How to solve ABS deformation at the bottom?

Question

I am printing small mechanical pieces in ABS:

• 100 ºC bed temperature
• 70 ºC Room temperature
• 250 ºC nozzle temperature
• 0.4 mm nozzle, at 0.15 mm per layer.
• 100.8 % scale to compensate ABS dimensional innacuracy.

The first layer is printed correctly, but later, corners warp and first 10 mm get deformed (See images).

How do I solve this? Unfortunately, I cannot increase room temperature over 70 ºC

Here is a picture while printing, we can see that the edges get warped even far over the first layer. (Sorry, the picture quality is not so good):

Answer 1

The up-curling of overhangs is frequently seen when printing PLA or PETG when the just deposited layer hasn't been cooled enough. The residual heat will allow the curling as the plastic has not been fully set (above the so called glass temperature) because of insufficient part cooling.

Knowing that ABS doesn't need much cooling (to improve the inter-layer bonding), you most probably will not require full power of the fan (depending on the cooling power of the fan). You do need a little cooling though, but not for the first (few) layer(s), so keep the fan off at the first layer. Be sure it is up to speed at the layer you require the cooling as the first few percentage of the fan is generally not enough to rotate the fan. E.g. my fans start spinning at about 20-25 %.

Answer 2

Results of the suggestions in comments and answers

Following are the results, coming from the great answers received on this page. I post them here in case it can helps further readers in achieving good results.

Note: when two numbers are indicated, the first is for the first layer, and the second for the rest of the piece. (e.g. 250 ºC / 230 ºC)

If you want to see the result, go now directly to the bottom of the answer :-)

Note2: Pictures are taken from the worse side. In some cases, other sides are much better.

First try:

• Nozzle temperature: 250 ºC / 240 ºC
• Platform temperature: 100 ºC
• Chamber temperature: 70 ºC
• Speed: 60 mm/s
• Fan: 0% / 50%

Second try:

• Nozzle temperature: 250 ºC / 240 ºC
• Platform temperature: 100 ºC
• Chamber temperature: 70 ºC
• Speed: 20s / layer
• Fan: 0% / 50%

Third try:

• Nozzle temperature: 250 ºC / 240 ºC
• Platform temperature: 100 ºC
• Chamber temperature: 70 ºC
• Speed: 20s / layer
• Fan: 0% / 100%
• 95% flow

Forth try:

• Nozzle temperature: 245 ºC / 230 ºC
• Platform temperature: 100 ºC
• Chamber temperature: 50 ºC
• Speed: 20s / layer
• Fan: 0% / 100%
• 95% flow

Fifth try (succeed):

• Nozzle temperature: 245 ºC / 225 ºC
• Platform temperature: 100 ºC
• Chamber temperature: 40 ºC
• Speed: 20s / layer
• Fan: 0% / 200% (I added an additional fan)
• 95% flow

My current settings: (in case it helps)

At the end, I opted for the following setup, which seems to adapt better to all kind of shapes:

• Nozzle temperature: 250 ºC / 250 ºC (slighty higher temperature help adhesion between layers and give better piece resistance)
• Platform temperature: 100 ºC / 80 ºC (80 ºC I had some piece deformation over 85 ºC, especially big pieces)
• Chamber temperature: 50 ºC
• Speed: 40 mm/s, or even 30 mm/s (Help adhesion and good precision)
• Fan: 0% / 200% (I added an additional fan, helps avoid deformation in corners, as described in the question)
• Scale the piece 100.5% (ABS shrink)
• Minimum layer time: 20s (For small pieces, this allows each layer to cool enough)
• Build Plate Adhesion: Brim
• 100% flow

Conclusions:

• The solution is to cool each layer as much as possible and as soon as possible, BUT avoiding warping.

• Use a very strong adhesion to avoid the warping, allowing a better cooling of each layer. In my case I started to use a cheap and strong hairspray (which works surprisingly well).

• Using chamber temperature over 50 ºC make it more difficult to cool each layer quickly, thus, it is not recommended.

• Using ventilation is a must.

• Different configuration for first layer and consecutive layers helps.

Answer 3

We usually stick the masking tape on the printer's bottom plate, so that the model is formed on the side of the masking tape which without glue, which looks good. When there is no masking tape, we sometimes manually adjust the height of the bottom plate to make the nozzle appress to the bottom plate when printing the first layer. At this time, the melted material can hardly flow out. The strong pressure will adhere the material tightly to the bottom plate, which can effectively solve this problem. However, this may damage the extruder motor.