Messages

3051

General Mach Discussion / Re: Just have to say...

« on: December 09, 2011, 06:05:19 AM »

My wife may kill me as I'm in the garage every night

Hey Bucko,
Seems Cupid's arrow of cnc has  found another target.
Mach certainly has a nice personality, but like the wife, also to has it's quirks, which after time
one either comes to accept, change or live with. One cannot dispute the fact that it will do as told
 and not talk back. The problem one finds is that it is rather lumpy when you try to get your hands
 around the whole thing and  and dosen't like to  wash clothes or feed it's mate. Just thought
I would give you a heads up since being cold, hungry, and without pillowing can become
old quickly.

BTW, watch out for sponsors like Brett, they share code a lot in their neck of the woods.
 
RICH

3052

General Mach Discussion / Re: Steppers are too slow

« on: December 08, 2011, 05:24:22 PM »

Hope I haven't started a forum war here

Let not your heart be troubled....
Just a friendly discussion looking for understanding......
RICH

3053

General Mach Discussion / Re: need help with settings to carve letter in DESK ENGRAVE

« on: December 08, 2011, 06:17:59 AM »

John,
CLick on the HELP tab and have a read.
RICH

3054

General Mach Discussion / Re: Lost step on large gcode program

« on: December 06, 2011, 08:09:03 PM »

A lost step can take place in the electronics side or the mechanical side and they can be related.
The electronics side is rather difficult to test without the proper equipment. The normal flow on the electronics side is
PC output to bob, BOB output to drive, DRIVE output to the motor. What we did was use a pulse counter which monitored
 the outputs noted above. The custom counter had 6 independant calibrated inputs and was accurate to some 20 ppm or so.
Not my equipment and can't remember all the specs. We varied the kernel speeds ie; 25, 35, 45  and sent a number of different
pulses relative to a movement. We also sent pulses which would  cause the motors to to rotate one revolution. So for any
sent number of pulses from the computer to the motor we could compare and see if there were any differences.
You could also send one to ten pulses and watch how the system repsonded. That took care of the electronics side.

Mechanical side components were motor output pulley, belt to a pulley on ballscrew, and finaly the lathe crosslide
attached to the ball screw nut. A circular indicator about 6"  in diameter and divided into 200 parts was attached
to both timing pulleys. A calibrated optical allignment scale ( 10"  measuring  length  was used ) was mounted on the
crossslide. To read the scale an optical alignment scope ( 40x at 12"  distance) and calibrated optical micrometer
which could measure directly to 0.0001" was used to read the scale.

Thus what we had in place was measurement of the electronics / pulse count and also mechanical movement
which could be directly related. Example; A movement of the axis commanded in Mach for one rev of the motor.
In the ideal world, then pulses should all match up from pc to the motor ( drive was  micro stepping 10x)
 the motor should only turn 2000 steps, and that number of steps would equal an exact linear movement of the axis.
 The counter would show any difference on the electronic side, the two pulley indexers should match based on the
gearing reduction, and  the linear travel should be be correct. You also had MACH's DR0 to look at.

So the above could be used for differernt feed rates, velocities, and linear travels. One must realise that
if the steps per unit are not correct then results will  be faulty. The ball screw should be mapped for linear deviation
in both directions of travel. Backlash of course is needed to be accounted for and same goes for bearing preload.
Even belt tension should be adjusted. The above would all be for some shorter length of the screw movement.
In this case it was for 3" as that was the travel I was interested in looking at for thread testing.

In general Mach DRO was extremely accurate, 25khz kernel was used, different motors had different stepping ability
 but were repeatable  per rev,  the pulley and timing belt combo was very accurate but note that belt tension can
cause  lost steps but repeatable motion after a rev in one direction, my ball screws have a different backlash and gain
when going in different directions, the nut contributes to backlash and definitely bearing preload influences the backlash.

So where is that goofy lost step, well you need the right calibrated equipment and measuring procedure in place to even
try and find it..... if it even exists under a set of circumstances. Note that all of the above are under somewhat limited
 conditions. Throw in complex gcode and movements and good grief and a bunch of other factors come into play
such that you don't know what the hell you have measured or what was the cause of the lost step.

Stepping or pulsing aside for now,
RICH

3055

General Mach Discussion / Re: looking for a circular pocket wizard video

« on: December 05, 2011, 06:09:04 PM »

absolute or incremental  Isn't there a Mach checkbox for this?

In Mach the tabs at the top of the screen:
Config> General Config > tick the distance  mode you want ( second column about mid way down)  and save settings
RICH

3056

General Mach Discussion / Re: looking for a circular pocket wizard video

« on: December 05, 2011, 06:01:15 PM »

Just take the time to play with the wizards and see how they work.
Practice makes perfect..........
RICH

3057

FAQs / Re: Incomplete Gcode load

« on: December 05, 2011, 05:57:30 PM »

Think of the license as an early Christmas gift you deserve because you have been a good fellow all year.
RICH

3058

FAQs / Re: Incomplete Gcode load

« on: December 05, 2011, 05:34:50 PM »

Post your xml file.
RICH

3059

FAQs / Re: Incomplete Gcode load

« on: December 05, 2011, 05:34:04 PM »

Works fine here. Attached is a pic in LC and also in Mach. About 1411 lines but i did mutiple depth cuts.

RICH

3060

General Mach Discussion / Re: Steppers are too slow

« on: December 05, 2011, 05:20:04 PM »

I have G201's and have an in line fuse upstream of each of the drives. The fuse is a fast blow and are below the max 7A rating of the drive. Have only blown a fuse one time and that was when the controller was turned on. Non regulated power supply here is capable of 30amps. You all may do as you wish but i will keep the fuses in mine. 

RICH