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Netfabb. But I think it's very buggy for retractions. I don't think they have updated for UM output for a few years! That's the most likely one. Slic3r, kisslicer might also do the fan thing.

I've never had this problem. The only thing is if you are in "layer view" when you clear platform and load a new model you have to go back to "normal view" before layer view works properly again.

As dimensioner hints - another possibility is that your nozzle isn't set to .4 in cura or your shell width isn't a multiple of .4. For example if you set the shell to 1mm then the UM2 will try to overextrude *all* infill (not just the shell) and it will print the shell in two .5mm passes and then all the infill will also be at .5mm which is tough to squeeze out of a .4mm nozzle resulting in some underextrusion also. ALWAYS set the shell to a multiple of the nozzle. Especially when printing at the absolute top limit of what the UM2 can do.

Bill please update your profile/description to include what type of printer you have (UM2).

underextrusion If you had followed my link you would see that at .1mm, 210C, .4mm nozzle 120mm/sec is the absolute fastest the UM2 can print. 100mm/sec is pushing close to that limit and I'm not surprised you have some underextrusion. I recommend not going over 60mm/sec or alternatively raise the temp to 240C (this is not a random temp - it's right off the graph as the minimum temp to print at if you want to print at half the max possible speed). It is quite possible that your machine has degraded a bit. This is common as the feeder can get ground up and also the isolator can get compressed/deformed or you are getting towards the end of a reel and the filament is more curved and getting more stuck in the bowden and isolator. There's lots more suggestions about testing for underextrusion and fixing issues elsewhere. But your problem might be too minor to fix at this early stage as you are printing right near the absolute limit. play/backlash From your description it sounds like one of the sides of a long belt is tight and the other side of the same belt is loose. This is most likely the cause of your backlash and takes about 30 seconds to fix. Loosen the small allen screw that holds the pulley tight on either end and the belt should quickly even out the tension on both sides. If not, then something is wrong with the existing tensioner which is *inside* the black block. Make sure to retighten the pulley - tight as all hell. The allen wrench should twist quite a bit.

Gorgeous. I suggest you make this same post here: http://umforum.ultimaker.com/index.php?/topic/467-post-your-latest-print/page-149&do=findComment&comment=85453

Peggy's method is really the only way, sorry.

Probably a grain or sand or similar in the head. The easiest way to clean it out is with "cold pull". Heat nozzle to 180C and push some filament through by turning the "big gear". Then let it cool to 90 to 95C (walk away for a few minutes and come back. Release the filament extruder pressure and pull very hard on the filament. About 5kg of force. If it takes > 5kg of force raise the nozzle temp by about 5C. If less than 1KG force repeat but with lower cooled temp. You should get a perfectly shaped casting of the nozzle tip including the last 2mm of the narrow .4mm drilled hole and the cone shaped tip. If not you did it too hot. After pulling the filament out, clip off the last inch (dirty areas) and repeat this several times. If you have hypodermics or acupuncture needles, pushing up from below the tip sometimes helps before you let it cool down from 180C. Alternatively remove the nozzle and burn everything out of it with gas flame and clean it out with hypodermics or wire from a brush or copper cable or similar. But the "cold pull" method is much easier. If you use ABS of course you will need a higher pull temp - around 130C (not 90C). Around 170C for nylon.

You have two problems: underextrusion and backlash/play. They are completely unrelated to each other. You should fix both. 1) Underextrusion. Either your spring is not set ideally or something else. I assume this is a UMO. What temp, speed, and layer height are you printing at? Here's a graph that describes the relationship between these 3 variables - print at half the speed of the blue line or slower: http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/ Don't you dare post anything without answering my question in point #1. 2) backlash/play. This can be caused by loose belts or high friction. In either case the head doesn't move all the way to where the stepper commands it. On UMO the short belts (on the motors) are more likely a problem than the long belts. Loosen the 4 screws, push down on stepper and tighten. If the belts are *too* tight then friction can be too high. Also on UMO it's extremely common for the wooden end caps to be too tight. Try loosening 1 end cap on each of all 4 rotating axes in the top gantry. Do that while pushing the print head around. You should be able to easily move the print head with your smallest finger on each hand pushing on the outer blocks. It's quite possible (likely even) that only one of your axes has excess play or excess friction.

Also note that different colors of PLA and different brands may need 10C or so hotter or cooler than the brand used for the graph test (UM light blue).

Look at this graph when choosing temperature's and speeds. At 210C and .2mm layer height the absolute max speed for a UM2 is about 60mm/sec (blue line in graph). You were too close to that absolute limit. I recommend you don't exceed half the max speed (30mm/sec should be fine at 210C). Anyway if you want to print 50mm/sec and .2mm layers then the graph tells us 240C is about right. I print at that speed often but if you want higher quality I would stick at 210C and 30mm/sec and be patient. http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/

I don't print much ABS but in PLA the fix is to use more fan. MUCH more fan. Add window fans, turn on a vacuum cleaner backwards and blow a hurricane at the thing: http://umforum.ultimaker.com/index.php?/topic/4094-raised-edges/page-4&do=findComment&comment=82015 Now with ABS, it shouldn't need nearly as much fan. ABS has problems with layer adhesion - you need the current hot layer to be hot enough to melt the layer below slightly so that you get a good solid bond. It's very easy in ABS to print too cold or to have too much fan and result in bad layer adhesion. So with ABS you want the highest possible fan but still get good layer bonding. Older slicers work better with ABS and they will turn the fan on during overhang passes and off on the rest of the layer. That's like on and off every few seconds. This is ideal. Cura is written in the "age of PLA" and so doesn't have this feature (overhang fan).

Easiest thing to do is to scale up by 25.4 in cura but I'm sure when you export to STL there is an option somewhere to do it in mm units.

Consider printing this extruder test: http://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/

You have a defective 3rd fan. Check to make sure nothing fell into it but some people get noisy ones. Mine is so quiet it is very hard to detect. Very hard. In a silent house I can't hear it until about 5 feet away and just barely. It is quieter than a typical refrigerator by a factor of maybe 1000x. Regarding the cube - you have underextrusion. It's intermittent. There are about 30 possible causes of underextrusion. With such a new machine I would first guess that you have filament issues on the back of the machine. Try putting the filament on the floor - this can make an immense difference! The angle that it comes into the feeder can be a problem. Also check the filament for tangles. Also loosen all the 4 long screws slightly. Sometimes they overtighten them at the factory. Make sure they are only finger tight. What is the hottest you let the nozzle get to since you received the printer? Other possibilities: - deformed isolator - clogged nozzle (partially clogged) - tangled filament - filament grinding feeder at entrance or on white part and carrying ptfe up through tube to nozzle - feeder spring too loose or too tight - bowden pushing too hard down against isolator - pt100 nozzle sensor off by 20C such that nozzle is 20C cooler than you think - pt100 nozzle off by 20C such that nozzle got very hot (say 290C) and wrecked the isolator - Filament > 3.00mm - Feeder servo too hot causing filament to soften/flatten - tangled filament, filament rubbing too hard on side of feeder

This is often because the end caps are too tight. You should be able to move the head using the smallest finger on each hand placed on the two blocks on either side of the head.

Robot fuzz does not support latest hbk nor um plus.

Did you measure the filament? Is it actually 3mm diameter? Or 2.9? 3mm filament is not supposed to actually be 3mm. That is the absolute upper limit. Typically it is 2.85 or 2.9mm. Not 3.0mm. If it reaches 3.01mm it will probably clog in the bowden.

The next picture in my gallery is one I took. Just about right. The pink filaments photos were taken I believe by Simon/Illuminarti.

The one on the left is not enough. The one on the right looks maybe a little too tight.

The UM2 splits the extruder into 2 separate parts - the feeder on the back of the machine and the nozzle on the print head. This makes the print head very light weight and you can have accelerations of 5000mm^3/sec. So I don't think it would make sense to use these extruders on the UM2 head.

Do you have a UMO or a UM2? Please update your profile to indicate which printer you have.

Yes. Severe underextrusion. What print speed, temperature and layer height are you using (these are the 3 variables that affect underextrusion - knowing only 2 of them is useless). Here's a chart with suggested print speeds - use half the value of the blue line in the chart for a given temperature (the blue line is absolute maximum): http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/

It's not accurate enough. The paper is .1mm thick and if you are putting down .1mm layer for bottom layer you want an accuracty of about .03mm. So you just print the skirt or print anything and the traces laid down should be .4mm wide and .1mm thick. The thickness is difficult to check but the .4mm width part is easy. You can use a ruler, a micrometer or just look at two traces and 2 traces should be twice as wide as one as they will be spaced .4mm apart. Or you can make sure the trace looks to be about 4X wider (.4mm) than it is high (.1mm). It's easier than you might think. And you can do it live *while* it prints. Although I tend to adjust this on every print for a while until I get the leveling perfect. I usually adjust all 3 screws the same amount. But sometimes one side/corner needs to be higher or lower. Just do small adjustments and it will slowly get better each time.