Another Corner Curling Up Issue?

[CoffeeCup]

I built an enclosure for my Makerfarm i3v and before I had it dialed in well and printing great test cubes. After putting the 3D printer into the enclosure I've encountered this issue. It seems like the right corner does not stay down on each layer as the head makes a sort of u-turn as it reaches that right corner goes back in the direction it came from which is the left. I've looked over my printer lots of times and can't find anything hanging up anywhere. I've printed 5 cubes and they've all had this issue. Anybody experience this? I'll be sharing a link to a video of it happening in a few minutes. Here's the video: https://youtu.be/VjbinM_nVyg

[Chadd]

IMO the print is getting too hot. You either need a cooling fan or you need to slow the speed down so that the part has a bit of time to cool. Also I am not sure what you are slicing with but that is kind of odd the way it is printing the part by going back and forth like that.

[printbus]

What material? Are you printing on a hot bed? If so, what temp? What is the hot end temperature? Which way is the hot end fan moving air?

IMO the print is getting too hot.

Yep, especially if the print is being done in PLA. You can tell by the way the upper portion of the cube squishes around as the nozzle drags through the top layer. Anytime you see that happening, print quality is likely to suffer. I don't print much in ABS, but I assume you'd have the same issue if an ABS print stays too warm.

So why is that corner the worst? As noted in the OP, the printing stops and turns around at that point, allowing more heat soak from the hot end into the print when it decelerates to and accelerates from the stop at the corner. It also appears layer shifts are happening at that corner - providing even more bits of time where the hot end is sitting still at that corner. Could be a hot spot in the heat bed there... Could be related to the airflow pattern caused by the hot end fan or simply convection currents.

If this is PLA, the enclosure may be causing more problems than it is worth. It takes a lot to cool PLA, and printing inside a warm enclosure isn't going to help. A good print cooling scheme would have the biggest effect. Slowing the print speed has been argued by some to have marginal effect. While a slower speed provides cooling time before the next pass, the slower speed can also enable more thermal gain from the hot end into the print. If this is to be a cube, printing with infill is a way to increase the layer time. You could print more than one part at a time. I don't remember what slicer supported it, but I remember setting up one real small print so that the hot end would move off the print at the end of each layer as required to maintain the minimum layer time I had specified.

[CoffeeCup]

Looking around online I saw that 140 degrees Fahrenheit is an optimal tempature inside an enclosure when printing with ABS. That is ABS I'm printing with. I built the enclosure because I was having warping and layer adhesion issues on a large about 6" x 6" build. While running the temp inside the enclosure gets up around 110 max. I have a filament bulb in the back adding heat I can turn that off. Also the front and rear plexiglass pieces are removable so I will trying lowering the temp a bit when I get home today.

*EDIT** Hot end is at 250c and heated bed at 110c. The fan on the hot end fan is blowing from the front towards the back

[Carrot_or_Stick]

Looking around online I saw that 140 degrees Fahrenheit is an optimal tempature inside an enclosure when printing with ABS. That is ABS I'm printing with. I built the enclosure because I was having warping and layer adhesion issues on a large about 6" x 6" build. While running the temp inside the enclosure gets up around 110 max. I have a filament bulb in the back adding heat I can turn that off. Also the front and rear plexiglass pieces are removable so I will trying lowering the temp a bit when I get home today.

140 seems high to me. My last ABS print (Hot-end: 230c / Bed: 100c) in my newly finished enclosure had the temp reach just shy of 90 degrees Fahrenheit and the print came out great. Try around the 100 mark to see if that helps.

[CoffeeCup]

Ran a print with the Light off and all plexi glass walls up on the enclosure. Started at 93 degrees and got up to 97 almost midway through the print before stopping it. Problem was still there.

Then ran with the Light off plus front & rear plexi walls removed. It started at 90 degrees and stayed about 91 throughout the print. The problem is no longer there. Going to run another to try to duplicate that result.

[printbus]

I'm of little help in ABS issues, but what are you using to adhere the print to the glass?

[CoffeeCup]

I'm using a cheap brand of hair spray

[printbus]

... I built the enclosure because I was having warping and layer adhesion issues on a large about 6" x 6" build...
...The fan on the hot end fan is blowing from the front towards the back

I interpret this to mean the fan is "pushing" air onto the hot end heatsink, which would be consistent with what MakerFarm and e3d both tell you to do. The boxed-in bottom of the i3/i3v X-carriage leaves nowhere for the fan airflow to go except back down onto the print. For ABS, that has led to warping/adhesion problems for at least some people. Flipping the fan around so it pulls air up from the print area, through the heatsink, and exhausting it out the fan helps.

[CoffeeCup]

I interpret this to mean the fan is "pushing" air onto the hot end heatsink, which would be consistent with what MakerFarm and e3d both tell you to do. The boxed-in bottom of the i3/i3v X-carriage leaves nowhere for the fan airflow to go except back down onto the print. For ABS, that has led to warping/adhesion problems for at least some people. Flipping the fan around so it pulls air up from the print area, through the heatsink, and exhausting it out the fan helps.

Yes that's right it's pushing air through the hot end sink and into the boxed end bottom of the x-carriage. Thanks for that bit of info I'll keep it in mind going forward and thanks to everybody else for the input as well. The second print with light off plus front & rear plexi walls removed repeated the good results. The inside of the enclosure stayed at 91 degrees fahrenheit. I wonder why I kept seeing such high recommended enclosure temps for ABS? 140 degrees fahrenheit. Perhaps they had a lower hot end and bed temp than my 250c/110c.

Next will be to see how well this setup performs on my large 6"x6" print. This will have to wait until my next day off so I can devote the entire day to it.