Need Help!- Motor Stalling - "hissie fit"

[John Tribe]

First my set up:
Toshiba Laptop with XP and a built in parallel port.
4 Axis HobbyCNC (only running 3 axis)
305 oz motors on a Widget Master table (8" by 8" working area)
Spindle is a Dremel with a 1/16" end mill bit

I have Mach3 with Motor Tuning at:
8000 Steps per inch 33.708 Velocity and 1.5 in/sec/sec Acceleration.

At these settings the motors run very nicely, not too fast as the table is small and I'm not in a rush.

Problem:
The cuts I want to make are quite complex (gear teeth) and accuracy all the way through to the end is imperative. By feeding in g0x2 I get good results and it is reproducible. However when I put in the gCode for a complete gear one or another motor will stall (not always the same one) and the DRO's keep going while the motor makes a really ugly vibrating sound, so the cut is destroyed, at times ending in a blue death screen.

I have a hunch its the computer doing something in the background that is messing things up. I have turned off the wireless but what else and how do I disable or turn off other interference.

[Crevice Reamer]

Hi John. Welcome to the Zone!

The laptop may not produce enough control voltage--maybe 3.5V instead of 5V. This is probably not your problem--just an observation. Also, the SPEED of the laptop may not kick out enough pulses to drive the motors reliably. Do you have any other programs running? Virus Protection? Internet Access? You should only be running Mach.

Are you using the solid couplers? This may be causing binding.

I assume you are using the 36 Volt PSU. Running in unipolar mode with 36 volts, this motor is seriously underpowered. Underpowered steppers tend to stall.

You might consider replacing the Hobbycnc board and PSU with (When available in a month or so) the new Gecko 540 and a 48V Power supply. You could then wire the 8 lead motors in bipolar parallel and get much more power out of them.

CR.

[John Tribe]

Hi CR,
I'm not sure how to check what voltage my Laptop is putting out and I may have to get into that a little later.

There seems to be always something going on in the Windows system. I have nothing running that I'm aware of although I might have Virus Protection running even though I have Internet access turned off. When running Mach3 I don't do anything else with the computer.

The table came with solid connectors so I used them after getting your message I immediately changed to plastic hose and with only a minimum testing that may have solved it as I haven't had a "hissie fit" yet - but too soon to say for sure. As to the binding I am using WD-40 on screws and slides - it this OK??

There are variable voltage "pots" that go into the stepper chips on the HobbyCNC board - can I up the voltage here??

Thanks for your help
John

Originally Posted by Crevice Reamer Hi John. Welcome to the Zone! The laptop may not produce enough control voltage--maybe 3.5V instead of 5V. This is probably not your problem--just an observation. Also, the SPEED of the laptop may not kick out enough pulses to drive the motors reliably. Do you have any other programs running? Virus Protection? Internet Access? You should only be running Mach. Are you using the solid couplers? This may be causing binding. I assume you are using the 36 Volt PSU. Running in unipolar mode with 36 volts, this motor is seriously underpowered. Underpowered steppers tend to stall. You might consider replacing the Hobbycnc board and PSU with (When available in a month or so) the new Gecko 540 and a 48V Power supply. You could then wire the 8 lead motors in bipolar parallel and get much more power out of them. CR.

[Crevice Reamer]

Do you have a multimeter? Harbor Freight sells a digital one for about $5. On the board itself, right behind the parallel cable connection, is a test point labeled 5VDC. You should measure 5VDC between there and ground, and not 3.5V.

Got to control panel and click on add/remove programs. Remove any virus protection or internet programs.

You still haven't told me what speed computer this is. Also, what micro step do you have the board set for?

CR.

[John Tribe]

Hi CR,
..... a test point labeled 5VDC. I read 5.03 volts

I have AVG which is a free Anti Virus program - I have turned off my internet connection which is wireless. Would you still remove AVG??

...what speed computer this is. It is a Toshiba running at 1.8 Ghz with 1 GB ram and 40 G hard drive.


....what micro step do you have the board set for? I have the board set for 1/8 microstepping.

I have made a cut of Design 22 posted by "Switcher" and my machine, following your suggestion of a flexible connector is much better. I am losing 0.1 of an inch on the z axis from the initial start to the finish of the cut.

[Crevice Reamer]

Yep! Remove the AV. You don't need AV if you are not connected to the internet--and it will do things behind the scenes when you least need it.

That computer is plenty fast, and 5 volts too. Good! Sometimes laptops can be problematic though.

Maybe you could cut down on the microstepping for the Z axis-say down to 1/4. That should help.

CR.

[John Tribe]

Yep! Remove the AV. OK Did that before the trial cut you see below.

I hope the little attachment comes through. Its not a perfect cut but its getting closer. I'm still not really sure that I'm not losing a little as things go along but at least no more "Hissy Fits" Thank you very much for that.

I'll also try reducing the microstepping as you suggest. You say only for the z axis?? Why not all the axis? Changing microstepping changes my scaling I think, so I'll have to go and redo the motor tuning right?

John

[Crevice Reamer]

Sure. Changing them all to 1/4 will give you more speed before any stalling while resolution will still be good. Yes you will have to recalculate your steps in mach though.

Looks like you are getting there.

Good Work John!

CR.

[John Tribe]

Hi CR,
As you say laptops are a little difficult at times.

I removed the virus ware and the computer is much more responsive and no funny pop ups from the bottom any more either.

I tried changing the micro stepping to 1/4 and got stalling so I went the other way and also tried 1/16 and again got stalling. Maybe something else is going on but for now I'll leave it at 1/8 as it seems "happy"

John

[neilw20]

John.
Take a look at this thread. It should assist you.
http://www.cnczone.com/forums/showthread.php?t=56302
My post #15 may be relevant to your case.

Some CAM generated programs generate a number of vectors all along the same path, so when Mach3 loads moves into the queue like A to B B to C C to D etc, and A to D is exactly a straight line, A to D would create one move sequence, whereas A..B B..C C..D causes extra un necessary Mach3 computations which uses up precious CPU time.
I have had code generated like
N010 G1 X1 Y1 F100
N020 X2
N030 X3
N040 X4
..
N090 X9
N100 X10
N110 Y2
..
Lines N020 to N090 are redundant and can be deleted.
Once deleted the machine moves smoothly from X1,Y1 to X10,Y1 then to X10,Y2.

I had tried code generated like this that was created in slices and it caused hopeless jerky motion an a 600MHz HP.
Once all the redundant stuff was removed it all worked correctly.
Simple rules:
The more CPU power you have the better.
Optimize vectors (if you need to)
Turn off graphics tool path display. - Often sufficient.
Stop/pause AV programs. Turn OFF file indexing. VERY IMPORTANT.
Use Win2000. Some things in XP can't be disabled. You should NEVER get blue screen.

Simple test.
Increase feed rates up to near maximum before the steppers lose steps. (Each axis may have a different maximum)
Use rapid feed manually jogging with the shift key down. Movement should ALWAYS be smooth. If it isn't the queue is getting emptied every time there is a jerk because the CPU is going off in the 'weeds'

Once I started using Win2000, 95% of my jerky problems were fixed.
The rest were caused by CAM programs generating silly code.