Please help! My large prints are lifting on corner.

[hoanggy 0]

So I just got my UM2 today and doing some prints. The small one are fine but the larger prints (more contact with the bed) warp after 30 mins on the edges. I used Brim set up and have support on. My thought is the temperature different between the layers closer to the bed is much higher than the top layers to the top layers shrink which lift the corners up. I changed the bed temperature but have no idea what's the right temp to put? Any idea? Thank you so much!

 

[ian 32]

good morning :-)

first did you try using glue stick ?

then how much brim did you use... for me when i need to create large flat parts.. i use a lot of brim.... it really does help.

Also I think the standard temp for the heated bed is 70... bring that down to 50..

Also for the first 1 hour... print slower ! and also for me this works atleast... cooling fans on the print head 100%

Also make sure that your print bed is really setup perfectly... so when the print head moves around.. you get a nice squeezed a little pla flow... not just a string barely standing on the surface.. like a thick paint stroke.. then you should have a concrete base for your print !!

hope that helps !

Ian :-)

 

[gr5 2,234]

Ian has great advice - all those things help the part *stick* better. But there is another technique that instead reduces pulling forces.

Another technique is to do all that but instead RAISE the bed temp a little and keep the fan off (although 70C is usually plenty). This second technique keeps the bottom 10mm of PLA *above* the glass temperature so that it is soft and mushy and the pulling/shrinking stesses deform it a little but not enough to pull it off the bed. This second technique usually requires the fan to be *off*. However only use this second technique for large parts - parts that take more than 15 seconds to print a layer.

If the top layers of the part print less than 15 second you need to turn the fan back on at that point.

A third technique creates a heated chamber. This isn't usually necessary.

 

[IRobertI 521]

If you do go the hotter bed and no fan option be aware that overhangs that are on the lower part of the part might come out, and I'll use a scientific term here, crap. Since the plastic is so soft it tends to sag down.

 

[hoanggy 0]

Ah! Thanks guys! I used ABS and it didnt work any time for a long flat print I knew about the head chamber technich from my previous experience with makerbots. I used to have to run 4 of them at the same time so I know the paint when you have to babysit them to make perfect prints. Im new to the heated bed and ABS plastic though. I changed back to PLA and it's all fine. They stick to the plate like hard glue. I still dont know how to work with ABS though. Maybe it's too cold where I live ( about 0 C out side). for now I will try to get my work done with PLA and mess around later with ABS. Thanks! I think Cura compare to Makerware is more stable when it com to slicing but the support structutrs arent the best. I'm having trouble with building parts with very limited contact with the bed to start with... Cura doesnt want to build supports for overhangs like "everywhere" like it says there. and the supports are a little bit hard to get off... Do you know what configurations are to have the best result?