METHOD - silicone baking mat bed insulation and surface adhesion by BETLOG

Last crawled date: 3 years ago

Silicone baking mats, used for 2 things:
The much LESS interesting use:
The pyramidal surface mat - thermal insulation between silicone heater pad/aluminium hotbed and the Y axis chassis.https://www.aliexpress.com/item/Creative-Pyramid-Silicone-Baking-Mat-Nonstick-Pan-Pad-Cooking-Mat-Oven-Baking-Tray-Mat-Kitchen-Tools/32807788480.html
I have been using the pyramid mat for a few months. Compared to proper stuck-on insulation this is probably quite insubstantial, but as a simple, removable method to retain and constrain heat under the bed, this works better than nothing.
The much MORE interesting use:

The flat mat - sticky interface between polymer 'buildtak' style bed surface and aluminium hotbed.https://www.aliexpress.com/item/Red-Silicone-Pastry-Bread-Bakeware-Tray-Oven-Rolling-Kitchen-Baking-Mat-Sheet-PML/32693285580.html
Lay the silicone mat out matte side up, without stretching or deforming it, and check that it is flat with no ripples or deformation, and lift the corners and allow the mat to 'roll' back onto the surface to eliminate bubbles. Not all mats arrive perfectly flat, so it's possible some will not be completely appropriate to use, however heating them to 60 or 80C has been known the help them 'relax' a little into their as-produced form. So just getting it flat enough to stick a build surface to without significant tension or distortions will usually be good enough.
A polymer build surface with adhesive on one side is stuck to the matte - NOT the shiny side - of the mat, and cut to size.
Silicone cuts like butter, just use a sharp knife and cut slowly or it will ripple and mess up your edge.
Note that almost nothing "sticks" to silicone in the intended sense, so in this scenario it is removable, but will not come off unless you want it to.
The silicone mat's shiny side is applied to the clean aluminium build plate, where it will stick, and yet be easily removeable.
Yes, I clean all of the surfaces with isopropyl alcohol. The matte side before sticking the build surface to it. The shiny side of the silicone and the aluminium build plate, before installing the silicone/surface onto the bed. Silicone likes to attract particles, so clean it and avoid putting it down anywhere until it's stuck to the relevant surface.
This combination at first seemed a little unreliable in terms of flatness and having the required hardness to allow the nozzle to 'press' the filament into it to get intended toolpath widths, but after heating it to 60C a few times these issues seem to be gone. I'm not sure If heat rectified it or if I'm just now 'doing it right", because now I find it very easy to use, right down to 0.1mm initial layers.
Print removal is trivial, especially when you allow it to cool completely first. Simply remove the entire surface/mat/print from the bed in a peeling motion (at which time the print usually just alls off) and carefully peel the mat/surface away from the print, IF it is still stuck.
Realign one edge of the mat/surface with the hotbed, and roll it back into the bed. I usually swipe the flat of my NTcutter bladed scraper across the surcae to encourage any bubbled to migrate to the edges, I suspect this is useless, but it does ensure that the mat is stuck down.
I always orient the mat/surface the same way on the bed. This may not be relevant, but consistency is important when you are testing things like this.
Heating the silicone/buildsurface imparts a static charge that makes it cling to the aluminium. You will notice this if removing it hot. In some localities/humidities this may cause static discharge, so be careful of your electronics when peeling it off.
The red mat is really soft. Cutting it with a blade is only difficult becasue it's so easy that the mat moves around, even when i'm holding it down with a steel ruler. You could probably cut it by pinching hard with your fingernails.
Also useful in the kitchen, and I use an offcut to solder on, or to herd bolts/nuts.
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I intend to also test the silicone mat/build surface method with the following:
Mats:https://www.aliexpress.com/item/WALFOS-3pc-teflon-Extra-thick-heat-resistant-teflon-BBQ-Grill-Mat-Reusable-non-stick-barbecue-grilling/32741735053.html
.https://www.aliexpress.com/item/Bakeware-Mat-Oil-Paper-Non-Stick-Baking-Sheet-For-Pastry-Kitchen-Tool-30X40cm/32840502560.html
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NOTE: The previous two items are teflon, not silicone, so obviously there may or may not be issues with prints sticking.
They are like stiff paper...not sure if i'll bother trying to stick a square of 3m adhesive to them and try then as surfaces.. im pretty sure prints would stick to them, but they are fabric textured, and kind of crumpled from shipping.
.https://www.aliexpress.com/item/Non-Stick-Silicone-Baking-Mat-Kneading-Dough-Mat-Baking-Rolling-pastry-Mat-Bakeware-Liners-Pads-Cooking/32799677298.html
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Is like fine fibreglass fabric wrapped in a thin layer of something vaguely gummy. You can crease it, probably permanently, but if it's clean and dry it will stick to aluminium plates...not half as well as the red one, but thats almost an adhesive type of sticking... but neither will slide off a hotplate, and both can be adhered to with buildtak clone and regualr 3m sheet adhesives....and then easily removed with no damage to any component.
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and surfaces:https://www.aliexpress.com/item/SWMAKER-10pcs-Wanhao-3D-Printing-Build-Surface-220-220-mm-Square-Polyimide-Tape-sticker-build-tape/32808421081.html
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This will not be stiff enough, but I may find something to mount it on.https://www.aliexpress.com/item/SWMAKER-10pcs-Wanhao-3D-Printing-Build-Surface-220-220-mm-Square-Polyimide-Tape-sticker-build-tape/32808421081.html
This will also not be stiff enough, but I may find something to mount it on.
.https://www.aliexpress.com/item/220-220-0-8mm-White-PEI-Sheet-Polyetherimide-Sheets-for-3D-Printer-with-468MP-Adhesive-Tape/32838696009.html
This has a lot of potential, I will probably be sticking a mat to this next. The qualities of the surface material will determine how it compares; I'm sure the flexibility and removeability part will be almost identical to chinesium buildtak.

2018-01-28--13-46-15minor update
red silicone mat - black polymer 'buildtak' clone
Printing 0.05mm thick first layers seems to be a lot easier than before I started using the silicone layer. I still level my bed by eye, and I have not at all been dilligent about doing it accurately for the last few weeks. Essentially just doing each corner once (frontL frontR, backR backL) and adjusting bed the usual amount ( so i can see there is a gap under the nozzle, but cant make that gap any smaller without it being obvious the nozzle is touching the bed firmly).
I suspect that the slight amount of compliance that the silicone layer gives is allowing my nozzle height to be a little more forgiving. Possibly my 'by eye' gap estimation has also improved .
Added photos of 0.05m initial layers... on a bed I didn't even clean properly. It seems I am being intentionally lazy about a number of things just to see if they still work because of the silicone.

2018-02-11https://www.aliexpress.com/item/220-220-0-8mm-White-PEI-Sheet-Polyetherimide-Sheets-for-3D-Printer-with-468MP-Adhesive-Tape/32838696009.html
It's crap. Heat warps it unpredictably, it seems to like being convex. I'm not even going to try to constrain this by sticking it down.
However this combo:https://www.aliexpress.com/item/SWMAKER-10pcs-Wanhao-3D-Printing-Build-Surface-220-220-mm-Square-Polyimide-Tape-sticker-build-tape/32808421081.html
andhttps://www.aliexpress.com/item/Non-Stick-Silicone-Baking-Mat-Kneading-Dough-Mat-Baking-Rolling-pastry-Mat-Bakeware-Liners-Pads-Cooking/32799677298.html
Works pretty well.
PLA is actually really difficult to keep stuck on this. I have 600 grit sanded it, and it still barely holds small prints. It's tenous if the nozzle bumps over anyhting, but it does usually hold.
The surface doesnt stick to the silicone as well as the red stuff sticks, but it does stick. Bubbles are evident, and less easy to squeeze out becasue the thin surface is easy to distort, but none of this is too difficult ot deal with, and what bubbles and distortion from the markings on the mat I do have seem to be irrelevant by the time the nozzle hits the surface.
I'm printing 0.04mm layers in the image I just added (2018-02-11--11-22-02.png), and i'm pretty sure the first two layers were effectively not above the surface, rather; pressed into it. Yet it's working perfectly anyway.

2018-02-17
The yellow Polyimide-Tape-sticker lifts far too easily on anyhting except tiny prints, and even then it's very difficult to stick PLA to. Pretty sure it will be well suited to PET-G though. I'll probably try using a sheed of adhesive to bind the yellow sheet to a layer of 1mm silicone I just got. Like the red stuff, but seems different somehow, tinner maybe. Will need to measure it when I start slicing and dicing.
I have gone back to the red silicone sheet with black buildtak clone. It still lifts at the edges on larger prints, but for small quick prints it is a no-brainer to toss on the red&black sheet. Considering how relatively easy it is to print 0.04mm thick layers after leveling my bed by eye only I assume that the silicone offers some degree of latitude by squashing away from the nozzle, and presumably it's thickness/density are perfectly suited to the viscosity of PLA and feed rate.... or something thats not just pure luck that I can print 0.04 layers almost without trying. For small thin-layered prints this is now my goto surface combination.