donmilne

I had an earlier result that looked much worse than that. So, I increased the resolution, increased shell thickness to 1.2mm and reduced the print speed to 40mm/s. The result was that the printer printed the body perfectly - no real blemishes at all, until it reached that flat top, then it instantly messed up, as you can see. That can't be a coincidence. Another thing I noticed was that the "air printing" at the seemed to me to be faster than I expected, but I don't see anything in the Cura settings that controls top layer speed similar to the bottom layer one. I also wonder if those sticky up ears might be confusing Cura, making it treat the top layer as... not the top layer. I'm thinking that it's trying to print the top shell too fast - the filament can't feed that fast, I've no doubt that when I remove the filament I'll find a gouge ground out of it. Any suggestions as to how I might kill off this problem? It's really a pain in the ass for it to work for 18 hours only to mess up in the last 5 minutes.

Now below is a picture of the result - I've actually been having this problem quite a lot recently - the printer does the job perfectly until it reaches the flat top, and then it messes up. Filament stops coming out, my UM2 is printing air.

Can anyone suggest what the problem is here? Below is an OpenSCAD rendering of a part I'm trying to make. It's a sleeve designed to slip over the standard UM2 spool holder and expand the diameter to one that fits the hub of other PLA filament I have. Inner_diam=53mm, outer_diam=74mm, height=90mm. Note also the retainer "ears" designed to stop the filament reel sliding off the adapter.

Yes, I noticed yesterday that their website is offline, which is ironic since my current project is a sleeve which fits over the UM2 spool holder to provide a better, smoother ride for the Spectrum reel. I guess you'll have to try one of the alternatives listed above. It'll be a shame if they folded already: I think I'll email them to check.

Everything is relative. In the near perfect silence on my computer room (I have a very quiet PC), the UM2 fan is the loudest thing running. This may be what the OP is talking about.

I ran into a problem with this feature yesterday. I was printing off IRobertL's replacement UM2 feeder, all parts at the same time. The UM2 printed each component separately as described above. However at one point I saw my whole print bed flexing, quite alarming! On closer inspection the y-axis bar was scraping the top of the feeder_v4_arm object while it printed the v4_feeder_body part that came after it. It's a testament to how well "brim+PVA" works that the tall component wasn't getting knocked over. I assume there's a setting somewhere to increase this clearance, but you might want to take a look at the defaults. My other suggestion is to print the shorter components first.

It's essentially a "skim coat" over the last layer, to reduce surface roughness. I think it would be an excellent tweak for Cura. Mind you, this might be one of those things that's easy for a human to do - convex hull of relevant outline, ignoring internal holes - but might be harder to automate and extend to shapes significantly more complicated than a square. I wonder if it wouldn't be easier to tackle the implied criticism of Cura's final layer pen path! E.g. try as far as possible to have a consistent fill direction.

Thanks, but I'd rather this thread didn't drift off into a general bed levelling procedure discussion - I think we've had that discussion before, and I was grateful for it then. Here I'd like to stick to the narrower discussion of how to make minor height corrections after you've done a first test print and seen what the results were. p.s. Thanks for the tip on how to add my printer to my profile.

That's quite clever, thank you.

I have a UM2. I don't see anything in my profile to indicate my printer. I'm afraid that the suggestions of "live" adjustments while printing don't appeal. Because the screws are on the underside of the bed I have trouble wrapping my head around whether a clockwise or aclockwise turn raises or lowers the bed. I prefer to have a direct software adjustment.

I've never consciously set any such feature, so if the behaviour changed then the default must now be different. I believe I do prefer the one-at-a-time approach. In the past I've printed (say) six copies at once, and if the filament jams halfway through then all six copies have to be junked. On the other hand, the things I've been printing recently are quite short. If they were tall and printed one at a time, I guess there would be a danger of the printhead running into a previous copy. Perhaps Cura has a test for this, and that's why the behaviour change.

Possible coincidence? I would check your cables.

Cura 14.6.1 + IRobertl's bugfix firmware + UM2 Over the last couple of days I've done two print jobs whereby I printed off two copies of an item at the same time (one gcode file). I was surprised to see my UM2 print one copy completely, before raising the bed again and printing the other copy. In the past it has printed layer N for all copies before moving to layer N+1, so all copies finished at the same time. Can someone confirm this new behaviour? And if so I'm curious as to what advantage it brings (except perhaps that can abort the print and waste less material when I see some problem in the object? Ditto if the material sticks or runs out).

I don't think think this feature exists already... Suppose I've just gone through the bed levelling exercise. I've done a test print and while I'm happy that the bed is level, I'm unhappy with the precise amount of "squish" in the first layer. E.g. the filament is getting smeared out too much, or else I see distinct cross hatching (not squished enough). Is there a way to just adjust the stored Z-zero up or down by a fine increment without repeating the whole levelling procedure - which will undoubtedly just get it slightly off again? If not, could such a feature be added to the firmware? I'm open to suggestions as to what the appropriate up/down increment would be.

The MSDS doesn't tell you everything - e.g. a PLA print can be quite rough and porous, so it could trap food particles which might harbor germs. IMHO it would all depend on what you wanted to make and how long you intended to keep using it.

With a name like Andrew White and your wording I assume you're in the UK? If yes, see my review of Spectrum Filaments. I've had good success with them, plus they're one of the few that are clear about the dimensions of the filament, i.e. 2.85mm and not 3mm. I hate to intentionally buy filament that even claims to be the wrong size, even when I know that in practise that isn't the case. Also it should be noted that Faberdashery I think doesn't come on a reel. I prefer a reel as I feel that buying short lengths results in a lot of waste.

Wow. I didn't even know that existed. Thanks for the link.

Luckily I bought my UM2 from a UK agent, so I didn't experience UM's awful customer service at that time. It was only when I tried to order additional filament from UM that I ran into a very similar experience as you describe. In fact, come to think of it, I'm still waiting for that order to be completed. Pretty disgraceful really. I don't think this is about growing pains, I suspect it's about having the wrong people in the job - people who know how to tinker with clever gadgets, but don't know how to run an efficient retail system. All it should take is to hire an experienced retail manager.

Did you try re-levelling the bed?

Buy your UM2 from iMakr, but I'd be very wary about buying filament from them - they will happily sell you whatever you order, not mentioning that it won't fit your printer (wrong spool size, or wrong filament diam). I've had good success with Spectrum filaments (see my review topic), others will have their own recommendations.

I got my UM2 from iMakr as well, and it was delivered on the promised day exactly. Frankly I think they're much more efficient as a retailer than Ultimaker themselves, so IMHO a few quid extra is worth it.

There's no need to apologise. That was just as aside: not even a complaint, more of a statement about my level of ignorance at the time. On the software being free... frankly, I can't imagine any alternative in a tool aimed at the domestic market. If I had been researching the market and learned that I have to pay e2000 for the printer, and then I have to pay another $xxx before it can actually do anything? And maybe another $yyy to get a design capability? I would think I was being ripped off and I'd have moved along to the next manufacturers website. Trotec can't tell you what's improved? No changelog? I wouldn't have high hopes in that case. Hopefully you have other options.

I can't say I'm very impressed by the multi-color printing examples. I'm pretty sure I've seen a YouTube video where a guy got exactly the same effect with a standard single filament printer, by staining sections of a single natural PLA filament and then feeding it into the printer. I have to say that I found even that trick a bit pointless - I guess I'm just not the arty type...

Even for the cheap ones it's an expensive investment, so I would be very sceptical about going for an unproven 3D printer. For me it was a tossup between MakerBot and Ultimaker, and in the end I decided that UM had better specs (e.g. it can do ABS) and better local support, e.g. with the Cura software being relatively mature and actively developed.

The UM2 itself is very easy to use. Sure, you can have an occasional problem with media getting stuck - as with any printer, but actually it's quite rare and anyone with eyes and ears and a bit of intuition can easily see where the problem is and correct it. IMHO, the UM2 is so good that you needn't even think about it. Your real problem is to find 3D design software that suits you and the kind of work you want to do, and that you can afford. The printer is a big expensive paperweight without that. See other threads for discussion of good candidates. And in case you have the same misapprehension that I had: the Cura software that goes with the printer is responsible for rendering a design on the printer - you need other software if you want to create your own 3D designs.