay procedure that is posted on the web site? I included the link. It works very well.

I am getting into inlays and I have cut 2 things:

1. A simple 5 pointed star
2. A moose

You follow the procedure (Make pocket with 3% step over, I am using a 90 degree, 1.25 V cutter)
and then you make the inlay which is a mirrored object, cutout with a 20% stepover using the same cutter) and they just go perfectly together.

Glue em up and run through the surface planer and they come out just poifect.

Even my son was impressed with his dad!


http://www.vectric.com/forum/download/file.php?id=13987


the inlay needs to be shallower than the pocket but the 45 degree allows it to just fit.

Also Aspire has some capability to do this easier. I have not played with it yet