Wrong pocket size 3.6.11

[butch]

I am getting a size problem on a prt-alpha 48x96 bought in 2007. I made a pocket .75x2.5x .5deep. But the shopbot is making it .71x2.4x.45. Also a round pocket that should be .375 is cutting at .337.
I loaded the 3.6.12 last week and this is first I noticed that this didn't work.
I made sure the variables were correct, 1273.2395.
But I did notice that when I redid the setup that it is setting up on 60.5x96.5x8 rather than 48.5x96.5x6. I tried other prt-alpha (there are two) and it didn't seem to matter. So I went into the variable list and changed it there.
I did a jog to the center of the bed and the far corners to assure that it is counting correctly, and that seems fine. It went to 96x47 mark and 96x1 mark and also 24x48mark with no problems. It is just the cutting that is off.
I am using Aspire to make the file, and have made certain that there is no offset.
Any ideas where to look?

[ken_rychlik]

If you cut climb instead of conventional it will change the size of the pocket by about that ammount. Which way are you cutting?

Kenneth

[ron_moorehead]

What version of Aspire are you using, If it is the newest I heard they had a bit size problem that maybe causing your problem but they have a down load to fix it. Check thier forum.

[ron_moorehead]

You should be at version 2.504 for Aspire.

Web link:

http://www.vectric.com/forum/viewtopic.php?f=27&t=7284

[dlcw]

Try creating two cut files. One that cuts to within about .0156 of the bottom of the cut. Make this cut a climb cut. Create an identical cut file but this time cut to full depth in conventional direction. This seems to be the way to handle runout and machine flex. If you create the two cut files using identical bits, you can save them both in one file and run the file.

This is the way I've gone with virtually all my cutting. I get clean, very accurate cuts this way.

Don
www.dlwoodworks.com (http://www.dlwoodworks.com)

[butch]

Thanks folks!
I will check the Aspire, but I thought I had the latest.
I hadn't thought about the difference between climb and conventional, I will test this out.
Thanks
Butch

[butch]

Wanted to clarify the problem.
It appears it was my fault.
I checked all the variables and reloaded etc. but kept getting the same issue.
I talked with Frank and he went through some variables to assure I was setup right.
I loaded 3.6.5 and ran the file and did get better results. But this was in a pine test board.
I changed bits to a new bit, and it then ran the .75x2.5 pocket at .74+ X 2.48+ in pine.
I then reloaded 3.6.12 and reran the file.
In pine, with new bit .74+x2.49+ and in maple the same. Now the pieces fit together.
So - trying to maintain the same, to eliminate as many variables as possible, turned out to be the actual demise.
I suspect it was a dull bit that caused the problems.
I did try to do a cut using conventional and that did improve the sizing.

Just wanted to pass along the probable solution and thank everyone for their help. Gets frustrating to do the same thing over and over and not find a solution to the problem, so it helped hearing from everyone.
Also thanks to Frank.

Butch