Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: ZASto on June 05, 2020, 11:15:49 AM

Title: Puzzled :(
Post by: ZASto on June 05, 2020, 11:15:49 AM

Yesterday I started to machine paper phenolic 4mm thickness.
At first try I had drifting to the +X direction (unfortunately did not check x0y0 when that happened.
On second try, drifting was in +X and -Y direction.
On third page it can be seen that I changed machining strategy by first drilling holes inside vectors that had to be cleared from inside. Holes were spot on. inside contour, again, was incorrect.

Gave up for now, but I'm still puzzled because machine is GAINING steps (moving gantry, steppers, belts).

Any ideas?

Title: Re: Puzzled :(
Post by: Graham Waterworth on June 05, 2020, 01:22:40 PM

Gaining steps is usually noise on the step wire, are you using shielded twisted pair cable on your signal wires grounded at one end only.

Title: Re: Puzzled :(
Post by: ZASto on June 05, 2020, 06:16:13 PM

Sorry Graham, forgot to mention PPort :)
For years, same computer running XP, same BOB, short wires from BOB to motor drivers, ...

Will have to investigate further (maybe just reinstalling Mach).

Title: Re: Puzzled :(
Post by: ZASto on July 13, 2020, 03:25:48 AM

An update:
Yesterday I fired up machine again and run the same code, and same thing happened.
Then I unplugged parallel cable from LPT port and plugged it to my GRBL breakout (just a board holding arduino Nano and DB-25), fired out bCNC (as G-Code sender) and the outcome was perfect, several times in the row.
Back to Mach - gaining steps :(

All tests conducted on thin scraps of MDF, so no high loads on spindle. And spindle is Kress FME 1050 FME-1, ergo no VFD which could introduce noise.

????

Title: Re: Puzzled :(
Post by: Graham Waterworth on July 13, 2020, 07:48:40 PM

Broken or missing ground wire, pc and machine not grounded together, or power supply failing on machine.  All candidates for random steps.

Title: Re: Puzzled :(
Post by: ZASto on July 28, 2020, 04:49:42 AM

Well, another test, fiddling with width of step pulses (in Motor Tuning), same results.

@Graham: No broken wires. Let me "explain" how the system looks electrically/electronically:
Dedicated enclosure with 4 drivers, power supply and BOB (5 Axis Mach3 Breakout) which works as it should, on input side powered by power supply that supplies motor drivers/motors, on thr output side powered by USB cable connected to computer MB, parallel cable M/F for step/dir/switches/... between BOB and PC.

In case of using Arduino, only Parallel cable is shifted from PC to Arduino (homemade PCB holding Arduino Nano and DB-25)

With GRBL on Arduino, everything is SPOT on.

Title: Re: Puzzled :(
Post by: ZASto on November 01, 2020, 04:21:38 AM

Just to conclude this:

I've changed the confuzer :) and no more "gained" steps.