print shifts and curls up

Hello there,

i have a couple of problems i hope you can help me with. I will explain it one by one.

1. when i start printing, almost all prints shifts during printing. I mean that the print does not go straight up, but almost every layer shifts a mm down. This will result in a 'not straigt print' I have attached a picture so that you can see what i mean...



What can i do about this.


second problem is that the prints curl up. See attachment picture for the result of a 'bigger print'. I use rough tape to let the pla stick. Works fine, but now i see that when i print 'bigger' things the pla is more powerfull then the stickyness of the tape and pulls the tape of the bed.



hope one of you has the solution.

many thanks

Iwan

 

thanks for the tips....i use 220 degrees for the extruder and 60 degrees for the hot bed.

About the belts..i will also look into that and tention it a bit.

I will post the results.

Iwan

 

Use Aquanet Extra Superhold hairspray with no tape. Print at 50C. Dry at 60C if you want it to dry fast. Use water if it is difficult to get off the bed.

Does it curl up before the layers start shifting? If so then the hot end may be hitting the curled part and stalling the stepper. This would then cause a shift each time it stalls.

 

60C for the bed is a bit high for PLA. Also for some PLA ( Prototype Supply on Amazon) I go up to 210-215C on my E3D hot end. My thermistor may read high though.

 

I use 65C and have no issues. Before every print i wipe the bed down with methylated spirits to ensure it's completely clean for adhesion. That's it. You will have to tweak you first layer print setting to get good adhesion too. Check the bottom of your prints, the lines should be squished together but not look like one totally smooth piece.

 

Yes - it is probably OK. I just try to keep it away from the 60-65C PLA glass transition temp because I only heat the bed for adhesion and have no problem with warping. For ABS you want to keep it close to the glass transition temp.

What brand PLA have you been using a bare glass bed with? Do you need brims for narrow parts?

 

Glass transition?

I'm using 3dprintergear's standard PLA with no brim (apart for a single layer perimeter to prep the extrusion) and no raft.

Originally I was using 50C as suggested but was having lifting issues so changed it to 65C for the entire print and resolved it. You must clean the bed with methylated spirits before each print if printing in plain glass.

 

http://en.wikipedia.org/wiki/Glass_transition
http://reprap.org/wiki/PLA
The glass transition temperature applies to an amorphous material and is where it starts to flow. There is no true melting point for amorphous materials.

Thanks for the details. I will try the higher temp and a clean glass. I would be very happy if thin sections stick but I'm skeptical. With Aquanet hairspray some prints are a bit too hard to remove from the bed.