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I'm posting his photo so people don't have to go to dropbox to see it:

Ah - you didn't mention about the firmware. Cura 2.* does some weird things with print speed. Consider making all the speeds the same. I don't think this is the issue but other less critical surface ugliness I've seen caused by speed changes. Again I don't think this is your specific problem but definitely have a look at *all* the print speeds in cura 2.*

Absolutely post on github - you get so much better results and faster results and faster discussion (if desired by the programmer) if you post this as an issue on github.

> I started to print however the feedrate seems to be stuck at what is was before hand where it fed properly. You mean it's turning backwards? when you switch from a UM2 to a UM2+ feeder, if you don't update the firmware, the feeder will be turning the wrong way. Instead of slowly extruding it will just slowly retract the filament as you print all the way back to the feeder. Is that what you mean? If so make sure you use the select the UM2 *plus* machine before updating the firmware. Also consider using tinkerMarlin which allows you to experiment with the steps/mm setting. Maybe your problem is completely different than "extruder turning backwards" in which case please include a photo of the issue if possible.

So the GUI takes all the profiles and turns them into many "-s" parameters?

He sent me an email. I told him to come to this topic and sent him a link. Before applying the glue, are the magnets typically loose or tight?

Oh. okay. Never mind then. There are several support patterns. I like "grid" but 99% of the time I don't use any support or I design my own in CAD so I'm not sure. Could you show a photo of your "detatching supports"?

That's just basic underextrusion. I would try printing either a little slower or a little hotter. I can see underextrusion in that wall and also underextrusion near the top and then it basically stops extruding at all and makes a stringy mess. I'm not sure what is causing your underextrusion - there are so many possible causes but I'd start with speed and temp. Especially temperature. What temperature did you use? I usually go for around 245C. Once I clogged a nozzle because I printed too hot (254C that time - yes exactly 254) and I let it sit a little too long in the nozzle (a minute?) at that temp and it baked into a gummy mess. I was able to get it out by heating the nozzle alone over a gas flame to about 200C and removing with a toothpick. ABS has a much narrower temperature range than PLA. PLA is pretty good from 180C to 240C.

Please post a screen shot of what you are talking about and if you can circle the zeroes.

Someone is asking me about the Mark2 kit but I've never built it myself so I'll ask here: he is having trouble getting the "fix magnets to the parts". He says super glue doesn't work because the magnets are too strong. Any ideas? These are the magnets here: http://www.ebay.com/itm/75-MAGNETS-6mm-X-3-cylinder-disk-STRONG-N45-rare-Earth-Neodymium-US-SELLER/122403885907?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

@nallath should be able to answer this. But why not just cut and paste the 330 -s options into a script and be done with it? Also I think there is a way to pass a file with parameters instead of passing them on the command line.

Watch this - there are a few techniques to get things to stick VERY well to the glass. It's a long video, sorry, but I didn't want to leave anything out. I tried to mercilessly edit it down to keep it as short as possible. Removed 1 second pauses here and there and speed up some of the video:

I get this sometimes also. So I usually change filament manually. I just push down on the lever on the feeder and pull the filament out. If there is a little blob at the end of a string I hope it makes it through the feeder and 2/3 of the time it does. When it gets lost I don't worry too much - usually it sits in the bottom of the feeder. sometimes it gets back inside the bowden on the next insert and gets back into the nozzle. So far I don't think it's been a problem.

And here I didn't realize you could even start a print - I just assumed you got the error because the cores were still cold after a few minutes

@rpierce - go to the menu system into the heater cores section and set the temp to say 100C and see if it starts climbing or just sits there below 25C (room temp). We need a bit more information. If the heater is totally broken then that would explain a lot. Also when you put the cores in make sure you push firmly. The clear part at the top should kind of snap in and up. It seems strange that both heaters would fail. It could be that the 24V signal on your white PCB is bad. There is a relay on there and if the relay fails (relays commonly fail) then that would mean everything would work including sensors but heat and servos would not. You wouldn't be able to home the head either without 24V on the white PCB.

Ah! That's almost certainly it then. It's trying to print a 1mm line width out of a .4mm nozzle. Spiralize is weird that way. I would put a larger nozzle on there. You can get a .8mm core from ultimaker or you can get a 3rd party version from shop3d.ca that lets you change nozzles. The problem on benchy is similar: overextrusion or not viscous enough (too hot). The pressure builds up and sometimes it just squirts out and makes a blob. There are many causes - not just spiralize. It could be that you are just printing too fast and pressure builds up too much. Or maybe too hot - cooler filament is less likely to spurt out the side of the crack along the nozzle. Or at least it only spurts out a tiny bit. I've never used innofil but 215C sounds too hot for the UM3 if it's PLA. The UM3 nozzle temp should typically be 10C cooler than that of UM2 or other printers.

Thanks for the picture. That's what I thought you were talking about but it's good to be sure. yeah that's typically overextrusion issues. Due to speed changes and many other possible causes. Basically lower speed in order to lower pressure. Lower temperature so that the viscosity keeps the plastic in it's place instead of bursting out as a little blob. So, um, I think lowering the temp is better. I'd try 30mm/sec at 195C although the default temp is probably fine also (200C i think?).

What you called the "inner side" was something impossible in the 3d world. I call it an "inner wall". The guide I linked to explains it better. It's hard to explain with words - easier to explain with pictures. But I'm glad you figured it out.

If you don't see something in layer view then it won't print. Cura looks at your nozzle size, shell width and comes up with a "line width" internally. For example if nozzle is .4 and shell is .8 then it will pick .4 for line width. Then it usually won't print any walls less than double that thickness (.8mm in this case). A quick test is to set your shell width to 0.6 and nozzle to 0.3 to see if more walls suddenly appear in layer view. It's okay to lie about nozzle width somewhat. 0.35 for a 0.4 nozzle works just fine. 0.2 for a 0.4 nozzle - not so good. That is called "backlash" or "play" (you can look it up on wikipedia). It is very important to reduce backlash on a printer. Sometimes it is caused by too much friction. Check your axes. Sometimes it is something loose like belts or parts inside the head. With nozzle cold and power off try pushing on the nozzle to see if it moves without the head moving. Try pushing on the whole head. How much does it move before the steppers start rotating? That distance is backlash. Belts can be tightened if that is the issue. Search for belt tighteners on thingiverse for ideas and solutions.

Well it's interesting that it only happens on the corners. I think maybe it is overextruding and only on the corners does the filament leak out. Ah!! I have a new theory I like. This is spiralize? Spiralize is weird. In non-spiralize mode if nozzle is .4mm and shell is .8mm it will make two passes. But in spiralize mode it will try to do it in one pass. So it will doubly extrude to get the .8mm shell and that's a LOT of pressure. That would make sense as to why it sometimes is just too much pressure and it occasionally leaks out suddenly and makes a bump. 1) What printer is this? 2) What filament size does your printer use (1.75 or 2.85)? 3) What is your nozzle size set to in cura and does that match your machine? 4) What is the shell width in cura?

Yikes no. You want zero visible gray faces. Only white faces visible from inside outside, all around. Well my suggestion was likely not the issue then. View the part in xray view in cura. It will show red if you have extra walls or holes in it -- that's my next theory. Sketchup is just very problematic. Did you follow my link? It talks about tools you can use in sketchup to make sure your part is a 3d object and doesn't have things like internal walls. Sketchup is designed to make nice looking things but not real things. CAD programs are meant to create real things. For example in sketchup you can just place an infinitely thin wall somewhere. There's no way to print that. I'm thinking you have more cylinders inside this object than you thought and it's confusing cura.

"bad layer bonding"? With PLA? I've never seen bad layer bonding with pla. But I've seen it with almost every other filament and it's easy to fix.

Well there are a few things you can try. Basically 2 ways to success. The first way is to fix it in sketchup. In sketchup you have the default walls (which is good) which are gray on one side and white on the other. You can click on any wall and reverse the faces (gray in, white out, or vice versa). Make sure all walls have white facing out. More fixes here: https://i.materialise.com/blog/3d-printing-with-sketchup/ The other way to fix things (or maybe you have to do this even if your model is perfect) is in cura. There are settings in the section "mesh fixes". If your model is perfect cura can fill in parts of your model like the photo above unless you turn all of these off. Click the gear and locate these (second or third to last category in cura and make them all visible). It's probably the "union overlapping volumes" on that is the problem and needs to be unchecked. Although if you fix things to make all visible faces of your part "white" then you might not need to mess with this in cura.

Yes. At least for a test. Everytime you switch to a slower speed it will overextrude for a few seconds and every time you switch to a faster speed it will underextrude for a few seconds. I have never needed to go below 20mm/sec. 30mm/sec should be plenty slow enough for high quality. I'm wondering if you should raise the temp to 230C. I have never printed ABS on my UM3 (only um2 and um2go) and when I do I prefer around 240C. Also for ABS it's important to do as little fan as possible. If you do too much fan the layers won't bond and the part will break easily along the layers ("grain"). Definitely don't go over 3% fan. 1% might be enough (this is for UM3 - for UM2 you want 30 to 50% fan). If you have zero fan then it won't do overhangs or bridges very well. If the layers don't bond they sometimes even peel apart in the middle of a print while it's cooling. Also with ABS I recommend you put a front and top cover. It can be as simple as a bag or saran wrap for the front and a copy paper box for the top (copy paper boxes are perfect fit for the top of the machine with plenty of space for the bowdens in the back). Doing these covers raises the air temp to about 35C which helps quite a bit with materials that have a higher softening temp such as ABS. PLA is much easier to print. Could you supply a photo - maybe that will help us understand your issue. I may be misunderstanding what you mean by "blobby" part.

The files are on github. Use google to search github, ultimaker and I think "bom"?