RoboDLC
Posts: 51
Joined: Sun Apr 23, 2017 2:30 am

My ABS prints break easily

Sat Jul 15, 2017 6:43 pm

I print my ABS model. It prints beautifully (as in it looks great). When I flex spots that need to flex a little bit, the ABS just snaps off. I am using only finger pressure, not pliers mind you. I can just snap off a 5mm thick piece, with not a lot of effort.
This shouldn't be, so I am clearly doing something wrong.
I am printing eSun ABS at 235 C, bed at 100 C, .3mm layers and 50% infill. In fact, I can, with effort, break a 3cm construct along a layer line.
This suggests that the layers really are not fusing/bonding.
My printer is not in an enclosure, it is in my basement where it is always cool.

What should I do? to correct this. Please keep in mind that I cannot afford a huge enclosure...

Many thanks,
DLC

jfkansas
Posts: 84
Joined: Wed Oct 01, 2014 2:12 am

Re: My ABS prints break easily

Sat Jul 15, 2017 8:03 pm

It helps to see the model.

Thinner layers will "smash" together a little bit better. Try .2mm. Print slower, maybe up the temp a bit to 240. Usually higher temps (to a point) fuse together better with the previous layer.

Gotta look at your infill structure also and infill to shell overlap. More shells (at least 2) should be a pretty strong wall.

RoboDLC
Posts: 51
Joined: Sun Apr 23, 2017 2:30 am

Re: My ABS prints break easily

Sat Jul 15, 2017 8:24 pm

jfkansas wrote:It helps to see the model.

Thinner layers will "smash" together a little bit better. Try .2mm. Print slower, maybe up the temp a bit to 240. Usually higher temps (to a point) fuse together better with the previous layer.

Gotta look at your infill structure also and infill to shell overlap. More shells (at least 2) should be a pretty strong wall.
All good points. I am pretty well versed with PLA, not so much with ABS. I have not yet figured out how to attach a shot of the model. This print was up on supports, and the bottom looks crappy for that. Looking at other posts, I have shifted from rectilinear fill to full honeycomb, put up "breeze walls" around my printer shell and raised the temperature a little. I am a bit afraid to get too close to 240 since I really can't trust the actual temperature to be correct and my stock J-head clone will surely melt the PTFE liner if it overshoots.

EDIT: I have two walls and three layers top and 2 on bottom.
I have my base speed set to 50mm/s, outline 60% speed, infill 80% speed.

User avatar
dkightley
Posts: 2045
Joined: Tue Mar 10, 2015 4:09 pm

Re: My ABS prints break easily

Sun Jul 16, 2017 5:59 am

. I have not yet figured out how to attach a shot of the model.
Does this help??
Capture.JPG
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

jfkansas
Posts: 84
Joined: Wed Oct 01, 2014 2:12 am

Re: My ABS prints break easily

Sun Jul 16, 2017 2:50 pm

Sounds like you are doing everything right, try the thinner layers. 240 isn't going to kill your PTFE. Could even be bad filament.
RoboDLC wrote:
jfkansas wrote:It helps to see the model.

Thinner layers will "smash" together a little bit better. Try .2mm. Print slower, maybe up the temp a bit to 240. Usually higher temps (to a point) fuse together better with the previous layer.

Gotta look at your infill structure also and infill to shell overlap. More shells (at least 2) should be a pretty strong wall.
All good points. I am pretty well versed with PLA, not so much with ABS. I have not yet figured out how to attach a shot of the model. This print was up on supports, and the bottom looks crappy for that. Looking at other posts, I have shifted from rectilinear fill to full honeycomb, put up "breeze walls" around my printer shell and raised the temperature a little. I am a bit afraid to get too close to 240 since I really can't trust the actual temperature to be correct and my stock J-head clone will surely melt the PTFE liner if it overshoots.

EDIT: I have two walls and three layers top and 2 on bottom.
I have my base speed set to 50mm/s, outline 60% speed, infill 80% speed.

RoboDLC
Posts: 51
Joined: Sun Apr 23, 2017 2:30 am

Re: My ABS prints break easily

Sun Jul 16, 2017 4:16 pm

That helped. The text was too subtle for me...
Looking at this pic it seems obvious to me that I am either going too fast or things are cooling off too quickly.
Image
Attachments
IMG_2945.JPG

User avatar
dkightley
Posts: 2045
Joined: Tue Mar 10, 2015 4:09 pm

Re: My ABS prints break easily

Sun Jul 16, 2017 4:38 pm

Looks like your issue includes this: https://www.simplify3d.com/support/prin ... top-layers

Also, thinner layers will reduce the "staircase" effect on the curved surface, and one dense support layer of 100% may help with under surfaces.


Note that creating a factory file from S3D with your model and profile loaded and attaching the file via the newly found attachment feature will allow others to see EXACTLY what all your settings are....and then you'll get sensible changes to your settings offered.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

RoboDLC
Posts: 51
Joined: Sun Apr 23, 2017 2:30 am

Re: My ABS prints break easily

Sun Jul 16, 2017 4:54 pm

dkightley wrote:Looks like your issue includes this: https://www.simplify3d.com/support/prin ... top-layers

Also, thinner layers will reduce the "staircase" effect on the curved surface, and one dense support layer of 100% may help with under surfaces.


Note that creating a factory file from S3D with your model and profile loaded and attaching the file via the newly found attachment feature will allow others to see EXACTLY what all your settings are....and then you'll get sensible changes to your settings offered.
You got it. I have made a few changes -
Switched from rectilinear to full honeycomb
Dropped from 50mm/s max speed to 40mm/sec
Increased temperature from 230 to 235 C
Reduced infill speed from 80% to 60%
Increased my extrusion multiplier to 1.10 since there seemed to be gaps in my fills and the whole thing seemed under extruded inside.
Surrounded my printer with a cardboard wall to hold in the heat.
I have attached my factory file with all this in it.
My printer is a Folgertech Kossel 2020 with the stock printhead, but I have built a 3.54:1 geared extruder for it that worked wonders on my PLA prints.

Thanks for all of the attention folks,
DLC
Attachments
threaded rod mount bottom(4).factory
(497.38 KiB) Downloaded 104 times

RoboDLC
Posts: 51
Joined: Sun Apr 23, 2017 2:30 am

Re: My ABS prints break easily

Sun Jul 16, 2017 5:45 pm

What I don't understand is that I did a print yesterday with four of these on it that turned out four perfect prints. Today, I have three failures. My attachment shows that it laid down a fine first and second layer, but subsequent layers were trash, clearly under extruded. Why? Same filament, temperatures, speeds and printer. I am beginning to think that really need a decent print head to get consistent results.
Attachments
Ickyprint.JPG

jfkansas
Posts: 84
Joined: Wed Oct 01, 2014 2:12 am

Re: My ABS prints break easily

Mon Jul 17, 2017 6:49 am

Honeycomb kinda sucks due to all the short moves. Use rectilinear at 45 and -45 angles.

Does the extruder click on that infill like it is skipping steps?

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