Bed leveling ideas

So the RoBo bed does not currently have a way to completely level the bed. I've been thinking of a couple ideas. Both of them will be leveling the whole build platform not just the print area, This may cause problems with the belt. This first idea could be simply modified to level just a print area, but you would lose a bit of build height.

Idea #1 is to use a t nut http://www.woodpeck.com/media/main_tnut.jpg Press that into the board and that would allow you to turn the screw to adjust the bed up and down, It can be turned by the bottom nut or a printed knob on the top of the screw. The bottom nut is to support everything so it doesn't fall down through the sliders, It's not turned tight but left lose enough so that the bolt can still rotate, it could be locked in with some thread locker. This could also be replaced with a spring, which I think would be better. This idea could be modified to work for just leveling a print area.

Idea #2, I don't like this one as much as the first. It uses 2 bolts and a coupling nut (a long nut) turning the top bolt will move it up and down, the coupling nut could be fixed to the sliders instead of the other support nut, and then a spring on top of the coupling nut to support the bed.

So what do you guys think?

 

I think I get how it works, The only thing that confuses me is how you adjust it if the bolt isn't moving? (Or is it?)

 

Ahh, Okay so you loosen the bolt also, and the nut will be on the top of the bed, so you could print a thumb knob for it and that would make it easy to loosen.

 

We'll be watching for it.. thanks

 

jeff remember when designing for 3d printing,

it needs to be easy to print (depending on your printer)
keep it simple if you can
make it strong (ie thicker, support where needs to have support etc)
minimize aspects of the design that would cause failure in the print.

 

Jeff, How are you doing with your bed leveling idea?

I plan to do something very similar as shown below. The only piece I need to make is the alignment spacer that slides over the original spacer to keep the bed from shifting. The spring keeps things tight. The lock bolt keeps everything square and the flathead screw from turning when the thumb screw is adjusted for bed level. The spacer is cut down so that when the thumb screw bottoms out the bed is the same height as the original design. This is the starting point. Bed alignment is then obtained by backing out individual thumb screws until level is obtained. Should only be a few millimeters. This should result in very little loss on Z axis. Using a flat screw avoids any interference to the sliding rails. The new slightly longer flat head screw may need to be installed to allow the bed to be raise to level. Since I do not have my printer yet, lacking the spacer dimensions, the amount of adjustment needed (assuming 5mm or less), I am unable to work out the details of the design, or test it out. If someone else would like to give it a go, feel free.

 

I remembered someone using only springs to level the bed. Seems pretty easy just not sure how it will work with the slider rails.
Something like this. http://www.thingiverse.com/thing:27720


This may cause issues with the belt though.

 

I used just springs. Haven't posted much on it yet because honestly I can't tell how it is working. I feel like due to my linear rails I can't get the bed level no matter what I do. I think my rails may be slightly bent. Honestly I am waiting for Robo to release a leveling solution or at least an idea that they have came up with.

 

Question Robo Team --- all these noted changes that the members are doing. Are these being implemented in the next batches of released of the printer? (August/September schedule releases)

 

Springs alone may allow the screws to wobble causing the bed to wobble slightly as it changes direction, unless the springs are very stiff. I would still recommend a lock but against the rail to keep the screw from wobbling or rotating when adjusting the thumb bolt.

But you are both right, the inability to level the bed is a fundamental flaw in the design, that can be fixed at very little cost. I can't imagine why the Robo group would not consider such a simple improvement, along with longer screws on the limit switches and the Z axis fine tuning mod Cambo suggested. Such fixes could improve the printer`s reputation and strengthen the brand name.

 

Well said. I am extremely happy I ordered one and will be even happier when it arrives. Some of the Robo prints that I have seen online are really awesome. Hope what I said above did not sound like a gripe session. The Robo guys do care about the quality of this printer and have demonstrated it in recent announcements: such as including a filament spool bracket and a cooling fan assembly. I’m sure more will come, many we can print out ourselves, others they may offer as upgrades.

 

I bought some springs and washers today. Got home to find I don't have a wrench small enough to remove the nuts holding the bed to the slides. Back to the store tomorrow. Lol.