Improved Z-stage

[jonnybischof 60]

I want to use the large hole to get an exact positioning in the x-y directions. The flange is just the easiest and strongest way to mount the bearing to the plate, but not useful for positioning. I also don't want to make a "loose" design, put everything together, and tigthen it down. Instead I want to make an exact construction with tight tolerances that will fit because it is made to fit. Installation becomes a lot easier that way...

If I get the fit perfect, than I'll actually have to press-fit the bearings into place with almost zero play.

I'll just order new parts - it may seem like a waste, but the three parts actually only cost me about 110$, including shipping and taxes. And that's for single parts. If I order batches of 10 or 20, I can sell the steel part kits for something like 75$. That's pretty cheap considering what you get for it

There will aso be some more steel parts, mostly small stuff which needs to be rock solid. And I'm considering a complete steel enclosing for the electronics, motors, and power supply. But Blexon.com only goes down to 1mm thickness, that's quite a lot for an enclosure...

Maybe I'll take 1mm Aluminum, should provide a good enough EMI shield and improved cooling properties.

 

[anon4321 16]

I was hoping you were going to offer a kit. I'll be the first in line...

That price even for a single run isn't too much. I was just looking for companies locally that could do the cutting.

However, having a kit with everything worked out is worth the money even if you include some for your profit. The first thing I saw with the local companies is kerf size and it immediately occurred to me that there are a lot of variables and specs to control to the point of being willing to pay more for something someone (you) have already figured out.

Are you also mounting the linear rods differently? Otherwise, I don't see how you will get the tolerance right with the press fit bearings. The rods will be either too far or too close. Or worse, not perfectly parallel. I assume that is why the original design has so much slop in it....

 

[gr5 2,172]

I expect the ultimaker heated bed upgrade will be for sale very soon. It is an all metal platform and once leveled you don't have to level again. It's very nice. It's the same design (same parts) as the UM2 bed and z stage.

Keep in mind that some Z screws are not single helix but double or even quad helix. I don't know what "trapezoidal" means - does that have to do with the qty of helixes? So when calculating steps/mm it's how much the Nut moves on one full rotation times 200 times 8. Just set steps/mm to that value.

 

[anon4321 16]

Cool. Sounds like the UM1 heated bed upgrade is going to be nice but it doesn't sound cheap...

 

[jhertzberg 19]

I determined that the UM1 leadscrew was 3mm pitch via the observation that when I had a bad z wobble, the banding period was 3mm.

 

[eldrick 65]

Just measure the thread-to-thread distance - that's the pitch.

 

[gr5 2,172]

Just measure the thread-to-thread distance - that's the pitch.

 

Or half the pitch if double helix, or 1/4 for UM2 quad-helix lead screw.

 

[jonnybischof 60]

Just measure the thread-to-thread distance - that's the pitch.

 

Re-measured the thread-to-thread: It's actually 3 mm, not 2.5. The thread isn't cut clean though, there's some kind of "line" in the center of the profiles, which isn't always really in the center.

Anyways, in that case I don't have to worry as my replacement leadscrew also has a 3mm pitch.

My design "as is" can't be mounted into an Original UM1, because I've increased the spacing of the z linear shafts (hoping to get more rigidity).

I guess the UM heated bed kit should be good enough. It's not what I'd do, but it is certainly far more balanced when you consider performance AND price.

And in the end, the UM2 delivers, and it delivers good...

I might do a "micro" printer when I'm done with all the primary projects. This one will probably have an all metal frame (except windows of course). Because of the reduced size, it shouldn't become too heavy, and I might even consider using Aluminum.

 

[jonnybischof 60]

Update!

I've finished the z-stage design for a first prototype run:

Just to be clear (because this thread is separated from the UM black edition thread): This z-stage will NOT fit any Original Ultimaker design!

It is meant to go into the Ultimaker Black edition which features several major differences to the Original Ultimakers. As an example, my platform is wider than the original and would probably collide with the motors (can only be used with direct-drive setup).

I'm considering the desgin "finished", meaning I've probably found a very sturdy and reliable solution. I'll report about the results as soon as I've actually built it up (due first week of August).

 

[lars86 42]

Hey Jonny, how did this turn out?

 

[lars86 42]

Bump!

[TheDeugd 18]

Hi @lars86, if you tag Jonny with @jonnybischof he will get a notification

[jonnybischof 60]

Hi @lars86, I had to make several changes to the one I last showed in this topic. Using multiple linear bearings in a row turned out to be a bad idea - very difficult to get them aligned properly.

This is why I switched to Misumi's LHSSL12 linear bearing with pillow block.

I think there is a newer sketch in my Ultimaker Black Edition thread showing this solution, which works pretty well so far. The metal construction is very stiff and moves well along the z-axis. I'm not 100% happy with how the leadscrew is mounted, but I guess it works alright..

Edited May 26, 2015 by Guest