polymorph

Well, I feel like a fool. I bought a one pound can of the same green grease that came with my Ultimaker. I have applied it to the rotating rods (with the sintered brass bushings) and on the Acme thread Z axis. I have not printed in a few months, now I find that I can barely move the X and Y axis by hand. Touching the rods, the grease has become a sticky coating. I'm going to clean it off and put some dripless oil on it. I think it may have reacted with the oil in the sintered brass, because it has not done this on the Z axis threaded rod nor on the linear bearings, which I had very lightly greased.

Yeah, there are definitely better belts out there. Not my field of expertise. Anyone have a link to a good website or webinar or something similar where I can learn more about the differences?

I know I am not willing to give up the speed. I'm still in the process of tuning mine up and making improvements. I have Bertho's ball bearing pressure plate upgrade and have turned my speed up to 100mm/sec. It flies! Had some of OlyMEGA over last weekend, they are all familiar with the Prusa Mendel machines and were very impressed with the Ultimaker's speed. At some point I am going to make this mod, too, and get rid of the short belts. I can hear a ticking sound in the rear left top corner, I think it might be the short belt riding up on the gear pulley teeth and snapping back down.

That is a ballscrew and nut, all right!

Ah! Yes, that is precisely the problem. You may have been looking at Acme thread, also, not ballscrews. Usually just the nut for a ballscrew is $35 or more.

For speed, low pitch is better. A two-start 5tpi would be better than a 12tpi single-start, or worse allthread at 18 or 24tpi. Right now, a single revolution of the stepper moves it, what, a few inches? I don't have my Ultimaker in front of me so I can't measure diameter/circumference. So already a 5tpi ballscrew would require the stepper to move 5 to 10 times as fast for the same speed. Might have to upgrade the steppers, drivers, and power supply for that. Ballscrews are spendy... $35 is pretty cheap for that length of ballscrew and nut.

We could replace the long belts with something less stretchy. There are higher quality toothed belts with less give, I'm just not sure where to find them. Ballscrews or acme thread could replace the long belts, but it would take two for each axis. It would change things a bit in terms of the driver PCB, although it could be done as an add-on. I think it would be a rather significant change. Speed is an issue, so I don't see hardware store allthread being a solution, however I've not run the math.

The hobbed gear is now available from Portland, OR: http://store.trinitylabs.com/hobbed-pulley-by-blddk/ Hobbed bar shaft, may fit Ultimaker but ships from somewhere in Europe so shipping may kill me. He also makes Makerbot-style hobbed pulleys, with a variety of hole sizes: http://shop.arcol.hu/item/hyena

Hm... what the heck did I use, then? No sarcasm, I believe you. I don't recall what I used.

I bought TurboCAD 18 Deluxe 2D/3D last year, then I moved on short notice. I've finally gotten to play with it a bit with my Ultimaker in mind. I learned AutoCAD (aging student, went back to school about 4 years ago) but only 2D and have not had any opportunity to play with it after my one year free student licensed version ran out. So... there are some cool things missing from the <$100 Deluxe, but it does do a lot. I'm still trying to figure out the ins and outs. It can export as SketchUp SKP files, then from there I export as STL. The Pro version will export directly as STL but costs quite a lot more. But I'd be happy with that workflow, once I figure out what I'm doing in TurboCAD.

It looks like Makerbot is dropping all their parts for people building/upgrading their own 3D printers. Everything but a complete Mk7 head and one other item is out of stock, and is findable only via Google. So I'm hoping someone else starts making those drive pulleys. There was an IndieGoGo project that ended in June, he calls them "Hyena". Also sells a shaft threaded on both ends with the grooved drive area cut into it, looks made for Ultimaker. Haven't checked the sizes.

Regarding reversing the stepper - swap the wires between the A and B drive coils, it runs backwards. Or just reverse the two wires of one of the drive coils. Again, it reverses. http://www.nmbtc.com/step-motors/engine ... uence.html I see someone found that their RepRap feeder motor reversed just by reversing the plug. A bit risky if you don't check and confirm the wiring first. http://www.nmbtc.com/step-motors/engine ... uence.html

I have found that simply heating it up to 220 and leaving it there for a half hour or so, all the PLA runs out the end. Then it comes apart easily while hot, and PLA dissolves in Acetone, or as suggested wipes up with a Qtip while still hot.

What did you find out? Did you solve the problem? Have you been cleaning out the knurling on the drive bolt regularly? Get a stiff steel wire brush and scrub it out. I have found it is a very fine line between too tight and not tight enough on the feeder. Too tight, it grinds into the plastic pressure plate too hard and the teeth in the bolt grind a flat in the filament. Too loose, it also grinds a flat in the filament. Once it starts grinding, it fills the knurling and it is more likely to slip and grind in again. Unfortunately, as filament diameter changes, the screw settings must change. But it'll stay stuck on the flat part ground out unless you also push the filament in -really- hard while it is feeding, for long enough to get past the flat spot. I printed an upgrade that replaces the plastic pressure plate with one that includes a ball bearing. However, the same problem is there - no spring pressure, so even slight changes in filament diameter mess it up. The ball bearing just allows you to set the pressure even higher. But I'm an hour into a 2.5 hour print job, I don't want to quit and start over, so I'm riding herd on it. The "knurling" on the bolt is just too sharp. It tends to grind into the filament. Then if you don't immediately clean out the knurling, it begins slipping and grinding much more often. As far as variations, I'm still using the roll of white that shipped with my Ultimaker. I also think having only one point of contact with the drive to the filament is a problem. A lot of stress on the plastic right there. I like the half-round non-sharp feeder wheel someone was making. But I think rather than a non-drive wheel pressing the filament into it, I'd like to see -two- drive wheels pressed together. In fact, I'd like to see a drive with four wheels - two sets of two drive wheels. Perhaps the first drive wheels have a clutch and attempt to spin a little faster. Or just a DC drive motor, the amount of current regulated to set up a pre-tension pushing the filament into the stepper-driven drive wheels. Like what happens when I grab the filament and push it into the feeder mechanism.

My laptop is suffering from Windows rot. My netbook connected without problems (cross finger, knock on wood) and printed a new ball bearing pressure plate. Next I think I'll print both of the parts you mention so I can use the 6mm/4mm tubing I bought. I also discovered that my temp was far too low (210C) and now have it at 230C. I did find that I need to print the outline 6 times to prime it properly, as it tends to dribble when just sitting there hot before the print. I also bought a digital micrometer good down to one micrometer, it works better for this than my digital caliper to measure the filament. Also, the pressure on the feed bolt is somewhat sensitive, in that too much causes too much friction on the pressure plate, so there is a relatively narrow range of pressure that is just right. I have other ideas to talk about but I should not take this too far off topic.

I could not remove the tubing from the fitting on the motor end, so with a brand new single edge razor blade I trimmed off the tapered part. Then as suggested, I put a slight internal chamfer in the end of the tubing where it pushes into the brass, but using a countersink bit because it gives a much cleaner finish than a drill bit. Now it moves so smoothly that only a fairly slight push by hand with the head at 210 will feed plastic easily. I trimmed the end of the PLA filament with a flush cutter. If you use regular wire cutters, it will mush out the end into a chisel shape with wide ends, and you may experience the symptoms you are getting. Sigh... but now I have software problems. I'm using Cura, which worked before, but now it is extremely finicky about connecting to the com port, or it freezes while trying to send the Gcode, as soon as I try to set the idle temp or move any of the steppers. But that's a problem for another thread.

It was slipping, or I'd not have turned it up that high. I agree that it is counterproductive! The tapering shown in the link is more of a countersink, something I think I'll do after trimming the end. I'm hoping that fixing the taper thing and printing a ball bearing pressure bearing will reduce the force required. Perhaps I need to turn the temperature up slightly, I had it at 210 but it will melt the filament quicker at a slightly higher temperature.

Hm. Forum didn't post my message asking for advice on removing the tubing, I didn't notice. Just as well, figured it out. Partly disassembled the head. Took the long bolts out, heated it up, head pulled right off the tubing. Took the blue clip from the compression fitting. Holding the compression fitting down, but the tubing will not pull out. I'm afraid to use too much force for fear of damaging something. The compression fitting dimpled the tubing, and the filament still inside had partly melted, filling it so the still expanded portion below the compression fitting could not compress. Got both ends of the tubing free, pushed the filament out rather than pulling it back. A bit more effort and the tubing came out of the compression fitting. I had to pull -really- -hard- to pull the filament out of the tubing. That does not seem right. Checking a few places on the filament, I find it is oblong so it is up to 3.05mm diameter in places. I'm sure if I check more thoroughly, it is larger in other places. Making the tubing that tight a fit seems like a mistake. With 4mm ID, no tapering of one end would be necessary. I didn't have any problems inserting it into the untapered end, anyway. I can clearly see, now that I know to look for it, that the inside of the blue-taped end of the tubing is tapered inside. Looking at the compression fitting on the Bowden feeder end, I don't know how I'm going to get that out. It is meant to be a one-time, permanent connection. I may leave it where it is at, and trim the end at the heater head beyond the taper. I don't understand why it would be such a tight fit. Reinserting the previously driven filament, I get it about 1 ft (sorry, 300mm) inside and I can barely push any more by hand. Are only a few of us having a problem? Did they recently change tubing? I got mine a few months ago. I feel like we need a 3 piece driver using curved pulleys like on the MakerBot driver, so the filament is kept mostly round and it doesn't have to dig in nearly as much. I think some of the friction is from it being out of round, and some is from the very rough, toothed surface against the inside of the tubing. Without the back pressure created by me putting the tapered end at the wrong end, less pressure should be required. The first thing I think I'll print is that pressure plate with a ballbearing holder, that should also lessen friction considerably. All meaning the filament should have a lot less flattening. Then later I want to make the Bowden Feeder replacement that uses MakerBot's half-round pulley driver.

The blue end has been drilled wider, so it's easier to stick the filament in it from the extruder side. Putting this at the hotend side will create plugs.Sigh... so I've heard. :'/ I'll keep that in mind when I reverse it, and rather than trim it perhaps I'll push something tapered into it to rewiden it.

I wonder what difference the end with the blue tape makes. Well, this is progress. Tonight I'll heat it up and take the head apart. Cutting off a few mm from each end shouldn't cause it to be too short. I do have the other tube on the way, at least. My big rush is that this weekend is a Maker Faire in Seattle, WA and our club, OlyMEGA has a big space there. Fortunately I'm not the only one displaying something, but I would like to have it printing. I was hoping to get my little CNC machine working, too, but it looks like this may take all my time before the faire.

There is that step in the instructions where it says to push the tubing so it sticks out 8mm. Then after you pull it back, it says again emphatically that it must stick out 8mm. But pulling it back in the plastic compression fitting slides it back 2mm. So I pushed it out another 2mm, so it stick out 8mm -after- taking into account the pullback in the compression fitting. Was that wrong? Have I compressed the end of the tubing so it constricts too much? http://wiki.ultimaker.com/Ultimaker_rev ... usion_head Sigh... looking over it again, I see it does -not- say 8mm after pulling it back. I also see I mistakenly put the end -with- the blue tape in that end. Now if only I can get it apart to start over.

I'm trying to get the filament out to start over, so I can print that new friction plate with a ball bearing. However, I can't get the filament to come out. I've even turned the heat up to 225C and let it sit for an hour to get it warmed up all the way through. I pulled with pliers 'til it snapped off. From the way the tubing moves, it is jammed up in the head. Any suggestions? BTW, I'm AlienRelics and Polymorph. I didn't mean to log in twice... I forgot I'd already created an account and made another.

I'm hoping I don't get a nasty surprise, McMaster-Carr does not tell you me what the shipping will be. I also ordered two ball bearings, 10-6-3 for the feeder upgrade. So I've got an extra. I ordered four feet of each the three tubing. I'm not sure how long the Bowden tube must be as I'm not home now to measure it. What I'm getting at is that I'd be happy to help you once I get the tubing and bearings. Later I think I might build this upgrade to the feeder. I like the increased contact area of the MakerBot driver: http://www.thingiverse.com/thing:19551 Of course, the key is to make another one right after the first one is working, so as to avoid the dilemna I'm in now where I cannot make a part I need in order to make the part I need.

I ordered a few types just in case: 1 4 ft. 5733K54 Crack-Resistant Tubing Made w/ Teflon® ® PFA Metric, 4mm ID, 6mm OD, 1mm Wall Thickness, Clear today $3.15 ft. 12.60 2 4 ft. 5239K12 Extreme-Temp Tubing Made with Teflon® PTFE 3/16" ID, 1/4" OD, 1/32" Wall, Semi-Clear White today $1.69 ft. 6.76 3 4 ft. 52335K34 Metric Extreme-Temp Tubing Made with PTFE 4 mm ID, 6 mm OD, 1 mm Wall, Semi-Clear White today $2.48 ft. 9.92 The PTFE specified that it has a very smooth finish inside, so I thought I'd try it, too.

Thanks, I am going to order some of this. I think I'm also going to try printing the Thingiverse mod to the Bowden pressure plate that adds a ball bearing where it presses on the filament. http://www.thingiverse.com/thing:21674 I had forgotten to mention that my filament is the 3.0mm (actually about 2.70mm) white that came with my Ultimaker. I was -very- impressed with the finish on the side of the test cube just before it stopped feeding.