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mvm

ABS cracking/layer adhesion problem

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mvm    12

I have a problem when printing in ABS.

For some reason, I never seem to get the same results as many other people. Whereas my prints in PLA, PETG, XT or Nylon all seem to be super strong, my ABS prints all seem to be much weaker.

Just yesterday I was printing a small model in grey ABS and even while printing, I noticed cracks appearing in the section where the walls get thinner (see picture).

Printing temp was 235 C at first, but I also tried 245. Bed temp is 70 degrees.

When the print is finished I can quite easily pull the prints apart along the print layers?

Is there something wrong with my particular type of ABS or is there something I simply do wrong??

 

ABS-Cracking.jpg

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Darqueone    4

Hi,

My recommendations would be to increase the bed temp, I print ABS at 95oC, this helps keep the enclosure warm and aids in stopping the previous layer cooling too much and shrinking away from the nozzle.

Increase the temp of the nozzle. There is huge variation in filament suppliers, some I can print at 235 others I have to print closer to 250, even the colour of the filament will impact the temp. Pretty much every roll will potentially have its own ideal temp.

Drop the layer height.

https://www.youtube.com/watch?v=POaL2GGBHGM this actually not a bad process to use to work out good temps for filament.

The longer the build time the higher the risk of cracking and infill % will also effect - drop the % down to bare minimum .

Good luck.

 

 

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mvm    12

Thanks for the quick reply.

I am printing the same print now a 245 C and bed temp at 90. Seems to be working better, although I still think that the final strength will be (a lot) less than the same print in PLA or PETG. For this print I have the infill set at 24%, it needs to be strong.

Layer height is already at 150 microns. Print time is just over 5 hours.

Will post my results later.

 

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Hi mvm,

I was forwarded this same message from 3D Hubs. I second what Darqueone has mentioned with regards to increasing bed temp in order to raise the enclosure temperature. As well as increasing the nozzle temp. I find the Full-scale XT Plus to need to be heated 10-15C more for the same filament than other printers I use. I print PLA at 220-225C and ABs at 245-250C. I have my bed set to 90C for my ABS prints.

Prior to raising the enclosure temperature I was seeing delaminations in prints and the exact weaknesses you have spoken of. Especially in large circular and long wall objects with thin sections.

Hope you get it sorted! Looking forward to seeing some pics.

 

Kind regards,

James Armstrong.

 

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mvm    12

Update:

I have printed the object again at 250 C en 95 bed temp. Results are better, but I find the final print still rather 'weak'.
This model has two walls atop a bottom, and when I squeeze the top of the walls together, it will break off at the base (see picture).
You do't even have to use much force to achieve that actually.

I have printed the same model overnight in grey PLA and the results is not only better lookig but much stronger. Squeezing there with the same approx. force will not give any problems.
Since there might be a problem with the particular spool of ABS I have, I have ordered a new spool with which I can try the print again.
 

@James,

I did indeed post the same question on 3D Hubs. The prints I am making are for a 3D Hubs order which I would like to finish in good order and with a happy customer of course.

 

ABS_CrackWeak.jpg

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mvm,

Good luck with the new spool of ABS. I hoep you get it sorted. I am only just starting in the world of 3D Hubs printing. If you ever have a chance to talk regarding, share some advice or have a chat, please do shoot me PM. 


Cheers,

James.

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Michael    0

Interesting that this thread started as I for first time after many successful ABS prints (print mostly in ABS) I got the same de lamination of the print layers on my model.    Yesterday I printed same model and no issue......today with same settings the print is flakey and layers seperate......what the!!!!

i use 245 deg extrusion temp with 95 deg bed temp.......

scratching my head on this one!!!

 

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Darqueone    4

Hi Michael, i have had this effect once but it was caused by being at the end of a roll of filament and because the filament was so tightly wound on the spool it wasnt extruding correctly.

Cheers

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Michael    0

Yea, except mine is a brand new roll (same brand as always) but black in colour......first time using black ABS......maybe that has something to do with it......but then yesterday it was fine???

cheers

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Darqueone    4

https://youtu.be/POaL2GGBHGM

 

Hi Michael, I would have been surprised if you had the same issue, The youtube link (I don't think the one I linked to previously worked) is actually not a bad process to try and find the right filament temp. Colour will definitely play a part in finding the right temp, pretty much every roll is potentially going to be different.

cheers

Kerry

 

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mvm    12

Hi guys,

I have had the advice to try even higher temperatures, like 255. 
Today I received a new spool of grey ABS filament with which I can try it again. I also purchased a can of 3DLAC which is a kind of spray-on adhesive (like hairspray) which should be extremely sticky with a hot bed (> 90 degrees) but which should let go of the print once the bed has cooled down.

That said, I keep saying to people that for many application PLA is a stronger material when it comes to tensile strength. With the PLA brands I have used so far, I never really had any of the extreme brittleness that some people talk about in articles or YouTube. Yes, it will not bend and break without flexing, but a well printed PLA part is very strong.
When I need a material that needs to be flexible, I use PETG more than ABS. PETG seems to have a much better inter-layer adhesion than ABS and is much easier to print.
 

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