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Up and running but not a fan of the metal buildsheet...  

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keith.j4
(@keith-j4)
New Member
Up and running but not a fan of the metal buildsheet...

  First off I want to say Ive been looking to get a Prusa for some time and im now stoked to have a Mk3s!

 Im comming from a clone kit ive had for the past couple years(Tronsky) which I had all dialed in and was working well enough,though wanted to have an orginal finally!.Though I do kinda miss having repetier to print straight from my computer with as I cant seem to get this machine to communicate with it as yet.

 Anyhow,the build was awesome as expected,,though yeah,,I ate all those gummies too quickly,lol.The only issue I had with assembly didnt manifest until I was trying to calibrate the final z hight setting...one of the Ubolts that hold the z plate bearings was a bit overthreaded and had some extra threads sticking up into the heatplate,,thus making a slight buldge in it,,no biggie though,,took the heatplate off and cut off the excess threads.Z axis is dialed in the way I like it now,,bottom of prints are smooth as sheet plastic:)

 The biggest issue I have been having though is getting prints to stick to the build plate,,did all the cleaning suggestions,alcohol wipe and all that along with adjusting bed temps,,still had issues though.Now my Tronksy had an aluminum heated build plate that I regularly used painters tape on and never had prints coming off,some minor curling would happen on larger based prints now and then but not much.With this past experience,ive decided to put painters tape on the metal build plate and it has seemed to pretty much solve the problem for the most part.Another thing that has helped has been reducing built plate temps,some of these prints ive run had default bed temps of 90c..that seems very toasty and I had alot of curling at edges soon after the first layer was down.Ive found 55-60 to be optimum.

 Anyhow,,great to be on board with an original Prusa!

 

Posted : 10/05/2019 4:39 am
bobstro
(@bobstro)
Illustrious Member
RE: Up and running but not a fan of the metal buildsheet...
Posted by: keith.j4

 [...]  The biggest issue I have been having though is getting prints to stick to the build plate,,did all the cleaning suggestions,alcohol wipe and all that along with adjusting bed temps,,still had issues though.

You are suffering from bed adhesion problems. Here's some copypasta...
 
Adhesion problems are usually due to either or both of 2 main problems:
  • A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. Take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails, and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent to give it a very light buff, but only infrequently.
  • If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. If your Live-Z is too high, you'll have a hard time getting anything to stick no matter how clean the bed is (and vice-versa).
And above all else, avoid touching the PEI print surface.
 
Try those 2 steps. If you're uncertain of the Live-Z results, post pics here of the 75x75 print bottom and you'll get quick help. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When it's right, you should be able to gently rub it without it coming loose. Then start lowering (more negative) the level until there are no gaps between layers. 
The good news is that a good dunk with Dawn should restore both sides to like-new condition. If you want more detail, I've dumped everything I know about Prusa PEI adhesion here, bed cleaning here and Live-Z calibration here.
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 10/05/2019 5:23 am
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