simon

I'm not sure the UM2 print head gets quite hot enough to make the process of printing in ABS as easy as it could be. If it went up to 265 C it would be better, and this is why (IMHO). With the Afinia, the print head does go up to 265 and it creates fine strings in ABS better than the UM2. When you're bridging over the sparse infill with the UM2, the plastic isn't quite hot enough to allow the you to print over 30mm/s ish. If you increase it to 45mm/s the strand breaks before it reaches the next plastic rib of the sparse infill. This short broken strand then sticks up above current layer, possibility because until it broke it was under tension, and when it breaks, it releaves the stress by sticking up. It takes a long time and many layers of solid infill to seal this area over and the end result looks like a quilted blanket. I think that because PLA can be heated well above its melting point and perhaps because of its visco dynamic properties, it creates a really fine string easily, which makes bridging a breeze. The UM2 is max'd out at 260 so the plastic isn't quite free flowing enough to produce this high speed, fine strand. Printing the sparse infill is easier at higher speeds because its always pushing down onto another piece of plastic, but the first layers of solid infill need to be printed more slowly because the plastic isn't quite hot enough. Therefore if we can't increase the print head temperature by another 5 degrees, it would be beneficial to independently control the temperature of sparse and the first 2 layers of solid infill. Then you reduce the first 2 layers of solid infill to say 30mm/s and the others could be nearer 40 or 50mm/s.

Ha ha, got it, thanks. Perhaps there's something else you could answer for me. I want to reduced the speed of the top layer, or at least the first 2 layers of the top layer. Its the bit specifically where it's bridging over the open box infill pattern directly underneath. Is that part of the infill speed or the print speed?

Thanks for the explanation

Thanks Daid, I'll try this after I finish my current print. While you're on the line, can you tell me what the other parameters in that menu are controlling i.e. x,y,z and Jerk? I thought that the head speed was controlled by Cura.

Just a quick question. Every time I turn on my UM2 do I need to use advance maintenance settings to reduce the acceleration from 5000 to 3000, if 3000 is what I'd like to use all the time. Material setting can be saved but it seems the movement settings can't. Or I am missing something?

I think I'll give that a go tomorrow. I'll also try the glue stick method too. Thanks

Second print was excellent, warping reduced to a minimum using the raft and no more under extrusion. Only problem is removing the raft material. It has to be said the Afinia made a much better job of raft and support material. The Raft would just peel off easily with Afinia leaving a perfect surface. On the UM2 the raft material seems impossible to remove without sanding it down. This is a major disappointment. I've got to find another way to make the part stick without using a raft.

After a few teething problems with my UM2 I finally produced my first ABS print today. Some areas worked well, and some, not so much. I just wanted to try out a model with some settings that I could work from. Extrusion temp 255 Bed 100 retraction 5.0mm wall 0.8 Top and bottom shell 0.6mm This is what I was trying to print First few layers were fine The first problem started when it tried to cover over the infill. I think some under extrusion and possibly something else caused the bridging material to not cover over the ribs of the infill properly. These short lengths of material ended up standing on end point vertically up about 2.5mm above the current layer height. The finished surface did eventually seal over but left an ugly box quilted effect on the surface. I also had a bit of warping, but I expected this because I didn't use a raft. I wanted to see how much warping I would get. I also had under extrusion However I was very pleased with the quality of the side wall. I'm now reprinting this part because I need 2. I've increased the material flow to 130% and it's eliminated the box quilt effect completely. I've also used a raft, and so far the part hasn't warped. Its half way through. I'll post a picture when it finishes.

Ok, great, I was wrong. The bit about it being a solder joint. It was a solder joint. You really can't see it with the naked eye but with a magnifying glass you could just about pick it out as looking a bit dodgy. It was one of the connections for the thermometer. My soldering isn't the best, but it seems to be heating up and holding a steady temperature now. Thank you gr5 and Sander, I wouldn't have found this problem without your help, it was too easy to over look.

It’s definitely some kind of component failure. I have been able to get the heater to come back on but as soon as it gets to about 70 C + it becomes unstable and starts oscillating rapidly and then goes out of control and reports 1125C. I don’t know if the failure is on the heater plate or somewhere else in the system. I’m a mechanical engineers rather than an electrical engineer so I don’t have skills or equipment to debug it. I have checked the value that the PT100 records using a thermal imaging camera and it seems to be working properly. It seems to report the correct temperature up to about 70 C but then becomes unstable. Like I said, this could be either the PT100 or something else. All the connections on the back of the plate look really neat and I don’t believe it is a failed solder joint. I also can't see any stray wire strands or missing insulation. But thanks for the help anyway :smile:

Ok, unfortunately I don't have a multi meter. Maybe if I better describe the failure mode we can determine the error. When heating up in pronterface (set to 105C) you could see the graph rising over time and the bed was getting hot correctly. At about 70C it seemed to flattened off for a few minutes then started to oscillate up and down by about 20 degrees very quickly. Then it went out of control up to 1125C, although it was actually about 70C. Just as the graph went through the roof, the display panel on the printer came up with the error. The heated bed wasn't moving at the time and I have checked the cables and connections before. To me, this seems like a component failure rather than a loose wire. The component was probably failing at the 70C point when it started to oscillate rapidly. Does anyone agree?

Same just happen to me also. Got my UM2 last week but with the wrong PSU. New PSU arrived today. Plugged it in, heated the bed, which seemed to get very hot, and error, contact Ultimaker. Damn I was really hoping that the new PSU would mean I could finally start printing. I'm really thinking that this beautiful unit is going to have to go back. So frustrating!!!

It's actually the fact that I need to print ABS production parts. There's nothing I want to print in PLA.

Got it thanks

Sorry, my photo links aren't right. Just what the video. The MOV on my dropbox is better.

I did my little test today with the DTI and here are the results. Setup Video (not sure how to get the video in) Its on the low res side, but you can make it out. Here's a mov version https://dl.dropboxusercontent.com/u/11059439/UM2/UM2%20x-axis%20with%20DTI.MOV Anyway, its quite interesting (to me). If you level the table by following the UM2 procedure (could be the UM1 as well but I don't know) then you are leveling it using the 3 point paper thickness alignment method. Nothing wrong with that. The head stops next to the adjustment screw which is the right way to do it. However we are using the paper thickness of 0.1mm to gauge this distance, which can be a bit subjective. As the video shows, if you traverse across the middle of the table in the x-axis the deviation is about 220 microns (on my machine). The difference will be a combination of the distortion in the glass and the rails. I don't have an engineering flat standard that would fit inside the UM2 so can't isolate how much of each there is, but my gut says its mostly the glass. I've only done one test so far and could probably isolate it further if I did, but I don't think its necessary. I just did it for interest because I can't print anything until I get the new PSU. Possibly because of the clips, the glass bows very slightly. During the calibration the table drops between positions so you are not aware that, in fact, the nozzle would come into contact with the glass if it didn't. This is not, in any way, a criticism of the UM2. I'm mechanical engineer and design stuff like this all the time. Nothing is flat, straight or in fact anything you want it to be. It's just one big compromise. The interesting thing for me is wondering what is happening when you print in the middle of the table which is normally where you would print. I guess that the molten plastic pushes the glass away a bit like an air bearing (but with plastic) or pressurized oil bearings. If it didn't the plastic would be unable to get out until the head had moved to a position where there was sufficient clearance. However, its also easy to see how, if you've leveled you platform on the tight side with paper (which is easy to do for a new comer), you could easily have increased the contact force between the nozzle and glass where the plastic could not extrude properly. If we're trying to maintain a 0.1mm clearance in the center to start a print, maybe a final clearance should be checked there as well. Perhaps the calibration process should consist of 2 phases, one to get the level and one to set the clearance in the center. It obviously works as it is, so I'm just chewing the fat really. I'd be interested in the opinions of our more experienced users (you know who I'm talking about). However, as it works for people as it stands, I won't be offended if the post finishes here.

Well actually I found out after I read Illuminarti's post and changed the baud rate. I didn't realise that the clonk/blackout was normal. The errors I was getting were a result of the baud rate being incorrect. I just assumed the blackout was the power supply failing again, but thanks for making sure I didn't slip through the net of ignorance :-). I have to say I'm really impressed with pronterface.

That's great thanks.

Ok, have tried Pronterface now and it does look pretty simple to use. The look of the website made me think it was going to be some kind of horrible text based unix type thing, but it seems to have a nice GUI. Unfortunately because I have the duff 5A PSU presently, each time I try to connect, it trips the printer and it re-boots. I've turned the bed temp down to 0C for everything, but it still trips. So I'll have to leave it until my new PSU arrives. BTW what values should I use for Baudrate, x y and z mm/min, etc.

One thing I forgot to ask is.. Could I accidently drive the x or y axis into a position beyond the limits of the machine using pronterface. Or does the UM2 'know' it's physical limits to prevent me from doing that by accident?

Thanks guys, sorry for not getting back promptly, child care commitments and supper took priority. Right, what I'd like to do is set the z-axis height so it compresses the plunger on the DTI a few mm's and then drive the x and y axis independently keeping the plunger over the glass. This is perhaps over kill for levelling, but I've read many times that bed levelling is v.important. Seems more so on glass. I already have a DTI which I use on my Afinia and measuring microscope so I might as well use it for the UM too. Although paper is fine I find it more accurate and easier using a DTI.

Hi Daid, looks quite involved... (difficult) for a newbie. Is this the right link for me 'printrun-win-slic3r-12july2013' to run on windows 7 64 bit? Is there anything else that would do it that looks easier to use? Not wanting to sounds ungrateful for the info of course.

Hi Sander, thanks for your prompt reply. I look forward to receiving it :-)

Its a little frustrating as I don't want to print PLA so the none heated bed approach is not and option for me. I'm only interested in ABS. Oh well, my Afinia is still going strong so I can print on that for now.

I'd like to level my bed using a DTI, which makes it easy to get it within 10 microns. Is there any software out there I can use (for free), which always me to control the x, y and z axis independently. The UM2 bed calibration function moves a bit too far and the needle will fall off the edge or hit one of the clips. I couldn't find a away to control it in Cura or via the UM2 control panel. Thanks.