26 Reply by jjc

  • jjc
  • Member
  • Offline
  • Registered: 2014-12-09
  • Posts: 36

Re: warping help.

I had to put my two cents back in the jar.

Tried to print a new version of a bar like design that I've printed before.  It's long and narrow and this new version has a pair of deep notches into the sides of the part near the end.  Basically, there are masses of plastic on the ends that are 'separated' in a sense from the mass of plastic in the center portion of the bar.

Both ends have lifted up in two separate prints, causing me to cancel each print before they were done.

So I've added a raft, and I've also added a .2" wide 'wall' around the part, that is spaced .2" away from the part.  I've also gone from 90% fill to 30% fill.  BTW, the part is so long, I have to rotate it 55 degrees to place it diagonally across the platform.  I'm running the 2.0 Duo, so the platform is not as wide as it is deep.

The whole strategy is to try to keep the part at the same temperature as much as possible.

In the previous failed runs, the warping didn't start until the part was about 90% of the height of the part (about 1 in) when printed at 30% fill, and started at about 30% of the height when printed at 90% fill. 

My thinking is to:

1) reduce the mass of plastic in the middle

2) use a raft so the mass is not flat against the glass/glue

3) use a wall around the part to trap heated air in the gap

4) use a wall to shield the part from air currents at different temperatures.

It seems the whole trick is to balance cooling against keeping the part warm enough that the temperature gradient throughout the part is not severe.

I'll post again when this latest print is done.

Engineer in the Medical Device Industry, used high end 3D printers, but exploring what can be done with inexpensive printers.  Own a Da Vinci 2.0 Duo

27 Reply by oscahie (edited by oscahie 2014-12-10 17:52:54)

  • oscahie
  • Member
  • Offline
  • Registered: 2014-08-17
  • Posts: 70

Re: warping help.

I've always used two things against warping: bed at 120ºC throughout the entire print, and either a brim or manually placed 'mouse ears'. I also print over a BuiltTak sheet, which has good adherence, but mainly the brim helps A LOT to keep the parts glued to the bed, and it's very easy to remove afterwards, leaving almost no marks.

However on tall prints which take many hours to complete I've had delamination on high layers, in the corners of the print mainly, and I'm not sure what can be done against that. I've tried printing with and without fan, with the case open and closed... and still getting cracks.

28 Reply by n2ri (edited by n2ri 2014-12-10 18:09:00)

  • n2ri
  • Member
  • Offline
  • From: St Louis MO USA area
  • Registered: 2013-02-03
  • Posts: 2,539

Re: warping help.

I have found that bed temp as cool as possible while maintaining adhesion has less chance of warp due to lower range of temps on layers. then tall/long prints need inclosure to keep upper layers warmer/closer to lower layer temps. the latter I havnt done lately due to sides open for drawing fumes through charcoal filtered fan, I need to rethink that part b4 doing long/tall prints again, as my vacuum Cyclone cracked in several layers plus inside is full of plastic hairs/threads lol. I just closed cracks with plastic model glue then worked at cleaning hairs off inside walls.

I like how jjc thinks though. some good ideas to try, plus a brim.

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

29 Reply by jjc

  • jjc
  • Member
  • Offline
  • Registered: 2014-12-09
  • Posts: 36

Re: warping help.

I really didn't understand the difference between rafts, skirts and brims, so I goggled it and found this:

http://www.simplify3d.com/support/tutor … and-brims/

I'd seen examples but couldn't relate the terms to the examples.  I design in SolidWorks, used to use an expensive Dimension Elite which was very good, but has only one 'dual extruder' and the second head was always used for support material, which was always a proprietary non-abs 'dissoluble' (in a nasty heated chemical bath).  It also used disposable platforms, and always used a raft.  It had a heated chamber and was really, really good for accurate parts.

But back to now.

Now that I know the definitions, I realize that last night I was intending to go the 'brim' method, and was trying to figure out how to add geometry to my model at 55 degrees so I could fit the brim on a model that completely uses up a diagonal area from the back left corner to the front right corner.

I ditched that idea and choose a raft instead then created a used a high wall skirt.  I actually made the high wall skirt higher than my part . . . just to keep things warm inside the skirt and slow the cooling of the part.

I've also made another jump (since I'm using the Duo) into using the second extruder for rafts and supports.  I had all kinds of issues with the second extruder not breaking off the filament when switching extruders.  I would get hairs and strings all over the part as a result.

And I did run into problems when I started today's print.  I had to cancel the print, clean the nozzles, and perform 'load filament' routines to get a good print started.

I also ran into something I haven't seen yet: The XYZ Software would report an 'unidentified cartridge' and wouldn't send the part to the printer.  I tried everything to clear it, then finally exited the XYZ software and started it up again and went through the whole print process again.

Engineer in the Medical Device Industry, used high end 3D printers, but exploring what can be done with inexpensive printers.  Own a Da Vinci 2.0 Duo

30 Reply by jjc (edited by jjc 2014-12-11 19:22:45)

  • jjc
  • Member
  • Offline
  • Registered: 2014-12-09
  • Posts: 36

Re: warping help.

wandering around the simplify3d forum I came across a post that talked about fixing the 2nd extruder drip problem when changing from one head to the other during a print.   You build a tall skirt like I'm doing and set it up (I didn't really understand how) so that the change over always occurs when starting a new layer on the skirt. 

Went back to my printer and noticed that the little bits of ABS from one extruder are, (yes!) embedded on the outside of the tall skirt.  The actual part is clean. not sure how to make sure this always happens, but . . .

--------------------
Update: The part finished printing late last night, so I just left it on the bed until this morning.  Everything seemed to work out - the part stayed on the bed and there was no pulling up at the end.

There is an issue with roughness in a certain section of the part's upper surface.  I've attached a couple of files (if someone can instruct me on how to place images in a post I'd appreciate it).

I think the roughness is more geometry related - not related to warping.  I might start another thread to open that up to more discussion.
http://photos1.meetupstatic.com/photos/event/c/7/c/b/event_432351147.jpeg http://photos2.meetupstatic.com/photos/event/c/7/c/e/event_432351150.jpeg

Post's attachments

Surface Roughness 1.PNG 350.76 kb, file has never been downloaded. 

Surface Roughness 2.PNG
Surface Roughness 2.PNG 439.84 kb, file has never been downloaded. 

You don't have the permssions to download the attachments of this post.
Engineer in the Medical Device Industry, used high end 3D printers, but exploring what can be done with inexpensive printers.  Own a Da Vinci 2.0 Duo

31 Reply by nicksears (edited by nicksears 2015-03-11 06:47:16)

  • nicksears
  • Newbie
  • Offline
  • Registered: 2015-02-14
  • Posts: 8

Re: warping help.

Any conclusions on this? The forum consensus seems to be counter to anything I've read elsewhere - everywhere else says a cooling fan for abs will cause cracking. You should only use a fan for abs for bridges and small parts.

The consensus elsewhere is also an enclosure for reducing cracking, but industrial machines (which we can assume do it better) r
Go one forget and heat the entire enclosure 50-100C+. That should be the avenue we use to prevent cracking for large parts (that and better materials). Honestly you shouldn't have issues unless they're rather large parts or it might just be crappy filament.

As for adhesion, a combination of glue stick, kapton, hairspray, and/or abs glue will work for just about any material. Abs should only require glue stick + 110C bed (works for me). Hairspray also works, kapton can work, but sometimes needs help from the other methods.