DIY Sheet press
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
i would suggest using 4 carjacks , one in each corner, to limit the instability of the platform, and their cranks should be connected to each other so that one single crank can be used to lift and lower them simultaneously
For the ones who don’t want to use band heaters 😉
Here are a few other options:
Cartridge Heating Element (10pcs, each 650w) 65 USD
PTC heating element (200w) (5usd) ( fixed to max temperature, watts will drop automatically when the temperature is reached, can not overheat.)
ceramic heater (750w) 18.90 USD
Please know that i have not tested the heaters, and i am not a specialist 😉
PET is 230-240c
You will get a hard brittle plastic output.
Try a Tee shirt transfer press instead.
I’ve been looking into economical heated press solutions, and I was wondering how viable it would be to just combine two domestic electric griddles into a redneck press. The issue is that I can’t seem to find an affordable electric griddle capable of melting PET, which is the kind that I have an abundance of. They all seem to go to about 200-230°C, whereas the temperature needed to melt PET is around 260°C.
I also discovered something called an “oil core skillet” which intrigues me when thinking of its application as a reduced-cost, even heating solution for a heat press. I can’t seem to find any information on the manufacturing process, though. All I see it that it uses a double-lined bottom with a heating source suspended in silicate oil which distributes the heat throughout the metal without creating a hot spot.
Just thinking out loud.
With all that welding for support how flat is your face plates?
What if you had those supports and then say a 25mm aluminum plate bolted to the frame, loose to allow expansion, and mount heaters to the aluminum, this should allow the heat to be much more even and cool much faster. You could even use a small fan on the end of each of your square tube supports to help it cool faster.
The aluminum should be flatter than the steel, especially if you can find some mic6.
Heaters dont heat , helppp. Is it problem Pid REX -C700? How to set it?
My heaters dont warm . Sonda work good . I have RX C700 it s that PID good?
@flo-2 thanks for the follow up on this project! However, I don’t think your pictures got uploaded. Could you try again?
Yes, it seems to me that without the ability to control all of the heating elements separately with PIDs or some other controller ($$$), putting the sheets in an oven at a relatively constant temp would be best. Having a fan for convection would help things a lot.
Another approach for a heated press could be to use a hot liquid inside of pipes but you’d probably need some specialized oil for it, or high pressure. Would have to heat it in a heat exchanger too. Totally feasible, and someday I’d like to try it and heat with a rocket stove, but its a pretty big project.
As for pressure, do you think it flows poorly because of the 5 tons being insufficient, or because the plastic isn’t completely melted due to the heating issues?
Also, similarly, in your previous comment you said that heating and pressing from both sides causes air bubbles – why is this the case? Does your design allow for excess plastic to flow out the sides (flashing)? This would require filling it with extra plastic and having a depth gauge/stopper to make sure it gets to the right depth.
I would love to see a video of the process if you have time!
Thanks again for all of the information! It’s very helpful.
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