Bed adhesion trouble. Please help.  

Re: Bed adhesion trouble. Please help.

I was wondering about the extrusion rate, and if it was somehow too low on the first layer. So I did the unthinkable..
I used blue painters tape on the pei.. what irony!

Well.. with the painters tape on the bed, and heat off, the pla stuck like glue, and I had no problem printing Adalinda the dragon in amazing detail.

I'm stuck..

Re: Bed adhesion trouble. Please help.

Well.. with the painters tape on the bed, and heat off, the pla stuck like glue, and I had no problem printing Adalinda the dragon in amazing detail.

It sounds like you know what you are doing.

Are you using the PLA supplied by Prusa?

Is your heated bed getting to the temperature it should?

What material are you using to with the IPA to clean the bed? I recommend a microfiber cloth, such that you might have received if you wear glasses.

It sounds as if a) the bed is not cleaned properly, or b) the filament is still too far off the bed and you aren't dialing in the Live-Z adjust enough. What is your Z-height after the Z-live adjust during the V2calibration?

Can you post a photograph, as clear and close as you can of the V2 calibration filament on the bed?

Thanks,

John

Re: Bed adhesion trouble. Please help.

Yes, please attach some pictures so we can see how squished your first layer is.
In the past, sanding + acetone did the trick for me in order to recover adhesion, but you already tried sanding... so who knows.
Do you have any tool to measure the bed temperature just to check it is warm enough?

Re: Bed adhesion trouble. Please help.

FWIW I found that the 70% IPA that I used did not work at all for adhesion - only after switching to 99.9% IPA was I able to use the PEI without glue etc.

Re: Bed adhesion trouble. Please help.

When you did the Live Z adjust, did you use negative numbers?
or Positive numbers,

negative moves the head towards the heatbed positive moves it away from the heat bed.

It sounds like you need to use negative numbers and move the head nearer to the bed...

also what is the first layer height of the print? the Mk2 has a minimum layer height which I believe is 0.2mm

best of luck with your printer, you will be pleased, when you get it sorted...

regards Joan

Re: Bed adhesion trouble. Please help.

Thanks for the suggestions and answers, guys. I will try to reply as best I can..

JohnOFII:

I have tried both the Prusa supplied PLA and my own Go-To brand, which have worked great for me with my other printers.

My heated bed is very accurate. I have measured it with a laser-probe and its spot on.

I have been using both Pec-pads and regular kitchen paper with the IPA.

My Live Z adjust is around -100. I have tried numerous runs with the calibration code, ranging from 0 to -300 and had some luck at one time with a setting of -70. It seemed my troubles was over, but when trying to recreate the success, it was back to not sticking.

I will post pictures tonight, after I get home from work.

I am starting to suspect the IPA. 99% IPA is hard to get in Norway these days, as it is deemed a dangerous substance and regular ethanol is restricted to 60%. I have used gasoline-conditioner which is IPA. I just don't know the exact percentage..

I will try sanding it again, and just use acetone. or break the law and make my own 99% ethanol 🙂
I have also ordered some IGUS bushings.. the supplied chinese LM8UU bearings are loud and not that snug to the rods.. (I did rotate them so that one row of bearings is directly under the rod..).

The prints, once the first layer sticks are amazing. I can't wait to get my printer delivering consistently.

Thanks again, really helps with my determination to get some feedback!

Best regards,

Klaus - Norway.

Re: Bed adhesion trouble. Please help.

joan.t:

I have negative numbers.

I know how the calibration works. As for layer height, I am just using the gcode files supplied on the SD card to eliminate any other settings that may be off when slicing a model.

The minimum layer height of the MK2 is actually 0,050mm or 50mu. (as the supplied treefrog model). The maximum however will be determined by the size of your nozzle, the settings in slic3r or other software, and the extrusion rate..

for now, tho, I am just trying to print the supplied tried and tested gcode files from the SD card..

Best regards,
Klaus - Norway.

Re: Bed adhesion trouble. Please help.

VortyZA:

I am not actually sure what the percentage is on my IPA.. as they don't really sell 99,9 IPA in stores here.. I have used the kind you pour in your gasoline in the winter to reduce water content in the gas. It is pure Iso Propyl alcohol (IPA) but they don't post the percentage.

I will try to use some other form of alcohol.. I have Acetone.. and by bending the law, I can actually make 95% ethanol (more than 95,6% is vapor).

Tried sanding with 800 grit, did not get any better.. but then again, I cleaned it with that IPA before printing.. hm..

Best regards,
Klaus - Norway.

Re: Bed adhesion trouble. Please help.

luis.r2:

I measured my bed with a laser probe, and its spot on.
Pictures coming tonight after work.

Best regards,
Klaus - Norway.

Re: Bed adhesion trouble. Please help.

I used a good sheet of paper to calibrate the Z now, I lower the head using the Live adjust feature are selecting auto home, I then lower it until the head just starts to touch the paper and I feel it sort of just scraping it. This is a decent sheet of paper though, not really cheap photocopying paper. After that I find its just + or - 20- 30 for perfection. Always clean with IPA before I print and unless I am printing something large, the temp never goes far away from 55 Degrees.
I did print some large flat boxes this week and raised the temp to 65 but ready somewhere that much more than can cause other issues.
Are your fans working? work checking as I sent a print once that wouldn't stick and SLic3r by default did not have cooling enabled.. I amended my profiles so that it was on automatically so I didn't forget in future also.

Keep at it, the end results are really worth it

Nick

Re: Bed adhesion trouble. Please help.

VortyZA:

I am not actually sure what the percentage is on my IPA.. as they don't really sell 99,9 IPA in stores here.. I have used the kind you pour in your gasoline in the winter to reduce water content in the gas. It is pure Iso Propyl alcohol (IPA) but they don't post the percentage.

I will try to use some other form of alcohol.. I have Acetone.. and by bending the law, I can actually make 95% ethanol (more than 95,6% is vapor).

I use isopropyl alcohol from the pharmacy/chemist. I would think that would be a good source of the material. I use 91%.

Something like this: https://www.amazon.com/Walgreens-Isopropyl-Alcohol-91-32/dp/B00A2OTRSA/ref=sr_1_13_s_it?s=hpc&ie=UTF8&qid=1479913011&sr=1-13&keywords=isopropyl+alcohol

Also - make sure your cloth is clean.

John

Re: Bed adhesion trouble. Please help.

I think I may have solved the problem!

It's "early days" yet, but after reading through your answers yesterday, I decided to try something else than my IPA to clean the bed, as the IPA has been the only constant that I haven't tried to change.

I sanded the PEI sheet with 2000 grit sandpaper (yeah.. that is ULTRA fine grade..) just to make sure I got rid of any contaminant left by the IPA should it be the culprit. I then wiped the bed clean with Acetone and a clean paper towel.

Did a basic paper / auto-home pre-adjustment, and printed out the V2Calibration. To my amazement it didn't go floating around the bed, but actually stuck. at 55C! So.. being skeptical, I took the string of printed filament to my basement lab, and put it under the USB microscope. (I am amazed that some of you actually can see the difference to squished and semi-squished with the naked eye..). I decided to lower the head 10mu more (from -0070 to -0080) and ran the V2calibration code again after cleaning once again with acetone. It stuck nicely to the plate and looked a little flat but not transparent or forced.

Now my printer is printing it's first custom gcode. I sliced it with Slic3r, even though I prefer Simplyfy3D. It was too tempting to use the ready-made profile in Slic3r for the first custom print.

I will, however, download and import the Simplify3D profile from Prusa3D.com and try it out to see the difference, or if it is as good as the Slic3r profiles, as I really like the way Simplyfy3D slices the parts better. (the toolpath is less messy, with less jerking and in my opinion better shortcuts).

I am extremly impressed by how the printer performs other than this first layer drama I had..
and I am equally impressed with the helpful souls of this forum. I would probably have spent much more time getting this to work, If I had not been inspired by the users that tried to help me out.

Who would have thought that IPA and IPA is just NOT the same..

If anyone's interested I will post my result tomorrow, when my 10 hour print is (hopefully) complete.

Best regards,

Klaus - Norway.

Re: Bed adhesion trouble. Please help.

Now to get my too expensive SLA printer to work properly.. oh well.. I guess this is one for the Formlabs forum..

Re: Bed adhesion trouble. Please help.

I think I may have solved the problem!

Thanks for the update, I hope you are successful!

I do hope you did something simple before launching into the 10 hour print (such as the whistle or Prusa Logo from the SD Card) just to confirm a full model worked beyond just the V2Calibration code.

The Prusa Simplify 3D FFF is an OK place to start, but it is quite different from the Slic3r configuration. A few of us have posted our FFF files on GitHub: https://github.com/PrusaMK2Users/Simplify3d/tree/master/Profiles I spent quite a few hours last weekend modifying the Prusa RC4 FFF into something that printed more closely to the Slic3r config in terms of smoother exterior walls.

John

Re: Bed adhesion trouble. Please help.

Oh! Thanks alot for sharing those configs for Simplify3D!

Last night, when starting my first custom print, I simply did not have time to print something simple.. It was 5AM in the morning, and I have a customer waiting for a part from this spesific printer to see if it can be used for his needs. He has pretty strict dimensional needs..

But if it's accurate enough for his needs, his prints will basically pay for the whole printer over a few weeks.
Any experience about how accurate the printer is comparing 3D model to finished print?

I am happy to report that it is still going strong, no sign of lifting or warping at 7 hours in..

Best regards,
Klaus.

Re: Bed adhesion trouble. Please help.

Wow.. So many profiles to choose from!

Which one to choose?!

Is the "john...." something one yours?

Re: Bed adhesion trouble. Please help.

Wow.. So many profiles to choose from!

Which one to choose?!

Is the "john...." something one yours?

Seems like you've found a solution to your problem, but I'm just curious about your Live Z Adjust values, you write them out different from time to time.

What you should do is printing a model, lets say the Prusa logo, and while printing you can adjust your Live Z Values until it looks good. If you need more time turn down the speed to 20% or so as soon as it starts printing. Don't use papers under the nozzle and Live Adjust without printing, you need to watch the print while adjusting. Im fine-tuning each print's first layer, depending on how the baseprint on the bed looks.

Your Live Z Adjust values should be between -0.400 to -0.100

Re: Bed adhesion trouble. Please help.

Yeah - use any means at your disposal (paper, geelers etc) to get an approximation and then use "Live Adjust" on a reap print. Only way to do it properly.

Peter

Re: Bed adhesion trouble. Please help.

I have also found I use a 40-50mu differnence when printing with Prusa ABS, changing from -380 to -445. I always use my go to prints I have left on the SD card, batman logo, Marvin and Prusa. I have a lot of them now but when ever I change something I print one of those, and especially when using new filament, even from the same brand. its good to have the standard and can compare easily.
I am thinking your IPA may not be as Pure as it states on the bottle.

hope the print is good

Nick