1 Topic by XaroRSA (edited by XaroRSA 2012-11-26 14:21:32)

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Topic: Large Prints warping

Good day forum.

I recently printed a 11hour print, fairly big, about 100x80x110.
I found a problem with the print.
The bottom temperature was set to 90degrees, and i suspect if i set it to 100degrees it would not have warped at the bottom.

But in the middle of the print/block, it warped badly, and i dont think the bed temperature would affect it there.
The warping was so bad that it eventually made a 'crack', as viewed below

The fill level was set down from 0.2 to 0.15, and the rest were on defaults.

http://i53.photobucket.com/albums/g79/XaroRSA/DSC_0609.jpg
http://i53.photobucket.com/albums/g79/XaroRSA/DSC_0608.jpg

Another thing i have is in the image below
http://i53.photobucket.com/albums/g79/XaroRSA/DSC_0607.jpg

What causes the printer to make this repeated error? and how can i fix the warping issue on big prints?
Aswell, can i set the print to 0.5mm layer for large block prints? How do i do it correctly with skeinforge/pronterface?

Regards and thank you forum!

2 Reply by macmub (edited by macmub 2012-11-26 21:48:35)

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Re: Large Prints warping

These are some things ive learned printing large objects.

1: clean bed, and re apply any tapes or hairspray etc
2: Have your case on
3: bed upto 100-105...you will find it wont go much passed 100
4: check flow rate with vertical wall test to confirm correct amount of plastic is being distributed (if to much or to little plastic comes out large prints usually go to shit.
5: nozzle 195
6: let the part cool down to room temp inside the printer, if it cools to fast it can crack and distort.

As for that 'seam' on the part, Id say that is where your z height is lifting for each layer.
If your using slic3r try 'ticking' on randomize start points in your print settings, that should make that go away.
I dont know how to change that in skeinforge.

Im sure everyone has there own tricks, these are just some of the things ive learned over the last week.

3 Reply by IanJohnson

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Re: Large Prints warping

It's actually where the inner loops switch to the perimeter, or when the perimeter goes to the fill.  Slic3r seems to be pretty good about hiding the layer change inside the print.  Retraction can help, make sure the Minimum Ttavel After Retraction is set to 0.  Otherwise the move from loop to perimeter is too short to trigger the retraction.  If your flow rate is too high, it might exaggerate those bumps, so make sure that is calibrated as well.

The best thing for cracking is going to be keeping the ambient temperature up during the print so there isn't as much difference in shrinkage from one area to the next.  Putting the case on, or otherwise covering it should help.  If you don't have a case, you could just tape cardboard to the sides and top.

4 Reply by jooshs

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Re: Large Prints warping

Additionally, you should try to reduce layers' printing times on these large prints.  Sometimes, the layers take so long to print that by the time the next layer starts, the previous has cooled enough there isn't great adhesion.  For any parts such as infill, perimeters that aren't external, and the like, you should speed up the printing and movements.  The Solidoodle seems to be able to hand 100-125 mm/s very well and it seems to be accurate enough for infill and and inner perimeters.  You can also reduce the infill if it isn't critical to be filled very much.  Many times you can see immediately that there isn't good adhesion and it appears as sort of a gap in the layers and it will start warping throughout the rest of the print. 

The previous suggestions, especially the enclosed print area are critical.  Ian, have you tried attaching any kind of heater to your hole on the side yet?

5 Reply by IanJohnson

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Re: Large Prints warping

http://solidoodletips.files.wordpress.com/2012/11/img_2861.jpg

I need to design some fixtures for it, most notably a hood on the inside to direct the air down.  Even though the air is hot, it is not hot enough to be blowing directly on ABS and the convection caused a bunch of delamination.  If I have something I think will be a challenge, or need the bed to be able to get extra hot in a chilly garage, I will preheat the inside and then shut it off when I start the print.  I can get the ambient up into the 60s, close to 70.  I wouldn't want to go hotter than that.

I got the heater from Amazon, about $17 http://www.amazon.com/gp/product/B003XD … 00_s00_i00