Computer vs. Control Comp. - advice needed

[Bill H]

I use MC to generate toolpaths for my Haas Mini Mill. Up until now I've always selected "Computer" as the compensation type for my contour cuts. Most of my projects have a tolerance of +/- 0.005", so as long as the actual cutter sizes are close to what I've specified in MC, the parts are within tolerance. Now I'm working on a part whose tolerance is tighter and I thought that using "Control" comp would be better plan, so that I could adjust the wear comp in the control to fine tune the cut and get the exact size I'm looking for. This idea turned put to be 20 miles of bad road! Paths that worked fine with "Computer" comp generate alarms when I try to convert them to "Control" comp, usually because of the size of the arcs in the lead in/lead out moves. What's really frustrating is that the toolpaths verify fine in MC, and it's only when I get them in the machine that things don't work right. So here's the question: With the Haas control, what's the best programming strategy for a project where you've got to sneak up on a critical dimension?

[K2csq7]

Have a small linear lead in/out before/after the arc. Most controls don't allow cutter comp to be activated/deactivated on an arc move.

My opinion is to use wear comp, start with a zero comp value in the control (or a bit of positive compensation to stay away from finish), then if you want to take another .0005 per side, add -.0005 into the comp value on the control.

[strabe]

I always use wear comp. Never a problem on the Haas' I used to run.

[BenK]

My opinion is to use wear comp,

 

+1

[Goldorak]

100% of my jobs are in wear comp when i need some tool compensation

[Tony35]

100% of my jobs are in wear comp when i need some tool compensation

 

+2

[Philcott]

Well there you go Bill. Most use wear as it gives you full control at the machine to make size adjustments. With wear you can also have quite small lead ins and lead outs.

[J Coulston]

I always use wear as well. Even if you use a linear lead MC will sometimes try to lead on an arc if leadin gouge check is turned on. If I am working on a small hole with a large tool I turn gouge check off just to verify that the toolpath does not violate the chain. Then turn gouge check back on before posting.

[André Lapointe@In-House Soluti]

I would recommend to use wear comp instead of control. You will get the same coordinate output as the computer comp but with the compensation code call as well so that you compensate on the control itself only for the tool wear instead of the complete diameter. This allows you to use smaller lead-in/out and generate a lot less compensation error related to arc radius.

 

Note that you generally need to use a linear move (longer or equal to the value you will compensate for in the control) to let the machine take his compensation and avoid to call this G41/G42 code on an arc move.

[Bill H]

Are you guys saying to use "Wear" comp in MC, or "Control" comp with wear adjustments in the offsets in the machine's control?

[Tony35]

Are you guys saying to use "Wear" comp in MC, or "Control" comp with wear adjustments in the offsets in the machine's control?

 

use wear in MC then adj. on the machine if needed

[chris m]

Wear in MC and make small comp adjustments in the machine

[MACHINEMASTERG]

id try WEAR comp

[Goldorak]

and don't forget to set the diameter to 0.000 in the machine

[jeff]

and don't forget to set the diameter to 0.000 in the machine

 

This^^

for Wear you want a starting value of 0 if your tool is the same as programmed tool size.

If you use Control, you want the value to be the size of programmed tool (dia or radius I cannot remember)

 

Wear will save you on headaches, it's all I use when not using Computer comp.

[K2csq7]

for Wear you want a starting value of 0 if your tool is the same as programmed tool size.

If it is a really fussy dimension, you may want to start with a bit of positive comp (leave some stock to make sure your tool wont cut too much).

[jeff]

If it is a really fussy dimension, you may want to start with a bit of positive comp (leave some stock to make sure your tool wont cut too much).

 

yes, this also.

I do this when the tolerance is within .001" or if I'm not too confident about my program lol

[MikronGuy]

wear comp here. with control comp the tool cuts to the centerline ( have to add radius of tool in machine tool register ) of the tool whereas wear comp cuts to the edge of the tool. computer comp cuts to the edge of the tool with no G41 or G42 generated. wear will generate G41 or G42 depending on the way you program.

[Buddy J]

Wear here also

 

For many years I used control because, back in the day, (DOS OS), I, (we), were doing strickly

simple 2D stuff and alot of our machines didn't have CRT's so we'd print out hard copies of the programs

and wanted to be able to see program values that matched the print. This habit carried on with me for a long time and like you, I'd come upon instances where internal radius's would conflict with tool size and alarm out. Wear is basicly conflict free

[Reko]

Wow, I guess I'm the dinosaur here. I still use control for finish contours.

[Guest]

Computer and wear, won't fly any other way

[within a thou]

Wear on everything saves a lot of time reprogramming

[kunfuzed]

If you do decide to use "Control" and not "Wear", send me your address so I can come down and punch you in the nose!

[Guest CNC Apps Guy 1]

Wear for sure.

[Mgrenier]

Reko,

 

Not a dinosaur, just somebody who uses a different approach to get to the same result.

 

I'm in the same boat as you.