Warning! this is a long post, but I think worth reading.
- Why ABS?
3d printing with ABS is challenging but also rewarding, that is if you plan on 3d printing things to be functional and not just trinkets and toys. Yoda heads rejoice.
There are a few things I have learned 3d printing with ABS and would like to share with the community. I find ABS has some nice properties for functional parts and once mastered it is a great material. It does have its faults but overall with some care it has some great properties and gives some satisfaction. I have no interest in making nice looking statues, I am more interested in making parts for my projects and prototyping parts. Kind of a prototyping machine as well as a production machine.
Let me break the news to you. If you plan on 3d printing anything larger than 50mm in any direction ABS needs a heated chamber. A heated chamber is the only way to eliminate the warping on ABS parts, but there is a side benefit to it that it does create stronger parts than other printers with no heated chamber and it does so naturally.
Temperature rules for my particular setup. But I suspect they can be carried over to different printers out there. I am omitting nozzle size as that comes down to a user preference, but if you’re looking for a material to make fine detail small items, then a heated chamber is not necessary. I tend to use .4mm-.5mm for higher detail and .6-1mm for lower detail and higher speeds.
Speed, ABS likes speed. If you print PLA at 30mm/s double the speed for ABS so make sure your printer has sufficient rigidity to handle the higher speeds, slow and low does not apply here.
ABS likes a all metal hot end. No PTFE tubing applicable here.
NO part cooling fans for ABS. It makes it brittle.
Heated chamber is very strongly recommended. 45-50C in range is fine.
Bed adhesion, I prefer ABS GOOP. (Will explain this later on this post)
Higher Quality Smaller items. <50mm in size
Nozzle temp - 230-240c
Bed Temp - 100-110c
Bed adhesion - ABS goop (Slurry is better, but much thinner application should be observed)
Print speed 40-60mm/s
Heated chamber temp = off
Mid size items higher quality. > 50-100mm
Nozzle temp - 250-270c
Bed Temp - 100-110c
Bed adhesion - ABS goop
Print speed 60-80mm/s
Heated chamber temp = ~45c
Large items. > 100mm
Nozzle temp - 260-275c
Bed Temp - 100-110c
Bed adhesion - ABS goop
Print speed 80-120mm/s
Heated Chamber temp = ~50C
- What is ABS goop?
ABS goop is basically what it sounds like; it is a thicker paste of ABS and industrial acetone. The consistency of ABS in this goop is close to chocolate pudding or a melted chocolate bar.
How do you make the stuff?
I make the stuff in a glass jar with preferably a silicone washer lid. I drop ABS scraps in it until it is nearly full. Then I fill up the jar about 1/3 way through. The ABS scraps should not be larger than 1/2 inch or about 1cm square. The smaller the better. Let this sit overnight. If he ABS is of good quality and the acetone is pure it will turn it to goop by morning. Add some more acetone if not fully gooped up.
What do I apply it with?
I apply this stuff by using a putty knife, but not a metal one. They sell chemical resistant putty knifes at home improvement stores, they are generally made of HDPE, this plastic will not get eroded with ABS/ACETONE combo.
- How to apply the goop?
Well this gets tricky, it does take some practice but it is totally doable. The first step is to set your machine to preheat the bed and nozzle, do not preheat the nozzle above 250c. After the bed has reached 60c you take the knife and apply a thin coat of goop rather quickly to the surface. This leaves a porous layer as the acetone evaporates quickly, (do this in a well ventilated workshop, and since you probably want a heated chamber it is not a big deal). The tricky part is to get a smooth even coat that ends up being about .1mm thick. This is slightly thicker than a piece of paper, the nozzle will dig into the porous layer and will stick to the bed nicely. No warping at all.
- Ok now you gave me your setting, what is your work flow?
I set my printer to preheat to 110c bed and 250c nozzle. I wait about 2 minutes and the temperature shoots past 60c, I quickly apply goop with my putty knife to the glass (mirror) bed and watch it flash up. The size of the application is dependent on the part I am printing, go at least 1 inch larger ~2cm than the desired part.
Once the system has gotten hot, bed at 110c, nozzle at 250, and heated chamber at around 40c I hit print and the nozzle shoots to 260c or 265c depending on what I want and starts printing its skirt, the heated chamber takes about 30 minutes to reach 50c on my printer as I only run a 100w ceramic heater, but once it is past 40c it is fine to start printing. The heated chamber is controlled independently.
Once the print completes, the 3d printer starts to cool off its hot end and bed. I wait until the bed reaches the same temp as the chamber, ~15-20 minutes to cool down to that temp. Then I turn off the heated chamber and turn on the evacuation fan that pumps the air in the chamber out through a carbon filter and soon out of the room, this eliminates fumes.
I wait until the part is roughly at room temp, depending on season that is 20-30c. I simply try to pull it off, the whole thing including the dry goop comes most of the time, sometimes it does not. The procedure for when the 3d print is stubborn is to use a plastic hammer (You can 3d print your own) and give it a light whack on the side. This causes it to come up, trim the brim, edges and enjoy a 100% warp free part.
Cleanup is simple in my case; I use a small putty knife, this time in metal and scrape the debris off the bed. Once in a while I take a paper towel and wet it in acetone and clean up the bed.
- ABS hardening?
While I have no empirical data, I believe ABS hardens when processed in a heated chamber. I have noticed my parts were denser and they were more difficult to cut and held their shape much more than non heated chamber parts.
- Other considerations.
At the risk of sounding like a guy who pushes his warez, I believe the extruder is a very important part in getting a good result with ABS. There should be a balance of strength, speed and precision to allow for a good 3d printed ABS part. I think my own creation, the modicum v1 is the perfect extruder for ABS. In case your interested, you can download it for free. link -> Modicum V1