Messages

11

General Mach Discussion / Step and/or PWM output not working properly. Very Weird MACH3MILL

« on: November 20, 2009, 03:07:41 PM »

Their seems to be a problem with the spindle control of RPM. When I run the calibrate routine the RPM moves from zero up to max is uniform controlled steps . After words, when I request a slow RPM say 350 the motor goes to full RPM. Above about 850RPM the control is smooth and predictable though not getting within several hundred RPM of the S*********x input. I have looked at the pulses with an “O-Scope” and both STEP and PWM INCREASE the spindle speed (more % in PWM, more Steps in Step in the lower speeds) which points to a software problem in MACH3. If I run in PID mode, the requested RPM (S*********x) is within 1% or better. BUT the speed zooms as much a 1000 rpm higher (for about 1.5 seconds) then comes down to the programmed speed. Playing with various PID settings will reduce the zoom effect, but add 5+seconds for RPM to ramp to the new value.  I find this a major problem when using a large FLY cutter as they are notoriously unbalanced and over reving the spindle cause serious vibration.
Does anyone know if this is a setup problem? If you have a fix, I'd love to hear it, this has been driving my nuts for months.

12

General Mach Discussion / Re: Tapping with Mach3mill

« on: March 07, 2009, 10:31:07 AM »

Hood, can you send me a link to the # of slots discussion from Art you spoke of?

TP, Thanks, I figured I'd start with two flute gun taps and thru-holes and sneak up on blind tapping until I have a lot more experience. That way the G-code will be pretty straight forward.

13

General Mach Discussion / Re: Tapping with Mach3mill

« on: March 06, 2009, 09:46:19 AM »

Thanks Hood,

After reading your response, I am now designing a "low profile" floating tap head that has a minimum of "Z" height loss. (The X2 does not have that much Z travel to begin with.) Thanks for setting me on the right path.

A second question would be the number of slots needed to get accurate Feed per Rev feedback. As  I understand it, the MACH3 needs 200uSec per slot to get a reliable read the pulse. I was thinking about 36 or 72 holes that would provide the "read time" up to 3,000RPM. Am I overthinking this too?

Jeff

14

Sieg Machines / Re: Anyone have Softlimits set for the X2?

« on: March 05, 2009, 12:14:55 PM »

I have only three micro-switches wired in series that give me a HOME position on my X2.

Absolute distance values will depend on where the HOME switches are mounted so giving you "my" numbers would be dangerous.
The way I set my soft limits was to:
1) HOME the machine and then use the JOG to move to the opposite end of travel and note the DRO values.
2) Go into the limits page and add these values (with a small safety buffer) to the soft limits and jog to the extremes. The drive should ramp the travel speed to zero before hitting a hard stop.
This will give you you working envelope.
Jeff

15

General Mach Discussion / Tapping with Mach3mill

« on: March 04, 2009, 08:34:49 AM »

Does anyone know how to switch between inches per minute to inches per revolution in feed rate within the MACH3 G-code?

I have added spindle encoding and slow speed (<100RPM) CW/CCW spindle control with the goal of being able to power tap while holding the tap in a rigid R8 tool holder.

What I need is to be able to make a tapping procedure that would control the number of turns (or degrees of rotation) in CW and then reverse for a number of degrees to break the chip and then return to tapping. I have ballscrews on the Z axis.

If some one has already done this, I would love to not have go through trial and error to get it to work.
 
It would also be nice to control the chip loading per cutter flute when drilling holes as well. Obviously XY axis are held rigid and will only be controlled with the normal IPM feed rates.

Any advise is greatly appreciated.

Jeff