# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum > MakerFarm Forum >  Best practice with ABS: no delamination, no cracking, no warping.

## abuharsky

Hello All.
I spent a couple of weeks, even months in a vain attempt to print anything bigger than 40mm cube from ABS plastic. 
There are no problems with printing small models, but with large models having constant problems: you just can not print any big vase without cracks and delaminations!

First, I tried few experiments with slicer(KISSlicer) settings for better adhesion between layers (slightly more flow rate, slightly more hotend temp - 240C, 250C instead of 230C, very low speed -  20-30 mm/s).

Second, I tried to make simple enclosure for printer using cardboard.



Third, I tried to print model inside thin wall to make thermos effect to get uniform cooling of the plastic.



although it did not work out all the details of cracked :X



I wanted to understand why this is happening.


At high temperatures, the plastic expands when low narrows, it creates internal tension. It is necessary to calculate or determine experimentally the value of narrowing:

1) look for the coefficient of thermal expansion ABS: 73.8 * 10 ^ -6 ° C-1 ( http://temperatures.ru/pages/tempera...o_rasshireniya )
2) remember physics 6th grade  :Smile:  ( http://goo.gl/fP6CPU )
3) calculate how much less will be the length of the extruded rod 100mm at the bed temperature of 100C and 230C of the nozzle
ΔL = a * L * Δt = 73.8 * 10 ^ -6 * 100mm * (230C - 100C) = 0,96mm - which is almost 1% of the original length.

Upon reaching room temperature, 25 ° C - it is 1,5% (ΔL = a * L * Δt = 73.8 * 10 ^ -6 * 100mm * (230C - 25C) = 1,51mm)


1% -  It is very small.

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Accordingly, with this small change in length of the plastic (1%) occurs corresponding to the internal pressure value of which is not too high.


The fact is, if the bonding strength is higher than the internal stresses - problem solved.


Then I tested the strength of bonding layers. 
Testing methodology is simple: on the printed cylinder with 2 perimeters I evenly apply pressure with finger on the wall as long as it is not cracked between layers. By  the depth pressing I detected the magnitude of the applied strength.


== Print speed affects the adhesion, but not much: I got about the same results for speeds 30-50mm/s;
== Much greater affect temperature of the extrusion: at 220C-260С I got the same bad result (plastic cracked from the slightest finger pressure), but the situation changed dramatically at temperature 270C-280C.
(Also, I have 2 different ABS filaments from different manufacturers, for the second filament I determined the optimal temperature in 260C.)


Finally, a few rules for successful work with ABS:
1) maximum heat for your particular filament (note that not all filaments are the same, they have different properties: viscosity, shrinkage, bonding and etc.)
2) the average print speed (I recommend 30-60mm/s)
3) calibrated heated bed and ABS juice for good adhesion of the first layer; ( http://www.makerbot.com/blog/2011/06...g-and-curling/ )
4) a bit of luck!


*UPDATE #1*
Most often china thermistors can't show you real temp of your nozzle, when you think its 250C, in real it may only be 220C(or 280C). Don't forget to fine tune your temp sensors.

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## abuharsky

At this moment I have few succeeded prints (big models up to 150mm in diameter and up to 180mm in height) at 280C without any enclosure and for some models with enabled extrusion cooling fan(!!!):


1) single perimeter, 30mm/s, 0.4 nozzle, 280C, extrusion cooling fan OFF
 (top no cracks, it is because of the fact that one of the perimeter for this detail is not enough or need support)





2) 2 perimeters, 70mm/s, 0.4 nozzle, 280C, extrusion cooling fan ON (full speed)

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## abuharsky

3) Vase 185mm height, 1 perimeter, spiral mode, flow 200%, 280C, 60mm/s speed


4) Vase ~150mm x 100mm, 3 perimeters, 280C, 80mm/s, gray low cost ABS.

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## AbuMaia

Very nice results! I currently print at 240, but I'll try increasing it some more. Thanks for the helpful post.

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## abuharsky

I have successfully tested  ABS from 3 different manufacturers at 280C - same result.

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## gmay3

Really cool info! I'm likely going to increase my extrusion as well. I've been printing at 225 all this time but might try 230 or 235 as a default.

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## pichuete

thanks for the info! ill try bumping up my extruder temp . in addition im having very good bed adhesion with an PEI sheet over my glass . it sticks so well that you can not even take off the printed part until it cools below 60c . and the best part is you dont need to add anything . no spray , slurry or tape .

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## usarmyaircav

> thanks for the info! ill try bumping up my extruder temp . in addition im having very good bed adhesion with an PEI sheet over my glass . it sticks so well that you can not even take off the printed part until it cools below 60c . and the best part is you dont need to add anything . no spray , slurry or tape .


Pichuete, how did you attach the PEI sheet to your glass?

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## pichuete

i used 3m adhesive transfer tape 468m , its as thing as a sheet of paper and transfer heat well . they sell it in different sizes  in my case i used the 0.5 in and apply  but if ill do it again i would buy 1 in . to cover the glass . they also sell a 12x12 sheet of this tape but i think it will be harder to work with this thing is very sticky

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## usarmyaircav

That tape can be spendy, I will probaboy go with a 12x12 sheet and cut it down to 10x10 as that seems to be decent route with the cost being about $12 on Amazon.

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## jimc

thats great and all but the vase models you are printing are not going to be prone to warping and are not any kind of warp test at all. almost anyone can print them in abs with their normal setting and come out great looking. its inherent in the design. to really see what you have as far as warping and layer adhesion you need to print the same object to compare results. for this make yourself an 100x50mm box with 2mm walls. print the box 2" high. use the same model over and over with each change then compare results. any way you look at it, you are not going to stop mother nature. abs will warp no matter what you do. why everyone uses abs anymore i have no idea. move on to pet. its 5-10 time as strong as abs, almost the same heat resistance and almost no warp.

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## abuharsky

> thats great and all but the vase models you are printing are not going to be prone to warping and are not any kind of warp test at all. almost anyone can print them in abs with their normal setting and come out great looking. its inherent in the design. to really see what you have as far as warping and layer adhesion you need to print the same object to compare results. for this make yourself an 100x50mm box with 2mm walls. print the box 2" high. use the same model over and over with each change then compare results. any way you look at it, you are not going to stop mother nature. abs will warp no matter what you do. why everyone uses abs anymore i have no idea. move on to pet. its 5-10 time as strong as abs, almost the same heat resistance and almost no warp.


First, warping can be stopped by setting highter temp on heated bed, I used 120C.
Second, warping can be stopped by using brim, I used 5-15mm depends on model.
Third, you can stop wapring using "ABS juice" or hairspray or some other...

Warping just slightly changes the model, but do not spoil it, you can use warped models, BUT you can't use models with delaminations. 

*The basic idea of my article - is to fight delaminations and cracks.*

Also, I don't post it yet, but I have already printed few boxes 100mm x 100mm x 80-100mm(height) with thick wall and bottom (about 2-4mm),



you can see more photos here -> http://www.thingiverse.com/thing:440203

Some of the boxes i printed with 1, some with 2,3,4 perimeters and infill from 15 to 50%.
Result: *every model with ZERO cracks and delaminations, most of models with ZERO warpings,* some models with little warpings(5-10mm) at the corners.
All prints on the capton tape without any sprays. Bed temp 100-120C.

About using ABS:
I spent a lot of time experimenting with ABS and all the time he peeled, cracked, and so on. Many times I threw this idea, but again came back to it and finally *found its secret*. ABS is very cheap, I buy it from a local manufacturer for *$8-12 per kg* and now I can print from it many things, there's a reason for me to use ABS.

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## beerdart

I rarely have any warp issues with ABS.

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## sniffle

wow thats cheap!! who is this?

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## abuharsky

> wow thats cheap!! who is this?


http://www.npo-plastic.ru/catalog1/prutok_printer/

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## sniffle

Awww thats really far away for me

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## adamfilip

How much ABS to Acetone?
confused about the ratio

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## AbuMaia

For what? For "ABS Juice" for print adhesion, I just got a 32 oz spray bottle from the hardware store, filled it about 24 oz full of acetone, then slipped in old brims and skirts. I didn't keep track of how much, though. It's still pretty thin, thin enough to be sprayed.

I also have another glass bottle of acetone in which I put much more ABS, to make a thicker slurry with which to repair cracks or glue parts together.

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## sniffle

Ive honestly been having great adhesion with glue stick.  We all have our things though.

So my prints are coming out looking much better right now after turning the heat up 15 degrees.  I need to do some of the test/calibration tests after i finish. printing the kossel parts for a friend.

I'm going to go down that rabbjt hole pretty far now that i can print nice looking parts.  Im hoping i can push the envelope on speed and accuracy and keep it there without too much work.

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## usarmyaircav

Sniffle what are you using for a power supply?  I bought one of the 350watt 30Amp LED PS that can mount on the printer, and while it works great with the Hot-End at 235 and bed at 105, if I put the bed at 110, I go from about a 7 minute heat up time to about close to 20.  I am using the relay that came with the printer.

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## sniffle

I use the same power supply as you.  5-7 min heatup time For 120 bed and 250 hot end.  Hot end is lightning quick bed is slow as it should be.  I got it off amazon ill look it up wheb i get home and post a link.


12v 30a Dc Universal Regulated Switching Power Supply 360w for CCTV, Radio, Computer Project https://www.amazon.com/dp/B00D7CWSCG..._k.BUub15SDVGZ

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## repreprep

hey abuharsky
thank you so much for your article!! it is very helpful.
i have a question:
does cracking appear while printing or after the print is done?
Also does anybody have experience with printing metal-ABS filaments?

thank you so much
Ole

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## abuharsky

> does cracking appear while printing or after the print is done?


in any case

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## jumi1174

I want to bump this thread up because I've been having layer delamination issues lately on a particular piece im trying to print.

I think it's ultimately a geometry issue, but I noticed abuharsky'ssuccess with increasing the hot end to 280C.  I've tried the same, but my hot end kinda fizzles out at 271C and won't increase past that.

Any ides how to get the temp higher? I'm using a 3mm hexagon hot end.

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## abuharsky

try to print at 270C

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## sniffle

the temps are limited in the firmware to 275 unless you change it higher...

Also if you are having warping issues with printing at that temp, you either need to increase bed temp(120 is plenty) or you need to build an enclosure to prevent drafts from moving across the parts...

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## abuharsky

> you need to build an enclosure to prevent drafts from moving across the parts...


I print without any enclosure with no delamination

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## sniffle

> I print without any enclosure with no delamination



I said or... that's an environmental thing... my crazy drafty house required it... that and my wife likes to keep the house a balmy 68 degrees... so when the AC kicks on, it causes my ABS to warp... So i built an enclosure to make a stable environment for my prints

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