Plasma Table Build - Plasma Bot 4.0

[posixPilot]

Don't grab the pins ... they are pretty fragile. Best thing to do is to plug it into the back of your machine, then grab the body of the plug where the 2 flat spots are, and twist. The section in front of the blue collar will unscrew from the body, releasing the blue collar.

Cheers
Mike

[EmptyNester]

Don't grab the pins ... they are pretty fragile. Best thing to do is to plug it into the back of your machine, then grab the body of the plug where the 2 flat spots are, and twist. The section in front of the blue collar will unscrew from the body, releasing the blue collar.

Cheers
Mike

Yeah, I thought that would do the pins in. I get it now, thanks.

Rege

[SeanMurphy265]

I'm not sure I follow. Do you mean that you grab the pins and try to unscrew the center part of the connector?

correct. It's four pieces. The 12 pin connector screws into the main socket. The collar slides in from the bottom of the connector and will screw into the plasma cutter.

[SeanMurphy265]

I was hoping to finish up my table yesterday, or at least get everything moving. I needed some 10-32 set screws and the hardware store had closed and I could not finish. I had to press the sleeves into the pinion gears and then drill and tap the holes. My pinion gears had set screws but they are not large enough to hold the pinion gears in place. I hope to have everything moving tomorrow!

[undercut]

Exciting times! You're not the only one looking forward to seeing this in action ....

[sportbike]

It's tomorrow.....is it moving yet?

Great progress on the build. Hopefully you don't run into too many bugs while getting it tuned in.

John

[SeanMurphy265]

I got everything together, but I need some help. The Z axis runs up and down like a champ. My X and Y axis are having some trouble moving. When I hold down the hot keys the gantry moves about a 1/4" X and Y. The Y axis is slaved (I have 4 motors) to the A. The gantry moves fine without the motors. When I mount the motors the gantry moves fine without power to the motors. When I power everything up tell it to move it sounds like it's in a bind.

I tried increasing the acceleration and that did not work, and I am not sure what I need to do.

I am using this configuration.
Slave settings
http://www.needfulthings.net/shopdro...ay;threadid=13
Motor tuning
http://www.needfulthings.net/shopdro...ay;threadid=81

http://www.probotix.com/downloads/ma...creenshots.gif

[Rambozo]

First thing I would do is pull the motors off, mark the gear positions, and do some small moves to verify that they are in sync. It sounds like you might have them out of phase. Do you have four motors total or five? What I mean is are you using dual motors for both X and Y? You might want to include what you refer to in the other forum as without joining no one can see any of that. Some better pictures of your setup might help, too.

[SeanMurphy265]

I am using 2 motors on the y axis. I am using a probotix 4 axis monster kit.

Sent from my A100 using Tapatalk 2

[Rambozo]

OK, all the more reason to pull off the motors and verify rotation and phase. It could be something as simple as reverse rotation.

[SeanMurphy265]

I'm going to check the rotation this morning. Do you mean phase as in pos or neg? Or phase as in moving at the same time?

[Brian Ski]

I'm going to check the rotation this morning. Do you mean phase as in pos or neg? Or phase as in moving at the same time?

I am with Rambozo... I think one motor might be wanting to spin the opposite direction. Putting the travel in a bind. Might even disconnect one and see if it runs correctly. The reconnect and disconnect the other and see if it goes opposite.

Couple pics would be cool...

[sportbike]

Can you just pull one motor off and run it with just the single motor? You may need to help it along with a little nudge, but at least it would be a start.

THe motors may just not be fully in-sync. They need to be pretty much perfect or it will twist your gantry and bind.

[Rambozo]

I'm going to check the rotation this morning. Do you mean phase as in pos or neg? Or phase as in moving at the same time?

Stepping motors are not like normal DC motors. There are uni-polar or bipolar designs for two or more phases. This is what gives them there steps. It is possible to get the phases wired wrong so that the motor will not move properly. This is often hard to tell when running the motor at speed, but is obvious when moving a step at a time. That is why you can either mark the gears or what I do is attach a big cardboard wheel to the gear, then you can put marks on it for distance and direction, and easily compare two motors to make sure they are moving the same amount. I have not seen a photo that shows how your motors are mounted, so it's just a guess. I've seen a lot of dual motors for X but only single motors for Y and Z. I would guess that most of your pairs are mounted so that they need to run in opposite directions from eachother. This means that you will need to reverse one motor from the other, this can be done with either hardware or software.

[acourtjester]

I may be wrong with this but if you have the software set just like in the probotic screen shot, you do not have 4 motors programed.
If that is the case you should only have problems with the slaved axis as one motor is holding and the other driving. That shold only cause a problem for the slaved axis the other should work. Have you change the velocity.
Set them low like 100 velocity and 40 acceleration (acceleration should be 1/2 velocity settings).
But then again I am no expert!!!

[Rambozo]

The tuning on your steppers in mach 3 is more about the mass they are driving and to prevent missed steps. You can also do low level stepper tuning where you adjust the current being used during microstepping, to smooth out the actual steps. This level of precision is not required at all for something as crude as plasma cutting. I would break down your problem into smaller chunks and test each component as you assemble rather than just putting everything together and it not working. Plasma is basically a no load tool, so one motor per axis is plenty. However, I understand that it's often easier to just use multiple motors instead of a more complicated mechanical drive system. Some pictures or even a sketch of your setup would help.

There is another motor tuning you can do with steppers as the following video demonstrates.

[SeanMurphy265]

Here is the where the Y motor mounts. The motor sits on top and there is a nut plate that goes underneath and the motor bolts to the nut plate.

[Rambozo]

I think there may be a slight communication problem, too. Typically the long axis is the X and the short is the Y. From what I can see your X axis is a dual motor setup and I can't see the Y or Z in that photo. And those two motors do need to run in reverse rotations. Be sure that they do before mounting them.

[SeanMurphy265]

Here is the diagram I followed.

[SeanMurphy265]

I'm wondering if the acceleration is too high. I had read where someone had suggested starting low and then going up until the axis stalls out.