Messages

1541

General Mach Discussion / Re: My machine is not repeating

« on: October 07, 2008, 11:55:45 PM »

Louie,
   I'm not familiar with the C1, but I have a C11, and I know the early ones used fast optos only for the step signals, and slow optos for all the others.  On mine, the slow ones were REALLY slow.  The current C11 uses fast optos for all signals, and works much better.  I'd suggest you look at your board, and determine the revision level, the contact Arturo at CNC4PC, describe your problem, and suggest this might be the problem.  At a minimum, he can tell you which are the faster outputs.  Are you using the outputs he recommends?
   One thing you can try, to determine if this is the problem, is to connect one axis connecting the DIR signal through the output you normally use for the STEP of another axis, and see if that one axis now works correctly.  If it does, then I think you have a smoking gun.

Regards,
Ray L.

1542

General Mach Discussion / Re: My machine is not repeating

« on: October 07, 2008, 10:19:19 PM »

That sounds like a timing problem on the DIR signal.  You should try changing the pulsewidth.  If you're using a BOB, it could indicate there is excessive delay through the BOB on the DIR signal, so when there is a change of direction, the first step in the new direction is taken before your stepper driver sees the DIR line change.  The solution there is to either find a faster BOB output to use, or get a better BOB.  What BOB are you using?

Regards,
Ray L.

1543

General Mach Discussion / Re: RF-45 conversion

« on: October 07, 2008, 11:56:49 AM »

I'd try it again - it's working fine for me....

1544

General Mach Discussion / Re: RF-45 conversion

« on: October 07, 2008, 10:42:59 AM »

Tony,

    You should spend some time on the Industrial Hobbies website.  The RF45 makes a very nice CNC machine.

Regards,
Ray L.

1545

General Mach Discussion / Re: Introducing myself

« on: October 07, 2008, 10:37:57 AM »

Bob,

    With 600 oz-in motors, I'd suggest you gear them down more than 2:1.  I have a Taiwanese BP clone I've just CNC'd with 850 oz-in motors, and 2.5:1 reducers, and it seems about right.  I think at 2:1 with smaller motors, you'll be very limited in rapids, and have problems with position loss on heavy cuts.  Also for the knee, if you go that route, you'll need a LOT more.  I'm going to 4.8:1 on the knee reducer.  At 2.5:1 I couldn't move it up at all.

Regards,
Ray L.

1546

General Mach Discussion / Re: CNC Gear Cutting

« on: October 06, 2008, 07:45:55 PM »

Try to keep in mind, there's resolution, then there's accuracy.  They're two very different things, and one without the other is kinda useless.  Unless you have an extraordinarily accurate machine, worrying about resolution discrepancies of 0.04 degrees seems a little silly to me.  And the postiion error due to microstepping is probably no better than this.  In fact, it's very likely worse.

Regards,
Ray L.

1547

General Mach Discussion / Re: Setting up Steps per inch - Need Clarification

« on: October 06, 2008, 11:45:03 AM »

Pete,
    The correct steps/unit is 10,000/

Regards,
Ray L.

1548

General Mach Discussion / Re: pwm base

« on: October 05, 2008, 01:26:09 PM »

There is a check-box on the spindle setup dialog to enable PWM mode (labelled "PWM Control").  The default is STEP/DIR mode.  If that check box is not checked, then PWM Base is disabled as well.

Regards,
Ray L.

1549

General Mach Discussion / Re: Auto tool zero - touch probe - please help

« on: October 04, 2008, 12:30:46 AM »

Josh,

    Have you measured the repeatability of the tool positioning doing it that way?

Regards,
Ray L.

1550

General Mach Discussion / Re: I'm Losing Position HELP!!!!

« on: October 03, 2008, 02:10:05 PM »

I assume you're doing this with rapids?  If so, then the first thing to do is repeat the test at a slower speed, and slower acceleration.  If the servos are faulting anywhere along the way, you'll lose position.  Is the position loss at both ends of the travel, or just one? 

Regards,
Ray L.
Santa Cruz, CA