Newbie Help: MK3 y axis assembly  

Re: Newbie Help: MK3 y axis assembly

With the power to the motors off, my Y carriage is a little easier to push than the extruder on the X carriage. This isn't a very scientific analysis, but might help you some. I tried the "tilt" test you described, and I guess I got to about 20 or 30 degrees away from horizontal before the Y axis started to move.
I don't think belt tension is the only thing to be looking at. Another thing to check is the alignment of the belt as it enters and exits the motor's toothed pulley and the idler pulley on the other end of the axis. Is the belt rubbing strongly against the sides of these pulleys? Is there anywhere else that the belt is rubbing or touching something? It should only touch the two pulleys and the Y carriage fixture - and that only on the upper loop, not the lower loop.

Re: Newbie Help: MK3 y axis assembly

Thanks for the reply RetireeJay,

I went through the suggestions that you've made but I still can't seem to get it to a more comfortable place. It's almost as though the Y axis motor itself is what is slowing down / stopping the tracks movement. (I mean I tightened the GT2-16 around the motor but that had to be done) And this could be completely normal, I just figured I'd mention it here where I can put it completely horizontal and have no movement in the Y axis. I've included a few pictures, maybe someone can see something simple that I'm completely over looking. I don't have the X carriage setup yet so I can't use that as a frame of reference, but i'll get there shortly.

Thanks again and all the best!

Re: Newbie Help: MK3 y axis assembly

Additional Pictures.

Re: Newbie Help: MK3 y axis assembly

Well, what happens if you disconnect the belt entirely from the bed? Maybe the problem is in the spacing of the rods or the alignment of the bearings, something other than the belt. You definitely want easy, smooth movement with the belt disconnected.

Re: Newbie Help: MK3 y axis assembly

Are you sure that thee U bolts are not too tight!?

have you tried adding light oil and moving the carriage back and forth?

regards Joan

Re: Newbie Help: MK3 y axis assembly

Hello again,

When I disconnect the belt entirely the bed moves around freely. It will slide once I tip it @ a 45 degree angle.

I double checked the U bolts to make sure that they were not too tight, loosing them until the bolt / screws would wiggle slightly in place. At this point I gave them a slight turn just to keep them from that movement, but nothing more. I have not added oil but I can see / feel the oil in place across the rods, and they still have free movement once the belt it off.

It honestly just seems that the motor is causing the belt to move slowly / with some tension. I'm trying to get the belt to have the perfect tension but it has been eluding me lol. Although I do appreciate everyone's help! I was just concerned that I had this section was too tight and wanted to get some help confirming / denying before I started connected the different sections. I'm still troubleshooting it but without much luck, I'd assume it was something stupid simple that i'm missing.

*(I was supposed to have the GT2-16 screwed in tightly to the Y Axis stepper motor correct? I mean if it wasn't then it would spin and defeat the purpose lol)

Re: Newbie Help: MK3 y axis assembly

I would think that a Y axis stage without the belt connected would start to slide long before you reach 45 degrees. Mine slides WITH the motor connected at about 20 - 25 degrees.

That said, it is normal for a stepper motor to exhibit some resistance to turning even with the power off. There's a rotating permanent magnet inside that moves "teeth" across the face of the steel armature and each alignment of "teeth" has some attraction, even with no power in the coils.
Rather than get hung up on this particular issue, I'd say go ahead and finish the build. The automated test wizard will tell you if the Y axis is not behaving normally, and you can always make adjustments or corrections then.

And yes, the grub screw on the toothed pulley does need to be tight against the flat part of the D shaped motor shaft. :geek:

Re: Newbie Help: MK3 y axis assembly

Thanks RetireeJay,
I appreciate your help! I'll continue with the build for now and send off an update once I finish putting her together.

All the best,
Alton

Re: Newbie Help: MK3 y axis assembly

Quick update, I was just putting the Y axis together and noticed that the linear bearings felt different then the first set that I put on. I followed the instructions about alignment and angle, with no loss of balls from inside the bearing. But some of them feel...gravelly...when sliding back and forth. I just assumed it was fine during construction of the previous section and that it would work itself out, as moving the back and forth across the rod helped a bit. But the last one I placed on moves smoothly across the rod like a dream. I took out the first bearing and checked to make sure it wasn't damaged or missing any "balls" but everything seemed fine. Could this be the issue and if so i'm assuming I would contact the company for more?
Cheers!

Re: Newbie Help: MK3 y axis assembly

Quick update, I was just putting the Y axis together and noticed that the linear bearings felt different then the first set that I put on. I followed the instructions about alignment and angle, with no loss of balls from inside the bearing. But some of them feel...gravelly...when sliding back and forth. I just assumed it was fine during construction of the previous section and that it would work itself out, as moving the back and forth across the rod helped a bit. But the last one I placed on moves smoothly across the rod like a dream. I took out the first bearing and checked to make sure it wasn't damaged or missing any "balls" but everything seemed fine. Could this be the issue and if so i'm assuming I would contact the company for more?
Cheers!

The stock bearings are hit or miss, i ordered some misumi's for my printer to use before it even arrived due to the threads regarding the bearings back early this year.

The stock bearings were not the greatest, id only have used a few of them some were junk right out of the box.