Print Problems BB-8 Outer Sphere
Attached is a photo showing two triangles that I've been trying to print on my MK3 in PLA. I've done all the triangles for the inner sphere for a BB-8 with no problems. I'm using Prusa Control with support only from the build plate and with a brim. In this case having support from everywhere wouldn't add more because everything is so upright. After about 7 hrs 43 minutes the nozzle hooks the part and brakes it free. Acetone is used to clean the bed. I've checked belt tightness and the tightness of the set screws in all the pulleys, everything seemed ok. Any suggestions Would be welcome.
Re: Print Problems BB-8 Outer Sphere
Are we seeing layer shifting on the left hand side of the part? Can't quite tell from the viewpoint. Can you add a close up of the surface detail where the defects are?
Re: Print Problems BB-8 Outer Sphere
I'm still quite new at the printing game, but I believe you're supposed to use Isopropyl Alcohol (rubbing alcohol) on the bed for PLA and acetone on the bed for ABS.
I know when I started using isopropyl alcohol on the bed my PLA prints stuck dramatically better.
Re: Print Problems BB-8 Outer Sphere
Thanks Martin for your comments. I too thought it was layer shifting on the first one. After checking all the normal suspects, I started printing the second example. At about the same height I saw the part shift to the extent that it broke free on one side. As a result, the nozzle hooked the top of the part but continued to extrude plastic.
The top edge of this part has two wide triangular tabs that connect to the adjacent part.
The bottom edge is half the thickness of the rest of the part because this overlaps the adjacent part in this direction.
I wish I could add more support at the bed.
As far as cleaning the bed. It was my understanding that alcohol could be use but if a failure occurres then acetone is used. I used this on all the many triangles that I printed for the inner sphere with no problem. If fact they are beautiful.
Re: Print Problems BB-8 Outer Sphere
Since acetone dissolves ABS, I think it's used to "clean" the bed surface after any ABS prints to get rid of any ABS residue.
The isopropyl alcohol actually cleans the bed by getting rid of oils & contaminants. BTW, I'm just referencing the Prusa support section on this ( https://www.prusa3d.com/material-guides/ ).
If this is off-base feel free to let me know. Again, still very new to this. I spent a couple days figuring out how to get the first layer of PETG to stick to the bed and it's supposed to be one of the "stickiest" plastics to print with.
Re: Print Problems BB-8 Outer Sphere
How narrow does it get at that point? I had a problem with a part that got narrow and at that point it detached from the bed. The problem turned out to be the thickness approached the number of perimeters at that point. Then it tried to force some infill in but it wouldn't quite fit and bulged up. After a layer or two the bulge was enough to foul the nozzle and after a couple of collisions it detached.
Setting 'Detect Thin Walls' in Slic3r sorted my issue out...........
S
Re: Print Problems BB-8 Outer Sphere
Well, I didn't believe it at first but it proved to be a loose "X" belt. It felt tight but I was easily able to tighten it by two notches.
After doing that, my 10 hour print came out perfect. Thanks for all the comments.