Y-Axis Layer Shifting

[ben2150]

Hello, I just recently finished putting together my FT-5 R2 kit. I started a calibration cube, but part way through it, the layer shifted in the Y-Axis. It typically starts off printing decently, then about the same spot for each print. Though, it seems to be changing from its earlier pattern. I can be pretty random.

Any advice that you can give would be greatly appreciated. Thank you!

[heartless]

the number 1 reason for layer shifting on Y axis is improper voltage to the stepper driver - usually too low

[csorrows]

Keep in mind the Y stepper driver should be at 1.2-1.4v not 0.7-0.9v like the others.

[ben2150]

Cool, thank you so much for your advice, I will try fiddling with the driver voltages as soon as I get home.

[vonPapst]

I have the same problem. it appeared after a month of normal printing. How can I check voltage on the motor?

[heartless]

you don't actually check the motor itself - you check the stepper driver on the board. a basic, cheap multi-meter (preferably digital output) is very capable of doing this

i typically use positive probe on the stepper driver (on the potentiometer itself) and the negative probe on the main ground of the board (ground lead to the power supply)

[csorrows]

So to further explain what we are doing, we are adjusting the vRef (reference voltage) which the driver uses to know the max current it is allowed to send to the stepper. If it is too low, it will not provide enough current to the stepper which could cause missed steps. If set too high, it could cause it to get too hot or a number of other electrical and magnetic issues and cause it to not move correctly or at all.

This is an important adjustment to get optimal performance from your printer.

[minimax]

DRV 8825

A4928

SilentStepstik 2100

I run my Y axys with a Silent Stepstik 2100 @ 0.8 vref...

Michel

[vonPapst]

Thanks for info. I've adjusted Y motors to 1.3 V and all others to 0.8 they were all on 0.43 V which I suppose is too low.

[heartless]

yes, that is far too low and will give you exactly the issues you were seeing.

Good work getting it sorted out.

[heartless]

I dont recommend using the ground on the stepper driver itself as it is far too easy to misplace the probe, or have it slip causing problems... using the main board ground is much safer and will still give you the same results

[ben2150]

Howdy everyone, thank your for your replies. I have been troubleshooting quite a bit. I have played with the voltages a bit, going all the way up to 1.3V for the y-axis. Unfortunately, it didn't solve the layer skipping problem. I checked the angles and spacing. I checked and tightened the belts and grub screws. I changed out the parts that connect to the y rails. I thought one side might be off. I also removed, cleaned, and oiled the y rails.
It seemed to move quite smoothly after the cleaning and oiling. At least, for a calibration cube, and half of a vase. Then around the top of the vase, it started some light layer shifting. Around the top, it did one massive layer shift. I have noticed that the right rail slider's oil comes out with some red material, unalike the clear oil from the left slider. It also coincides with the catching that happens with the right side. I thought it was the belt or motor, but I am pretty confident they are not the problem.

[heartless]

hate to say it, but it looks like you may have some rust in that right slider. =(

if it were mine, I would pull that side apart and thoroughly clean and inspect it.
If any of the balls are showing signs of rust, you may want to think about getting a replacement

[ben2150]

I will try that after I try Dustin's suggestion. He said that the red is just the grease put in by the manufacturer. He suggested loosening the screws on the right slider a bit to see if that solves the problem.
Though, the fact that the right slider is the only one putting out the red coloration, that doesn't seem likely. Even so, I will see if it helps. I think I have fiddled with the screws a bit, without much change in the results. Do you think the manufacturer's oil/grease seems like a likely cause of the red coloration?

I will definitely try taking it apart, and see if any of the bearings are rusty. Thank you for your advice!

[csorrows]

That is in fact rust. I cleaned out all of my blocks and installed new lube. After some time (a few months), I did get the same stuff. I wipe the rails down about once a week and lube them. I have not had any issues with binding or anything, but I know it's not the original grease as they have been thoroughly cleaned out. It looks the same as yours. I get it on both of my Y rails but not my X rail.

I think it's just something that these chinese blocks suffer from.

[JoeKilday]

How does one clean these rail interiors properly? I want to know how you do that right.

You lube these every week, huh?
Why oh why aren't these SS316. Twenty cents worth of material is why.

[heartless]

i don't know about the current ones being shipped, but mine did not have any "red" grease in them. they did have a sticky shipping lube that needed to be removed for smooth operation.

What i did with mine - before assembly - was to use a good penetrating spray (i like PB Blaster, myself) and spray them thoroughly, work the slide back and forth (being very careful not to let it slide off the end), wipe things down, spray some more, work it, wipe it, spray some more, etc, etc, until they were moving super easy and all traces of the sticky shipping lube were gone.

I did have one that wanted to kind of hang up every so often, but after working it over with the PB really well, even that one was moving pretty smoothly.

[csorrows]

I just did this tonight in fact. I only do it once a week when I have been using it.

I just use a paper towel and wipe down the rails and use my nail to get the paper towel into the grooves on the sides. I then lay a bead of lube about 4 inches long inside each groove then work the block back and forth. If I start to get any binding, I will tear the blocks apart and clean them out again but this seems to keep them going just fine. Keep in mind, it's best to unplug the steppers before working them back and forth to keep from backfeeding current into your drivers. YMMV.

I use SuperLube oil.

[JoeKilday]

Oooh ok. I misread you saying you took the block off the rail and the bearing balls out and cleaned it that way...

[csorrows]

Oooh ok. I misread you saying you took the block off the rail and the bearing balls out and cleaned it that way...

Yes, I did that when I built the kit. But, I was more describing the little quick maintenance I do to keep them working well.