HDPE Stickiness - different materials

[Bogdan Kecman]

I removed the HDPE from the RM and doing more tests with PP attm. Here are some results on HDPE stickiness, might help someone


Stickiness 0-10 (0 none, 5 great for print bed, sticks but unstick when force used, 10 sticks even on low temperatures)

HDPE to :

 - MDF (wood, fine grind, compressed with glue & water): not tested
 - plywood: not tested

 - acryl (clirite, plexiglass): 0
 - Wood (bare, polished): 0
 - Wood (bare, rough): 0
 - PS: 0
 - CD rom: 0
 - DVD rom: 0
 - styrofoam (white, like one RM plexy parts came on): 0
 - ABS+PCK (PC): 0
 - Glass: 0

 - paper: 1
 - cardboard: 1

 - Duct tape: 2

 - PP: 6
 - PE-HD (HDPE): 9

[gpvde]

the prints are looking good, but because off the stickness problems, one site is always thinner then the other. see picture that i took from the heartlid

[unfold]

sweeeeeet! 

[mr_seeker]

A friend of mine used balsawood (I asked him on the phone) with the lowest density, at 230C extruding temperature. He said it sticked fairly well... I trust him, he is doing this longer than I am

[Forrest Higgs]

Okay, Bogdan!  What would you recommend printing HDPE on?  Polypropylene?

[Bogdan Kecman]

well, I suggest using HDPE for both HDPE and LDPE .. you can control stickiness "Ratio" with the temperature ... higher the temperature of the raft - better it will stick / harder will be to remove ... so some "good value" must be empirically chosen...
 

[Forrest Higgs]

That's good in that I have about a dozen sheets of 300x300 mm HDPE.  I looked at your list, however, and saw that PP looked like the best fit given your criteria of wanting a "5" value.  I have a few sheets of PP, so I've prepared one of them to print HDPE on for now. 

[Bogdan Kecman]

well, with PE you can choose what level stickiness you want, with PP 6 is a max .. so I'm using PP for PP and PE for hdpe (this PE tables I have has density between hdpe and ldpe)

[Forrest Higgs]

It seems to be sticking pretty well.  I'll know more after I've printed a few things.  I'm trying to do that guyed beam example that I did in ABS in HDPE.  With you trying it in PP we'll know just how useful the guying idea is over a range of warping prone plastics. 

[Bogdan Kecman]

mine testing is delayed ... I have some weird problems http://www.bitsfrombytes.com/fora/user/index.php?topic=337.0 so I'm unable to print more then few layers ... solving this first ..

[Forrest Higgs]

I just finished the first test beam.  The raft peeled on one end during the last 5-10 layers of printing.  That left me with about 1-1.5 mm of bowing over 150 mm.  I'm going to play with the raft parameters and see if I can keep it stuck down for the whole print exercise.

[Bogdan Kecman]

raft peeled from the bed or from the object ? ...

what I figured out is that it is better to make raft bit bigger then to increase temperature of the raft, as bigger raft (especially now with new skeinforge where you can tell in mm how big you want it to be around the object) can be easily removed when you want and it holds the object almost the same as the smaller but hotter raft does and the hotter one is super hard to remove ... especially with PP .. I had to cut & sand the plate after some prints as raft became one with the plate

[Forrest Higgs]

Actually, what I've done is to even out the print surface very precisely so that the stickiness of the raft is even on both ends. 

[Bogdan Kecman]

that's super important, yes, especially with PP/PE .. bit hard with warped bed ...                       

[Forrest Higgs]

Blew a thermistor halfway through the print, so I had to rebuild the head.  Will take till tomorrow for the high temperature epoxy to set.  No worries, though, it appears that I've solved the HDPE warping problem thanks to Bogdan's realising that you can print on polypropylene.  That gave me a firm print surface to work with.