My ABS is weak.

3D Printing
, , ,
1

My ABS is weak. Do you change your extrusion multipler between PLA and ABS? +IGentUS is making awesome PLA prints (Aria a few posts back was in PLA), but ABS, even with a semi-enclosed print area, and slower printing, just isn’t making things stick together. The parts come out, even at 50% infill, feeling light, and a firm twist will get them to fall apart.

I’ve printed from 230C-260C, from 50mm/s to 120mm/s, extrusion multiplier from 1.0 to 1.3…this last one is 1.3, and it looks good, but man…30% over what the actual, ‘request 100mm and get 100mm, really entered the right diameter values’? That just doesn’t seem right.

2

What ABS Brand? What layer height?

3

Monoprice, but I’ve experienced it with two other brands.

4

You aren’t running a part cooling fan are you? Also try and set your extrusion width a little higher. I have never liked the strength from the default 0.48 width for my 0.4mm nozzle. I like 0.52.

5

If none of the above helps how has it been stored? I know I harp on about it in many threads but could water absorption be a cause of your problems? Try dry drying a good length out in the oven for a couple of hours and see if it prints better.

6

This roll came out of the factory bag 48 hours ago, and it’s Winter in Colorado…humidity is in the single digits.

Eric: Part cooling fan: I wasn’t before, I am in this current print.

0.52 on a .4 nozzle would work out to 25%, so ballpark for the 30% I’m playing with now.

7

@Mike_Miller extrusion multiplier or extrusion width? They are different.

8

ABS is a little softer than PLA, so the teeth of the hobbed gear can sink more deeply, causing it to require more turns of the hobbed gear to push through the same amount of plastic.

I’ve never had problems with ABS parts being weaker than PLA parts necessarily but agree on not using cooling fans except minimally.

9

Low temps can definitely result in significantly weaker prints. A good extruder can still squirt out below optimum temp abs, and as a result layer adhesion really takes a hit…

10

I never use a fan on ABS parts and rarely have layer adhesion problems and they are from being not hot enough. Did you autotune your new hotend ?

11

I did. I’m thinking it was under-extrusion. 230c, 1.3x flow seemed to make things a lot better.

12

May be worth checking your e steps then as that’s a huge multiplier.

13

You did measure the filament diameter, right?

14

The e-steps were calculated with the bowden disconnected from the hot-end and pla. 100mm requested was 100.3 mm fed into the top of the extruder (with PLA). 1.70 measured, 1.70 entered, @Thomas_Sanladerer .

I think @John_Davis had is nailed with the change in effective diameter due to the softer plastic. 1.3 just currently makes it print better. 1.05 with PLA makes for perfect Layer 1 infill.

I think my home-hobbed bolt in my Wade’s extruder is holding me back. It doesn’t like speeds much above 70-80 mm/s. I see a Gear-head extruder in my future (http://printrbot.com/shop/gear-head-extruder-v0-01/).