Trouble with ABS on i3v 10" [PICS]

[jumi1174]

I'm having trouble getting ABS prints to stick on my 10" bed. I'm trying to print a test cube with sides of ~4 in. First layer goes down nice, really smooth and squished, but then about halfway through the total print, the corners start coming off.

Based on older threads in this forum and suggestions from around the net, I've compiled a list of solutions (in no order):
1. Bed at higher temp (115 C and higher)
2. Wide brim
3. High skirt
4. Glue stick (instead of hairspray)
5. ABS slurry (instead of hairspray)
6. New fan shroud + fan
7. Enclosure for printer

As you can see in the pictures below, I tried a combination of 1, 2, and 3:

(Fresh off the heat bed)


(Underside of glass, fresh off the heat bed)


(Bottom of print)


(Good view of how the bottom is compressing in the corners, warping the print)


I set the bed at 120 C for the first layer and 115 C for the rest. I created a brim of 8mm and a 75 layer high skirt 4mm away from the part. I was hopeful that all this worked because the skirt or brim never warped. But alas, when the piece finished, the cube itself had started curling (albeit less severely) at the bottom corners. I wasn't running any air conditioning near the print, and I taped up areas on the extruder where fan drafts where blowing on the bed. I also sprayed the bed multiple times with a liberal amount of hairspray for good adhesion.

I guess the next step is to try the glue stick or ABS slurry? Is it really this much trial and error to get clean ABS prints?

Any advice or thoughts?

Thanks in advance.

[beerdart]

Bed temp 70c ABS slurry raft or brim using Cura has been good to us. Its very difficult to eliminate part shrinkage on a dense part.

[Steven57]

250* then 240* extruder, 115* then 110* bed, Elmers Purple glue stick, no brim, 1 layer skirt and I haven't had any warps. I do have an enclosure started with 8" sides.

[TopJimmyCooks]

no expert here but both my brother and myself have had success with designing parts that have some internal strain relief and only one main axis of shrinkage. That cube is going to be super hard since it has about equal strain from shrinkage in several different directions. IE the sides are contracting inward unconstrained, pulling up on the corners.

look at the hotend fan shroud for Clough42's itty bitty double extruder - another thread on the front page here. it has mouse ears and only contacts the bed at those locations. so the whole thing may shrink some, but in a way that doesn't pull hard enough to pull the pads off the bed.

Try the minimum fill percentage you can deal with and still fill the top.

[jumi1174]

Thanks for the replies. I tried using the Elmer's purple glue stick, and it helped, but there is still a decent bit of warping in the corners. I'm designing an enclosure now, so I guess the next step in the mean time is to try the ABS slurry.

no expert here but both my brother and myself have had success with designing parts that have some internal strain relief and only one main axis of shrinkage. That cube is going to be super hard since it has about equal strain from shrinkage in several different directions. IE the sides are contracting inward unconstrained, pulling up on the corners.

look at the hotend fan shroud for Clough42's itty bitty double extruder - another thread on the front page here. it has mouse ears and only contacts the bed at those locations. so the whole thing may shrink some, but in a way that doesn't pull hard enough to pull the pads off the bed.

Try the minimum fill percentage you can deal with and still fill the top.

Could you elaborate on this please? What do you mean by "internal strain relief" and "only one main axis of shrinkage?

[Roxy]

Could you elaborate on this please? What do you mean by "internal strain relief" and "only one main axis of shrinkage?

Take a look at this post: http://3dprintboard.com/showthread.p...ll=1#post38860

I didn't have a choice in the matter. I switched from ABS to PLA and that helped. But it didn't help enough to resolve my warping problems. Two things were done to stress relieve the long beams. I added code to take the 'normal' beam and drill holes in it. Both big and little holes. And on the bottom side of the beam, I cut very small notches so there was only an inch of material pulling the edges up of each little section. The top is solid with no notches. By the time that gets printed, there is enough strength to keep the beams from warping.

I suggest you pull the attached file into OpenScad. You will be able to rotate things and change parameters to have it build different ways. It might give you some ideas on what you can do to make your design more Print-able.

[roybfr]

When printing taller objects I started adding more external walls/perimeters and lowering the infill in order to combat warping and worse layer separation. I also moved to hairspray on kapton tape, but IMO that over ABS slurry is just a matter of personal preference.