Printing flexible TPP adhesion issues
 
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Flavius-Tech
(@flavius-tech)
Active Member
Printing flexible TPP adhesion issues

Hey there,
Can anyone help me find a way to print on prusa mk2s flexible but low elastic properties filaments?
I want to print phone cases. Due to the high surface of print i supose that is harder to make it stick.
First layer is working fine, but when it reaches layer 4-5 it starts to lose adhesion, i had some samples for different flexible filaments and all works fine till layer 4-7 when it starts to dettach from bed.
I tested with different glues including the one from the prusa package but no effect.
I increased first layer width at 150 and 200% and first layer looks amazing, it looks like molded plastic case.
I tested variable bed temps, best was at 50 when print started to dettach but only in coreners and margins. at 90-100 bed temp the prints dettach completely from bed at layer 4 to 6-7 and those are last layer for phone cases, after that it starts walls of cases.
Print temps for filaments are recommended by the producers from 230 up to 260, i used 240 and 250.
Printing speed was set at 20mm/sec even if on some filaments producers claim that can be printed at 40-60mm/sec.
To resume, is there any glue or something stronger to use on prusa? Anyone tested different glues?
Thanks

Posted : 23/08/2017 11:44 am
JeffJordan
(@jeffjordan)
Member Moderator
Re: Printing flexible TPP adhesion issues

the larger the surface, the better it should adhere.
but the magic about getting anything sticking properly to the pei surface is getting the first layer setup right and cleaning the sheet (at least sometimes) with pure acetone.

by the way: with flexible filament you usually have the problem getting it loose from the heatbed, after the print is completed.

dem inscheniör is' nix zu schwör...

Posted : 23/08/2017 3:25 pm
Flavius-Tech
(@flavius-tech)
Active Member
Topic starter answered:
Re: Printing flexible TPP adhesion issues

Thank you for reply, so i clean with acetone and not use glue stick anymore? The filaments are flexible but the elasticity is low. I do not have any online shop for ninjaflex so i have to order from outside and it takes time.
Some of samples was from Colorfab NGEN Flex, from 3d kreator etc.
The first layer is sticking ok but when printing advance upper the case starts to separate from bed. I see the air start entering under case, at layer 6-8 it will dettach completely.
I will try without any glue. I usually clean bed surface after every single print with Isopropylic alcoohol. I will buy acetone if that helps and test . Only few grams left to test, and then i order full spools, i tested samples so i know which works better.

Posted : 23/08/2017 3:42 pm
JeffJordan
(@jeffjordan)
Member Moderator
Re: Printing flexible TPP adhesion issues

even if you think the first layer is sticking ok, it might well be that the print gets loose after a few layers (because of the tension that builds up between the layers due to the different temperature coefficient of molten and solidified filament). do yourself a favour and find the optimal live z adjustment setting for your assembly.

about the glue stick: some users really like it... but personally I think its only required in special cases.
some people here use it for flexible filament, to get the printed object loose without ripping off the pei sheet, because (as mentioned above) the flexible stuff really sticks to the pei like the 😈 .

dem inscheniör is' nix zu schwör...

Posted : 23/08/2017 3:56 pm
Flavius-Tech
(@flavius-tech)
Active Member
Topic starter answered:
Re: Printing flexible TPP adhesion issues

Here is the link for live stream http://xtz.ro:9090/stream
I started again , i donno if the fillament is enough, i cleaned with acetone, and no glue this time, and i got live z from 200 to 130, is not squished.

Posted : 23/08/2017 4:27 pm
Flavius-Tech
(@flavius-tech)
Active Member
Topic starter answered:
Re: Printing flexible TPP adhesion issues

Thank you JeffJordan!
Seems acetone changed entire surface adhesion. I allways thought isopropylic alcoohol have same effect to bed surface.
Furthermore i made some researches and found out that glue coming with prusa kit after a certain hight temperature it transforms into a pouder like and make the prints warping.
I hope those who have same issues like me will read this topic. Do not use glue when you print at high bed temps it will ruin all prints. Use glue only for prints with less then 60 degreese celsius for bed.
Also as JeffJordan recommended to adjust live Z, i increased z height a bit because it was too squished to bed.
See ya.

Posted : 23/08/2017 8:33 pm
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