How serious are the extruder problems?

[armstrom 0]

After seeing the print quality people have been able to achieve with the ultimaker I've become very interested in purchasing a kit.

However, after reading the forums I'm a bit put-off by the number of problem reports I'm seeing related the the extruder system. I'm not seeing any clear indication of what the root problem is. Some people claim it's the knurled screw, or a poorly assembled interface between the tube and the hot end... or one of a number of other theories.

So.. what's the current state of things? If I order a kit today should I expect to fight with extruder problems or are they isolated problems? I understand that being a kit implies there is a great deal of variability in the final product due to assembly but I would like to know that I will be able to achieve results similar to those I see on the ultimaker site without having a huge failure rate due to extruder problems.

Also, I understand that a heated bed is in the works. I assume this is something that will integrate directly with the electronics of currently shipping units (it seems to already have outputs for a 12V heater and an input to read the temperature).

Thanks!

-Matt

[Daid 306]

If you push the machine too hard, the extruder drive mechanism is the first part that looks like it fails. However, I think this is related to the hotend, not the extruder at all. Comparing the amount of kits in the field and the amount of problems, I do not think it's that bad.

I say, things are good. The machine works really well for me. I'm just not pushing it speed wise. And I had 1 blockage so far, which was cased by me retracting a blob of hot filament combined with not having the hotend properly assembled.

[armstrom 0]

Thanks for the reply. It looks like there is at least one redesigned extruder feed system. I belong to a hackerspace and most of the members there have one of the reprap models. I'm still trying to figure out if I can justify the extra cost over one of the other models. I'm not a fan of the build platform moving in two dimensions but it's hard to argue with the price difference... If I could be sure the ultimaker would be reliable and also give the type of high quality results I've seen online it would be easier to justify. But if I'm constantly pulling my hair out trying to get a good print I'll feel pretty bad :(

Also... is it simply not possible to retract the filament to avoid hairy prints? I understand this is not currently supported but it isn't clear to me if it's a limitation of the firmware or a fundamental hardware design limitation.

—Matt

[Daid 306]

I've been reliably printing out stuff for a few months now. And my quality is only going up. I am promoting myself here, but Cura does wonders. It's just easier to use, giving less headache.

Retraction with the bowden tube is harder, but not impossible. I've only been playing with retraction a bit, but with my last modifications in Cura, retraction starts to do it's job. I've had some virtually stringless prints. However, it requires a low temperature, which ultimately lowers your printing speed. And it still generates some imperfections. So it's a bit of a tradeoff.

As I understood, RepRaps are fun. If you like tinkering with the machine. While the ultimaker is more for you if you just want to print stuff. A reprap is cheaper. However, how much is your time worth when you want to print something? The Ultimaker took me 8 hours from unboxing to first print. Virtual zero calibration after that (especially now with volumetric printing). For RepRap I always think about this youtube movie:

 

31 days to get a blob!

Not sure how the PrintrBot compares to everything (I hope to find out soon)

[mm_build 1]

I also use a hackerspace, and dare I say the reprap ppl are slightly jealous of my ultimaker. I was up and running within a week (some teething problems), while the rep rap people took years to get to where they are... I'm printing at twice the speed and half the resolution. There are also some Makerbot people and... well let's just say they look like this ->

The extruder AND the bowden/hotend connection are the weak parts of the Ultimaker design, but many people have been taking steps to making them better. It's important to realize that the ultimaker is just as open source and modifiable / hackable as any reprap design. For the amount of "hacking" you would to do get a reprap up and running, there is far less trouble to upgrade the ultimaker's extruder with whatever design you have in mind.

Also, I am sure the ultimaker people are keeping an eye on what people are saying and doing, it's only a matter of time before they unveil any number of boot-strap modifications and upgrades. The community is getting larger as well, (safety in numbers). For the record I have had very little problems with my extruder or hot end. The hot end can be finicky, especially if you like to disassemble and reassemble it. But it is nothing that is insurmountable. The extruder is a pretty basic deign, but it "works" for the most part.

[thomix 0]

Don't worry too much about the extruder, just don't expect to be printing at the insane speeds some of us seem to achieve I started at 100 mm/s and although some very small prints came out, its just too demanding. Turning down printing speed solved all my problems (mostly extruder); I've upgraded my extruder to prevent slipping, but now other problems pop up. Patience is the key!