Terrible bed adhesion
Hi all, ever since I upgraded my Mk2 to Mk2.5S I’m having really bad issues with bed adhesion and bed temperature and I wanted to see if anyone had some insight because I’m getting to the end of my rope here. I’m noticing two primary things.
- I’m having trouble getting my prints to stick, particularly I’m seeing warping on the edges/corners of my prints that often leads to the print failing. This happens with both PLA and PETG, even for prints with large flat bottoms that should stick well.
- My bed temperature readout on the screen is constant but if I read the temperature with an infrared thermometer the temperature is often 10-20C cooler in some places during my prints, which I suspect is contributing to the first problem.
What I’ve tried to improve adhesion:
- Cleaning the PEI magnetic bed with isopropanol or dish detergent.
- Using glue stick, either a small amount smeared around with a damp cloth or a thicker layer covering the whole bed.
- I very lightly sanded one side of the magnetic sheet with 220 grid sandpaper to give the plastic something to grip onto.
- I incrementally increased the bed temperature all the way up to 80C and still saw corners warping with PLA.
- I carefully leveled the bed using the G80/G81 gcode commands and thin washers.
- I enabled 7-point mesh leveling.
- I tried several different types/brands of filament.
- I adjusted the first layer calibration as low as I can without scraping and clogging the nozzle.
Nothing seems to help. This is particularly frustrating because I actually upgraded to the magnetic bed because my bed adhesion was so good I had trouble getting my prints loose.
Anything else I can try? I’m having 75% or so of my prints either getting knocked off the bed or getting cancelled because the warping is so bad I’m afraid of damaging the print head. I’m really wondering if there is some sort of issue with the magnetic bed preventing it from holding temperature correctly all the way across the plate, leading to poor adhesion.
Thanks!
RE: Terrible bed adhesion
I have recently been through the saga of upgrading a MK2S to a MK2.5S and a MK2.5 to a 2.5S
Here are is what i have done to get them to a point where i am happy.
- Clean and re-apply (liberally) heat transfer paste between heatbreak and heatsink. I strongly advise this is done.
- Re printed all hotend parts from My Mini Factory so there is correct alignment of the filament path. Again strongly advise to do this.
- Added an M907 command to my start G-code to increase extruder motor current.
- I am in the process of adding cooling to the extruder motor. Outside of an enclosure the motor temps are fine but when i'm doing an ABS print in my enclosure with one of my hot profiles it can get a bit toasty.
- Made my own part cooling duct because i think the standard duct is poor. My duct allows better cooling so i can turn down the fan creating much less air wash over the hotend, bed and printed part. This means more stable bed temps, less part warping and better over hangs.
- Upped my power supply voltage to 13.4V
- Insulation under the heatbed
- Turn on 7x7 mesh bed levelling
- Because of the changes my profiles are heavily modified.
- I have both smooth and textured beds. On the textured bed i went over it with a fine wire brush. It makes no difference to the finish on the bottom of the part but bed adhesion was much improved. On the smooth beds as long as they are clean the adhesion is very good.
- I have a pinda heating procedure in my start G-code so every print starts with the pinda at the same temperature.
I can't think of anything else right now but don't be afraid to bump up your bed temps but just bear in mind that the standard part cooling duct just chucks air all over the place which cools the bed in that area and also promotes warping of the part. I think there are some improved ducts on Thingiverse.