Y axis seems to travel too far...

[Justin]

Hello people. I'm new to cnc, 3D modeling, etc so any advice is helpful

I've completed assembly of my cnc and downloaded all the necessary software. I'm connected to my computer via UGS, and going through jogging the machine

here is my issue

I've set me step size in UGS to 1mm but I find that when I move the y axis forward or backward under "machine control" it seems to move much more than 1mm. Both the x and z axis movements travel much less in distance compared to my y axis. I'm assuming this is not supposed to be the case. I've checked the voltage on my y axis POT and have a steady .6v, and have even replaced the chip and recalibrate. Am I possibly missing something?

I took some time and created a g code file in fusion 360. When I run the file, everything seems to be good except for the y axis. The machine will bottom out on both ends of the y axis until I pause the file.

Any help is appreciated. Thanks guys

[Derek the Admin]

Hi Justin. I'd be happy to help you. Can you confirm how you have the jumpers set on the Y axis?

Can you type $$ and then enter in the command line of UGS then let me know what value you have for setting 101?

Thanks
Derek

[Justin]

$101=40.000 (y, step/mm)

[Justin]

100 = 40.000 x
101 = 40.000 y
102 = 80.000 z

[Derek the Admin]

Thanks for getting back quickly. I just wanted to confirm that you had factory settings there, which you do.

There are a few possibilities here.
1) You don't have the jumpers properly jumping M0 and M1 underneath the Y stepper driver. Is it just like your other ones?
2) A G20 is being set prior to the Y movements. I doubt this. It sounds like you are jogging things just as you should and the X and Z respond appropriately.
3) The CNC shield has a fault that is preventing it from recognizing that it has been properly jumped with M0 and M1. I have not seen this failure before, but it is possible. If we determine this to be the case we could send you a new board. As a work around though, I could show you how to pretty quickly clone that extra port on the shield to Y and pick up use there.
4) The Uno board is putting out excessive pulses for some reason. I've never seen that happen and this is probably the least likely of the scenarios.
5) Something else, but I think it's going to be one of the above.

We'll get ya going in pretty short order.

Derek

[Justin]

I will check the jumpers again tonight to see if that's where the problem lies. In the meantime, i would not be opposed to cloning the extra port on the shield.

[Justin]

I checked to see that all of the jumpers are in the correct position. I also tried switching the x and y axis motors. The behavior seems to to be consistent with that port only.

[Derek the Admin]

Ok, thanks for letting us know the jumpers are good.

Let's try to clone that axis to the free port.

Alright, first and foremost, the kit had 7 jumpers. You are currently using 6. Remove both of the jumpers from the Y port. Place them on the cloning points as shown in this protoneer diagram:


The jumpers go left to right.

You will have one jumper left and won't be able to achieve the 1/8th microstepping that jumping M0 and M1 does, per the assembly instructions. We can however go to 1/16th microstepping. Take that one remaining jumper and place it on M2

Put the stepper driver on that port marked "A". Plug in the Y motor to the pins on this port.

Boot grbl. Type in $101=80 then press enter.
That makes grbl understand the new microstep setting on the Y.

Give that a shot please and let me know if you have questions. If it doesn't work we can send you new boards.

Derek