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DIY Sheet press

This topic contains 44 replies, has 12 voices, and was last updated by  Anne 1 week ago.

1
Flo flo-2

DIY Sheet press

04/03/2018 at 11:32

Hi there!
We (preciousplasticvienna) are experimenting quite some time now making 300x300x2mm sheets (you can check our instagram for pictures) and now we want to produce bigger plates. (500x500x10mm)
Since that size doesn’t fit our bought 38x38cm sheet press, we will build one ourselves!

The press should:
– produce ~520x520x10mm sheets so that cou can cut off the edges to get 500x500mm output
– have both sides heated so we won’t have to turn it around
– have an exchangeable mold so we don’t have to wait hours inbetween producing plates
– be time efficient (30 mins per sheet at max. would be great!)
– consume at max. 3kW so we don’t need an extra plug (not the most important thing but would be great)
– not cost more than 500€ to build

my drawings: On the first you can see the rough overall design. There will be a carjack mounted on the bottom to build up the desired pressure. It presses together the two heated sides of the press.

On the upper right of the second picture you can see my idea of the heating. the small circles are short rings of a metal tube that are welded onto the base plate. Onto these rings wwe want to mount the heating coils that are used for injection and extrusion too. We are well aware this is not the most energy-efficient design, however it is the most doable and budget-friendly one we could find. We will compensate that with using good insulation.

On the third picture on top you can see the guiding of the heated moveable plate, we are not so sure whether we really want to include this since it is a big source of problems because of the small tolerance.
On the bottom right of picture #3 you can see the cross section of the mold for the sheet and on the bottom left holes in the base of the mold in order to get the sheet out after molding.

We will begin shopping for parts shortly and are happy about any feedback/ideas/suggestions etc.!

All the best
Flo

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In reply to: DIY Sheet press

warrior
01/08/2018 at 18:39
3

I’m interested to know why you used band heaters instead of flat heating elements, those are designed for flat panels like the one on your heat press so heat spreads evenly and much faster, wasting less energy

In reply to: DIY Sheet press

warrior
01/08/2018 at 20:04
1

@xxxolivierxxx you’re right, this is far from optimal! We chose to try this method just because of the cost, we couldn’t find any affordable flat heating elements that fit our needs. Only with cost of 500€+. We will try to make up for that energy efficiency loss with good insulation, let’s see how that works.

In reply to: DIY Sheet press

warrior
02/08/2018 at 07:28
1

@andyn We will! Already got a device for that, as soon as biggie is finished, we’ll test it!

In reply to: DIY Sheet press

new
02/08/2018 at 08:42
1

Hi, i can’t download the CAD drawings of the machines. I need help on that

In reply to: DIY Sheet press

warrior
02/08/2018 at 08:49
1

@macbeda there aren’t any cad drawings for this machine public yet. If you mean the shredder etc. go to preciousplastic.com
All the best
Flo

In reply to: DIY Sheet press

warrior
02/08/2018 at 13:25
2

@flo-2

That would be great if you could measure the power consumption. I’m building a type of press myself that I want to make as energy efficient as possible. (So it can run from solar electric, or low-capacity power grid). The thing is, there’s really no good data to compare it with.

 

Andy

In reply to: DIY Sheet press

warrior
09/08/2018 at 22:38
5

Update 09.08.2018
WE FINISHED THE MACHINE TODAY!!! we assembled everything after some intense working days with sometimes over 13 hours a day of welding, painting, screwing, buying missing parts, insulating, connecting the electronics and all that stuff.

We also gave it a test run and it worked very well up to 180°C so far! More testng will follow. Our machine “Biggie” draws a maximum of approx. 3,6kW, however it won’t draw 3,6 kWh per hour! (less) We still need proper testing for these numbers.

We installed 32 heating elements grouped into two logical groups (top side and bottom side) with 1 Temperature PID and Thermocouple per side. Due to insulation with rockwool (temperature/fireproof up to 1000°C) Biggie keeps its heat quite well, which is a big ecological advantage.

In the following days/weeks/hopefully not months we will upload step-by-step instructions on how to build this machine, so stay tuned! More facts & figures will follow too!
Until then,
All the best

Flo
Precious Plastic Vienna

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In reply to: DIY Sheet press

starter
10/08/2018 at 19:07
2

Looks fantastic!

I’ve got a few questions:

* What are the dimensions of your mould?
* How many tons is that jack?
* If you’ve successfully produced some sheets, does the pressure from the single jack seem to be adequate (no voids, square/flush edges, etc…)?
* Is the frame rigid enough to maintain its shape, and thus a uniform thickness of the sheet?

Thanks!

In reply to: DIY Sheet press

dedicated
10/08/2018 at 22:29
1

i have a hard time to imaging this actually efficient working, what stable temperatures do you reach that way ?
thanks in advance,
g

In reply to: DIY Sheet press

warrior
10/08/2018 at 22:44
1

@nickchomey
Thanks! Our mold Inside is 516mm squared, the outside is 600mm squared. The plastic is 10mm high and the mold is 55mm. The carjack can do 5 tons.
Since we finished building yesterday, as you can imagine, we haven’t made long-term studies yet 😉 so I cannot answer the other questions just yet. The Frame should be able to handle the 5 tons with ease. I did some calculations and the beams will bend a maximum of 1.55mm when applying full load. That is totally in the elastic part of the metal bars, so that should work.

In reply to: DIY Sheet press

warrior
10/08/2018 at 22:53
1

@anne-barbier I think you under-estimate the power of about 3.5kW of heating power combined wirh modern insulation. As stated before we dud tests with up to 180 Degrees Celsius and it worked even better than I expected. It climbed straight up to 180 and stayed there with a tolerance of <1%. Thats good for melting Hdpe, but the higher temperature of 200-240 degrees for PP should also be easily archievable. So as an educated guess, 250 degrees should be archievable too^^ Updates eill follow.
All the best
Flo

In reply to: DIY Sheet press

dedicated
11/08/2018 at 09:32
1

@flo-2 : yeah, i guess so 😉 I’d have then one more question: is there a problem with getting flat heat elements ? Seems you have those heatbands from ali-express, 6Euro the piece. I am just asking because I couldn’t really find those on ebay or tc-direct.
thanks,
g

In reply to: DIY Sheet press

warrior
11/08/2018 at 10:13
1

@anne-barbier yes exactly, we have used band heaters. There are flat heating elements available too, but the ones we found are waaay more expensive (triple or quadruple the price of the band heaters) and that was just way out of budget for us, unfortunately. 🙁

In reply to: DIY Sheet press

dedicated
11/08/2018 at 11:18
1

@flo-2 gotcha, thanks! so a cheap variant could be then second hand kitchen heat plates for cooking, i think they should have even some PID controllers inside … never tried but will do soon.
g

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