Y axis linear rail carriage is not properly moving

[Pecosaurus]

The problem I am having with my Folgertech FT-5 R2 is that one of the linear rail carriages for the y-axis linear rail motion of the 3D printer is not moving properly, which is causing the 3D prints to shift along the y-axis. What is happening is that when I quickly move the linear rail carriage along the linear rail with my hand it seems like it is moving well but a little noisy, but when I slowly move the linear rail carriage along the linear rail, the carriage stops or binds in certain places but not always constantly stops throughout the rail. The places where it stops are towards the end sections of linear rail while towards the middle, the linear rail carriage moves fine without stopping. Also, after these stops happen, I am able to easily move it along the linear rail, so it is not a really bad binding of the linear rail carriage. This is happening even after I have already taken the carriage apart, cleaned all the pieces of the carriage off, sanded the corner green pieces like a man on a video on youtube suggested to do, and put it back together once already. I also lubricated the linear rails and worked the lubrication into the ball bears by moving the linear rail carriage back and forth a bunch of times. I did these and other suggestions that were mentioned in other forum chats of FolgertechForum that worked for other but are not really working for me. They helped a little bit but the stopping of the linear rail carriage is still there but not as bad.

Also, the linear rail that the linear rail carriage is moving on has a bunch of scratches throughout the linear rail going across the short width of the linear rail, which are mainly around the end sections of the linear rail and not so much in the middle section of the linear rail. I am not sure if these scratch marks are the cause of why the carriage is stopping or not in certain places but it could be a possibility. I don’t know how to fix the problem I am having. Do the metal wires on the carriage that are guiding the ball bearing along the outside part of the ball bearing path/track need to be completely straight? Should I replace all or some of the ball bearings in the linear carriage with new ones? I am getting a little frustrated at getting this linear carriage to work properly because all the things I am trying are not working for me. I did purchase a replacement linear rail and carriage, just in case, I needed to just replace the linear rail if it is not fixable. Should I just replace the problematic linear rail carriage and possibly problematic linear rail with the new one I got. What do you think I should do? What are your suggestions to fix the problem that I am having?

Here is what the linear rail carriage currently looks like:

Here is a photo of what the scratch marks on the linear rail look like:

[csorrows]

The block should only be touching the rail by the balls in the groove. Those scratches will effect it in no way.

Seeing as the block only catches at the ends of the rail, it sounds like the problem is possibly in the rail itself.

You mentioned lubricating it but did not include what you used. This is an important detail.

[Pecosaurus]

The lubrication I am using right now is Slick 50 Supercharged 1 Lube Lubricant & Protectant. Someone on Youtube that did a video on fixing these linear rail carriages from stopping/sticking while moving along the linear rail recommended to use it.

I cleaned off the grooves of the linear rail with a tissue/paper towel and the color of the lubricant and the other stuff in the groove is black and gray. Like this:

The insides of the linear grooves look like this:

I have been printing a bunch of prints since I finished building the printer. Then the prints started shifting along the y axis. I inspected the linear rails and the other rail had a similar problem that I am having now with this one that I am asking for help with and the one that I am having problems with now was moving along the linear rail fine before. Then, I put the printer back together and the one I am working on now also got this problem. I am not sure if this problem happened because when the two ends of the x-axis which are attached to each linear rails somethings become not aligned to each other/both sides of the x-axis became not squared when I moved the x-axis back and forth manually. Then, I took both of the linear rail carriages apart and clean them, and reassembled them. The other one is moving fine now and the problem one that I am working on now was still stopping in places one the linear. Maybe this can help you find what happened and how to fix the carriage/slider that I am working on now and getting help with to fix.

Thank you for your help and your suggestions so far.

[csorrows]

First, the gray lubricant you are seeing is either original machining gunk from China or material from bearing/rail wear.

I would start by completely cleaning out the block. I take them apart and would recommend this method if you are confident and patient enough to put them back together. The other option is to use something like WD-40 to dissolve everything and flush it out. The downside to flushing it is that it's pretty difficult and time consuming to work all of the WD-40 out after the cleaning. Compressed air does help here.

Next I would re-lube it with a medium PTFE lubricant. Super Lube is pretty commonly used here. I use Super Lube 51004. You don't want anything very heavy here as there is very little load on the bearings and they have a tendency to skid when changing direction with heavy lubricants.

I wipe off the rails and run a small bead of lubricant in the bearing groves about every 10 - 20 hours of printing time. The one little bottle lasts a long time. I still get some gray in the oil after going through all of this but it's not much.

I hope this helps. YMMV.

[Pecosaurus]

Thank you so much for your suggestions. I have taken apart the blocks a bunch of times already so I will probably do that method to clean out the block. What mixture do you recommend cleaning/washing the block pieces in to take out the original machining gunk from manufacturing? Should I use a water and isopropanol alcohol mixture or something else?

For the lubricant for the linear rails, is the lubricant I am currently using also good to use instead of Supe Luber 51004, or is it a heavy lubricant and I should not use it?

Also, I think I will start new with the replacement block and linear rail I have because I think I might have made thing worse with the block and the linear rail while trying to find ways to make it better and the metal wire ball bearing guides/guards default to not being really close to the ball bearing and the metal block piece and the little green pieces sticking out and the ball bear keep falling out when I try to put the block on the linear rail. But, I will take all your helpful advice and suggestions that you gave me to properly maintain the new block and linear rail.

[carefudundae]

I highly recommend watching Alex Kenis' video on youtube about this subject. He seems to have a lot of experience and knowledge/understanding on the topic.

I had similar issues that were resolved by following his suggestions. My big takeaway was to use grease after cleaning for long term operation with minimal maintenance... but some of the other 3in1 oils, etc. are good too, but may not last as long. It's also possible that the tolerances in the rails/bearings aren't all that great. Check out his videos below.

part 1: https://www.youtube.com/watch?v=loBHYcifzRM
part 2: https://www.youtube.com/watch?v=Nh-3J-CcZYI

[Pecosaurus]

Thank you for the video. They helped me understand how to clean the bearings and I will probably clean the blocks by taking them apart and putting them in a solvent instead of flushing them out as the guy did in the video because it seems a little too messy.

[csorrows]

or the lubricant for the linear rails, is the lubricant I am currently using also good to use instead of Supe Luber 51004, or is it a heavy lubricant and I should not use it?

I have no experience with that lubricant but seems as it would be very thin and not stay in place long. From what I have learned over the years, the key is the PTFE and viscosity.

What mixture do you recommend cleaning/washing the block pieces in to take out the original machining gunk from manufacturing? Should I use a water and isopropanol alcohol mixture or something else?

Anything that will break down the gunk and lubricant will work. I use IPA for normal cleaning and standard WD-40 if it's pretty gunky, like for the initial cleaning. WD-40 and a pipe cleaner works great on the passages in the block itself.

[csorrows]

Thanks for those videos. I will watch them as well. I'm always learning.

[Update]

After watching those videos, I would probably lean toward Super Lube 92003 or 21030 in the future as they would probably require less reapplication and are not as high viscosity as I assumed they would be.

That being said, I just ordered a tube of 92003 to try out.

[Pecosaurus]

Thank you for the advice and suggestion you gave me. I already purchased Super Lube 51004 already though but I might get Super Lube 92003 or 21030 in the future.

[Ron]

Sorry for being late to the thread, but are you certain the rail is not bent?
It does happen in shipping, sadly.
Any bow or kinks at all could cause such a problem, even if they are seemingly tiny.
It doesn't take much.
The scratches in the photos are witness marks that would seem to support this.

[Pecosaurus]

I don't know if the rail is bent. The only reason why that it might not be is that the linear rail block was moving fine when I assembled the 3D printer and then I was able to print many hours of printing without the prints showing any signs of layer shifting along the y-axis. Then, the prints started to shift along the y-axis and I found out that it was being caused by the linear rail block not moving along the linear rail 100% smoothly and is stopping in a few places. The only way that I can think of something that could have bent the rail is the times that the x-axis linear rail and beam became not fully parallel to each y-axis by the linear rail blocks not being in the same place of their own linear rails relative to each other.

Also, I am working with a new linear rail and block and the block moves smoothly along the one original linear rail that came with the 3D printer kit that was not being the one with problems that I am experiencing now without the linear rail block stopping in any places on the rail. But, when the new linear rail block is on the linear rail it came with, It is stopping in a few places and is not running as smooth as it moves on the good linear rail. Does this mean the new linear rail is bent or is there inconsistency in the metal of the channel of the linear rail, that the ball bearing of the linear rail block, that needs to fixed by sanding or something else? What do I need to do to fix the linear rail?

[Ron]

If I understand correctly (perhaps not), the new rail is stopping in approximately the same place as the original one?
Just a thought-
It is possible that the 2020 channel that supports it could be bowed or bent.
Then when you clamp the new linear rail to it you are bending the linear rail to conform to the shape of the 2020 channel.
Do you have any sort of very straight edge (such as a steel ruler) that is completely straight?
You could use it to check the components for straightness?
Eyeballing it probably isn't good enough.

Also, FWIW, I am only running four t-slot nuts to hold my rails in place, one at each end, and the other two spaced more or less evenly in between.
You don't need an awful lot of them.
And my FT5 is now an H-bot/Bowden drive setup so it matters a lot that the sliders run freely (they do).
In fact you could probably get by with only one at each end.

You can also check for bowing by laying the linear rails on top of the 2020 support channels and "feeling" with a sheet of paper between them to see if there is a gap anywhere.

This is a puzzle...

[Pecosaurus]

Sorry If I was not clear. But, I have not put the new linear rail on the 2020 channel that the linear rail I am trying to replace with the new linear rail yet. I just took it out of the package that it came in and the linear rail came/shipped to me where the linear rail block is stopping in a few places on the linear rail. Then, I tested if the problem is the linear rail block or the linear rail by putting the linear rail block on the good original linear rail that came with the 3D printer. From that test, I found out the linear rail is the problem that is making the linear rail block stop while moving on the rail. What I am trying to say is that I have not put the new linear rail on the 3D printer yet so the idea of the 2020 channel being bent or bowed is not a thing or the cause of the linear rail being messed up and the block stopping in a few places on the linear rail while moving across it. But it might be a possibility that it is the reason that the linear rail, that I am trying to replace on the 3D printer, that I used on the 3D printer from the beginning that got messed up after printing with it for a bunch of prints.

Also, I don't know if the new rail is stopping approximately at the same places as the original one but there is a possibility but, that would not be because of the 2020 channel possibility being bent or bowed.

[Ron]

Aha, I see.
Thanks for the clarification.
So you put the carriage block from the new rail on the original rail and it still binds, although not necessarily at the same spot.
It would be interesting to see what would happen if you then put the old block on the new rail.
It sounds more and more likely that there is something wrong with the old rail.

I would still suggest checking the rails, both old and new, and the 2020 channel for being bent or bowed.
And then only fastening the new rail to the 2020 channel with a few t-nuts.
You really don't need more than a few to do the job.
When the carriages are running smoothly there should be very little thrust along the lengthwise direction of the rails anyway.
The paper check (laying the new rail on the 2020 and looking for gaps with paper strips) is a simple and quick way to check.
And it requires no special tools or anything.

I do hope this helps...

[Pecosaurus]

It is kind of difficult for me to explain the situation that I am experiencing to you so you can fully understand what is going on and what problems I am having in words. It would have been better to explain it verbally to you all so you can fully understand what I am trying to say so you can help me find a solution to the problem I am having at the moment. But, I can not do that on a forum so maybe a photo that I can reference from can help me explain it so you can understand what is going on right now.

The linear rails and blocks on the y-axis of the 3D printer in the picture are the original linear rails and blocks that came with the 3D printer kit. The right side linear rail and block in the picture is the one I was having problems with that is affecting the print quality of the prints by causing layer shifts along the y-axis of the prints. This is the linear rail and block that I am trying to replace with the new linear rail and block. I did not test the new linear rail block on this linear rail, yet. In my last response, when I was talking about the original right linear rail and the new linear blinding up/stopping in a few places but not necessarily in the same spots, I observed this with the linear rails' respective blocks. So, the original linear rail's block was stopping in a few spots on its linear rail and the new linear rail's block was stopping in a few spots on its linear rail. I have not to test if the new block was binding in the same spots in both the new and original rails or not, yet. The left side linear rail and block in the picture is the good linear rail and block that is not giving me any problems right now. This rail is the one I tested the new linear rail's block on to see if the reason why the new block was stopping on its rail while moving across it was being caused by the block itself or by the linear rail having defects in the metal of the channel that the ball bearings of the block roll on or maybe having the possibility of being bowed or bent. (Which I do not think is the case because when I place it on the table it does not look like it is bowed or there are any bows in the linear rail because it looks like it is sitting flat on the table.) The new linear rail's block moves really well on this linear rail, as I stated in my other previous posts on this forum.

I don't know if this will help you understand my situation further with the linear rails without giving you the wrong interpretation of the information that I am trying to tell you about.

Also, If I find out that the new linear rail is bent or bowed in any place/s on the linear rail and it is not just defects in the metal of the channel, what do I need to do to fix it or is there no fix to this and I just need to buy a new one?

Thank you so much for your help, your advice, and your patience.

[csorrows]

There is always the option of posting a video somewhere and linking to it. The forum does have YouTube integration. Just mark the video hidden.

[Ron]

OK, as Chris said, this may indeed need a video to refer to at this point.
If there is any defect in the right side rail of any sort (bent, bowed, kinked, dinged, etc) or its carriage, almost certainly the only option will be to replace them as a set.
You will not be able to effectively straighten or unkink it.
Because of the high precision (ideally) mating of the carriages to their rails, it wouldn't take a lot to cause a binding situation and normally you should not mix carriages between rails.
If it were my printer and I already had a new rail and carriage, I would just replace the problematic rail and carriage and try that.
Sooner or later that is likely what you will need to do anyway.
Hopefully that will resolve the problem.

A (possibly) dumb question-
Because you are running the original drive system (dual Y motors), are you certain that you have the axis drive current set to a high enough level?
I understand the witness marks on the rail and so forth, but perhaps there just isn't quite enough torque to overcome small imperfections on the one side.
Just a thought...

I converted my printer to an H-Bot setup quite a while back and I run the left and right motors at 1 ampere each.
As a result they are now independently wired and operated from one another, so it is a whole different ballgame.
Yours being the dual motor system, you will need 1.5-1.8 amperes for the pair (please refer to your build manual).
And is it possible that something else is binding such as the e-chain?

I'm sure you have thought of all of this, I'm just checking.

[Pecosaurus]

I have already changed the current set between 1.5 - 1.8 for the y-axis stepper motor driver. I have not adjusted the x-, y-, and z- steps yet after I made the current changes to the y-axis stepper driver and the other axis stepper motor drivers. I don't know if I am supposed to do that every time after I have adjusted the current of a stepper driver.

Also, I do have a new linear rail and carriage but the new carriage is binding and stopping on the new linear rail that I have purchased. That is the one I am asking about to find a solution to stop the carriage from stopping on the linear rail while it is moving along the linear rail,

[Ron]

OK, to be honest I am a bit confused now.
Obviously I have missed something.
Sorry about that.

Setting the motor current is a completely independent thing from adjusting the number of steps per mm.
Setting the motor currents will only adjust the amount of power the motors receive from the control board, and in turn that will adjust the amount of torque the motors will generate.
Because these are stepping motors, the steps/mm does not change if the drive current to the motors are changed.
It is always 200 full steps per revolution on the standard Folger Tech motors regardless of the motor current and this will not change unless you change to different motors.
They are then micro-stepped electronically to achieve a finer resolution and smoother operation.
For example if you are 1/16 micro-stepping them, they will require 3200 "steps" to complete one motor shaft revolution.
Past that, the number of teeth on the motor pulley, the pitch of the belt and the number of teeth on a driven gear like the Z axis determines the final "steps/mm" setting.
None of this changes unless you change out mechanical things.

But if the current is set too low (sounds like it is OK though) the motors cannot provide enough torque and will go "out of sync" to the commanded motion steps.
In other words, they will stall and skip steps.

If your new track and carriage are binding, there is something wrong with them and they should not be used.
They have been damaged somehow, perhaps in shipping.

Try this-
I assume that your printer is using the standard FT setup with two Y motors, right?
Loosen up the screws that fasten the X rail support plates to the Y rail carriage on one or both sides by at least one full turn.
I suggest doing at the left side for sure because it is much easier to get to.
Home the motion first and check to see if the X bar is parallel to the framing.
Then using manual motion commands in the user interface or Pronterface or whatever, run the Y motion at normal print speeds (if possible) from back to front and back again a few times in a row.
Don't re-home Y between the motions.

So...

If it does not bind, skip or rack (go out of parallel with the front or rear cross bars), tighten the carriage screws again and repeat.
If it then binds, the problem is very likely that your tracks are out of parallel horizontally or are skewed vertically from side to side.

But if it does bind, skip or rack even when the screws are loose, you will need to either slow the motion down, increase the motor currents, or the tracks may be extremely out of parallel in one axis or another (don't forget vertical).

Measuring with a tape measure is not remotely good enough to see if they are parallel by the way.
And the two sides could also be out of level with one another.
I have long disagreed with the method for installing them in the manual by spacing from the top-most rails (sorry Chris).
The mechanically safer method is to use a 19 inch long piece of dowel rod or conduit as a spacer and to adjust all four corners of the middle rails from the base of the printer.
The precise length of the spacer is unimportant as long as you use the very same piece to adjust all four corners.
This is because the base is by far the more stable and reliable of the two reference planes.
It is also, IMHO, much easier and quicker to do.

Sorry for the novella, I am just throwing out everything I can think of to try to help.
Clearly something is out of whack.