Stickyness, long printing and ABS

[fxmouton 0]

Hello everyone,

I'm meeting some annoying issue those days. I try to print some pieces using ABS on my Ultimaker2. But I've got this unbelievably annoying problem with the objects I try to print : they regularly start to dance with the printhead.

I try different things : http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#nostick, recalibrate it as well, try different quality of impression... Times to times it's working but I had to throw away some unfinished pieces.

But the other tricky thing I'm meeting is also, on long prints, I've got some http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#grinding. I met different cases mentioned 3dverkstan, but it keeps happening. Sometimes I can prevent it when I'm around, helping the filament to go inside the feeder with my hand. But the printer is at my office and I mind a little bit staying 18 hours long for some printing just to be sure nothing will happen.

I'm getting mad because when the first layers stay on the plate, most of the time the filament stops after few hours. Following http://umforum.ultimaker.com/index.php?/topic/10005-working-w-abs-but-not-w-pla/, I try to clean as much as I can the nozzle, so I don't think the grinding is due to a clogged nozzle.

So if you've got some other explanations for those problems or some tips to prevent them, I had to say it could be really useful because my researches haven't been effective.

Thank you!

 

[tsagos 8]

Hello

Give us some details about temps, speed, layers etc. Temp is related with the grinding you are getting. Bigger temp means easier flow so the feeder motor doesn't require so much force to push the fillament.

 

[reibuehl 41]

I used to have similar problems in the past and the best method to prevent it for me was to add a door to the UM2 and heat up the room to at least 30°C. In the future I will try to cover the top too to avoid the room heating.

 

[nick-s 0]

I am regularly using ABS and have found the following to be very reliable:

Have a clean glass bed and cover with a wash of ABS (the same colour as you intend to print with) dissolved in acetate. This holds the print well and has the added advantage of giving a great smooth bottom to the finished part. Once the print is finished let it cool slowly (which also helps reduce distortion) and you will hear it pop off the glass so it is easy to remove once cooled down.

I have a door covering the printers front and box mounted on top. The box has an open bottom for the Bowden tube and cables to enter, but this is not a problem as long as the room the printer is in has no drafts such as open windows. I was initially worried about the box over heating the printers drives etc but monitoring with a laser thermometer showed it to get to about 55 / 60 deg C on the motors. I have been doing this for a while and they seem fine.

My standard settings are:

layer 0.06 to 0.10mm

shell 1.20mm

retraction Y - "No skin" setting

Bottom / top 1.20mm (to match shell and I need quite robust parts)

fill 25%

speed 50mm/sec - but also see below speeds which seems to over ride this

Bed adhesion brim + wash as above

nozzle 0.4mm

initial layer 0.3mm

travel speed150mm/sec

bottom speed 20mm/sec

infill speed 50mm/sec

top/bottom speed 30mm/sec

outer shell speed30mm/sec

inner shell speed 50mm/sec

min layer time 5sec

NO FANS at any time

Bed temp 100 deg C

Nozzle temp 250 deg C

These speeds and layer heights can make for some slow prints, but I need the quality. I am sure you could speed them up a little if not needing high quality.

Hope this helps in at least giving you a starting point.

 

[tsagos 8]

I didn't like the default settings. They never worked for me.

Its really worring that you get grinding with a temp of 260c. try to setup the extruder motor so it doesnt apply so much force onto the fillament.

Up your print bed to 100-103c to get better adhesion. I'm allways using ABS slurry when I print with abs.

@Nick S: I really cant understand how you guys print without fans. I cant manage to do it if there is even a suspicius of an overhang over 40 degrees.

 

[fxmouton 0]

Thank you gentlemen, I've got plenty of stuff to try! :-)

Yes, it's weird, maybe I should unscrew the hidden srew at the top of the feeder even if it seems to be already unscrewed at its maximum.

I'm thinking about printing that kind of feeder to avoid the filament dust to be stocked inside the feeder as well.

I will let you know how the situation will go

 

[mcgyvr 2]

Welcome to printing ABS..

Many factors come into play even the design of whatever you are trying to print. ABS shrinks more than PLA (twice as much I thought) as it cools.

I ALWAYS use the glue stick and the brim feature turned on (10-15 lines)

I also have built an acrylic enclosure for the UM2 to attempt to keep the heat in/drafts out.

I've also needed to add ribs/holes or other features to my models to avoid thin/thick areas. Same applies for injection molding.. Different wall thicknesses can warp/bow,etc... real plastic parts too

 

[fxmouton 0]

Thanks for all your advices. Indeed, I made new tries using Nick s recommendations about the settings in Cura.

I also saw this post and I downloaded the files. The recommendations are 250˚C for the nozzle, 110˚C for the plate and no fan. And it works! I need also the plate to be really clean, but I almost have no more problem with stickyness.

 

Nevertheless, the print almost crash as you can see on this pictures :

 

You can see at the 75% of the print there some under extrusion. To prevent a complete fail, I try to help the feeder, pushing manually the filament. As you can see, there even is a part which hasn't been printed at all. I took the pictures just after the print. So if you have any idea about why, I'm interested into your advices!

I launched a print this week end and the nozzle seems to get blocked. Honestly, I have no idea why. Could it come from the fact there is some dust into the feeder which come to the tube then to the nozzle?

I feel a little bit despaired due to the fact this kind of things happens every time the print duration start to be long.

 

Thank you!

[tsagos 8]

Check filament diameter. I had a case with cheap fillament that it was too fat (over 3.1mm) for the bowden tube. Too much friction and it the feeder could not feed the nozzle with material.

Also if your coil is too tight you will have same results.

Get some 30-28 gauge needles to unclog your nozzles. Go for the shorter ones, they are more difficult to bend.