There's surprisingly little understandable explanation of the impact of texture on adhesion and release on print beds... But we can reason it through. (And steal from the real scientists 😇)
Obviously, texture also applies to PEI, Polyurea, and in fact, every other plate!
3. Textures
Warning. I'm not a scientist. I could be completely wrong and talking out of my hindside, and then there's the language barrier I use as an excuse 😅. So, if you're an expert and know the real answers then feel free to contact and correct me!
I've added some links to external sources at the bottom of this post, for those scientifically inclined.
3.1 Guesswork
(I sometimes have the feeling people just tried and threw whatever they could find at their printer. In a way, that makes it even more fun 😉)
Let's start with the basic variants: textured and smooth.
Aruco code (only for X1C users)
Typically you set the type of plate in your slicer. The X1C will use the Aruco code on the building plates to make sure you have actually placed the right plate in the machine, matching the one you used in the slicer.
3.2 Smooth
If you have a flat film on top of your build plate, then the whole adhesion is driven by intermolecular attraction. When the plate cools down, the filament will have a different expansion (crimping) rate compared to the film on top of the building plate, and the metal carrier below. These films are typically attached to their metal carrier with an elastic 'dual side adhesive tape' - and are themselves often more elastic than the steel carrier plate - so they may compensate for crimp of the printed model. That's why you may need to use a release agent (glue!) to make sure materials such as TPEG won't tear up the top layer of your smooth plate.
Summarizing:
- At lower temperatures the intermolecular bonding will be lower, and thus it will be easier to remove objects from the plate
- Bending (flexing) the plate will add lots of forces to the layer where plate and filament have bonded, which helps defeating that bonding and helps releasing the objects
(For clarity, I call the point where filament touches the buildling plate surface the bonding layer.)
3.3 Textured
Textures add a few new ingredients to the mix:
- They increase the total surface between filament and plate
- They increase friction between filament and plate once the filament has solidified
- When the plate is cooling down, the irregular surface will add countless micro fractures to the bonding layer, breaking up the intermolecular binding between filament and building plate surface
Once cooled down a little (down to build plate temperature) the printed material will crimp, but should still be bonded to the textured surface. Once cooled down further (to room temperature) the bonding should have decreased enough to almost spontaneously release the prints.
3.4 Texture and calibration
Note that any texture will add some height to a printed object. Your printer is calibrated to the top of the ridges, but after printing you'll measure the size of your object to the bottom of the valleys. This has to be compensated for by your slicer or printer.
3.5 Softer coatings
Polyurea coated plates have a softer, more flexibel top layer, and thus will hold on tighter to the filament at lower temperatures. You will damage those surfaces with materials that grip too tight, unless you use a release agent.
3.6 Flexible (softer) filaments
Flexible filament isn't bothered by all those forces, and that's why it's harder to remove.
3.7 Scouring PEI
Once the first layer is in place and has cooled down enough it adds to keeping the object in place, both by the additional horizontal friction, but more importantly, by the better bonding between the PEI material and the filament. Once the plate cools down to room temperature that bonding decreases to the point where the PEI plate releases the printed objects by itself.
When you clean up PEI with water and soap and alcohol you improve the binding by removing anything that might increase the distance between bed and filament.
When you use a scouring sponge on PEI, you're also adding more (micro) texture, increasing the surface and thus increasing the first layer bonding.
Even a smooth plate (especially PEA and smoothly coated PEI) might work better after using a scouring pad, but you might also completely destroy it. In other words: be careful and make sure you know what you're doing.
3.8 Epoxy + Glass Fiber
The epoxy top layer may be incredibly smooth, but the intermolecular binding between the filament and the epoxy is weak. By scouring the surface (with a pad or very fine sandpaper) we're both increasing friction, as well as increasing the surface (it's a bit of the same thing).
Note that the nozzle would (if possible) never touch the buildplate (except when wiping) and that it might never touch the glass fiber inside the board (unless that is very close to the surface). In other words: wear and tear on the nozzle are defined by a. if your printer does a wipe, b. the distance surface-to-weave, and c. the type of epoxy used.
As the whole top layer of the board is smooth epoxy you shouldn't find any imprint of the weave inside the glass fiber (or carbon fiber!) build plate on your model. If you want to leave such an imprint you have to use a PEO.Carbon / PET plate.
3.9 Epoxy + Carbon
What use is a carbon fiber plate if everything is limited by the epoxy and the glue / stickers used? For now I suggest not to waste a penny on them.
3.9 PEY / PEO
On PEY / PEO / HxH plates the structure is microscopic, and only intended to imprint a 'visual pattern' on your print. It doesn't do anything for adhesion. For all practical purposes, these plates are smooth, flat, and should never be scoured.
More about those plates here.
To be continued...
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