I am having an issue with the first layer sticking on top of a raft as seen in the picture. I am using simplify3d as the slicer with standard parameters for the printrbot with e3d v6 nozzle. Any suggested adjustment I should make? The raft printed beautifully, its the first later of the print on top of that the issue.
I can tell from the picture your layers are not cooling properly which may be the cause of your sticking issue. What material are you using and temp? Is the fan set to turn on at after the raft layers?
I am using 3D Solutech Real White PLA at 210C. The fan turns on after first raft layer, so its on by the time it gets to the first model layer. Very odd… I am thinking the problem might be need more air flow as you pointed, as the temperature on the garage the printer is on is at 90F, not sure if that makes a difference or not.
Yeah - looks too hot perhaps…
Are you using the stock unheated bed? I had a similar issue after dialing in my z-offset perfectly, but the issue was more pronounced which made it a little clearer. The bent aluminum sheet used for the bed simply isn’t flat. It has hills and valleys in it that vary a few tenths of a mm, which isn’t much but since we’re talking about printing at a .1 mm resolution it becomes significant.
I was able to minimize the issue by lapping the bed plate. Use spray adhesive to put a good quality 80 grit sandpaper on a dead flat surface - I used a 24"x24" granite tile. Spray the paper with water, and rub the plate against it. Keep spraying the surface every few minutes to wash away the swarf. Every now and then wipe the plate clean and draw a cross hatch pattern on the surface with a sharpie. Take a few passes on the sandpaper and look at your plate again, you will see that the sharpie is worn off of the high spots, but remains in the low. Keep going until you feel the plate is flat enough.
I spent a couple hours a day for three days doing this, and I didn’t get mine completely flat. I think I would have gotten better results with a better sandpaper. Make sure you use something that is wet/dry rated. Also consider starting with 60 grit instead of 80. I figured 80 would be a good coarse starting grit but it cut very slow. I don’t think I would go much lower than 60 though otherwise I think you’ll get more deep scratches than you can get out.
This is a pain in the ass and takes a lot of work. You can also just get an upgraded build plate, or deal with the first layer issues if they’re not otherwise affecting your print quality or adhesion. Unfortunately adding a build surface doesn’t help, I first noticed this after switching to buildtak as a print surface which is why I spent the time to really dial in my offset. The buildtak sheet wasn’t rigid enough to overcome the plate surface issues. Something thicker may work.
Turn your fan off for the first 2-3 layers of your actual print, it looks like the cooling fan is curling the first layer above the raft. This is because it’s printed with a slight gap to allow the raft to be removed later.
plastic is cooling to quickly causing the edges to curl
Environment temps and weather can effect the print. If you don’t have proper ventilation in your garage the, temps and humidity from outside can affect the quality of the print. Unlike ABS, you don’t want heat building up when printing and I would image a 90F garage isn’t helping.
I would recommend experimenting bumping your print temp down to start. 210 C on a printrbot for PLA seems a bit high. I never had to print over 200C for all brands of PLA I’ve used on my printrbot. A second external fan may be beneficial too especially if you are printing at fast speeds.
The solution in my case was to decrease the temperature to from 210 to 200. I also stopped the fan on the first later of the print on top of the raft. The picture shows the original settings on the right, and the updated settings on the left. A definite improvement.
Many thanks for all the suggestions!
