I have a very large print (at literally the max my width my printer can do). The side towards the front is pulling upwards apparently hard enough to pick up the tape off of the bed.
Two questions.
1) Any idea why this is happening and what I can do to fix it? My first guess at this is that because I have a very large, open frame printer (IdeaPrinter F100L), that the part towards the front is getting too much draft, causing the plastic to dry too quickly and create an upward force on the tape. (Perhaps next time I print something this large I can put something in front of the printer?)
2) How should we handle large prints that have defects in them for customers? This print is only half of the entire object and takes a day per piece. This same problem happened to the other print in the same spot on it (towards the front of the printer).
Just been dealing with a difficult large print for several days ourselves. Basically, you’re right, it’s caused by uneven cooling. The lower layers stay heated from the build plate while the upper layers cool, causing contracting forces in the print. Now on small pieces, these forces are usually not enough to lift the print, but are actually still present inside the finished piece. In big pieces the effect is much worse, and the outer corners/edges will lift.
The best way to fix this would be an enclosure with temp. control… but there’s a few other things you can try that will help.
1. More solid bottom layers. This will simply help strengthen the structure to lessen warping.
2. Use a tall and close-proximity skirt - This helps trap hot air around the outside of the print to keep it evenly warm
3. Check that your build plate has consistent heating - many plates have dead zones where the wiring is, or where there is no insulation (usually around the edges) Use an infrared thermometer to find out. If there’s a big difference in some areas, position the print in an area where there’s minimal variation.
4. Lower the bed temp after the first layer to as low as possible before you start losing adhesion. This will help create a less extreme temperature gradient in the piece.
5. Reduce fan cooling as low as possible without letting the layer quality suffer.
The worst part about these prints is it takes forever to retry them! Good luck.
For prints like that I usually use a brim, it helps spread the pressure out and prevents warping of the parts. Unless you have a closed build area and a heated bed, that might be your best choice.
Lot of comments on build surface, I too would also recommend 3D-Eez or PVA glue. I also print on a heated bed, mk2b, perhaps you can add it or something similar to your bed somehow.
Nobody really touched on the options to enclose the printer, so here goes:
- In an emergency, like when you’re working on an order, and start experiencing problems, rip some cardboard boxes up and makeshift some panelling!
- Longer term, you could get some clear acrylic sheets online, or some clear pvc. This way you retain visibility. You could design and print any fixing brackets required, or punch some holes and tie with string. Make a door so you have easy access mid-print etc.
The back is enclosed already, and even doing just the sides might help. You can also heat the chamber, either with a hairdrier or a heat gun.
The only thing is My first print bonded so tightly I thought I was going to bend the build plate trying to remove, so I highly recommend covering with a thin layer of Elmer’s disappearing purple(haven’t tried others).
Also I used to use ABS juice, but prefer the build plate 3m “glue plate”
This company also sells an acrylic enclosure for like 7 bucks!
