Odd circle test results (Page 13 of 24)

Anyone had luck fixing this problem? My printer has the same problem, but I don't seem to have much wobble in my carriages, but my pulley belts do seem to be sliding left and right.

Here are my results after the carriage upgrade. My backlash on either axis is pretty much nil, but still have some minor deviation. I'm going to replace the front idler brackets, then put some bearings on the back drive rod.

Probably not going to achieve perfection without flanged bearings so let's not give up hope.

By the way, you can't use those brackets until you get the lawsy carriage installed. They have no tensioning mechanism. I'll make a longer post later tonight on what I had to do. It's not 100% straightforward how it all works.

They will replace the bushings on the back drive rod and 2 of them will go inside a printed pillow bearing. The stock pillow bearing is trash--bushings do nothing.

Yes

I still need to order some but they are 6x13x5mm flanged bearings and the pillow bearing can be printed from the stl in this thread. I'm gonna snag them from McMaster-Carr because I can probably go pick them up from the warehouse.

http://www.soliforum.com/topic/4824/how … -for-ever/

Edit: No metallurgy needed, just freezing the rod for that pillow bearing. Tight tolerances.

Also, where did you get your LM8UUs? I hope you ordered about 12--3 or 4 of the ones I got were total trash and unusable. The rubber would just snag. One wouldn't even go on.

OH That bushing!  Okay, I thought you meant the side bearings.

I got 12x from ebay.  Were your rods already cut to length or did you have to hack saw them?  I can't find rods of exact lengths and if you couldn't either, I suspect that unless you sanded the edges from a hacksaw cut, they would snag. 

I haven't tested my LM8UU's on a rod yet.

Yea... McMaster Carr have EXPENSIVE rods.  Seriously... 8mm rods should not be $30 per.

I know and agree but I'm always preparing for the worst case scenario. 

Would you mind sending me a part # from mcmaster?  When I click Shafts, and then input 8mm as diameter, only the Stainless Steel and Keyed shafts come up... neither is $12.

Edit: NVM I found them...

Alright, so here is what you need to do to get the lawsy carriages up and going on the SD4. Before you even start, go to home depot or lowes and take every single M3 thing you can find, and I mean everything--washers, bolts, nuts, everything. You will find a use for all of them, because the SD4 doesn't give us all the parts we need like the SD2 and SD3 would. Also, print those suckers at 100% infill with 2 perimeters, and print spares. Print all parts at once, they will fit. It will take 5 hours I believe. If they warp, well, you need to address that before you continue.

One note I want to add also: Do not spin those LM8UUs on your rods. You could mess up the rods.

Loosen the set screws on the collars and pull out the rods. My rods were burred very badly and could not be removed from the case without significant sanding. If you have to sand them to any degree, they are probably ruined. I could not get my LM8UUs to slide on them at all, but I didn't try too hard to fix the rods because I had new ones.

Slide the right rod out of the front and the left rod out of the back. If you take the door off, you can do them both from the front, but... effort. Or take them all out from the back. Whatever. You're gonna have to remove the Y stop to get the collar off the left rod.

Take your old X carriage out. I decided to re-use the rods from my X carriage so I smacked the ends off with a hammer. Not hard, considering the carriages look like they were printed with 30-40% infill. Junk.

Now you're ready to start putting it together.

First, here is a full picture of the setup prior to putting the extruder on:

Slide in your Y rods after you put bearings on them. You may need to use masking or painter's tape on the LM8UUs to ensure a snug fit in the printed parts. I used blue painter's tape because it's all I had on hand.

After you get those bearings on there, install the X motor on the left side of the carriage. If you skip steps like I did, you'll have to take stuff apart because installing the motor is not possible once the left part is on the rods--the bearings get in your way of reaching the back left screws of that motor.

Alright, so, you need to take the part that sits in-between the two X rods and screw the two parts that hold the LM8UUs to it. Pay close attention to the orientation! It matters. The part that tensions the X belt should be closest to the front of the printer.

Slide your X rods in a bit, put that center piece on the rod with the bearings, and slide them the rest of the way through. If they look bent up (see my first picture above), don't panic. They bow a bit. You can either take them out and fix it, or just print and they'll correct themselves. Considering we can't print circles, it's wise to have a rubber mallet on hand for the step of sliding them through.

Okay, so I hope you printed an MK5 hotend mount, because you need it for the next step. Screw that sucker into the center piece using the provided screw holes. If you don't have a bolt that goes all the way to the part where you drop nuts in, no big. I'll eventually get some that are long enough.

Now, I found it easiest to go ahead and put the extruder motor on next. But first, you need to remove the metal casing that holds the fan on. It won't fit otherwise. You don't need that fan, I don't know what it does or what it is for, but you definitely don't need it if you have an E3D. Maybe it cooled down the stock hotend? Who knows. It burnt plenty of plastic on its own so I doubt it.

I was so impressed with the size of this screw that I took a picture. It held the fan and heatsink on the back of the motor. Don't forget to put *THAT* fan back on. You definitely need that or your extruder motor will overheat and do weird things. I've run without it and the results are not good!

Now, you need to remove the X stop from the wire sheath. For some dumb reason Solidoodle decided it was a good idea to add stress and more wires to the nylon sheath and X axis by making that switch move instead of keeping it stationary. Who knows what they were thinking. Either way, if you can get it out without cutting the molex connector you are a champ. But I didn't even try because it already had to be spliced for the RUMBA. So I cut it, pulled it through, and attached it to the right of the carriage where it belongs. You'll need an M3 bolt to put in the hotend mount o the MK5 so the switch can actually be activated.

Now the fun parts! Installing the X belt sucks. It just sucks. You'll get it on eventually.

Cut the Y belts. You're gonna punch a hole in both sides. Punching holes in the belts also sucks. I used flathead screwdrivers and a lighter. Expect smoke and bad smells. Pushing bolts through the holes is hard, but you'll get it eventually. Don't forget a washer, they are important. Once you do this, you'll find they're too long. Darn. Experiment and cut them until you can get enough tension on them. I don't have a length. I just guessed, but I had spare belts so I wasn't scared. Be prepared to order new belts if you go too short. Be cautious.

And here is the final setup:

I skipped some details, but read the directions for the lawsy carriage, and then read them again. Otherwise you'll waste a ton of time like I did

After you're all done, play with your VREFs. This carriage is much, much easier to move, so you might find it is too high. At first, I had some serious step skipping, but it turned out to be a wire bumping into a belt. Someday, I will fix my god awful wiring, but that day is not today. I'll do it tomorrow. Or the next day... or the next day...

Big, BIG ups to wardjr and AZERATE who texted with me during this whole process!!! couldn't have done it nearly as fast without y'all.

Oh, and if your question about this is: "is it worth it if my circles will still suck?" YES. I pretty much have zero Y backlash now, or at least, it is extremely minimized. And your prints will be so much cleaner. Just do it.

Oh I'll get one! Thanks for the tip! I have to cut them again to use new idler brackets.