Canvas Build Surface

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etotheipi
Posts: 6
Joined: Fri Mar 04, 2016 4:09 pm

Canvas Build Surface

Post by etotheipi » Sat Mar 05, 2016 7:17 pm

Hi all, I just recently ordered an M2 and joined the forums. I don't even have the printer yet, but wanted to share my success story using canvas & epoxy for my build platform on old MBot Cube 2, where this technique was absolutely necessary without a HBP. I am looking forward to trying to get my prints working without this on the M2, but expect I might go back to this because it is absolutely care-free.



Pros:
  • PLA, Nylon, kinda-ABS, stick perfectly to the cold build platform: the filament extrudes into the threading of the canvas and holds tightly
  • Lasts a damn long time: I've done hundreds of prints and only had to change it a couple times, usually when I have a tough battle to get something off the plate and it tears the canvas
  • There is absolutely no maintenance. Just relevel the bed once, and prints will stick well for the lifetime of the canvas.
  • Have been able to print nylon on the cold plate, as long as it's not too wide of a base
Cons:
  • Sometimes things stick too well and are difficult to pry off. I have a large knife ... machete? ... that I use to slide under the print and work around to get the print released.
  • Bottom surface of the print is ugly. It has a textured pattern. For me this doesn't matter because a lot of what I'm printing are board game organizers, etc, where the bottom surface isn't exposed.
  • I have tried with ABS a couple times, but it didn't work as well as I expected it to. I'm not sure why. It might've been bad luck at the time and that it actuall works well.
USEFUL TIP: If you do this, I highly recommend you add a drop of food coloring to the epoxy before laying it on the build plate. The first few times I added epoxy without, I could not tell what parts of the plate had already been covered. I ended up with some areas that had no epoxy or lumped with too much.

Process:
  • Get some strong sheets of canvas.
  • Will also need epoxy and kapton tape.
  • Get a large, heavy stack of books, to put on the plate while it is drying/setting
  • Cut out a piece of canvas the size of your plate (perhaps slightly bigger)
  • Put the kapton tape over the surface as you would for normal printing. Place the plate on a large sheet of cardboard, as this can get messy.
  • Mix the two parts of epoxy and preferably a little food coloring (as mentioned in the tip above)
  • Spread epoxy evenly over the kapton surface. Make sure you get all the way up to the edges. Work quickly as the epoxy will start to set in a few minutes.
  • Carefully center the canvas over the platform and press it down and smooth it out with your hands.
  • Put a stack of books on it for a few hours until it sets/dries.
  • Re-level your printer to the new plate height. It should be a bit tighter level than normal, to ensure that the filament is extruded into the threads of the canvas.
I haven't had an adhesion problem since I did this, besides a couple times I tried to print ABS on it (but that might've been user error). If I print a really wide PLA object, sometimes I get a little bit of curling at the corners, but it's minimal.

I hope someone else gets some benefit out of this technique, as it was a lifesaver for me. I wanted to spread the word as widely as possible!
canvas_build_plate.jpg
My build plate after 100+ prints

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Jules
Posts: 3144
Joined: Wed Jan 21, 2015 1:36 am

Re: Canvas Build Surface

Post by Jules » Sat Mar 05, 2016 10:18 pm

Interesting. What kind of surface does that give you on the bottom of the print? :)

etotheipi
Posts: 6
Joined: Fri Mar 04, 2016 4:09 pm

Re: Canvas Build Surface

Post by etotheipi » Sat Mar 05, 2016 11:09 pm

Jules wrote:Interesting. What kind of surface does that give you on the bottom of the print? :)
It's not pretty -- I wouldn't use it if you care what the bottom of your prints look like. Not only are you going to get a threaded pattern, you usually get fibers from the canvas attached to the print (in my case, black). And if you're like me and procrastinate on replacing the canvas after it's got a hole in it, then you get an artifact shaped like the hole (as in the first picture). This artifact has no effect on the usability of the tray, but is obviously quite an eyesore.

Both pictures are of large PLA prints without a heated build platform. And they came out perfectly in terms of shape with no warping -- especially important for the second one which holds 25 stacks of 10 cards each, meaning the slots need to be perfectly sized and straight. No one will ever look at the bottom of these prints, but obviously that's not the case for many other applications.
Attachments
canvas_bottom_ex3.jpg
The artifact on the bottom was due to printing this on canvas with a large hole in it
canvas_bottom_ex2.jpg
Printed on a smooth black canvas surface, which left some black fabric on the bottom.

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