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View Full Version : Stepper motors are still going at the incorrect speed. Need help with Mach3



Apples
12-23-2005, 08:19 AM
I have this system on a plasma table.

Cut area 3m x 2m
Geckodrive G202's
48Volt 13amp power supply
Running two 1200oz-in steppers on the x axis.
And one 270oz-in stepper for the y axis.

Using CorelDRAW, AutoCAD, SheetCAM and

Mach3.

The motors are all tuned up right. They have the correct steps per unit etc.

--------------------------------------------

----------
The problem:

If the velocity is set to 10,000mm/min in the 'motor tuning' page for both the x

and y
axis. And I go and jog the gantry in the y axis it will move along at the correct

speed of 10,000mm/min. This will be shown in theDRO.

But, if I jog with the x axis the motors will move at 14,000mm/min instead of the

10,000mm/min that was setup in the 'motor tuning' page. This problem will also

happen if I run a g-code through Mach3. Say for example I run a square shape.

The feed speed will be set on 5000mm/min. The y axis will feed correctly at the

set 5000mm/min. The x axis will move faster than the set speed that it is meant

to. It will move at 7000mm/min instead of the 5000mm/min required.

I have checked that the speeds that the DRO are reading are correct.
How I done this was, Made the machine run for a distance of 1meter and counted how

long it would take to travel the 1meter.

From those results it showed that the DRO are giving me correct readings.

I have alos cut out a part in 10mm steel with the plasma. You can see how the

edges are smooth and perfect, then the gantry
makes a right turn and the x axis starts driving. The x axis moves faster than

the y axis and therefore the cut edge is very poor.

I am only a newbie to this so I have tried everything that I can think of.
I wiped all traces of Mach 3 then reloaded Mach3 again. Making sure to re-boot

after the instalation.

So I am stumped as to what is going on.



Can anyone help?



P.s on the gecko's I adjusted a 'trimpot' which is the 'low speed vibration'

trimpot screw. Maybe this has effected the motors etc...
I adjusted the screw at the back of the Gecko untill the vibration in my machine

went away.


Peter
Australia

ger21
12-23-2005, 09:04 AM
I have checked that the speeds that the DRO are reading are correct.
How I done this was, Made the machine run for a distance of 1meter and counted how

long it would take to travel the 1meter.

From those results it showed that the DRO are giving me correct readings.



This may not be terribly accurate depending on the acceleration values. Are X and Y accel set the same?

If you go to MDI page, and enter G1 X1000 F5000 (from X0), what does the feedrate DRO read?

ger21
12-23-2005, 09:06 AM
Say for example I run a square shape.

The feed speed will be set on 5000mm/min. The y axis will feed correctly at the

set 5000mm/min. The x axis will move faster than the set speed that it is meant

to. It will move at 7000mm/min instead of the 5000mm/min required.


Can you post the g-code you used for this?

CJL5585
12-23-2005, 09:37 AM
I have this system on a plasma table.

Cut area 3m x 2m
Geckodrive G202's
48Volt 13amp power supply
Running two 1200oz-in steppers on the x axis.
And one 270oz-in stepper for the y axis.

Using CorelDRAW, AutoCAD, SheetCAM and

Mach3.

The motors are all tuned up right. They have the correct steps per unit etc.

Peter
Australia

Are you running the two 1200 in/oz steppers off 1 Gecko, or do you have each of the 1200 in/oz steppers running off its own drive?

Jerry

Apples
12-23-2005, 06:22 PM
Hi everyone,

Thanks for the relpy's.

Here is a G-Code of the square.

I ran this on the other computer which is a laptop. And It ran fine with Mach3. Both axis's moved at the correct 1300mm/min.

--------------------------------------------------------------------

N0000 (Filename: square.tap)
N0010 (Post processor: Plasma1.post)
N0020 (Date: 18/12/2005)
N0030 G21 (Units: Metric)
N0040 G53 G90 G40
N0050 F1
N0060 S500
N0070 (Part: square)
N0080 M06 T1 F1300 (Plasma, 2.5 mm kerf)
N0090 (Process: Plasma, 0, Plasma, 2.5 mm kerf)
N0100 G00 Z12.7000
N0110 X125.3229 Y210.4756
N0120 Z3.0000
N0130 M03
N0140 G04 P1
N0150 G01 Z1.5000 F2540
N0160 X200.3229 F1300
N0170 Y135.4756
N0180 X125.3229
N0190 Y210.4756
N0200 X120.3229
N0210 M05
N0220 G04 P5
N0230 G00 Z12.7000
N0240 M05 M30

-----------------------------------------------------------------

Cheers,

Peter

ger21
12-23-2005, 06:29 PM
Did you use the same .xml file, or a different one? If different, try copying the one that worked to the other computer.