Printing ABS: horizontal cracks, do I see warping ?

[karl112 0]

Hello there,

I was trying to do my first print in ABS last night and I noticed the part seems to crack in horizontal layers. Or at least I looks like that.

It looks like the layers don't stick together properly...

 

 

I am not sure about what I do see in my printer. Is this the "warping" that is very often talked about?

The print is done with 20 % infill and it is my impression that the part is very rigid due to the infill. I am not sure if a distortion of that scale is even possible with this infill.

I tried to raise the extruder temperature when I noticed the first cracks but I could not raise it any higher than 260 °C.

Printer: UM2

Printing speed: 30 mm/s

Bed temperature: 90°C

Extruder temperature: 260°C

Layer height: 0.2 mm

Fans are off at all times

Infill: 20%

Does anyone have some experience printing ABS ?

All hints and tips are kindly appreciated...!

Regards,

Karl

 

[jonnybischof 60]

Your settings seem quite ok...

What material are you using exactly? (brand)

I've had ABS which gave me the strongest printed parts I've ever seen, and I've had ABS which didn't hold together very well at all..

Could it be a humidity issue? I heard ABS is more susceptible than PLA. I've never kept my PLA particularly "dry". Usually it hangs on the UM for weeks... Maybe ABS doesn't like that?

 

[profepaco 0]

I am ready to print my first ABS models.So I am very interested in whatever comment in this thread.

I have been reading a lot, and it seems that large ABS models like yours need a heated chamber, i.e., you should close the front open space of your UM2.

It seems Ultimaker cannot offer in his models a front door because there is a patent about this. You can offer a front door if no heated bed is present. However, I have been considering to design a front door for my UM2. Using glass or metacrilate, with hinges to fasten the door. It not so difficult.

It seems that if you close the front space (even with a box) your models has more chance to be finished without problems. This is not my experience it is what i have been reading whilst waiting for my UM2.

 

[gr5 2,167]

Put a box on the top that doesn't interfere with the bowden tube, then put clear plastic food wrap on the front. Try again.

 

[jonnybischof 60]

I'm printing ABS right now. Part is getting rock solid...

Have to say though, I'm using the pretty expensive "Smart-ABS" by Orbi-Tech.

I only closed the sides (UM1) with bubble wrap (pretty good heat blocker), the top is open. But closing the top can help with temperature problems.

Make sure there are no noteworthy holes in the sides or the bottom (especially in my case with the open top), because that would generate a nice ventilation... If the bottom and all the sides are tightly closed, then an open top is not much of a problem. You do need more energy because the heatbed will need to heat more, but printing-wise it shouldn't matter much.

 

[karl112 0]

I'm printing ABS right now. Part is getting rock solid...

Have to say though, I'm using the pretty expensive "Smart-ABS" by Orbi-Tech.

I only closed the sides (UM1) with bubble wrap (pretty good heat blocker), the top is open. But closing the top can help with temperature problems.

Make sure there are no noteworthy holes in the sides or the bottom (especially in my case with the open top), because that would generate a nice ventilation... If the bottom and all the sides are tightly closed, then an open top is not much of a problem. You do need more energy because the heatbed will need to heat more, but printing-wise it shouldn't matter much.

 

Hello JonnyBischof, Hello Gr5

I am using Formfutura Premium ABS "Frosty White". I have to say that it is not cheap. It was like 50 CHF a kg....

trying again this night with bubblewrap in the front a cardboard box on top.

I am also thinking about a real front door made of acrylic glass and maybe some sort of bonnet...

Kind regards,

Karl

 

[jonnybischof 60]

My print from yesterday was finished without problems. ABS prints quite well on a PEI build plate. Sticks well when heated, and pops off when cooled down... Well-invested money

But it's difficult to get these PEI plates really flat. They need to be fixed on the four corners, but also on the sides.

I noticed my part has shrunk significantly! With the heated chamber, it printed perfectly, no odd angle walls because of uneven shrinkage during printing. But - it must have shrunk while cooling down... I can't use the part because it doesn't fit the things it was designed to hold.. -.-

(And I gave some clearance..)

About bubble wrap:

While it doesn't look too good, it certainly does a good job keeping the heat inside. So it's probably one of the best possible solutions (except maybe double or triple glazing... ) to close the machine.

Closing off the top will probably decrease the heat-up time for the bed. I'm recording times atm for non-enclosed heat-up and will compare against the time it takes when fully enclosed.

But once everything is on temperature, I think there isn't so much heat lost when only the top part is left open. - If it gets to temperature at all. On the UM1, if you don't enclose any of the sides, it takes ages to get it to 100°C, if it gets there at all. (Depends on the heatbed construction of course...)

 

[Dim3nsioneer 557]

I haven't printed any ABS yet but some _XT with 75°C bed temperature. For this temperature I put a cork disk on the bed while heating up. You don't reach higher temperatures with this, but you reach them earlier due to reduced radiative loss.

 

I noticed my part has shrunk significantly! With the heated chamber, it printed perfectly, no odd angle walls because of uneven shrinkage during printing. But - it must have shrunk while cooling down... I can't use the part because it doesn't fit the things it was designed to hold.. -.-

(And I gave some clearance..)

 

That calls for design for manufacturing...

 

[jonnybischof 60]

...

That calls for design for manufacturing...

 

Sketchup isn't very helpful with this problem...

I'll just print that part with PLA, didn't have any problems last time.

 

I haven't printed any ABS yet but some _XT with 75°C bed temperature. For this temperature I put a cork disk on the bed while heating up. You don't reach higher temperatures with this, but you reach them earlier due to reduced radiative loss.

...

 

Great idea! Will try that instead of closing the top. Much simpler to just put a cork on the build plate

 

[Dim3nsioneer 557]

Great idea! Will try that instead of closing the top. Much simpler to just put a cork on the build plate

 

Just don't forget to take it away before print starts... :cool:

I'm also thinking about covering empty areas on the bed with something (cardboard?) during the print. I can reach something like 105°C with my 12C powered heated bed, so this might be necessary in my case if I would like to print ABS (which I don't right now due to the fumes).

 

[jonnybischof 60]

That should be interesting...

At the FabLab Zurich they have 2mm thick, dense cardboard (not the "shipping box" type). This could be very suitable... Have to ask them where they get that stuff from.

About the fumes: If I start writing strange things, it's because the printer is doing ABS right next to me at the moment...

 

[karl112 0]

 

Hello,

 

so far the bubblewrap and the cardboard cover on top seem to work well.

My print is not finished yet but when I peek inside, I cannot see any horizontal cracks.

 

I was wondering why Ultimaker is not equipping the UM2 with a front door made of maybe acrylic glass.

Just made up a design for a front door.

The hood is also in the works and will be finished by tomorrow.

 

[profepaco 0]

 

 

Hello,

 

so far the bubblewrap and the cardboard cover on top seem to work well.

My print is not finished yet but when I peek inside, I cannot see any horizontal cracks.

 

I was wondering why Ultimaker is not equipping the UM2 with a front door made of maybe acrylic glass.

Just made up a design for a front door.

The hood is also in the works and will be finished by tomorrow.

 

I explained before in this thread why they cannot... there is a patent..

 

[gr5 2,167]

Bertho just built this recently:

More on his blog here:

http://www.vinland.com/blog/?p=191

 

[karl112 0]

Bertho just built this recently:

More on his blog here:

http://www.vinland.com/blog/?p=191

 

Thanks for that picture link...! Really good stuff to be found there...

I think I should do something similiar for the UM2.

Thanks again...