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Great information, thanks! Some people have found if they seperate the temperature probe wires *farther* from the fan wiring then their temperature is more stable. So just moving the wires a little bit might be enough. edit: I'm talking about the probe wires *below* the circuit board on the head. Once the signal goes through the amplifier it is not so sensitive to crosstalk.

Oh. Maybe not. I misunderstood and thought you meant you had a non-standard print head. Like the E3D possibly. If you do this modification: http://www.thingiverse.com/thing:46157 then 4.5mm is about perfect retraction distance for UM Original.

Yes, I print at 240C when I'm in a rush. If I'm doing .2mm layers and >50mm/sec (like 75 or 100mm/sec) I usually go 240C. But I get worse stringing. Other than stringing and some bumps it comes out fair quality - good enough for mechanical things. I'm thinking your retraction distance might need tweaking if you have a different extruder. Maybe do a test print - two columns or something and for the first 20 layers try 2mm retraction, then 3mm retraction and so on. Mark the position where you change with a marker. Oh wait - UM Original - can't adjust on the fly. Well then print the same thing (two 10mm cubes side by side) at many different retraction distances from 2mm up to 6mm. You want the exact right distance so the PLA goes from the top of the bowden to the bottom but doesn't actually pull back enough to let air into the nozzle.

If while quickly spinning you accidentally push too hard it goes back to the main menu. So it's a pain. But after 10 tries or so I got very good and was able to get every block. But then I just got the same level again and stopped. For a while I tried to use left or right side of paddle to affect direction (which works) but that made me lose more often.

I don't want to give it away. Someone showed me at Makerfaire NYC. I played through one level and then just got another level. My daughter somehow shortcutted and got to the next layer with only getting one column of blocks. Didn't see any prize or anything - it just keeps going forever I think. Anyway I guess I'll give a hint - it's not in any of the menus. There is no hidden menu or hidden menu option. I'm kind of afraid people will get pissed off if they see there is a game in the UM2 yet it isn't doing... whatever it is they think is more important (better slicing algorithms, less underextrusion, less noise, who knows!).

Underextrusion issue is more complicated. Not sure what is causing it. If this is UM2 then probably extruder is slipping backwards. Some people seem to have worse underextrusion right after retraction but I have no idea why. Maybe the retraction distance is too far? maybe the extruder slips a little when the retraction starts? This can usually be made better by increasing the nozzle temp - 240C would be good. Or slowing down the print a bit. Try 50-80% of your current speed. The problem with 240C is you tend to get worse stringing at higher temps.

There are two issues. You have underextrusion where there are holes and kind of dashed layers. The extruder probably slipped back a bit and it takes a little whie to start extruding again. Plus you have stringing where some strings are hanging out. For the stringing issue: Do you have "enable combing" checked? That keeps the extruder inside the part if possible instead of jumping directly to the next location to print (and causing some stringing sometimes). Also do you have "retraction" turned on? You want it on for this part. There are 6 retraction settings 2 of which are on the printer if you have UM2. You want it 1) checked 2) min distance: 0 3) min extrusion: 0 4) combing - checked I think - sometimes not checked is better though. The last 2 are probably fine. On UM Original settings in cura, on UM2 settings on printer: set retraction distance to 6mm if your bowden wiggles much. Or at least 5.5. If your bowden is rock solid and tight then 4.5mm is good. Speed is probably fine as is. On UM2 I have it set to the max: 35mm/sec. On UM Original I have 40mm/sec but the max in the firmware is I think 25mm/sec.

That can help also - as each layer is touching more of the layer below on those curved overhangs.

You need as much fan as possible. If there were a 200% setting then you would want to use that. By default fan comes on very slowly and not full fan until 5mm or so. If you make the fan go from off to 100% on the second layer you will get underextrusion because the head will cool to fast and it takes 30 seconds for the PID temperature controller to compensate. So I recommend having the fan come on even for the first layer. You will need a warm bed (70C) if you print first layer with fan on. This will help a lot but it won't be perfect. It will be better. OR FLIP IT OVER I don't know any way to get this perfect. I guess you would have to flip it over - that would make good curves but the hidden side will be a bit stringy. You will want 100% fan for that also when it bridges the back of the phone. You will need at least 4 layers to get the top layer perfect as each layer will get better (they will all be a bit low and slightly underextruded but each layer will get better).

No. 1mm/sec is fine. 300mm/sec is fine. Install prontrface. There's a link in my post above. Move 100mm at a time. Listen carefully where the thunk is coming from. Something must be rubbing or getting stuck or something very weird is happening. I doubt it's the electronics but I'm not certain. In fact move both axes at once and see if they both pause at the same moment. If so then it's probably your power supply is fluctuating from 19V down to 6V or something like that and the 6V isn't enough power to move the steppers. But this seems very unlikely. In order to move both axis at the same time, home X and Y using prontrface, then use gcodes in the right window: G1 X100 Y100 will move both axes in a diagonal line to the center of the print bed G1 X0 Y0 will go back to home Repeat those. You can set the feedrate also (in mm/minute): G1 X100 Y100 F1200 (1200 would be 1200mm/min or 20mm/sec). Once you set the feedrate once it stays with that feedrate until you tell it a new one so you don't have to keep sending the same feedrate.

Actually since people might end up here on a google search I'll give more information to others who want to compile with the gui: How to compile Marlin yourself - I assume everyone here is doing this for the UM Original but if for UM2 marlin source is instead here: (Ultimaker2 marlin source: https://github.com/Ultimaker/SecretMarlin) First get the source code files here: https://github.com/ErikZalm/Marlin Then edit Configuration.h – this is by far the hardest step and it's not bad. I recommend you go here: http://marlinbuilder.robotfuzz.com/ and use that website only to get the Configuration.h file. Then run winmerge or some other diff program to compare the latest ErikZalm version of Configuration.h to the one from robotfuzz which is usually a few months behind. Edit the ErikZalm version to match the robotfuzz generated version. Make any other edits as necessary. It sound complicated but it is extremely clear and well commented. Sometimes with paragraphs of explanation. configuration.h file detailed explanation: http://airtripper.com/1145/marlin-firmware-v1-basic-configuration-set-up-guide/ Then you need to build Marlin. There are instructions that come with the erik zalm download in the "README.md" text file. Basically you download and install arduino ide: http://arduino.cc/en/main/software Then copy the sanguino software as explained in README file. Open Marlin.ino file in Arduino IDE by double clicking it (not pde file as stated in README - I think that's old). Select board as "Mega 2560" as explained in README file. Go to "file" "preferences" and select "verbose output" so you can find your hex file. Then build it by clicking the check box in the upper left corner. At the bottom you will see it compiling Marlin. At the end of this it says where the hex file is. If you are currently connected to your UM through USB you can just click "file" "upload" and you are done! But you should locate that hex file and save it somewhere along with the Configuration.h file used to create it so you can recreate the same version with maybe one change. Also you can upload the hex file using Cura in expert menu. Alternatively you can build Marlin with somewhat more detailed step by step instructions the command line way (which I don't prefer): http://www.extrudable.me/2013/05/03/building-marlin-from-scratch/

By the way it's "Marlin" the swift and agile fish! Not Merlin the magician. I'll edit your topic title. Oh - someone already did.

Yes. It's pretty well tested. I've tested it. Other's use it. Yes. Very easy. You can use Cura to upload it using cura expert menu. Save this hex file!!! In fact save the configuration.h file that comes out of robot fuzz just in case you want to upgrade to a newer version of Marlin some day. Then you can do a diff (winmerge works well) on your configuration.h file and some future build of Marlin you do. Make sure you can find this hex file 3 years from now - label it well and clearly. Marlin is pretty safe - you can install different versions over and over and if you screw up you just install a newer one. Also it's easy to go back to the one that comes with cura (also in the expert menu).

MAXTEMP almost always means a loose or intermittent wire. It's almost always at the top of the print head. It usually happens on a movement far away from the center such as on larger parts or towards one of the 4 corners which puts minor stress on the cables. When I had this problem I was able to get it to happen either of 2 ways: 1) Turn on the heater (no need to wait for it to warm up) and push the head around to the 4 corners of the bed. Occasionally it would trigger MAXTEMP, cut power and ignore me until I power cycled. 2) Push and pull on the wiring at the top of the print head. My fix was to switch to the backup cable (meant for a second extruder). Switch on both ends. Also make sure you use that black E shaped strain relief or this will happen to cable #2 as well. Also I'm very good at continuing a 4 hour print when it fails. The basic solution is to: 1) Figure out exactly what height it failed - typically I rehome, then command the head to different Z heights (usually using prontrface G1 Z10.0 commands) 2) Edit the gcode file and remove everything up to the part where I start the new layer. Leave in the home command at the start, add a command to move to the right Z height so it doesn't hit the part e.g. G1 Z10.0, set the extruder to where it left off (otherwise it emits 2 meters of filament). Let me know if you want more details like the reset extruder to position A command, guide to gcodes, and where to get prontrface.

Do you get Maxtemp or Mintemp? Or something else? Usually mintemp or maxtemp is a loose, broken, or intermittent wire (moving the head around can usually duplicate the problem). But there is some other error that occurrs if the head doesn't heat up as fast as expected. The head has enough power to melt the brown plastic part made out of PEEK. So if the readings are off by say 50C you can destroy that part and make a mess. If you are getting mintemp/maxtemp then it's probably wiring and I would change over to the spare cable (at both ends of the cable of course - both at the head and underneath at the PCB). If it's the other error I would test that the head doesn't boil water at 95C and that it *does* at 105C and if that works I would keep my eye on the temp to see if it is bouncing around a lot and if it looks fine then I wouldn't worry too much -- well maybe I would time how long it takes to heat up and ask other people how long it takes for them. You might just have a bad heater wire that means it takes a little longer than normal to heat up. Also it would mean some of the heat is ending up at the point of higher resistance and you may be burning the connector where the heater hooks up.

I've also had much worse trouble with hangers or strings on my white PLA. White PLA is tackier/stickier and no matter how low I go with the temperature I get these things. Most other colors aren't so bad.

This is bizarre. Are the belts popping out of the pulley's? Skipping a tooth? Look carefully at both short and long belts. If you turn off power and push the head around does it feel smooth or is there a periodic resistance?

Oh - that. You need to retract. Is retraction on? Look at the extruder gear - it should turn backwards on moves like this. Also you can look in cura layer view and non-extruding moves are blue lines. If the blue line has a vertical component (a vertical line) at the start then that is a symbolic representation of retraction. If no vertical line then your retraction settings aren't right (there are 5 settings). Also I recommend this part - it makes it so 4.5mm is plenty of retraction. Without this part you need more like 6mm retraction: http://www.thingiverse.com/thing:46157

You can do it using prontrface also if you don't have an ulticontroller. You can get prontrface here - it's free: http://koti.kapsi.fi/~kliment/printrun/ I think prontrface will help you set all those parameters up - it certainly queries Marlin for you and displays all the motion settings such as acceleration in the window on the right. You might have to look up the gcodes for setting Z acceleration but it's very simple. Here is the complete list of gcodes (scroll way down): https://github.com/ErikZalm/Marlin/ more details on gcodes here: http://reprap.org/wiki/G-code

I'm not a mac person. Someone else might help. Or google this forum for mac plugin. You have to put them in the right folder and the correct folder might not even exist yet so you just "have to know" the name. So if no one else answers search the forums.

Ultimaker2 marlin source: https://github.com/Ultimaker/SecretMarlin Instructions are in the README file. Here's my explanation: Basically you download and install arduino ide: http://arduino.cc/en/main/software Then copy the sanguino software as explained in README file. Open Marlin.ino file in Arduino IDE by double clicking it (not pde file as stated in README - I think that's old). Select board as "Mega 2560" as explained in README file. Go to "file" "preferences" and select "verbose output" so you can find your hex file. Then build it by clicking the check box in the upper left corner. At the bottom you will see it compiling Marlin. At the end of this it says where the hex file is. If you are currently connected to your UM through USB you can just click "file" "upload" and you are done! But you should locate that hex file and save it somewhere along with the Configuration.h file used to create it so you can recreate the same version with maybe one change. Also you can upload the hex file using Cura. Alternatively you can build Marlin with somewhat more detailed step by step instructions the command line way (which I don't prefer): http://www.extrudable.me/2013/05/03/building-marlin-from-scratch/

To print multiple parts "all at once" you can set the gantry height to 0 in machine settings. That's a quick way. The cool head lift is a very nice option for fixing the top. One way to fix the bottom brim is to move the head a tiny tiny tiny bit away from the glass. Another way is to maybe print the bottom layer thicker. I usually print bottom layer .2 or .3 and the rest thinner. Did you do that? This can help a lot with that extruder slipping on the bottom layer. Now finally - the blobs on the corner. Not certain how to fix that. I think it's probably caused because it slows down quite a bit at each corner from 30mm/sec along the edge to about 10mm/sec at the corner but the extruder still has pressure. Really not sure what to do. You could lower the speed to 10mm/sec of course but that just seems silly. Maybe lowering the acceleration to around 1000mm/sec would do it? And hopefully not slow down the print as much as lowering to 10mm/sec would! Raising or lowering temp might help: raising because pressures won't build up so much, lower because built up pressure is less likely to force out too much pla. Not sure what will happen.

Maybe it works anyway? If your UM is still relatively new then you should be able to get a free replacement at support.ultimaker.com. It's not easy to swap heaters - you have to change the firmware a bit. Actual code changes. Easier to unsolder and move faulty components over. Is anything actually broken other than the plastic? Can you just solder the heater cable instead of screwing it in?

I think maybe it *is* a PT100 RTD in the print head. I'm pretty sure that's what Illuminarti claimed after reading the Marlin code for the UM2. Maybe he's wrong. But this is a new device for me. I've heard of thermocouples (which are sensitive to noise) and thermistors (which typically get damaged a bit if they hit 250C) but not these "resistor thermometers" which can typically go up to 450C and aren't so sensitive to noise.

At first I thought - robert is clever - he thought of something I didn't consider. But thinking about it more I think the moves during calibration are single LONG moves. So I don't think it's USB related. I would check the power supply voltage - the 19V - see if it is dropping down to 12V or something a few times per second. I would get prontrface - it's free: http://koti.kapsi.fi/~kliment/printrun/ Connect to the printer with that and do controlled movements of 100mm at a time at different speeds. Try to figure out what is going on. I've never heard of this. Maybe post a video?