Pros and Cons of PEI/MIC6 vs glass?

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86bg
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Pros and Cons of PEI/MIC6 vs glass?

Post by 86bg » Fri Mar 17, 2017 2:21 am

First post!

Just got my m2 last week and have put it through dozens of hours of printing already. Ordered a second glass so I can clean/remove parts without interrupting printing.

After ripping off the Kapton which i already ruined with a blade, I scrubbed my glass with Dawn, followed by 99% alcohol rinse followed by a shake-dry and Aqua Net application. The prints when finished were stuck so well to the print that it was a nightmare to remove them and required a razor blade. However, in one corner of a nearly full print bed of parts, i had 2 parts that were peeling up and on the bottom of them, showed obvious signs of lack of fusion to the bed when compared with the other glass-like parts. Prior to this print (10 hours) I leveled the bed carefully. This leads me to believe that the glass is not flat! I cannot prove this until I take it in to work (Machine Shop!) but that got me thinking even more about these MIC6 beds i keep hearing about.

So, my questions are:
  • From your experience, is the glass warped/being warped by the heat?
  • What are the pros and cons of MIC6 vs glass?
  • What is the function of PEI?
  • Can you order it from a local aluminum supplier cut to size? Is it milled to size?
  • Why would you need/want PEI?
  • Without PEI, does MIC6 require bead blasting?
  • What is the function of PEI?
  • Is it just a more resilient Kapton equivalent?
I do work at a machine shop and know how to use the machines, so any preparation can be done in house (if needed), and I might even be able to buy the MIC6 from our aluminum supplier without shipping costs.

Thanks in advance!

Also, why do I get no response from my printer when I do a G90 G1 X 15. ? (the only command I've tried) and how do i read the current absolute position relative to the z height offset? I know how to read the z offset already. Do you guys use the makergear quick start for z offsetting?

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atomic_peach
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Location: Philadelphia, PA

Re: Pros and Cons of PEI/MIC6 vs glass?

Post by atomic_peach » Sun May 14, 2017 3:51 pm

Finally caught up on unread threads and still didn't see this answered for you. Most of this info is scattered in various threads, so I'll post what I know to directly answer your questions.
86bg wrote:
  • From your experience, is the glass warped/being warped by the heat?
Glass can technically have some surface out of flatness depending how it was manufactured, but I have never seen any warped enough to affect a print. It shouldn't warp when heated, no at the low temps it is heated to on a printer. What you are probably seeing is the lack of uniform heating across the plate. Someone posted a FLIR comparison of glass and aluminum on the heated bed to show this issue.
86bg wrote:
  • What are the pros and cons of MIC6 vs glass?
MIC6 is a cast, precision milled/ground sheet of aluminum. The casting helps prevent stresses in the surface so it remains stable when machined, thus allowing a high precision (i.e. flat) sheet to be made easily. Aluminum has a much greater thermal diffusivity than glass, so it helps disperse the heat across the entire plate faster and more efficiently. Again, look at the FLIR images linked above. Essentially, MIC6 provides a better thermal, flat sheet than glass, but it is heavier and it is more expensive.
86bg wrote:
  • Can you order it from a local aluminum supplier cut to size? Is it milled to size?
There are many suppliers for MIC6 and I'm sure some can cut it to size. Most often they saw the sheets, but you can mill it if you can anchor the sheet. Might be best to have a supplier cut one slightly oversize and you mill that to fit the bed. McMaster sells smaller plates than a full sheet.
86bg wrote:
  • Without PEI, does MIC6 require bead blasting?
I'm not an expert on printing on bare MIC6, but I do not believe it is required. MIC6 does not come as a polished surface. I'm sure the bead blasting helps in part removal and gives parts a nice bottom finish. I think I read someone simply sanded his with 1000+ grit sandpaper.
86bg wrote:
  • What is the function of PEI?
  • Why would you need/want PEI?
  • Is it just a more resilient Kapton equivalent?
PEI is a good neutral plastic that adheres to almost everything you can print with. You can put PEI on your glass bed and never use hairspray, glue, ABS slurry, etc. again. The key with PEI is keeping it clean as even finger print oils can prevent adhesion. A quick wipe with alcohol prior to printing is all you need. If you lose adhesion after many prints, you can take some fine sandpaper to it and get a great surface again. PEI is also rather resilient to scratches and such when removing prints. I wanted PEI because it is cleaner and easier than most other solutions and I am happy with it.
86bg wrote: Also, why do I get no response from my printer when I do a G90 G1 X 15. ? (the only command I've tried) and how do i read the current absolute position relative to the z height offset? I know how to read the z offset already. Do you guys use the makergear quick start for z offsetting?
M114 - Get Current Position should work. I see no reason the printer would provide a response to a G1 code. I use the Quick Start app for initial setting and leveling but I'll use Octoprint to make any fine adjustments (there is an EEPROM editor plugin that makes it way too easy).

Hope that helps! Welcome to the community!

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Tim
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Re: Pros and Cons of PEI/MIC6 vs glass?

Post by Tim » Sun May 14, 2017 5:03 pm

86bg wrote:This leads me to believe that the glass is not flat
Don't rule out the possibility that it's not the glass that isn't flat. There have been a number of posts about a tendency for the frame and rail to flex ever so slightly, leading to a low spot in the middle of the X rail that appears to be a high spot in the middle of the bed. If that's the case, then the flattest surface in the world isn't going to help, but a trivial solution like easing up on the X axis belt tension may help a lot.

That said, though, there are a lot of good reasons to use MIC6 plate and PEI. In my experience, careful sanding of the PEI surface is as good as hairspray for adhesion. I never liked the polyimide tape; too much hassle.

Quark
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Re: Pros and Cons of PEI/MIC6 vs glass?

Post by Quark » Mon May 15, 2017 6:45 am

I had considered a Mic6 plates as well when I had a hard time getting my bed leveled, seemed like the glass was warped up in the center. Like Tim said, I eventually found that my x-rail was hanging low, so I shimmed it and its all good now. I don't print very many large things end to end, so heat dispersion wasn't that big an issue for me. I just slapped PEI sheet on my glass and yeah, its working great. I print mostly PETG and its working well. I used to use hairspray and it was perfectly fine, but I realized that I needed to make things simpler once I showed my GF how to use my machine. :lol: :lol: :lol:

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