Is this issue temperature? Z-Height? Some thing else?

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tofu702
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Joined: Thu Apr 21, 2016 6:39 am

Is this issue temperature? Z-Height? Some thing else?

Post by tofu702 » Thu May 05, 2016 8:22 pm

I've been having some printing issues and I'm not sure what the cause is. Prints tend to be bulgy and the first layer seems to be missing some material in certain regions (I think it's might be peeling over, but it's hard to tell). Is this a temperature issue? Not getting the Z-Height quite right?

I'm on a Rev E which has Kapton tape on the glass. I've been using Simplify3D + Makergear PLA with (generally) the default settings (70 degree bed + 220 extruder temp). The photos below are w/ default settings, though in prior prints I have tried a bit lower extruder temp & bed temp, but adhesion has been an issue.

Photos (Simplify3d + default "High" quality settings): https://goo.gl/9RnNQd

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Jules
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Re: Is this issue temperature? Z-Height? Some thing else?

Post by Jules » Thu May 05, 2016 9:37 pm

You might need to do a couple of things, in this order:

1. Your filament isn't sticking on the bottom layer -

a. You're too far out with your Starting Height - the threads on the bottom layer are not even touching each other, so you need to reset the Starting Height and get that gap tighter so the threads start bonding to each other.

b. Start using an adhesive on the kapton tape - hairspray helps with a lot of gap problems, and you need adhesive for that print - looks like there is a gradual curved "overhang" when the frame is upside down and that first layer is against the plate.

2. Make sure the outline direction that you are printing is From Inside to Outside.

3. Lower your printing temps a little - that's too hot for PLA with overhangs. Fixing the gap problem and using some adhesive is going to make it easier for the filament to stick to the plate, but (particularly with overhangs) the PLA is going to warp and slump more the higher the temp you print it at.

Get the gap fixed, then try 210°/60° with a lot of fan pointed at it to cool it off as quickly as possible. (Cuts down on the warping and slumping). Go even lower than that if you don't experience bonding problems.

4. And you might have to print that with support under the overhangs, but that kind of gradually curved underside is very hard to get a nice surface on the underside, even with support.

tofu702
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Joined: Thu Apr 21, 2016 6:39 am

Re: Is this issue temperature? Z-Height? Some thing else?

Post by tofu702 » Tue May 10, 2016 8:35 am

Thanks Jules! I think I haven't yet gotten the Z-Height perfect so I'm trying to nail it first and then move on to looking at things like temperature and adhesives. I've been printing some of the calibration squares suggested on other threads, to try to really nail the Z-height (I assume this is still considered a solid technique on the Rev E).

For this particular model, it seems to print much better with thicker layers. I think that has something to do with the layers handling overhang better. I'm experimenting with another high quality print right now and will post when I have results.

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Jules
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Re: Is this issue temperature? Z-Height? Some thing else?

Post by Jules » Tue May 10, 2016 1:53 pm

tofu702 wrote:.....calibration squares suggested on other threads, to try to really nail the Z-height (I assume this is still considered a solid technique on the Rev E).
It's okay to use the calibration square for testing to get a look at your thread height and overlap, but remember that making changes in the software is not going to help you at all with a Rev E machine. The only thing that modifies the gap for the Rev E machines is to physically reset the Starting Height using different feeler gauges. :)

tofu702
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Joined: Thu Apr 21, 2016 6:39 am

Re: Is this issue temperature? Z-Height? Some thing else?

Post by tofu702 » Thu May 12, 2016 9:30 pm

Thanks Jules!

Update: this is working a lot better with proper Z-Height, lower temps and hairspray. I'd been resisting hairspray because I was afraid it might be messy, but it makes a world of a difference.

For those who encounter similar problems with PLA, here are my notes. Nothing here is earth shattering and much of it is from other forum posts:
  • Really make sure the Z-Height is exactly right. The calibration box was quite handy in checking this, though as Jules said, lots of the other posts involve adjusting settings in Simplify3d that aren't applicable to the Rev E.
  • Use hairspray. Yes, it technically prints without it, but you'll end up with a bunch of issues and need higher bed temperatures. (Yes everyone says this all over the forum; it's really true). After this, I'd go as far as saying that Makergear should ship the M2 with a can.
  • Also, clean the bed / tape throughly frequently. It gets dust and grease that can mess with adhesion.
  • I used 50 degree bed temp and a 205 extruder temp. This entirely fixed warping.
  • I was printing with 0.1 mm layers. Insta mentioned on another thread to use thicker first layer, so I did. I think that helped.
  • For structures like the one in my pictures, try to print with an orientation that doesn't require supports for the aggressively curving edges. It's hard to generate such supports adequately. In my case, I ended up needing substantially more support in another orientation, but the overall print quality was better.

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