Small sheet press

Precious Plastic Machine Development
#1

Hello

I’ve been trying to find a way in which I can use an unmodified oven to create sheets of plastic. I’ve made the first version of a sheet “heat” press and it seems to be working well…

Most of the materials used have been left-overs from the other precious plastic machines… Two 3mm sheets of mild steel have been used that just fit within the oven. These plates are what the plastic melts upon and is pressed between.

In these tests HDPE has been in the oven for about 20~25 minutes @ 220 ‘C. The second plate is only placed into the oven 5 minutes before removal. Once removed the second plate is put over the first and then both into the press. After pressing and a few minutes to cool off, bags of water are used to speed up demolding.

There are some adjustments that need to be made in order to strengthen the top plate and fasten the wooden plates, and I’m sure much more…
In the mean time here is a rough Solidworks model if you would like measurements or to make any adjustments: https://grabcad.com/library/sheet-press-1

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4032×3024 2.19 MB

#2

@jerzeek I haven’t tried a full sized sheet just yet… I’ve just finished reinforcing the top plate, so might have something in the next couple hours ~~~

#3

I have some questions for you guys. can we create sheets thinner enough to work with a vacuum forming machine ?
If so, what plastics can be used for this kind of application ? what plastics and what thicknesses work good and what doesn’t ?

#4

Hahaha what a coincidence. I posted this today http://onearmy.world/community/forums/topic/new-machine-idea-heat-press/

#5

I have seen some guy was using electric-grill to melt HDPE into sheets.

#6

@flo-2 im not to sure about that one, electronics is not my area of expertise . :confused:

#7

Hey @timslab
Great work! The sheets are looking amazing @kettlekekkers ! I am also thinking about building a small heatable sheetpress, however I would like mine to be heatable with adjustable degrees like the other PP machines. Have you got any ideas where to buy heating elements for such a machine? I searched the internet a lot, but I cannot find anything apart from oven heating spirals…

#8

hi @timslab

yep , mostly milk jugs

hydraulics is the way to go,

yeh i can see you’ve got some MDF in there, i would just go with some 8mm steel plate, for reliability

even this shop press does’t do the best job, as the heat is taken away when i transfer it for pressing,

2448×3264 1.27 MB

#9

Hey @kettlekekkers,
Those sheets come out looking great. Is that a mixture of shredded milk cartons and bottle tops?

I think I need to strengthen the base of my press a bit, it’s not reaching super high pressures yet. I’m hoping for at least 1t

#10

the result

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3264×2448 681 KB

#11

@timslab
hey , ive been using this clothes press to create sheets of plastics
i use a 12tone shop press also between two plates of steel to finish off the plastic so it stays flat,

the shredded plastic is placed between like a nylon bbq liner, or re-usable baking sheet first, then heated from the top in this clothes press, when its melted, i transfer it to the shop press,

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3264×2448 1.17 MB
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#12

Looks nice Tim!
some cool patterns in the making 🙂
did you already try full size sheets?

Greetz, Jerry