Messages

481

General Mach Discussion / G43/G49 Question

« on: November 08, 2011, 11:59:39 PM »

I'm (slowly) bringing up a KFlop on my machine, and one of the things I have to get working is tool length compensation, using the knee.  I'm curious how G43/G49 work on a "real" CNC machine.  Will execution of G43/G49 result in any movement, or does the movement occur only when some subsequent block commands it?

Regards,
Ray L.

482

General Mach Discussion / Re: Another Wacky Mach3 Behavior....

« on: November 05, 2011, 02:14:55 PM »

Terry,

I've already restored an XML from about two weeks ago, which made the problem go away.  I've also sent the XML to both Brian and Greg.  Hopefully one of them will tell me WTF changed to cause this.  There is something wrong with the logic, though, that allows something like this to happen....

Regards,
Ray L.

483

General Mach Discussion / Re: Another Wacky Mach3 Behavior....

« on: November 05, 2011, 11:46:19 AM »

I am not a programmer but I always thought G52 was associated or used  relative to a work offset, G54~G59 etc?
If you are in G53 mode, why not use one of the G54-59 offsets?
N.

G52 applies a temporary offset to the current fixture offset.  It's handy when your datum shifts, to simplify programming.  In this case, I load a piece of raw stock, then face off the top, and use G52 to shift the fixture zero to the new top of the material.  At the end of the program, I remove this offset, and I'm ready to start the next piece.  It normally works just fine, and I've used it a lot, but something has gone wonky in Mach3 making it now misbehave.

Regards,
Ray L.

484

General Mach Discussion / Another Wacky Mach3 Behavior....

« on: November 05, 2011, 01:04:56 AM »

Today, in the middle of a 4-hour job I've run successfully before, my quill drive retracted to the upper limit.  This happened on a line containing "G51 Z-0.050".  I found I could run the following sequence consistently and repeatedly:

G52 Z0.0
Home Z axis
Manually change Z DRO to +0.75
G0 Z0.0
G52 Z-0.050

When the "G52 Z-0.050" is executed, the Z DRO jumps to some random, large-ish, negative value, like -7.4901.  If I repeat the sequence again, the Z DRO jumps to the previous value -1.2500!  So, the second time I do it, the Z axis will jump to -8.7401, and the time after that to -9.9901.  Now here's the really interesting part:  Exiting and re-starting Mach3 does NOT fix the problem!  Unplugging and re-connecting the SmoothStepper does NOT fix the problem!  It is now stuck in this mode, and I can't get it to behave properly!

Regards,
Ray L.

485

General Mach Discussion / Re: Relative motion of cutter to table

« on: November 03, 2011, 10:35:26 PM »

Ray are you using a canned cycle or a macro or a sub?

(;-) TP

Terry,

D) None of the above.  I have a G-code post-processor that re-writes the G-code with a whole lotta changes.  The peck drill cycles are pure G-code, using nothing but G0s, G1s, G4s, and S-words.

Regards,
Ray L.

486

General Mach Discussion / Re: Tool hight measuring after tool change - macro ?

« on: November 03, 2011, 07:51:16 PM »

FWIW - I *used* to do tool length setting this way, but I don't any more.  I find it MUCH quicker and easier to simply measure the tools using a height gauge.  I will use touch-offs when doing a one-off job, and not use the tool table at all, but when doing "production", where I will be re-using the table, measuring off-line is much faster, because it doesn't require mounting all the tools just to measure them.

Regards,
Ray L.

487

General Mach Discussion / Re: Relative motion of cutter to table

« on: November 03, 2011, 07:48:40 PM »

Heres hoping for your sake its not something in Machs plugin interface that is the issue then. Have never seen any issues myself and I use the SS on all my machines but maybe just dont do the one thing that triggers it.
Hood

Well, I think I made some progress today, in narrowing down the "trigger" - this issue has always reared its ugly head during peck drilling cycles.  My peck drilling cycles do a rapid down, feed down, dwell, rapid up, repeat as needed.  As the hole gets deeper, the RPM, feedrate, and peck depth are reduced.  Today I took out the RPM changes and dwells, and successfully drilled over thirty 3" deep holes without a problem - first time I've ever been able to do that many holes in a row.  Hopefully this will give Brian or Greg a clue....

Regards,
Ray L.

488

General Mach Discussion / Re: Relative motion of cutter to table

« on: November 03, 2011, 10:43:11 AM »

Only reason I was asking is sometimes things go crazy for you, TP also has/had that happening and I seem to recall him recently saying he doesnt use Home switches. Probably a wild shot but just wondering if Machine Coords are massive and maybe rolling over or something when things start going weird.

Hood

Hood,

No, my problem is a confirmed bug in Mach3 with the SmoothStepper.  For reasons we still don't understand they sometimes "sync" when they shouldn't, which means Mach3 updates its position counters with the values it receives from the SmoothStepper.  Unfortunately, these are somehow wrong, and result in the machine zero spontaneously changing mid-program, which should never, never EVER happen.  It's a completely random (though, sadly, not all that rare - happened three times in as many minutes yesterday) occurrence.  Brian, Greg and I have been trying to nail it down for almost two months now, but no joy....  It's become such a problem for me, I'm in the process of switching over to a KFlop right now.

Regards,
Ray L.

489

General Mach Discussion / Re: Relative motion of cutter to table

« on: November 03, 2011, 09:44:39 AM »

Ray, Just curious, do you ever RefAll?
Hood

Hood,

No, not really.  Not sure what that would accomplish, with no reproducible machine zero reference position.  I touch off to the part/vise/fixture.  I will, someday, install homes/limits, but it just hasn't been a priority.  I do have switches on the quill, mostly to protect from damage if it's over-driven, but nothing yet on the other three axes.

Regards,
Ray L.

490

General Mach Discussion / Re: Relative motion of cutter to table

« on: November 03, 2011, 12:14:47 AM »

Home switches are a convenience, not a requirement.  I've never had them on any of my machines.

Regards,
Ray L.