donmilne

The problem with any question of this sort that is that everyone will recommend the supplier or product they're familiar with. Few will have direct experience of many different suppliers and many different regions. For what it's worth, I was very happy with the service and manufacturing quality from ColorFabb (e.g. a minor problem with my order was quickly corrected). As to it's printing performance, I'm still experimenting to find settings that work best with the ColorFabb formula. UM white works great for me, right off! I keep going back to it for critical prints. However, like the OP, I'm less than impressed by UM customer service.

I also know from recent experience that you can export models in Wavefront .OBJ format, without the need for third party plugins (Pro version, I don't know if the free version does). Cura supports OBJ too. p.s. I hope you're aware that while Sketchup makes great looking visualizations, they are not necessarily suitable for 3D printing. It isn't just a matter of file format, it's a question of the file (in whatever storage format) describing a watertight solid model.

Um. Just to correct a small matter of terminology, the "Atomic method" refers to a method of cleaning the nozzle by pushing a short length of filament in there, allowing it to melt and then cool, and then pulling it out - taking captured dirt out with it. Removing the tube is just... removing the tube, though that is of course a necessary first step before you can use Atomic's method for cleaning the nozzle.

So when did this change from PID to bang/bang happen? And is there still a build switch defined in the source code? [Edit] Actually, belay those questions: it's all in the other thread.

p.s. I'm surprised that turning the heaters on gently is more of an EMF problem than turning it 100% off to 100% on.

Looking at the three cases in the last picture, I see a huge difference between the first two cases, but I'm not convinced I see any meaningful differences caused by the new nut. I mean, I do see some differences, but nothing that doesn't look minor and random as between any two prints.

"Memory fragmentation limits in Windows"? That's a new one on me. Are you talking about some feature of your C++ lib?

In what way were the cylinders incorrect?

So what exactly was the problem? Was it size, or something else?

Cura has been known to have trouble loading very large models. Does it do the same thing no matter what order you load the models? (implies the two summed together are too large), or is one specific model the problem?

Nobody can tell you that a UM2 won't give you any of those problems, that would be asking to prove a negative. All I can tell you is that I've had none of the problems you mention with my UM2 except for underextrusion, which is greatly improved by switching to Robert's feeder, and doing tests on the filament to see what temperature it likes best.

That was the same bad assumption I made: the software doesn't cause the feeder stepper to skip back, that's entirely the stepper motor itself. It hits its current limit which means it simply doesn't have the torque to complete the step, when the active poles changes it flips to the nearest stable position - which looks like a backwards step. Basically, unless someone in the know contradicts me, my understanding is that there was a deliberate design decision to give the UM2 a weaker feeder motor than the UM1 had, because the UM1 was perceived to have a problematic feeder mechanism - the problem being that when the filament stopped moving the motor ground a divot into it, causing the print to fail. Basically, I think this might have been a mistake. Print failures due to underextrusion are no more useful than print failures due to grinding. In hindsight a better solution might be to keep the stronger motor but distribute the load on the filament, e.g. with two drive cogs. Of course we don't want to make the feeder so strong that it can actually damage the hotend or the bowden tube.

It would be nice to have a clearer statement of the setup differences between the two printers.

Actually there is no "of course" regarding grinding. The UM2 isn't supposed to grind, it is supposed to skip back instead. However sometimes it does grind, and the significance is that there is nothing you can then do except abort the print and cut off the bad piece of filament. Perhaps you thought that grinding was some kind of generic term. It isn't. It refers to when the knurled drive on the feeder motor has ground a curved divot out of the filament. The knurled drive therefore no longer pushes the filament and the print stalls completely. It's a bad situation since the hot end can overheat - in addition to wasting filament. As I understand it the UM2 was designed with a weaker motor that the UM1, so it theory it doesn't have the power to grind, instead it will fail to turn and instead skips back to the last stable position. So I think we do need a proper answer as to which failure more you get.

I'm still using XP, very happy with features, driver support and stability. Forced to upgrade? Pah! (just remove the tick from the auto-update checkbox).

+1 to what Pm_dude said, plus I'd say to use 100% fill. You want it doing the same thing on every layer so that the only variable is your tweaks. I would start off fairly light then tighten until you can just see indentations being pressed into the filament as it feeds. Then tighten a quarter turn at a time until you like the printed result. I've found that I can tell by the knurled indentations on the filament if it's being squeezed the right amount.

I have a feeling that "one of the better CAD programs" may be beyond LePaul's budget. For fun, here's a parametric OpenSCAD script for a shoebox :- wall_thick = 2; x_size = 200; // external dims y_size = 100; z_size = 110; difference() { translate([-wall_thick,-wall_thick,-wall_thick]) cube([x_size,y_size,z_size]); cube([x_size-wall_thick*2,y_size-wall_thick*2,z_size-wall_thick*2]); }

Show me a fan that can blow without sucking!

I think we need to get some idea of the settings which were used for this print. E.g. print speed and temperature, and whether the feeder was grinding or skipping (making the chock sound).

IMHO Solid Print is making it sound harder than it really is. E.g. material? Not an issue - for beginners it'll always be PLA. The finesse stuff can be learned as you go along. What really matters is (1) is what kind of object you intend to print - e.g. arty curvy stuff (faces?, horses?), or engineering shapes (boxes, cylinders). And also (2) what your background is, e.g. do you have any programming experience? or CAD experience? Personally, I have lots of programming and engineering experience, but my artistic qualities are sadly lacking. I have tried many 3D design packages, but the only ones that struck a chord with me were OpenSCAD - which has a scripted approach for creating engineering type shapes by combining simple solids, and also SketchUp, which I love for woodworking plans but unfortunately while the image looks great it's hard work to create watertight models which you need for 3D printing. You can create watertight shapes with SketchUp but the software itself doesn't enforce it, so you have to be quite disciplined yourself. I believe there are third party plugins that can test a SketchUp model for validity. I went from 0 experience with any kind of 3D design software to creating my own model within a couple of hours of encountering OpenSCAD. I thoroughly recommend that you start with that (it's also free).

All fans suck, it's a vital part of their function... :-)

I can't say that the price looks very appealing to me. $1500 + shipping + customs seems like a lot, I'm not sure I'd want to take the QA risk for that. On the other hand, as a source of spare parts it might have value, UM customer service and spare part pricing being what they are.

I don't think so, I think you need two separate accounts. I recently ordered spares for my UM2 from the online shop and I seem to recall I had to register for an account. It would make sense, since I wouldn't expect forum membership and online shopping to operate at the same security levels.

It's actually "Sebastian's one" that I use, but I don't regard it as a separate design. I see it as Robert's design - with an additional pulley to guide the filament in. Just about all the components are exchangeable.

At first glance this looks like Robert's feeder with fewer curves, though on closer inspection I see that you have a separate backplate. I just read your blog about this and it seems that your design goal was that you should never have to remove the motor to service the feeder mechanism. I approve of that goal, but as far as I know it's already true of Robert's design too? E.g. counting the M3 screws clockwise from top right, as far as I know you never have a reason to remove screws 1 and 2, therefore the motor can never fall off.