sbob

I liked the idea of hiding the underextrusion by adding another layer, making the side walls 0.8 mm thick. So I printed at 90mm/s and 230C, re-checked the combing enable option. The result was that the added material amplified the warping problem so much that the print crashed. It was not that the plastic lifted from the tape, it was that the tape lifted from the plexi-glass print bed. I used a brim and when that was printed I added tape on top of the brim that I then folded around the edges of the print bed to hold it in place. No luck, it lifted the whole thing and tore the tape... My conclusions from all this is: 1. Cura needs to both reduce the number of, often unnecssary, long travels and to add retraction in order to not loose pressure that leads to underextrusion. Or compensate in some other way. 2. Printing a box this large is not possible without a heated bed. Maybe if the temperature is set lower and print speed slower, but then it would take more than 30 hours to print it, in my case. Luckily I have some of the parts needed to build a heated bed lying around so I might give this print another try some time. Thanks for all the help, I have learned a lot about printing!

Sounds plausible. Explains most of the underextrusion, probably also the parts between the five 7 mm holes on the back side. Why it started to underextrude completely in the last few layers is still a mystery though, although the filament looked a little gouged so maybe debris clogged the nozzle? Did another print where I unchecked the combing enable option and increased travel speed to 200 . Now it retracts a lot everywhere, leaving little knobs where it does. These knobs make the outer surface uneven, with some holes in it, and there is severe stringing messing up the holes so not a total success. The underextrusion got slightly better, but still showing the same type of patterns. I guess I have to re-think how I print this thing. Either print slower or split it into several parts, the four walls and bottom printed laying down on the bed and then glue them together. Any ideas on printing slower, would it improve the underextrusion problem?

It is a UM1. I have posted the Gcode at: https://www.dropbox.com/s/c6vtl7jye25u12y/CNC%20Foam%20cutter%20box%201.gcode Checked the STL file and it is 1.9 Mb. I also looked in Cura. There are more blue lines than I would have thought necessary, but since I have not looked that closely before it could be normal. Does it retract every time there is a blue line? If I understant illuminarti correctly UM will slow down for details, and then behaves a bit like a caulking gun and oozes even though you stop pressing. That would explain the bad part after the little round hole. It also would explain why it then slowly gets better, as pressure builds up again. Still, would it not have done the same after the text in the middle? Or after the big holes? Will try "Horrible settings" tomorrow.

I am having problems with underextrusion that are a bit different than the other recent thread about underextrusion. I am trying to print a rather largish box for a CNC circuit board. With my normal settings it would take 15 hours to print according to Cura (Which probably means 30 hours IRL). In order to get it down to reasonable levels I have printed it at: 0.2 mm layer height. 90 mm/s 230C 0.4 mm wall thickness, 0.6 mm bottom and top thickness and 20% infill. When first experimenting with these setting there was no problem at all printing a 20mm cube, it was even possible to print at up to 150 mm/s. When I printed the box everything was OK to start with. However, the problems started when there were details and not only smooth surfaces. I got lots of ugly underextrusion, see picture. After the details it was back to smooth walls, but then it got even worse! As you can see in the picture the top layers are hopelessly under extruded. While printing the top layers I tried to change the settings while it was printing to see what was wrong: - I slowed it down to ~30mm/s - no change. - I then looked at the filament and the extruder and changed flow up to 150% - it was making deep marks in the filament so I think it has strength enough but is slipping on the filament. The spool was running smoothly. The funny part is that it was working fine until after the details halfway up. So it seems that my settings were ok. Have there been any previous problems with the temperature regulation? Might the reason for my problems be the same as for random underextrusion? I would really appreciate some help. I could of course revert to printing really slow, but since it works sometimes it would be nice to not prinitng for 15+ hours.