Throw away your short belts - direct drive.

[chopmeister 0]

No bending, flexing or whatever. Solid as a brick.

 

Haha, glad to hear that, that was the purpose! Do add the print on the YM page if you don't mind, so people know it works. I don't have a decent pic of this model, I use a previous iteration on my printer which is not as pretty as this one.

(and I must say it does look really nice on your printer!)

 

[mbartels 0]

Haha, glad to hear that, that was the purpose! Do add the print on the YM page if you don't mind, so people know it works. I don't have a decent pic of this model, I use a previous iteration on my printer which is not as pretty as this one.

(and I must say it does look really nice on your printer!)

 

Uploaded the image but it's not showing. Do you need to authorize it in some way?...

aaaanyway. i'm at work and can't stop thinking about that little gap. Need to fix it as soon as i get home

Does Cura automatically stop if the machine settings are filled in right?

 

[chopmeister 0]

Funny, it was up there for a moment, I saw it, and now it's gone with a 404 error. ?!?

As for the endstops, that's not about Cura per se, but about the firmware. If the travel length is set up right in the firmware, it should work as normal.

 

[mbartels 0]

Well, i'll try again when at home.

Built the printer and upgrade firmware on first Cura start, so it's everything alright i guess. I didn't alter anything.

 

[chopmeister 0]

That should work, I have no clue if software endstops are turned on in the default firmware though, somebody might know more about it, I don't use the firmware from Cura.

A simple way to try is to start the printer and home it, then move slowly towards the end to see if it will stop with the endstops removed. If it does, you're good. If it doesn't it's an easy fix.

 

[zoev89 73]

I also upgraded to direct drive. I used nick his mount and mirrored it in Cura so I can mount it on the left side. I don't see the problems with the nick mount that the motor wobble. Yes if I press on the motor the mount flexes but when the printer is running the is no movement in the mount. Used abs with 25% infill. I used the Marlin software and my actual printing area is no 210x210. As chopmeister said I removed the back limit switch and let software do it. I bought new axis at conrad. I have mounted the pullies the other way around and that gave me the extra room.

Here you see also that the pulllies are the other way around then default:

 

[pigplastique 19]

Hi Mischiminator,

I used this one http://www.conrad.de/ce/de/product/237205/Silberstahl-Welle-500-mm-8-mm?queryFromSuggest=true.%20Worked%20well%20for%20me%20and%20not%20really%20expensive..

You might only need one, because you could use the longer one from the printer for the other axis.

 

[pigplastique 19]

just by hand with an ironsaw. But after I had to drawfile the edges a bit. The rod seems to be slightly to thick an the beginning ( was a bit hard to get it through the bearings ) but after oiling it and moving the printhead a few times around, it worked really fine...

I did the mod nearly one year ago and I never regreted it !

 

[duesentrieb 0]

Did this mod some days ago. Works awesome, improved print quality and made the machine more reliable (no short belts loosening over the time and making holes oval). I used Nick´s corner which is absolutely great and fits perfect (Thanks, Nick!). I did not use longer rods, but made some small blocks which moved the ball bearings more into the middle. Just drew sth. up in 5 mins which is like the mod linked somewhere in this thread. I combined this with Astrosyn dampers to reduce the noise level significantly and Chopmeisters Twister Blocks (Well done, dude!). After improvising a heated chamber ABS prints also come out great. It´s not an Ultimaker Original anymore… But I love it and the print quality is better than ever. Also printed out a new small drive gear for the extruder because I installed an Astrosyn damper on the extruder motor also. The small gear looks perfect. Didn´t know that an Ultimaker can make such detailed prints. You can see the small polygons if you have a very close look at it.

 

[duesentrieb 0]

By the way no woobling with Nicks mount or anything. Perfect as it is. Should have mirrored it, but anyway. The twister blocks are also great, easy to print, easy to install and the hole gantry system seems to be more stable. Had some problems with the reptar blocks, before.

 

[Titus 170]

Didn't the dampers introduce some play in your machine? That's what they did to my UM original(not direct drive)

 

[brendon-schenecker 0]

I have not noticed anyone installing this on UM2. I assume the improvements would be comparable? Will the same parts work?

 

[zoev89 73]

I would expect that it is also possible on the UM2. Order some length of rod and cut it to the right length is not the problem. You will have to look into the motor mount that is used for the UMO. It very likely needs some modification before it fits on the UM2. That is the pioneer work that needs to be done. Can't say how difficult it is but given the fact that I will go to the meeting on Monday I can have a look at the UM2 design. My UMO has this modification.

 

[Dim3nsioneer 557]

There is one major difference between the belts on the UMO and on the UM2: the first ones are of the type MXL and the second ones of the type GT2 (trapezoidal profile vs. half-round profile). Backlash is significantly smaller for the GT2 belts. Thus, direct drive isn't really necessary on the UM2. Furthermore, tightening the belts is easier and better defined on the UM2 due to special distance holder parts for the motors and integrated belt tensioners in the xy-blocks.

[Bolt 0]

Sorry to dig this old thread out but I've got a question. Hope you guys can help me. I've got an UM O that is modified here and there, and now I finally want to make this mod.

My question is regarding the couplers: Which couplers do I have to use? I always see flexible couplers, but why did nobody try star couplers or even rigid couplers with this mod?

Let's assume the motors and axes are nearly perflectly upright and in the right angle to each other, wouldn't a rigid coupler eliminate ringing and backlash even more?

[Dim3nsioneer 557]

Theoretically yes. Practically I have no backlash problems on my direct drive UMO with flexible couplings. So I stick with 'never change a running system'...

[andywalter 7]

Hi everyone, just thought I'd post what I've done to my Ultimaker Original as far as the x/y drive is concerned. The whole x-y system is very rubbery, so initially I ditched the 2 short belts and fitted a direct-drive using 2 Oldham couplings I made. This needed one new 8mm shaft - I was able to re-use one of the 2 originals as they're slightly different lengths. Better, but not good enough for me. So I've gone to a direct-drive using a high helix-angle rolled stainless-steel screw, 4 of these, plus 2 plastic nuts on each leadscrew which are carefully tightened against each other to eliminate backlash without introducing too much friction.

Leadscrews are part number SPSS11/40 x 300mm long, and the plastic nuts are SPN11/40POM

and you can see these on this web-page:

http://www.abssac.co.uk/p/High+Helix+Lead+Screws/70/#.VqKnPFK-BGF

Warning: these are NOT cheap! the screws are around £14+vat each, not too bad, but the plastic screws cost an arm and a leg each at £27 each !!! So you're looking at around £325 for this lot, and that's before you add-in any machining, 2 more Nema 17 motors, etc.

I have my own lathe & mill so did the necessary shaft-turning etc myself. I'm posting 3 pics here.

1st shows my UM - has a home-made heated baseplate in 12.5mm aluminium, 2x40-watt heating elements controlled by K-type thermocouple system in black box on RHS, and at the back right you can just see 2 white gears on my custom filament feeder which uses 2 clamp rollers (one on each of the white gears) so both rollers are powered, and there's never any filament grinding whatsoever. Works beautifully. The snake-like grey ABS flexy-cable protector at the back takes power to the HBP. You can also just see the aluminium arm supporting the HBP underneath; the originals were those 4 wood arms which sandwiched two long vertical bearings - I've kept the innermost 2 wood bits, but replaced the outers with carefully machined replicas which stops the HBP bouncing around at the front edge.

2nd image shows a closeup of the motor coupled to shaft using Oldham coupling. Each shaft has 2 bearings, the same as used on skateboards, with 8mm i.d. & 22m o.d. These sit in recesses in the angle-steel brackets.

3rd image (a bit blurry, sorry) shows two black plastic nuts back-to-back on the leadscrew, with a short angle-aluminium strip attaching that to the wooden block holding the 6mm shafts through the nozzle bit.

3 of the 4 original 8-mm shafts going through the wooden blocks have gone completely; I've retained the x-axis (left <-> right) at the front of the UM, which you can't see. So the vertical height of the nozzle is controlled by the x-axis leadscrew at the back of the UM, and the original 8-mm shaft at the front. It's a bit klugey at the mo' and I plan to improve this by eliminating all the wooden blocks, but at the mo it works well.

A few points: the helix on these screws matches the belt-drive pitch exactly, so there's absolutely no change to any software settings at all. One turn moves nuts 40mm. The two original motors are on one axis (Y I think), and 2 almost-identical ones are on the other axis. I've wired these in series, so there's the same current passing through the step-motor driver chips, but because there's now approx twice the resistance & twice the inductance per phase, I can expect a slower current rise-time in each (pair of series-connected) windings. OTOH I now have 2 motors so a bit more torque to play with. In practice it seems to work fine - I mostly print at 50mm/sec & traverse at 100. Oldham couplings with delrin inserts are used - these are a lot more rigid torsionally than the spiral-helix-aluminium flexi-connectors you see in places, and more rigid than the spider coupling shown in previous append.

What are the results like, you ask: in a word, far, far better than I ever had before. Tomorrow I will post some closeups of test-shapes (featured in Make magazine) but must go now - it's late!  Andy.

Edited January 23, 2016 by Guest

[Dim3nsioneer 557]

Great mod! I once wanted to do the same thing on my UMO in order to further reduce backlash. But then I postponed it and finally decided backlash was small enough. But it's great to see it works. This might be something for a really big machine...

Have you tried yet to go faster than 100mm/s for travel moves?

[andywalter 7]

...Have you tried yet to go faster than 100mm/s for travel moves?

No, and I'm not that bothered to do so. Does it save that much time on a print? I reckon most of my machine's time is laying down plastic at speed=50. I can do a test case if you like - is there some way for us to communicate directly via this site and you send me an STL? If not I could post my email addr here.

Meanwhile, I've taken some close-ups of a test case; http://www.thingiverse.com/thing:533472/#files and you can download the STLs.

Make magazine (Vol 42, Dec 2014/Jan 2015) tested a lot of £D printers; The Ultimaker Original+ scored 3/5 on the negative_space_tolerance_test.

Make mag reviewed more 3D printers in Vol 48 Dec2015/Jan2016, and on the negative_space_tolerance_test the Ultimaker 2 Extended & 2 Go models both scored 4/5.

Very few printers managed 5/5 on this test - it's one of the harder ones I reckon! Rostock Max V2, and the Up Box,  managed 5/5, so I reckon I'm up there with the latest UMs at the very least. I don't know the precise parameters Make used - i.e. layer size, speed, fill percentage etc, so it's hard to know exactly how good/bad things are.

On my original UM with drive belts I could only press out 1 of the 5 ABS plugs.

On my latest direct-drive modded UMO I can now press out all 5.

The negative_space_tolerance_test object is a block 54mm long with 5 holes in, and each hole has a plug which in theory is loose. The holes are about 7.5mm dia and the 5 plugs have gaps of 0.2mm, 0.3, 0.4, 0.5, 0.6 all round. The idea is to see how many of the 5 plugs you can press out with just your fingers.

Looking at these photos, the 2 runs aren't exactly comparable - the old ones were with a layer-height of 0.2mm, while my latest used 0.1mm. So I'll do a 0.2 mm in a bit, but it's worth posting what I have so far. I'm also not sure what the old fill-percentage was, but current one is 100%.

____________________________________________________________________

UM Original with belt-drive. 0.2mm layer height. Note wavy edges.

____________________________________________________________________

UMO with direct drive. 0.1mm layer height, 100% fill. There's some ringing, making a "shadow" of the embedded numbers.

____________________________________________________________________

Belt-drive, this is the hole with 0.6mm clearance in. You can see the 0.5 clearance plug still in-situ - it snapped off as I tried pressing it! Despite a fair bit of light showing through, the 0.5 was well & truly stuck in.

____________________________________________________________________

Direct drive, this is the hole with 0.6mm clearance. It just looks a rounder hole.

The plug in the 0.5mm clearance hole above is a loose fit, only held in by a few whiskers.

____________________________________________________________________

Belt drive, top view of the 0.2 & 0.3mm clearance holes - a bit of light shows through but these plugs are not going to be shifted!!!

____________________________________________________________________

Direct-drive, top view of the 0.2 & 0.3mm plugs. Both plugs are a loose fit in the holes & can be freely rotated with your fingers.

Hope this gives you an idea of what this great little m/c can do now! Andy.

Edited January 24, 2016 by Guest

[Dim3nsioneer 557]

Faster travel move is maybe more important due to less oozing than for saving time.

I think the quality of your print may be improved further. It actually looks overextruded, so maybe you want to print at a lower temperature. And you may get rid of the ringing by reducing the acceleration to something like 1000-3000 mm/s2 and oiling the main axes on a standard configuration UMO.

I once made a backlash test, you can find the model here.

[andywalter 7]

Thanks for the backlash test shape - will give it a go. I assume it's all perfect squares.

I'm taking your advice re faster traverse reducing oozing, and 150 mm/sec seems to work ok. Have also reduced the feeder rate (by increasing the filament diameter I pretend I use).

These 2 seem to reduce the spiders web effect. Photos below are untouched objects with no clean-up yet.

I've done a couple more test objects - identical runs, except I've rotated the 2nd by 90 degrees so in effect I've swapped the axes over. In the first, the indentations forming the digits are done by the Y axis, & I show the opposite plain face which has a lot of ripples; these ripples do settle down after the X axis has traversed about 2.5 cm - just off the right side of the picture. I've removed a small amount of Y-axis backlash on my rhs nut pair, so it's better than the runs shown in previous append above.

__________________________________________________________________

digits formed by Y axis movements.

__________________________________________________________________

digits formed by X axis movements.

__________________________________________________________________

In the second object, the numbers are formed by the X axis moving, and the precision is better, with far less bouncing.

Running the nuts along the spiral, I can feel that the X axis is really nice & smooth with a uniform feel to it. The Y axis by contrast has some periodic tightening-up feeling, every 20mm of movement, i.e. each half-turn of the shaft. I'm now looking closely at my Oldham couplings, and I can see there's a bit of misalignment causing this. So I need to sort this axis, and when I have the Y as good as my X I'll be fairly happy. Andy.

[gareee 39]

Did Ultimaker ever add this upgrade to the printer themselves? Seems like they would/should have by now.

(New ultimaker 2+ owner here.)

[andywalter 7]

Did Ultimaker ever add this upgrade to the printer themselves?...

Not as far as I'm aware. But look closely at my append - these parts aren't cheap. Then you have to add the mfrs markup -say 100% ? Though it would not be too hard to mfr your own plastic nuts, moulded around a shaft - that would bring the cost down a lot. Andy

[atagunov 0]

 

Hey, @meduza, perhaps a stupid question: why did you decide to make the translucent side windows protrude so much? Why not just cover it with a single glass sheet? (Or use a solid piece of plywood in the first place for extra strength..)

[andywalter 7]

Am not Medusa, but here's my guess: I find that some parts like to lift off my heated base plate, typically things like the bottom corner of a box when I've built-up a couple of centimetres of wall height; the top layers contract, levering up the bottom. Using a raft can leave a large mess to be cleaned off large area like the bottom of my box, so instead what I often do is extend the bottom of the box by say 10mm with a thin plate, typically .4mm thick, all the way round to form a flange. Then after I've printed maybe 2mm of the box, and well before any lifting starts, I will put something like a steel ruler on top of the flange while the printing continues, and add some small plastic G-clamps or whatever, so that I really clamp the flange down onto the HBP and there's no way it's going to lift up. These clamps usually stick outside the frame of my printer. Maybe meduza's doing the same?

Edited June 20, 2016 by Guest