Lifting corners

Good afternoon all,

I'm hoping someone could help me out. I'm at my wits end with this problem and can't seem to find a solution. I've purchased a Rapide Lite 200, finally received it 2 weeks ago, and for the most part, I'm extremely happy with the print quality. However, I've come across a problem that's been driving me nuts and I can't seem to fix it.

I have a laptop stand, that starts with pads on the four corners. This is where the problem starts:

about 4 to 5 layers up, the corners start to rise/curl (See attached photos). If i just leave it, they rise so much that the extruder nozzle will push the printed section right off and cause an outright spaghetti storm. I've adjusted temperatures (from 190 all the way to 225), layer heights (I generally print between .15 and .2). I leave my shell number to 2, but I've also tried 3. I've changed my speeds for perimeters and infills from 60 all the way down to 20 with the same result. I'm completely lost. I'm running Repetier, using Slic3r with PLA filament.

I'm new to the printing scene, I thought I had a pretty good grasp on this, but it turns out I don't.

Any help or direction would be GREATLY appreciated.
Thank you so much in advance,

That's a very common problem, and there are a number of mitigation strategies people use. Many of them work well, but none are perfect.

One technique is to use the brim feature of your slicer. This puts a wide border around the bottom layer to give it more surface to adhere to the bed. I do this on troublesome objects, but the main solution I use - at least for PLA - is PVA cement. In the US, we have elmer's glue - basically it's white glue. I dilute it 4:1 with water and wipe it on the hot bed with a paper towel. Some people have success with glue sticks, but I find they build up too thickly on the glass. The main argument against the white glue like I use is drying time, but with the bed hot, the liquid dries literally in seconds - before I have the cap closed on the bottle, it's ready to go.

Some people have reported success using blue painter's tape and no heat. but I have never tried that. I find taping the glass to be extremely cumbersome, and since my solution works fairly well, I haven't gone in that direction.

For ABS it's a different story. I have found nothing for ABS that works nearly as well as PVA glue does for PLA. My current solution here is to use kaptan take. My main complaint with this method is that it alters the appearance ot the first layer - giving it almost a mirror-like shine. Also, even after cooling, it can be difficult to remove an object. Many times the tape gets destroyed trying to remove the object, and it's a real PITA to re-tape. I have tried PET tape and so-called ABS-juice, but neither has worked for me.


EDIT - I wrote this whole message without looking at the photos. You are not having so much of an adhesion issue as a curling issue - again a very common issue. Using a fan for cooling PLA can help, but it doesn't always. I have no first-hand experience with it, but I've read that for ABS you can put your printer in an enclosure to try to retain heat and that it can help this.

Edited 1 time(s). Last edit at 04/04/2015 11:40PM by jbernardis.

You don't mention bed temperature. That may be on the high side. Aside from that, you can keep trying speeds and temperatures or working with a part fan. That said...

I had a hot-end fan shroud I was trying to print (out of ABS) that had a similar aggressive overhang starting with the first layer and gave me so much of the condition you're seeing I got impatient with repeated attempts and changed the STL to make the sides vertical, a configuration that was successful on the first try. If you're not seriously committed to this exact configuration you could remove your chamfers or make them smaller or more vertical.

Thanks very much for the suggestions - IMBoring25, I've set my bed temperature to 65 on the first run, then dropping to 60 afterwards. I've also tried 55/50 with the same results.

I guess I can try starting my fan after the first layer, perhaps this will help keep the form once the layer has been printed.

What you experience is curling due to overhangs. The simplest thing to do in most cases is using the cooling fan to cool down the extrusion as it is laid down.
It can also help, especially in cases where overhang starts from the very first layer and total surface of a layer is relatively low, to slow down the print so that it gives more time to the extruded plastic to cool.

What I do not get by looking to your pictures is how the bottom of the case will be printed... in the air? I see no support, so I cannot imagine how print will continue.

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3Dmaker4U
What I do not get by looking to your pictures is how the bottom of the case will be printed... in the air? I see no support, so I cannot imagine how print will continue.

That's a profoundly salient point, and it may solve everything. Not only is the bridging about to become a problem the way it's being done now, but if the part in question is such that it can be printed upside-down, the features that are now problematic become simple.

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3Dmaker4U
What I do not get by looking to your pictures is how the bottom of the case will be printed... in the air? I see no support, so I cannot imagine how print will continue.

The object in question is a large arc/curved object. I'm not sure if you're familiar with 12 South's macbook stands, but that's what I'm after. I have since put rafts on the object to help strengthen, but I don't think supports will be necessary.

Good luck...I'm not seeing that without support. Better than what I was anticipating, but not by much.

That is going to be a difficult object to print, and will definitely need support. Not only does the overhang angle become excessive as it nears the top, but you cannot expect the small feet to remain stuck to the bed as the two halves grow in height. As you are new to FFF printing, I suggest you get some experience with simpler designs before tackling that one (OTOH if you do not give up in frustration, you will learn a lot figuring out how to get it to print reasonably).

Dave