[Mud]

I have been running a project on my new X4+ and after about 5hrs of run time the machine will lose position and start plunging 1/4" away from where it should (See first Pic). Not sure why the sudden loss of position, but was hoping someone might point out things to check. The X4+ using Mach 3 w/ Rev 3 profile seems to use extremely fast rapids, could this be it and if so how do you adjust rapids. No binding on any of the axis, very light tension on Gibbs. I'm at a loss, any help appreciated.
Thanks.

(Circled is the area where machine started to plunge for new z depth, just right of where it was cutting)


(Another pic, but circled the other half of end mill )


p.s. Sorry for the bad pics, took them through my enclosure .

[Ed from NY]

Sorry for asking the very obvious, but... Is it always in the same position? Did you look at the gcode? Was it right after a tool change? Was there a different noise before this happening (the noise of the stepper loosing steps is very distinctive)? Were you near by to notice a collision a little before or too high of a feed rate?

Probably not the gibs if it only happened after 5 hours... unless you just started going in that part of the table, or they were not properly adjusted and shifted positions.

Adjusting the rapids is in Mach3 under the "Config" menu. There is an option "Motor Tunning". But, again, that usually will happen right away, as opposed to 5 hours into it.

Did you clean your mill, taking it apart all the way and removing all the original grease?

BTW, at times I notice loosen steps when jogging in Mach3. Never in a program, always when jogging manually. No apparent reason.

[gn3dr]

Might be worth asking were you doing anything else close by when the machine was running?
Something similar happened to me recently when I was Tig welding in the same area while my X4+ was running. I think it was because of interference with the HF from the Tig welder causing the mill to loose steps. Lesson learned for me. Nothing similar has happened since once I don't weld at the same time as milling.

By the way any chance you could post some pictures of your enclosure?

[neilw20]

Make a short program to rapid backwards and forwards fairly close to the limits, with lots of instant direction changes.
If you hear any clunks on direction change your feeds are too fast.
While it is rapiding try to restst the table movement. Any clunks?

Clunking usually occurs when when steps are missed.
Once you slow it enough it won't loose position, unless it has stiff spots.

Mach3's low level driver controls acceleration and deceleration. Anything that makes the PC hiccup can interrupt the smooth pulse train to the driver.

Make sure drivertest.exe works perfectly.
As it happens after 5 hours, when the steppers are well warmed up, it sounds like your rapids are a bit fast.
Are the current reduction switches set to reduce the stepper current after an axis stops?

If current reduction is on steppers run cooler, but the holding torque is reduce.
It is possible another axis move can overload a stopped axis by excessive tool loads.

Programming problems can be caused by stale variables. #123 was zero yesterday.
Program runs and changes #123 to say 100.
Next time a program runs, #123 will still have 100, even after powerdown. That one gets you the next day!.
It broke an cutter for me on the second pass around a job that worked the previous week with no drama.
#123 was zero when run the first time a week before. Another program used #123 and left it with 100. Subtle gotcha that one.

Be ready to blame a program. Just because it worked today doesn't mean it is bullet proof tomorrow.



Another cause can be noise injected via mains/earth wiring. Are you running the PC and the machine on the same power circuit?
That always helps.
Do you ever get EStop occurring for no good reason? Usually PC/Mains earting problem

[Ed from NY]

Another idea...

Load the table with an equivalent weight or heavier, put a DTI on the head. Run the program on air and at the end check a reference against the DTI.

As it happens after 5 hours, when the steppers are well warmed up, it sounds like your rapids are a bit fast.

You mean the steppers loose their oomph when they get hot? Interesting.

Programming problems can be caused by stale variables. #123 was zero yesterday. Program runs and changes #123 to say 100. Next time a program runs, #123 will still have 100, even after powerdown. That one gets you the next day!.

Pardon my ignorance, what is this #123 and which of these registers are stored in the machine? What are they used for? Any links? Thanks!!!

Another cause can be noise injected via mains/earth wiring. Are you running the PC and the machine on the same power circuit? That always helps

Meaning (help cause a problem ?) we should run them in different circuits right? Sorry you got me confused.

[Mud]

Lot of info to absorb, thanks to everyone for the replies. The machine and computer are not on the same circuit, older home doesn't let me put too much load on one breaker. No E-Stop episodes either. I will try slowing the Rapids down first and start the code again (cutting air) and see if it loses position at all. I'll post back if that works. Please post if you have any other advice.
Thanks again.

[neilw20]

Another idea...

Load the table with an equivalent weight or heavier, put a DTI on the head. Run the program on air and at the end check a reference against the DTI.

You mean the steppers loose their oomph when they get hot? Interesting.

Pardon my ignorance, what is this #123 and which of these registers are stored in the machine? What are they used for? Any links? Thanks!!!

Read about parameters in the Mach3 manual. Most are persistent.

Meaning (help cause a problem ?) we should run them in different circuits right? Sorry you got me confused.

If you run on DIFFERENT circuits you are more likely to get problems.
Noise etc, induced on neutrals and earths are the culprit.
Your PC won't overload the power point. Plug 'em in together.
Common earths etc make for LESS noise with computer hardware.

Isolate the problem. Don't just try things. That could taker 30 hours or more.
Is it electronic? Loose connectors. Chinese crimping. Static electricity.
Is it electrical? Noise and interference. Other power tools. Fluoro light surges.
Is it mechanical? Things getting stuck or not running smoothly.
Is it software? Windows causing CPU to go off in the weeds. APIC timer probably.
Is it a setup/config problem? DO you need rapids that fast. I run only 50%.
Is it your program? Try to induce the problem with a different program.

Tick the boxes using human logic. Eliminate each cause systematically

[Mud]

I had a closer look today at my machine and noticed that the machine must have lost steps much earlier. I know the pics are bad, but look at the top right of the part On the black hold down clamp you will see that the tool cut half way through the bracket before it started on the lower right area. Looks like my machine is loosing steps on X .

[hughlss]

mud, have you solved your problem yet? It occurred to me that you could try changing the stepper motor in case there's a mechanical problem there. Maybe swop the x & y stepppers and see if the same problem exists on the x axis or changes to the y axis, or disappears altogether - which might indicate an electrical contact problem - test all your crimps.

hugh

[syil canada]

If you could forward me the code you used, i wouldn't mind taking a look at it.

[email protected]

this will be the best way , before you start checking the machine.

thanks

keith

[Mud]

hughlss,

Haven't had time to run the code again with slower rapids, will try again after I finish the Hunny Do list

If you could forward me the code you used, i wouldn't mind taking a look at it.

[email protected]

this will be the best way , before you start checking the machine.

thanks

keith

Thanks Keith, email sent with code.

[irv]

Hey Mud,
I've got an X4(not plus) with a similar problem. It happened to me a couple times on the same program. The first time, the X-Axis moved about 1/2 inch, the next time, the X-Axis moved about an inch and a half.(at a different point in the program)
I tightened up all the connections on the 4-pin connector at the X stepper, and haven't had the X-axis move on me since.

I did have the Z-Axis move on me though, about a half inch(up, thank goodness) and it happened exactly when I clicked to Slow the feed rate down... Coincidence? Don't know yet. I need to keep messing with it.

[irv]

Since the last post, I've run 5-6 different programs on the X4, and haven't had any strange Axis movements.

I have, however, had a few random E-stops. It happened twice during a facing program. The program just stopped(spindle and all) and Mach3 was flashing "E-stop button pressed"... and I hadn't touched anything. I started it over... it happened again at a different point in the code. I started it again, and it worked fine.
It happened again on another program, but this time everything just stopped, and Mach3 went back to the beginning of the code (no E-stop warning). I ran it again(with no changes) after that, and it worked just fine.

I'm thinking its just another case of "Syil Loose wiring" which also could be causing Mud's problem.

Thoughts?

[neilw20]

Examine and tug EVERY crimped connection.
Poor choice of crimping tools creates this sort of stuff.
As for the E-Stop, have a careful look at earts on LPT cable and make sure screwed in.
Also ensure all earthing screws in X4 make proper contact.
Electrical interference often occurs running machine on a different phase to the PC/laptop. Try and use the same power point.

[Mud]

Sorry for lack of update, but been busy with the Honey Do list
I set Rapids to 40 units/min (conservative) and let loose with the code, after 10hr run cycle all is well. X4+ held it's position and cut through the 304ss with little problems. Thanks for all the help, just needed to slow those Rapids down a little.

[neilw20]

Don't you just hate specmanship.
Find the maximum limits and back off by a healthy margin to allow for sagging power dropouts and overloads, and you will never have problems.
I fail to see why you need to 'cut air' at ridiculous speeds.
If you had a tool changer, then cycle times might be an issue but not with these little machines.
Well done, with an easy fix.