Warping, Part not sticking to raft

[marting]

If I print somewhat bigger parts with a flat bottom I always get warping at the edges. The raft is sticking perfectly to the perfboard but the part itself just lifts off the raft. The wind barrier is closed. I'm using software version 1.18 and was able to mechanically align the build platform so that I needed at most 0.2mm in calibration. I also preheated for 1 hour before printing and printed in a room with 22°C. Any thoughts on what else I could do to eliminate warping?

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[roller]

I found similar issues with 1.18 - I think they have altered settings to improve raft and support removal ... unfortunately it's too easy. 1.16 seems to make prints that are a little better bonded. Otherwise others have suggested pausing and putting a dab of superglue/acetone/MEK/abs glue in the corners once the first few layers are printed on top of the raft to hold them in place.

Keeping any drafts from your printer and warming the microclimate around it will also help. Some just throw a cardboard box over the whole thing once it's printing.

[marto]

Yeh I am getting exactly the same issues.

I can't use 1.17 or lower as I need the bed levelling. If I don't then it pulls the raft up in the corners.

Adding holes and changing the shape to break up long thin parts helps. I also found printing 4mm raft helps with the adhesion but not a great deal.

Steve

[marting]

I tried 1.18 because my bed was also not level, almost 1mm off in one corner but it didn't really help against warping. With 1.18 sometimes it also happens that on one corner the parts sticks to the raft so strongly that it's impossible to remove without breaking the surface of the part and on the opposite corner it warps because it does not stick to the raft at all.

So I wanted the bed to be level. I carefully measured where the highest point was using the calibration function in 1.18. Then I just needed to squeeze the metal brackets holding the perfboard with a pipe wrench at the right point to lower the perfboard somewhat at that point. Now the bed is almost level, just 0.2mm out. But still I get the same amount of warping. I will try reverting to 1.17 or 1.16 as suggested.

[Tiertime-Edward]

If I print somewhat bigger parts with a flat bottom I always get warping at the edges. The raft is sticking perfectly to the perfboard but the part itself just lifts off the raft. The wind barrier is closed. I'm using software version 1.18 and was able to mechanically align the build platform so that I needed at most 0.2mm in calibration. I also preheated for 1 hour before printing and printed in a room with 22°C. Any thoughts on what else I could do to eliminate warping?

Please close the wind barrier when printing the model. Also please select a thinner layer thickness, like 0.2mm.

Did you print the clibrate model which for calibrating the vertical? See the instruction, http://www.pp3dp.com/index.php?option=c ... &Itemid=55.

[marto]

I have done the calibration with mine and I am printing @ 0.2mm with the barrier closed.

I have been told printing on fast is better as it allows less time for the plastic to cool before coming around to do next layer. Do you agree? Or has anyone else had experience with this.

Steve

[roller]

The common reprap rule of thumb is to print slower not faster for warping. Better bonding occurs at slower speeds reduces lifting away. I believe the theory also goes that by printing faster the print shrinks as a group and more powerfully than printing slow where some shrinking occurs as each layer occurs which exerts less warping force... but it's been a while since I ABS printed on a reprap so my memory is a little hazy but the rule of thumb was definitely slower is better.

[mr6k]

Here's a thing for a materials wish list. How about a material like ABS but one that has a much lower coefficient of expansion. Then I guess the lifting/peeling and shape deforming issues would all go away. (Not PLA though. It is too brittle, and decomposes in a lot of user environments) Of course other threads are talking about the possibility of printing pliable materials and I guess they won't lift, just stretch!

cheers

Peter

[roller]

So your saying you want a plastic with the same properties but completely different behavior ... it's good at least you are not without a sense of irony.

Seriously, other resilient plastics that are starting to become available for 3D printers are nylon and polycarbonate. Again the shrinking/warping properties will be different as will the strength stiffness. I am sure we'll hear more once they're a little easier to obtain.

[marto]

@marting: When you did the calibration of the bed level did you find that the center was slightly higher than the edges?

This was the case with mine and I am wondering whether this could be a factor in our prints lifting off the raft.

Steve

[roller]

The Mini runs a bit cold in the corners and 1.18 seems to have a little less layer adhesion (as did 1.17) presumably designed to help support separation but with the Mini I found it happened when I didn't want it too. Perhaps try the adhesive in the corners method.

[marto]

So I did a 7hr20min print lastnight with 0.2mm on fine with 4mm raft and it only lifted slighlty in one corner.

I found that there was one patch which didn't stick very well and one section which I couldn't get off so it could still be something to do with my levelling. I wonder how the software patch for the different heights works... and if this could be responsible, or maybe I need to redo it again with a bit more care.

Don't get me wrong its a big, complex and challenging part. Which is completely functional just aiming for perfection here. Could never do it on my reprap.

Steve

[Dicky]

@marting, perhaps your room temperature is low? I printed a big model and got no warping or break in the model. My setting is 0.2mm, room temperature approx 24C, and I closed the wind baffle.



The build platform is not level enough when I received the mini printer, something like 1mm lower in the left. But I followed PP3DP instruction and manually calibrated the leveling. I also found another very good instruction, it would be useful to you. http://3dprintingsystems.com/UP_Mini_Pl ... ration.pdf I successed and get platform much leveled, but still not solid level. I calibrated the platform again with the software. I was very careful in the software calibration, as it affects the print quality if it is not done well. You must be more careful.

I have started my object lists printing. I have lots of models queue for printing on the mini printer.

[scubamatt41]

Seriously, other resilient plastics that are starting to become available for 3D printers are nylon and polycarbonate.

Yeah I want nylon

[wilsonj]

I have some 3mm nylon, which of course I can't test on the UP. But I should have some 1.75 by the end of this month, or early Jan.....

As expected the filament is unbreakable, unlike PLA and ABS.

[marting]

@marting: When you did the calibration of the bed level did you find that the center was slightly higher than the edges?

This was the case with mine and I am wondering whether this could be a factor in our prints lifting off the raft.

Steve

Yes, the center was higher that the edges. I took care of that by removing the heated platform and sanding down the plastic bracket below it. It was simply too high.

I thought to reduce warping one should print fast and with a layer thickness of 0.35 to reduce the build time. Seems I got it all wrong I'll try printing on fine and with 0.2 layers.