gr5

I'm confused too. I usually do all-at-once. The 2 or 3 times I didn't it "primed" right over part of my second print and made a bit of a scary mess and dragged it around while I tried to grab it with my fingers. The gcode shows retract only. Maybe look at some more gcode before and after this bit? Other (competing) printers/slicers do the start of the "skirt" near the front edge of the printer - a line maybe 50mm long to clean the nozzle before starting the skirt. I don't want to always have to grab the initial prime with my fingers. Especially yesterday when I was trying to talk to people at a show at the same time.

That happened to me several times in the past few days and it was always that I had left the nozzle hot for 10 minutes wihtout priming it just before starting the print. You have to grab that gear and make sure it's primed before starting. However it's also good to do the first layer at 230 or 240C. I always set the temp to 0 in cura and set temp to 240 and when it is passing 230C I start the print (you don't have to wait for warmup if temp is 0 in cura), then when first layer is done I lower to the temp I want - which could be anywhere from 190 to 240 depending how I feel. 220 is a nice compromise for UM2 and 210 for UM1.

In the expert "cool" settings there is a "minimum layer time". This should be 5 seconds which will cause upper layers to print slower so that other areas have time to cool. I don't know if the "spiralize" overrides this setting. 5 or even just 3 seconds should be enough with fan on. 5-7 seconds are needed with fan off.

Most important things: 1) 100% fan by the time it gets to the overhang - there is probably zero fan on the first 2 layers. 2) not too hot. 220C should be okay but 210C better. 200C even better but then you have to print more slowly or it will underextrude.

I'm away from home so replies are slower than usual. Illuminarti also. Well it's probably feeder issues. The first thing to check is for filament tangles. And how the filament feeds - you want it as straight as possible as it feeds into the feeder. I sometimes put my filament roll on the floor in a wooden holder I built. Also, is the feeder (hopefully it is) on the topmost/loosest setting? The two white squares in the slots of the black feeder should be all the way to the top. Watch the feeder on the back while you print - does it slip backwards just when the bad extrusion starts? It could also be that your print head is a tiny bit too close to the glass. Although I think this is unlikely as once the bad extrusion starts it never seems to recover. Please answer about the slipping backwards feeder. Also there could be temperature issues (too cold). Does the temperature of the nozzle bounce around? Go to the tune menu and watch the temp while it is printing. It shouldn't change more than 5C. 250C is dangerously hot - I don't like to go over 240C. If you leave PLA in there at 250C for a whole minute it can cook it into a brown goo that may never completely come out of the nozzle without burning it to ash in a gas flame.

I'm pretty sure if you contact support.ultimaker.com they will send you a new nozzle for free. If it were me I would purchase some THF on the internet and leave the nozzle in a cup of it overnight.

The feeder stepper motor for the Ultimaker machines is on the back of the machine so the head is very light weight. The default acceleration is 5000. Some people lower it to 1000 which some people find makes ringing better. Default jerk I believe is 20mm/sec. That's basically the max instantaneous velocity change at a vertex. So yes, you could lower this proportionately (if you cut one in third, cut the other in third. Maybe). edit: "velocity change"

Please provide more details. When you tell the heater to heat up, does it show current temp as for example 21C? Or 0C? Or is current temp > goal temperature?

You should be fine. Do you have the old hex file in case you want to go back to an older version again? robotfuzz works quite well. yes I suspect the only thing is the steps/mm for extruder. So you can calibrate that and set it to whatever you want.

Yes. There's a ton of ways to do this - maybe the easiest is you can just add a gcode to do this.

240C is a safe temp. You will not burn the PLA. You will be able to print much faster at 240C than at 220C. The biggest disadvantage of 240C is that you are more likely to get stringing.

This article explains how to increase the current to the extruder. I don't recommend it as you are likely to instead grind your filament. It is better to slow it down instead: http://umforum.ultimaker.com/index.php?/topic/4222-pulling-force-of-um-extruder/?p=35887

If you are at 250C and extruder skips you should slow down the print. You can simply reduce the "feed rate" from 100% to say 80%. Or slower. Increasing the flow will make things worse.

To post a photo first go to the top of this page and click on gallery, then upload. Later make a post and to include picture click on "my media" next to smile face.

Not enough voltage for arcing. But if the resistance was between .1 ohm and 1 ohm due to not clamped down on the wiring then that will cause a lot of heat. Your current fix is probably permanent. But if not, you can ask ultimaker for another pcb. Contact support.ultimaker.com. You should probaby do this before 3 months from when it was shipped. If it was me I wouldn't worry about it and if it happens again I would just fix it myself.

It doesn't look like underextrusion to me. The infill completely covers the whole area except for the edges. I think it's backlash due to either something loose or something too high friction (both can cause backlash paradoxically). Check out this explanation plus the post above that shows photos of parts with backlash: http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/?p=14474 Grab the nozzle tip and push it around and make sure nothing is loose. Backlash is usually the belts but sometimes in the print head assembly.

You can remove the M92 temporarily to view it in layer view, and then put it back in before printing. Not the most pleasant work around.

These gcodes are from long before 3d printers existed. G1 is supposed to be linear I believe and G0 is just supposed to move the axes in any order (uncoupled). But for Marlin it just does them both the same way. But Cura seems to sometimes use G0 and sometimes G1 as needed.

After print starts - go to "tune" menu.

I think you need to move the bed slightly closer to the nozzle. When you level. The bottom layer shouldn't drag the circle around like that.

By the way there are many contributors to Marlin including some very smart people. That code you looked at has been looked over by me and probably 100 other people. It seems strange at first but it is pretty well done. It even looks 12 segments/blocks ahead of time so that it doesn't have to stop. For example if printing a circular path the old firmware (before marlin, before sprinter) would come to a complete stop at every vertex. The new software hardly slows down at all due to the "jerk" setting which isn't jerk but more maximum instantaneous velocity change at a vertex.

It is VERY IMPORTANT for the X,Y,Z,E axis to all 4 move linearly. In a straight line. If the extruder ran max speed for a block it would finish early and you would get overextrusion for the begining and zero extrusion for the end of every line segment. One way to think of this is that all moves are in a straight line in all 4 dimensions. Even the acceleration is matched in all 4 axis so that it is a straight line even during acceleration and deceleration.

Good to know - nice technique. 35C is pretty hot. You probably don't get shrinkage issues as bad as me - it's like printing in a heated chamber.

I made a few changes to the default mexmixer settings. I like my supports at least 6mm diameter or even 8mm and the base needs to be 8mm or more and it's important to use "brim" in cura or the supports may get knocked over. Where the supports touch the part I set the diamter to I think 1mm or maybe even smaller so they snap off easily. I used wire cutters that got in there carefully and pried the part off (the cutting blades never quite reached any plastic). Also I set the tilt of the supports as vertical as possible. Something like 70 degrees (where 90 is vertical)? Also it's important to have fan at 100% or you get lips on the supports and they might get knocked over while printing.

This is called the "thin wall problem". There is a "torture test" item on thingiverse designed to test many things including this very problem - it has a box where each of the 4 walls get thinner and thinner. I have lost track of which version of cura handles thin walls like this better and why and what the issues are/were because cura has changed it's strategy on these twice. Basically a good slicer can get in there and fill that gap. You can fill .1mm gaps by just underextruding with a wider nozzle as though it's a .1mm nozzle. It works pretty well. The PLA flows in there like honey into a groove. Like spackle into a nail hole even though the putty knife is wider than the nail hole. But you need a sophisticated, mature slicer. And this may be in some obscure option in simplify3d. Or maybe you just didn't tell it to do 100% fill in thin walls or something and it's doing a sparse infill (say 10% infill).