Unresolved Really bad ribbing

I still have z ribbing. Tried just about everything. Dropped the FR to 80 percent. I am at a loss honestly. Here are pics of 2 parts I just printed. I think I'm going to have to go the support route.

 

I was having some bad Z Ribbing for the past few days, it went away most noticeably when I filed the end of my Z rods and re-tightened my couplers and oiled the threaded rods. Quality seems pretty good now. (all from Ziggy's thread)

 

In all the industrial CNC machines I've run over the years, all the ball screws were supported on both ends by bearings. Of course being machines that cost upwards in the millions of dollars you have to expect better solutions.

I've been considering designing a Z axis rod and bearing support that would definitely help to constrain the z axis screws. Another mod would be to put support bearing on both ends and use a belt drive instead of the direct drive system now used. This would al;so allow for a single stepper to drive both screws and free up a stepper slot to use for an additional extruder. Granted it's more parts and increases the complexity, but if it works for Industrial machines, I don't see why not here.

I may eventually invest in some real ball screws for my machine.

 

Here are some parts I decided to print in Mattercontrol. The only change I made was to the temps and the z offset. Looks way better. Oh the 2 parts on the left are from Cura and the 3 in the right are from Mattercontrol

 

Whoa, I'm impressed. Matter Control always gave me problems, glad it's working for you though.

 

Checked belts, screws, loose motors/parts, level bed, oiler, good filament. Literally the only thing I have not done is the extruder calibration because I'm kinda confused on it and what to edit and stuff.

 

I printed 4 big gears for the gear cube overnight and they turned out great, Printed 4 small ones this morning and they also turned out great in Mattercontrol. I'm user the Slic3r Engine. Not sure if it's Slic3r or Mattercontrol that is fixing things. Either way I think I found my setup. For now anyways.

 

Managed to print this thing including the gear cube with mattercontrol. Turned out great.

 

What did you end up doing to get it to print that well?

 

The only changes I made in Mattercontrol was that I changed the temps to: Bed 50, Extruder 198, I changed the speed to 120mm, changed the top layers to 4 instead of 3. I used Slic3r Engine. Set my offset to .4 I think it is. Checked Offset can be negative. Then I uncheck "Avoid Crossing Perimenters". It took almost and hour to slice parts with that checked. It sounds like a lot of changes but really it's almost the stock settings.

 

My printer had ribbing as bad as any of the examples in the pictures here, but I've completely gotten rid of all of it. My vertical edges are perfectly straight now.

My route to fixing them, based on on info I found here:

1) My stock rods were not perfectly straight and wobbled a lot from side to side. Through experimentation, I found I could get rid of a lot of the original ribbing by rotating one of the rods by itself until the wobbles cancelled each other out. This prevents a good level, but the auto level takes care of the small imbalance pretty well.

2) I purchased new, straight threaded rods from a local bolt shop. Before I installed them, I filed the ends down so the cuts were straight across the rods. I also cleaned them thoroughly before I put them in.

3) After removing the stock rods, I made sure the coupler was mounted to the motor shaft the best way. There's a picture somewhere, but I don't remember where. I did not adjust the motor mounts at all.

4) Before installing the new rods, I placed a ball bearing into the coupler, making sure it was centered.

5) I wrapped the new rods with Teflon tape, then installed them into the coupler. Before tightening them, I made sure they were as straight and centered as possible.

6) After leveling the bed with the new rods, I still had a some ribbing, but it wasn't as closely matched to the treading on the rods. This last bit was caused by over extrusion. I calibrated the filament feed and flashed custom firmware with the changes, but I still had a bit of ribbing going on. I finally conquered it by measuring each filament and entering the correct value, then manually tweaking the extrusion rate until everything fell into place.

 

I don't have any real pictures of my before prints, but they are represented pretty well by the other pictures in the thread.

Here's a picture of something I printed a few days ago. I didn't spend a lot of time to get the best picture, and the actual print looks better than it does in the image. If you zoom in and look at the edges of the base and the edges of the cams, you can see that there isn't really any z-ribbing. I still need to tweak my corners, but I think it's speed related, because on the side wall where the hole is, you can see that the corners clean up nicely when the machine slows down due to the small layer size.

 

I'd just replaced my fan housing, and needed to adjust my z-offset after removing and reinstalling the hot end.

I've got a bit more distance from the bed than I used to have on the first layer, but instead of worrying so much about the thickness of the first layer, I've been working on trying to find a balance between minimizing any flare (elephant foot) and good adhesion. The way I've got it set now, I have a nice 90 degree transition between the brim and the first layers, and I don't have any trouble with ABS sticking to the bed. I've been using ABS pretty much exclusively for the last couple of months, and I haven't had a print lift in quite some time.

I still have some occasional warping at the edges, but when it happens, the brim is still solidly adhered to the bed so it is usually just a cosmetic issue. Instead of a ruined print, I just have a corner that is a little out of level. I think I might have even better luck if I get around to modifying the firmware so I can raise the bed temperature a few more degrees.