Jump to content

Recommended Posts

Posted · Ultimaker - Black Edition

That is looking good. If it's worth doing, its worth overdoing! I know I am probably approaching the project too practically when I ask this, but what do you hope this printer will be able to do that a normal UM cannot?

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

That is looking good. If it's worth doing, its worth overdoing! I know I am probably approaching the project too practically when I ask this, but what do you hope this printer will be able to do that a normal UM cannot?

 

To be honest, not that much!

The Ultimaker is an awesome printer - as long as it works. There are a few issues which just come from the machine being built "economically" instead of "without compromise".

I'm mostly doing the latter - increasing the machine's build quality, reliability and lifespan. And of course there's the matter of accuracy. UM doesn't use precision parts (concerns the shafts, mostly), and the wooden frame warps with changing temperatures / humidity. The UM black edition v2 will have the whole gantry built up from aluminum. Warping from changing humidity will be gone.

I'm not perfectly happy about that (aluminum actually warps with changing temperature, too), but steel would simply be too heavy. I might do an all-stainless-steel version for the super-enthusiast (and for myself), but I doubt people would really want many of these.

My frame will expand by about 0.4mm over it's total width for a temperature rise of 40°. That's not much, but steel warps only about half as much. And of course the whole frame shouldn't experience a temperature rise of 40° in the first place. I'll take measurements with the prototype to gather some numbers...

Of course there are some real improvements, such as the vastly improved z-stage (which has yet to prove how much better it actually is) or direct drive. I'm also redesigning all the other components, such as the material feeder or sliding blocks, and using a higher quality hotend (the E3Dv6). But really - no reinvention of the wheel here.

My goal is just to build a 3D printer that you can assemble and that WILL work realiably and with maximum achievable accuracy for a long time.

Z-height will probably be a little higher than the UMO, but that's only a detail... V3 might also get a bigger build platform, because with my frame that is not a problem. But I first have to find a bigger heated bed...

I also expect the black edition to be quieter than the UMO due to it's rigid build.

Some improvements about cooling are also planned - I'll see what comes out of it.

One of the most important upgrades will be my improved electronics platform. But this project is huge and will take a long time to get done.

Apart from the fact that the UM black edition will cost around 3 times as much as an UMO kit, there are some drawbacks:

My frame is bigger and heavier (with the same build volume) than the UMO's because it uses 30mm extrusion profiles + 5-6mm walls, where the UMO just has the 6mm walls.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

so it will now look a like the one made by Harold Reedijk .....

http://3dprint.com/31029/colorfabb-xt-3d-printer/

https://mail.google.com/mail/u/0/?tab=wm#inbox/14a4a9f09d6526cb?projector=1

And I wonder, if you would stick to the XY size of the UM, wouldn't it be easier just to buy the heated bed upgrade kit to build the Z stage...

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I think the 5 biggest things you can do to improve print quality are (in most -> least effect order):

- Replace the pulleys and belts with quality ones preferably with GT2 versions

- Do something about the plywood Z stage. Jonny is building his own and I'm sure it will be able to hold a army tank but the UM Z stage upgrade is very good if somewhat expensive. I rarely run into leveling issues now and rarely need to level.

- Switch out the linear system (thick/thin rods, bushings and bearings for the thin rods) with higher quality components such as those from misumi

- Switch to direct drive using high quality couplers.

- Switch to printed XY blocks such as Twisterblocks.

A fifth one might be to switch to a hotend like the E3D V6. Not sure if it will help quality but it will allow you to print materials requiring higher temps. It might have better retract/ooze control since they indicate it has a sharp thermal transition.

I've done most of the first four except swapping out the small XY rods and bearings. I'm working on an E3D V6 mount and fan.

The positioning and smoothness of the linear system seems very good now. Previously when the first layer fill was printed starting in the middle of an area such that it returns to the middle to finish the other side, you could plainly see where that point was due to lack of precision in positioning. Now, it is very faint indicating that the extruder returned to nearly the same position.

For me, I think that is as far as I would take it. At this point, upgrades aren't yielding much improvements for the cost/effort.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I don't know enough about it to know if it is worth it. It probably really helps out with flexible filaments. I'm not so sure that rigid filaments would see much difference. I would suspect that the added weight to the extruder would offset the precision of retracts Any added weight increases the probability of ringing and requires reduced XY acceleration.

But these are just my assumptions. I haven't read through the flex drive thread yet.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Jonny,

I'd really like to see some pictures of your UM Black. I've been passively following your development for a while and I like your 'no compromise' mantra. I'd like to have a copy of it - if money were not an object.

I totally get it about the oldham coupling, the motor on top and angular contact bearing on bottom. From a mech engineers point of view its a very conventional setup and a solid improvement over stock.

Matt

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

so it will now look a like the one made by Harold Reedijk .....

http://3dprint.com/31029/colorfabb-xt-3d-printer/

https://mail.google.com/mail/u/0/?tab=wm#inbox/14a4a9f09d6526cb?projector=1

And I wonder, if you would stick to the XY size of the UM, wouldn't it be easier just to buy the heated bed upgrade kit to build the Z stage...

 

Lol, the guy likes screws just as much as I do :D

Actually, yeah, our printers are quite alike. Except that I use less printed parts and more lasered metal parts. And I did all the changes I mentioned before.

The UMO+ HBP? Well, it's nice. But mine is better. My z-stage is built from stainless steel and Trespa HPL, as opposed to the "cheap" aluminum plate that makes the rigidity of the UMO+ kit. My z-stage is also heavier (= higher vibration immunity) and has a larger bearing height on the z-shafts, making it even more stable.

I'm also introducing a triangular arrangement of the z-shafts and the leadscrew, even further increasing the build's stability.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Jonny,

I'd really like to see some pictures of your UM Black. I've been passively following your development for a while and I like your 'no compromise' mantra. I'd like to have a copy of it - if money were not an object.

I totally get it about the oldham coupling, the motor on top and angular contact bearing on bottom. From a mech engineers point of view its a very conventional setup and a solid improvement over stock.

Matt

 

If I make a picture of the UM black edition as it is now, it's just going to be a lot of expensive stuff in boxes :)

I promise there will be pictures over the christmas holidays!

/edit:

About flexible shafts. It's an interesting concept. When I'm done with the UM black edition (which - finally - IS going to be soon) and my delta-bot build, I'll continue making a printer specialised for flexible filaments. Meaning no Bowden. Flexible shafts will be on top of the list for prototypes...

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

@Jonny; I'm also introducing a triangular arrangement of the z-shafts and the leadscrew

Do I understand correctly you place the leadscrew a bit more to the front vs the shafts ? how do you find the optimal spot?

btw, like what your doing ... makes me want to start building myself .... someday ...

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

The optimal spot would be to place the leadscrew in the center of gravity of the z-stage. That's of course not possible, but at least I moved the leadscrew a bit closer - it's only about 20 mm, but it's better than nothing.

I can't tell how much better - I'm not the type who calculates stuff like that, I just try it :p

UMBEv2 Z stage shaft triangle

 

Don't look at the drawing too closely - there are some unfinished parts (like the hotend mount which is barely a sketch) and lots of hidden parts.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

The optimal spot would be to place the leadscrew in the center of gravity of the z-stage. That's of course not possible, but at least I moved the leadscrew a bit closer - it's only about 20 mm, but it's better than nothing.

I know that the z-stage is pretty heavy already, but could you put some weights between the leadscrew and the back to make the leadscrew the center of mass? With the z motor on top and the bearing at the bottom you can get away with more than one can with the standard configuration.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Wouldn't be a problem at all, as long as "inside" the triangle is good enough. There's only 7mm from the z-stage's rear wall to the frame's wall.

But there's one reason why you don't want the leadscrew to be too close to the center of gravity: If that were the case, you'd probably introduce rattle on the linear bearings.

Now, they "lean" on the shafts - no rattle.

So there's a tradeoff between distributing the force and keeping a certain imbalance. Adding weights could improve the very uneven balance as it is now. But I doubt that will be necessary - this setup should be rock solid thanks to the 100m long bearings and the steel construction :)

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I was thinking of steel bar at the rear of the platform, against that back wall between the smooth rods. You could tune the weight to just enough to give you a slight lean. Too much lean means more wear on the bearings and shafts.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

a preloaded z stage would seem more stable to me than a perfectly balanced one. What is the primary issue with the bulk of the mass being displaced from the lead screw?

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I think the 5 biggest things you can do to improve print quality are (in most -> least effect order):

- Replace the pulleys and belts with quality ones preferably with GT2 versions

- Do something about the plywood Z stage. Jonny is building his own and I'm sure it will be able to hold a army tank but the UM Z stage upgrade is very good if somewhat expensive. I rarely run into leveling issues now and rarely need to level.

- Switch out the linear system (thick/thin rods, bushings and bearings for the thin rods) with higher quality components such as those from misumi

- Switch to direct drive using high quality couplers.

- Switch to printed XY blocks such as Twisterblocks.

 

These kinds of lists are very helpful! I am glad I found pretty much all of them myself, though I am not sure which upgrades I will end up with. The printer really should not become another project - it's meant to be a tool to do projects!

 

  • I am on the fence when it comes to pulleys. If I do it, I go all the way and spending close to $100 on some pulleys right away is a bit steep.

  • The UM printbed upgrade looks good. I feel no printer is complete without a heated bed and easier leveling is more than welcome.

  • Direct drive is something I want to look at later. I have a feeling the couplers can be eliminated completely, but how I am not very sure of yet. I would prefer the stepper motor and axle being a single unit and I think that can be done.

  • New blocks are an easy and nice upgrade.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Yeah, the pulleys aren't cheap but to be honest, the ones that come with the UM1 are almost defective. Tightening the screws basically pulls them off center leading to small amounts of error and binding. Replacing them is probably more of a must-do fix then upgrade. While the plywood bed is weak, it basically works. The pulleys on the other hand end up so out of round that you almost have to address them.

I think Jonny obtained some good quality pulleys from robotdigg.com for about $2 USD per pulley. Mine came from adafruit at about $8 USD per pulley. The belts came from SDP/SI at about 35 USD for a for set of 4 long and 2 short.

Just note that 303 tooth GT2 belts are shorter than the MXL belts and do NOT work with XY blocks that take up the slack in the stock belts. This includes the wooden blocks on the UM1. The 300 tooth MXL belts have a center-to-center distance of 284.48mm but the stock XY blocks take up some slack. 303 GT2 belts on 20 tooth pulleys have a c-t-c of 283.00mm, 304 toolh are 284.00mm and 305 tooth belts have a c-t-c of 285.00mm. 303s work perfectly without an adjuster. 304s might work with the standard blocks and 305s might work but might require a separate tensioner. 303 seem the must common and in fact are the only size stocked by SDP/SI. Other sizes are special order.

chopmeister redesigned the clamp for the twisterblocks so they don't take up slack and fit neatly into the GT2 tooth profile of the belt.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I was thinking of steel bar at the rear of the platform, against that back wall between the smooth rods. You could tune the weight to just enough to give you a slight lean. Too much lean means more wear on the bearings and shafts.

 

UMBEv2 Z stage rear steel plate

There's a pretty heavy steel plate at the back of the z-stage. It holds the linear bearing carriages in place and acts as the counterweight. Of course it's by far not enough to put it into balance - but I'll see how it works once it's assembled.

I got the lasered metal parts yesterday (delivered early :)), but the Misumi is still on it's way and should arrive on the 30th of december.

I'll also have to create production drawings for the z-stage's Trespa base and CNC-mill it. I made all the structures bigger, so hopefully this time I won't break 4 expensive milling tools just for one part...

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

a preloaded z stage would seem more stable to me than a perfectly balanced one. What is the primary issue with the bulk of the mass being displaced from the lead screw?

 

The primary issue is uneven wear on the linear components when you have unevenly distributed forces.

Now, the bearings and shafts are made from hardened steel - so it'll take a little something to actually wear them off. But if you overdo it, you could quickly wear down the bearings and lose their tight fit.

This is why it's very important to have actual linear ball bearings, and not bushings. Because canted bushings tend to get stuck, whereas ball bearings still roll (you just wear down some balls more than others).

I believe it won't be an issue with my design, so long as the linear components are high grade.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Looking at your frame I worry a bit that rigidity mighty be a problem. It seems to me that it's all unbraced squares, except for the back. Do you have plans to counter that or do you think that is not an issue?

I think that is one of the things the Ultimaker frame does very well. It is amazingly rigid without much bracing or heavy parts.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Don't worry. I'm using Misumi's stainless steel corner pieces for the upper four corners. They're not drawn yet, but they should be pretty rigid...

The bottom is an 8mm Trespa HPL plate, to which the profiles get screwed with an M8 screw. That should be rock solid, too.

On top of all that, there will be plywood panels on every side, I might even make inner and outer walls for better thermal insulation and aesthetics.

Should there still be any kind of play in the frame, I have space enough to slap some more steel plates on it (much like Harold's XT parts). But I doubt that will be necessary...

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Working hard on the sketches...

UMBEv2 preview 2014-12-23

I added the frame's corner pieces I mentioned earlier. The Misumi part number is "SHBLBCB6".

They cost a whopping 9 EUR per piece - But from what I've seen from Misumi so far, they'll be worth it. Also, they use up virtually no space at all - wall panels can simply be placed over them which makes things easier and nicer.

Btw: Nominal load on these parts is 1000N. Not too bad...

I've also been working on my new E3Dv6 mount. The new version is smaller, but still stronger and easier to print. First prototype will be printed some time this week. (My printer is at my workplace...).

/edit:

Done for today... Limit switches are now also integrated. In it's current (theoretical) state, the printer should be ready to print.

I'll start printing the parts and assembling it in the next few days. Parts are due to arrive around new year, CNC-milling might introduce a little delay but only one part is needed to get the printer running.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

Jonny, just thinking, wouldn't it be handy to make these rod bearing plates in 2 separate pieces, so you have more flexibility in the belt length to use ?

Black Edition

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I did that in my first sketch. But then I realized it would become very difficult to get the gantry aligned when you have every single piece for itself. With these long brackets, the shaft spacing is defined and very accurate (this is a 5mm thick, lasered aluminum part!). On top of that, you just place the first two brackets flush on one side, getting them perfectly aligned. Then you place the other two brackeds flush onto the first two and have them perfectly aligned as well.

The only thing that you still need to care about is to make sure that the aluminum extrusion profiles form perfect 90° angles.

Yes, it means you need to calculate the spacing for your belts carefully. I'll probably have to re-order these parts for better belt tension, but the second batch should be just right for the belts I'm using. It's very easy to adapt these brackets for longer or shorter belts. I'll probably make different sizes anyways as soon as the "standard" size is finished.

The first sketch here has a bad gantry sizing anyways - it can move further than necessary in the x and y directions. There is no use in being able to move the hotend beyond the edges of the build platform... (of course, a few millimeters more is good. But I have about 1-3cm surplus just for nothing.

I did this because I had already ordered all the expensive precision shafts from Misumi and then redesigned the whole frame. Now the first prototype will be a bit off in dimensions, but it should work well. And it'll be easy to adjust the spacing once I can re-order a new set entirely.

Oh and by the way, I "should" have taken into account all of the aluminum profiles' length tolerances (+-0.5 mm !) so that there won't be any problems with that. There will be a very small error introduced by that (the 90° angles will be slightly off), but that should be negligible.

 

Share this post


Link to post
Share on other sites
Posted · Ultimaker - Black Edition

I see you can just replace them... you could also cut them in 2 and use precice spacers between each to get good alignment.

do you have any good link to learn about tolerances & material quality etc... was looking at link below, how to compare with your misumi, and the quality of f.e the UM2 shafts ?

http://www.dold-mechatronik.de/10mm-h6

http://www.misumi-europe.com/en/online-shop/proxy/precision-linear-shafts

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!