Messages

71

General Mach Discussion / Re: Developing new macropump, faster way to retest?

« on: June 14, 2010, 06:04:34 PM »

Solved. Wrote an autohotkey script to restart

Thanks

72

General Mach Discussion / Developing new macropump, faster way to retest?

« on: June 14, 2010, 04:53:46 PM »

Like the title says, I'm working on changes to the macropump, but all this restarting mach to test stuff is wearing on my nerves. Is there a faster way to restart the macropump code from inside mach3 without restarting?

Thanks

73

General Mach Discussion / Re: Yet another steps per inch post - losing my marbles?

« on: June 12, 2010, 12:46:20 PM »

That worked perfectly. I'll need to test it over the entire distance of the table, but it's close enough for today's jobs.

One more question. I've modified my Cycle Start button warn the user of different things to check before the machine starts. It works, but the problem is, I'm using an OEMButton function to "push" cycle start after the code in the script. The downside is, it makes you have to push the button 3 times before it starts. Once to run the code, once to move the gantry to the starting position, and again to actually start the spindle and begin cutting.

I guess the question is, is there a vbscript function that can tell mach3 to do a cycle start, without calling the OEMButton function?

Thanks

74

General Mach Discussion / Re: Yet another steps per inch post - losing my marbles?

« on: June 11, 2010, 10:22:33 PM »

Thanks, I will give that a shot in the morning, I'm curious how you came up with that number though.

75

General Mach Discussion / Yet another steps per inch post - losing my marbles?

« on: June 11, 2010, 08:23:24 PM »

Hey guys

Ok,
direct drive motors, so no gear reduction.
1.8 degree motors = 200 steps per rev.
10x microstepping = 2000 steps per rev.
8tpi 2 start screws (4tpi effective) = 8000 steps per rev.

This is the part I'm not sure of.

I want  to run metric programs and DRO's, so divide 8000 by 25.4 ?
=========
I set steps per in the mach motor screen to 314.96
EDIT: I also thought maybe it was the rounding, and set it to 314.96062 with the same result.

When I run from zero, to 700 mm, the measurement I get is approximately 1mm farther than it should be.

Am I missing something here?

Thanks


EDIT2:

Swiped from another post, but modified to fit my numbers:
4 TPI = 1/4 = 0.25 inch pitch 0.25 x 25.4 = 6.35mm pitch
so
200 steps per rev x 10 micro steps = 2000 steps per rev
1 rev = 6.35mm so 2000/6.35 = 314.96062 steps per mm.

It would appear my way of calculating it came up right too?

76

General Mach Discussion / Re: At the end of my Rope!!!

« on: June 10, 2010, 05:46:14 PM »

I'm not sure if you guys have something like this in your town, but I regularly purchase computers, monitors, keyboards, etc. from the local state surplus center. It's where all the old stuff that the college tosses out when they upgrade, the city offices do the same, I've even got a couple that came from a bank. While it's not top notch hardware, most of it has been perfect for use with mach3 and my machines. I've paid anywhere from 20$ to $75 for complete systems with video cards, sound cards, cd drives. Sometimes when I see a very common unit, I buy it just to salvage the parts for future builds.

I can say though, avoid these 'mini' computers. Go for the full size desktop PC cases, they're easier to swap parts around in, and I've had better luck with them overall.

EDIT: The place here has a testing station where you can plug in each unit and make sure it works, but once you pay for it, there are no returns.

77

General Mach Discussion / Re: need a macropump

« on: June 10, 2010, 01:17:11 PM »

Is this one file run over and over, or is it different files each time?

78

General Mach Discussion / Re: There is a God!!!!!Keygrabber Axis Gain question

« on: June 06, 2010, 10:40:54 PM »

You can do this in Keygrabber. (Move multiple axis at once)

Go to the Misc Settings tab, there should be an area marked "axis lockout".

If you select "When Pressed", you should have simultaneous axis movement, while "When Released" limits to one at a time.

I disabled multi-axis movement on my machine. The way I zero, I found it too easy to accidentally move an axis that I wanted to stay in position. Maybe with a different controller it wouldn't be an issue though.

Hope that helps,
Z

79

General Mach Discussion / Re: Why is it running off at random?

« on: June 03, 2010, 10:32:15 PM »

Gerry,

I've never used a screw with more starts than one. Does using a 2 start screw with the same TPI double your linear speed at the same rpm?

80

General Mach Discussion / Re: Why is it running off at random?

« on: June 03, 2010, 01:44:36 PM »

I have struggled with the *exact* same problems 

1/2" screws at 5' are really hard to get straight. Even with a "straight" screw, by nature they will begin to whip at high speeds. Over the 5' span, gravity alone causes the little 1/2" screw to sag a little. I switched to 8tpi 1/2" screws on one machine, and it's better since they don't have to turn as fast, but I still think I'd have been better off with 5/8" 6tpi. The problem with that is, that requires all new bearings and motor couplers. I was also concerned that the motors may have a hard time dealing with the extra mass on fast, tiny movements. Maybe someone else has experience with this.

I also made some of those dampers, and aside from making a LOT of noise, they did little, if anything to help. I took them off after a few hours of messing with them. They may help for other problems like resonance, but not for my problems.

On the machine that I'm talking about, I'm using those plastic anti-backlash nuts, and those things can be finicky. I could feel some small bumps / burrs on the acme screw, so I took some fine sandpaper and ran the screws back and forth with the sandpaper wrapped around it until things felt a bit smoother. After that I cleaned everything up really well, lubricated it again, and it's been better. I still run it slower than I'd like though. I decided I'd rather have my projects come out decent rather than wrecking every other thing I cut. Steppers have a lot of torque when they turn slower, but it quickly fades as they increase in RPM.