Which bed to use  

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ScottM
(@scottm-2)
Active Member

My MK3S came with the smooth steel bed, as they all do. I was wondering if I should buy one of the textured beds. I print only PLA right now, but want to experiment with TPU, PETG, ABS and other filaments. Would having both smooth and textured sheets be a good option? Also, I just fought with the printer for a couple of days to get my old PLA to stick to the smooth bed. Would PLA stick better to a textured bed? It seems logical.

If I have both beds, how do I tell the printer which one I'm using. I saw another post that said the option isn't in the firmware.

Posted : 28/11/2020 1:36 pm
JoanTabb
(@joantabb)
Moderator

Hi Scottm, 
First of all, are you using the 7x7 Mesh Bed levelling option (available on the Mk3S LCD menu) it tests 49 points instead of the normal 9 points and gives a better first layer. 

PLA should stick really well to Smooth PEI Build plates, 

PETG and TPU   CAN stick TOO WELL to smooth PEI Build plates   Prusa suggest using an adhesion reducer like Windex... (other options are available but they tend to be messier)

Have you seen the Knowledge Base article?
https://help.prusa3d.com/en/materials

Different folk have different opinions on Textured Build Plates, 

I clean mine well with soap and water, rinse with hot water and dry with plain paper towels, and keep my fingers off the build surface... 

I DO NOT USE IPA or any other surface treatment and My PLA sticks to my Textured sheets (I have several different prusa textured sheets and one non prusa textured sheet. )...  I do use 70C for the bed temperature 

PETG tends to adhere well to textured surfaces and usually pops off, when the print cools. 

TPU often sticks too well to Textured build plates, and again Windex applied before the print,  will reduce the adhesion. 

If a print sticks too well, try dribbling IPA around the base of the model, on a cold build plate and leave it to soak for a couple of minutes, then try flexing the build plate again...     the IPA should help release the print from the build plate. 

I have not had chance to try the Silk Build plate yet! 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 28/11/2020 2:07 pm
ScottM
(@scottm-2)
Active Member

Hi Joan,

Thanks for your feedback.

Yes, I switched to using the 7x7 option. Currently, my PLA is sticking well. I have older PLA that wasn't, so I put it aside for now and will try it on my other printer, which has a glass bed. 

Prusa has a Black Friday deal on for the beds, so I ordered a new smooth sheet and a textured one to try it out.

Posted : 28/11/2020 4:37 pm
Walleye
(@walleye)
Eminent Member

Hi,

 

It depends on what type of filament you are mostly printing. For example, while I started with PLA and the smooth sheet, I now print more PETG. So a textured sheet makes more sense for me now because it releases PETG easier. If you aren't doing a lot of stickier filaments, or your prints have a smaller footprint on the bed, a smooth sheet will probably work best for you. But at some point, you will probably buy a textured sheet anyway - just because.

Perhaps it's a bit counter intuitive, but a textured sheet grabs the first layer less because it on touches on the high spots of the texture. So there is less contact between the first layer and the sheet. Though with filaments requiring higher extruder and bed temps, like say ABS, this will work against you because the extrusion is softer and will flow better into the low spots and "lock" into the rougher texture more. So a smoother sheet with a coating to prevent extra adhesion will often work better.

To find the sheet selection setting, just scroll down the menu until you see SHEET: Smooth. Then just push the selector knob to pick TEXTURE. You can have multiple sheets setup to choose from if you wish.

If I have adhesion problems, the first thing I do is wash the sheet with dish soap and warm water. Then if that fails, I start to look for other reasons. So Joan speaks wisdom. Though I will use IPA between washings because I'm somewhat hoof-handed and thumb fingered at times and often touch the sheet when I remove a print. I can get by with IPA for 3 or 6 prints between soap and water washes. It's just more convenient for me to do so. But it won't ever replace a good scrub with water and soap.

The 3x3 vs 7x7 auto-leveling is really a wash for me. I have done extensive testing between the two settings on my machine and I have concluded that I get nothing extra from selecting the 7x7 pattern. My prints are no more accurate, have no better finish/quality, nor stick better/worse to the bed. All it really does for me is take more time and add a bit of extra wear and tear on my machine. And while I completely understand this can be a YMMV thing and works for some, it's not always as important as it's often touted either.

Posted : 29/11/2020 6:15 pm
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