gr5

There have been similar problems recently that were fixed by replacing the vertical rods and the bearings that go on those 2 rods. It's probably too late to get a warranty replacement. But there are some new things coming out of UM to be announced probably Sep 19 at MakerFaire NYC... I'd wait until then.

Make sure ultigcode is not turned on. Look over the generated gcode and compare it to gcode that works. You can edit start.gcode to match what works. That should at least help with the part where it prints in the air.

I suspect it is nozzle temp is too cold for the underextruded layers. Leave the printer in the TUNE menu while printing and monitor the temp closely when going over the problem layers. Consider increasing the nozzle temp a bit if thats the problem. There maybe some temperature isulation factor between the temp sensor or the heater and the block causing the PID controller to oscillate for the bottom/problem area. Consider printing at anywhere up to 240C (240C is a safe temp for PLA but don't go any higher). The warmer you go the easier the plastic flows (less viscous).

But this is a VERY fast print so even if the fan comes on around z=3 to 5mm the maximum cooling might be a 10 layers later.

Joris asked that his name not be used for the feature so it was changed to Spiralize. It really doesn't work very well for things other than vases and cups. It also addes a little bit more material at the bottom of the cup where it meets the walls as that is the most likely place for the cup to leak. This is a bizarre setting that is (and always was) quite a hack and doesn't work with for example objects with hole through the sides. And it does strange things at the Z seam as the layer above might not start at the same point as the layer below (this was always a problem). Be aware also that if you ask for .8mm shell it will do it in one pass so it will be the equivalent of .4mm shell with 200% flow.

Peel off the sticker and add a drop of oil. If that doesn't fix it order a new one. There are several suggested replacement fans on this forum somewhere. Check the voltage (is it 12V? 19V?) first before ordering a new one.

kayoo - why post a topic and not even follow it? Click on "follow this topic" in the top right. If you ever read this topic. I have win7 64 bit and cura works fine - it's not the operating system.

No change to Marlin needed. Which of the above 4 methods do you normally use to print?

Just use the "skirt" or "brim" option in Cura and it will print a line all the way around your part when it starts printing. Make sure that line is squished into the tape (or glass bed) like in the picture. If not abort the print and adjust the bed accordingly.

Right. Cura puts a feedrate into the gcode file that satisfies the "minimum layer time" condition. Then when you tell the printer to print at a faster speed, Marlin doesn't know anything about minimum layer time. It just knows the requested speed in gcode and multiplies by the feed rate %.

@IRobertI - in openScad you can convert the code to a visual part using either F5 or F6 key. One is much faster than the other - sometimes 1000X faster. But to export to STL you have to do the slow one. Plus the fast one is buggy - but still very very useful in tweaking the code/parameters. Also the fast one lets you do things like make the subtraction visible as a part in another color.

Not much idea. Some people blew out their darlington transistor when they added a second fan so I guess you want one that uses not much current. The voltage is 19V and many 12V fans blow up at 19V. Some 12V fans are fine at 19V but only run at 2 speeds: full and off. So the whole 50% duty cycle thing doesn't work with those fans. Somewhere around 70% they suddenly start spinning. Hard.

Either do it a lot slower, or do it with no load (not inserted all the way to the nozzle). That way you should get more consistent results. It should take, I'm not sure, but maybe a whole minute to extrude 30mm through a hot nozzle. Maybe 3 minutes.

Not recommended. The fan isn't designed for high restriction fan hoods and the one that comes with the machine works very well. Most printed fan hoods work worse than the one that comes with the machine. Or if you melted it make one out of kapton tape. Also if you print a fan hood with PLA and it is anywhere close to the nozzle it may melt so ABS is recommended for fan hoods. Adding a second fan might be good though (on the other side).

meshmixer treats Y axis as the vertical axis. Most cad programs treat Z axis as vertical axis. So think of it as a "top down view".

Also note that messing with feedrate will override the "minimal layer time". Say your minimal layer time is 10 seconds and you are on a small layer or printing a very small part that normally only takes 5 seconds. Cura will tell the printer to print at half the normal speed to spread that 5 seconds out to 10 seconds so that the layer has time to cool before the next layer. But if you set feedrate to 200% then it will only print that layer in 5 seconds and you have defeated the feature.

The "feedrate %" affects all 4 axes equally X,Y,Z,E but realize that each axis also has a max velocity. So if Cura requests a move at 300mm/sec and you choose 200% feedrate then it will print at the XY max speed which I believe is still 300mm/sec. The problem with going faster is the Uno chip can't go much faster than that. I'm quite sure the hardware can go faster. I usually print at 100% because after 2 years I am more patient and just let it print at 35mm/sec. Plus I have 2 printers. But there was a time when I *always* printed at 100mm/sec and that way I could mess with feedrate and the % equaled the mm/sec. Nice trick, eh?

As Daid says the only part that is at risk is the teflon isolator. It's the white part located just above the nozzle. You can see it without taking anything apart. Even at 240C it tends to deform under pressure of the spring over even just 100 hours of printing apparently. At 270C it will deform that much faster. When it deforms you tend to get underextrusion. You can test for underextrusion by printing this at 230C and anything above 6 or 7mm is fine: http://umforum.ultimaker.com/index.php?/topic/4586-can-your-um2-printer-achieve-10mm3s-test-it-here/ You can usually fix the isolator by drilling it out. But that isn't always enough. It won't actually melt until around 300C. Make damn sure your 3rd fan (at the rear of the print head) is spinning and blowing air before you attempt this! Also aluminum is a good conductor of heat which might be a problem here if you make a new isolator out of aluminum - you don't want the bowden to melt. So maybe use stainless steel? I don't know. Not sure what temp the bowden can handle. https://answers.yahoo.com/question/index?qid=20070512125006AADRFoq

Overhangs are difficult. Fan is your friend here. You really need the fan at 100% right from the start which is not normally recommended. This will help somewhat but it still won't look so good. Have the nozzle start out hotter than normal as the fan will cool it and the PID controller will need half a minute or so to adjust. Then slowly lower the temp to the desired final temp. Or just print the first layer at 240, then lower to 225 for second layer, then 220 for third. I'm really hoping UM comes out with a recommended dissolvable support structure for dual extruders. Soon! Is there any way you can cut the part in half and glue it together after printing or flip it onto another side? You can wet sand the part to remove all the bumps at the chamfer. You need to keep the plastic cool (if it's PLA). Then to make it look nice you can put some baby oil on it afterwards. Or you can use a vapor solvent to smooth it out after sanding. Or paint it with automotive primer.

For better quality print slower and cooler. 190C and 20mm/sec will give the best quality. Make sure shell thickness is a multiple of nozzle, so .8mm is good. No infill needed. 210C at 35mm/sec is still very slow but quite good quality.

Always save the gcode as you can "load settings from gcode" to figure out how you sliced a particular model years later. Also I have a notebook by the printer and everytime it starts printing I note the date/time/ name of gcode file and any custom settings - usually just nozzle and bed temp but sometimes retraction settings also. And if I change feedrate or temp throughout the print that is noted and if it fails in some way that is noted. So now a year later I can go back and tell you exactly what I did to achieve such failure of a print

That would be nice - yes - a 10mm^3/sec cylinder where I can set the speed to e.g. 50% to get 5mm^3/sec. And play with the temp at the same time. And no text.

I see you have a mendel. What is your overlap %? If it's higher than 30% then you should lower this to 15% and instead tighten your belts as you probably have some backlash (aka play) and fixing this with infill overlap is not the best solution. But to answer your question, Daid has a newer version of Cura - not released yet - that will allow you to create regions of your print and adjust any parameter for any region. So you will be able to do exactly this in the next major release.

Zews I don't think 3D printing is ever going to satisfy the level of perfection you are looking for. However, if you go back to the first knob you printed with the moire pattern, you can probably let it sit in a vapor of Ethyl Acetate to give it a much more polished look and smooth out those imperfections. I've seen lots of other people do this (with ABS and acetone - Ethyl Acetate works on PLA ) and it makes the parts come out very smooth and pretty. acetone and ABS (this image gives you an idea of how much more "perfect" an imperfect print can be smoothed to): http://boingboing.net/2013/03/03/smoothing-3d-prints-with-aceto.html ethyl acetate and PLA: http://www.printedsolid.com/smoothpla/

Do you really need automated starts? It's really a good thing to watch the first minute of the print as the bottom layer is the most common fail point. Anyway I would leave the 15mm part - after that it extrudes a bit "E" is extruder. G92 resets the position so that: G92 E0 Tells the extruder that it is "now at position 0". Then after the extrusion move over to the side and down to the bed - maybe: G0 X20 Z0 Then do the wipe G0 X40 Z0 Then maybe lift slightly G0 Z1 Then let it move to the start of the skirt/brim/whatever. The Z1 lift is optional but if you don't do the lift it may pull up some tape as it drags over to the start. Maybe Z0.1 instead. Edit: oops - meant Z0, not Y0. Fixed now.