[KE8MIR]

Hello
a former coworker of mine bought a cnc plasma machine about a year ago has had little problem with it till last week
cutting out thin sheet metal parts the machine will drift off and end not where it started.
this machine is a small shop build. I do believe the person that built it only made 22 machine before they went out of business.
he's running G3 software and Teknic CPM-SDSK-2310S-RLN drives.
he's asking for help on why it is drifting now after running ok for 10 months
any help would be helpfull

[awerby]

It sounds like lost steps, which stepper-powered machines are prone to. If it was working well before, and considering it's a plasma cutter, the first thing to check for is stuff accumulating on the sliding surfaces, or the screws or gear racks if that's what propel it. Plasma cutting is a very messy process, and if these surfaces aren't well protected, the crud will stick to them and cause all sorts of problems. If that turns out to be the issue, look into bellows and other methods of shielding vulnerable parts. Has it got a water table? Those catch most of the flying debris, but not all.

[KE8MIR]

I went and looked at the machine late last week. It is a strange machine to me
the x axis [cross table] has one drive on a rack and gear drive. The y axis [along the table] has 2 drives on a rack and gear.
I did get ahold of teknic and they advised me to reprogram the x drive with clearpath software, this is done by a USB connection to a laptop
that i can do. the y drive has 2 drives how do they do that as you can only reprogram one drive at a time
And yes the rack and gear drive are out in the open with real cheap bearings

[TMToronto]

There are videos that show/discuss how to tune axes that have two servos. Here is a short guide from Teknic - https://www.teknic.com/files/downloa...Motor-Axis.pdf

[Teknic_Servo]

Hi KE8MIR,

I’m an applications engineer with Teknic. I thought it would be helpful to provide some troubleshooting suggestions and some clarification on ClearPath motors.

As a bit of background, ClearPath is a servo system, so it won’t lose steps. ClearPath also has optically isolated inputs. These inputs require a certain amount of current to assert and are therefore very noise-immune. (We have many customers successfully using ClearPath on plasma machines and other noise-prone applications.)

However, it’s possible (or perhaps even probable given your description) that steps from the controller are warping into signals that optically isolated inputs cannot reliably read. Here are two things your coworker should try:

1. Check the Earth Ground connection – make sure that all of the machine ground points are still reliably secured to Earth Ground with no contact degradation.

2. Open collector outputs (which I believe some Masso controllers have) need a resistor to be truly compatible with optically isolated inputs. Be sure to use the wiring diagram on page 49 in the ClearPath User Manual that shows the incorporation of this resistor: https://teknic.com/files/downloads/c...ser_manual.pdf

If he tries or has already tried both suggestions and he is still seeing issues, please have him call Teknic. We can help him use ClearPath’s built-in diagnostic tools to further troubleshoot and find the root cause. He can also send in a contact request here: https://teknic.com/contact/

Best regards,
Bridgette G. – Teknic Servo Systems Engineer

[KE8MIR]

i read the guide twice and also watched a video on the setup. They should have come up with a better system than
what the guide says. I will have to improvise on how to come up with a weight on the gantry. I did text the builder to see
if he had the original config files for this machine.
I will go thru the machine on Sunday. i did send him text to check the grounds on the drives.
will report back on Monday.

[KE8MIR]

Sorry for the late reply had a medical problem
we ran the motor set up program and the motor was not acting right all the way thru the set up program (making loud Humming Noise)
removed motor from machine and found a real stiff spot when turning motor over by hand.
there has to be a bearing going bad in this motor, the co-worker told me he was going to order new motor for this axis
As i am just out of the hospital have not checked with him yet.
When we ran the motor set up program the motor only moved about 1-2 inches

[KE8MIR]

new motor installed ran the motor setup program
now the motor will not respond to input commands
the led on the breakout board will light showing it enabled but motor will not move
also the mach 3 is showing the position changing but no motor movement