We've just launched our map. Add yourself by clicking here!

close

V4 Sheets interesting results

This topic contains 16 replies, has 8 voices, and was last updated by  Juan Pablo Bosch Araoz 5 days ago.

4
Vicente Varella v-varella

V4 Sheets interesting results

11/12/2018 at 11:56

Hello Community,

Here we are gonna start sharing the different sheets that the sheetpresses are able to produce. The idea is that everytime that we achieve a good result or we have some conclusions about what went good or what went wrong we post it here.

In conclusion this thread will become the place where everybody can show his results (sheets) and discuss about them so we can together learn from each other’s experiences.

Also, make sure to subscribe to the index thread if you are interested in the materia.

16 replies
8 subscribers
4 saved
4 likes
sort on most likes
helper
11/12/2018 at 16:22
2

Showing the machines

In order to put in context, it makes sense at the beginning to talk about the machines we are currently using to make the sheets.

At the Eindhoven workspace we have two different machines that even though they still need to be improved, they are fully up and running and are providing us sheets every day.

The first machine is called the “Hot press”. Is called that way because it has heating elements both top and bottom. It’s an all in one machine that heats and press the plates together.

Good points:

– Very user friendly and it requires comparatively less metal.
– It only needs a very simple metal frame with the dimensions of the plate.Bad points:

Energetically inefficient and very time consuming.
– It needs to use teflon sheets in order to prevent the plastic to stick on the surface of the press and this teflon sheet generate wrinkles.
– Pretty slow.

The second press is called the “Cold press”. This is a two step process where first you heat the mould with the plastic on the oven and then you move it to the press where you press it.

Good points:

– It’s more efficient since you don’t have to cool down the machine every time you make one sheet.
– Kinda fast.
– It’s significantly more precise watching the output that it’s been delivered.Bad points:

– It’s much more difficult to make.
– The process of making one sheet requires much more equipment and is more dangerous since you have to carry the hot mould from the oven to the sheet.
– Mould making expensive and difficult.

Attachments:
helper
11/12/2018 at 16:25
0

Test: Trying to make an PP sheet.

Objective: Make a nice PP sheet.

Machine: Cold press

Tools:  1000 x 750 x 13mm Mould

Process

PP is relatively easier to process than HDPE. Lower viscosity makes it easier to spread into a sheet. The material shrinks around a 4% and that helps to take the piece out of the mould. The sheet we made is 1000mm x 750mm in size and 13mm in thickness. It was made with 10kg of blue PP granule.

Conclusions

PP is slighly less good material to work with than HDPE depending the demands.  It’s softer than HDPE so it’s easy to cut, but difficult not to make scratches.The result has very smooth finish, almost marble-like look. It feels really tough and durable. You can see that on the center of the plate the pellets are easily recognizable. Meanwhile the rest of the surface has a direction towards the edges. PRovably because we put a bigger amount in the middle.

Attachments:
helper
11/12/2018 at 16:26
0

Test: Trying to make an PP sheet.

Objective: Make a nice PP sheet.

Machine: Hot press

Tools:  1000 x 1000 x 13mm Frame

Process

Same than previous one, but with the hot press.

Conclusions

– This machine leaves some wrinkles on the surface.
– They come from the teflon foil.
– This machine gives the user the opportunity to have a more expected result. Since you are putting the pellets inside the frame and you don’t cover the result until you press it.

Attachments:
helper
11/12/2018 at 16:28
3

Test: Trying to play with different colors and the flow when it press.

Objective: Achieve interesting patterns by putting different heights of pellets.

Machine: Hot press

Tools:  800 x 500 x 10mm Frame

Process

This time we wanted to try different colors and how do they behaves when they are at different heights. We set different mountains of colors as you could appreciate on the pics below. We put the pellets when the press was still cold, after we pressed different times every 20 min. And once the plastic was fully melt (more or less) we pressed it till the corner of the frame.

Conclusions

– The mountains help create a pattern that could be used to design interesting sheets.
– The plastic should have been few more minutes on the making, few pellets are not fully melted.
– We didn’t placed the frame in the middle of the press and that affected the result. (pellets not fully melted near to the edge of the machine.) plus that could brake the machine if we do it again.

Attachments:
starter
11/12/2018 at 16:47
2

This is so awesome. Upscaling is the shiznit and sheets and beams are the greatest.

my question is how is it all coming down to a real DIY project. the shredder is hard enough to make (I think most people have failed in fabricating a shredder that can actually shred), and it’s not like there are good-enough compressors and pistons laying around in scrapyards.

This is great for project kamp, for building in general, and as a potential income source for PP – but how can the community use this information? Will the end result Sheet Compressor be cheap, available, reproducible, and durable enough?

Anyway – you guys amaze me. truely.

shhigg.

starter
12/12/2018 at 00:11
1

I love your hydraulic cold press machine, I wish I can use it as a case study to build my press

helper
13/12/2018 at 11:58
0

@shhigg Yes indeed, making the machines easy to make and replicable is one of the objectives. But also getting good quality products from it is a must. We are aware of the problems that come along making the actual machines and we are also working on that.

But take in mind that for the next generation of machines we want to prioritize quality since it’s been demanded from the community in order to be able to produce valuable products. And for that a more engineering background is going to be needed. So if people don’t have it would be a matter of finding the right partners to work with. Also considering that good quality products are going to be achievable a bigger investment is justified.
Anyway thank you very much for your comment, let me know your thoughts.

HEllo @maltiti, here you can find the post where Mark explains his full process while mking that machine. And during the upcoming months he is going to work improving that machine in different topics. 🙂

helper
13/12/2018 at 12:39
1

Test: Trying to achieve a transparent PS sheet

Objective: Trying to make a transparent sheet

Machine: Hot press

Tools:  800 x 500 x 10mm Frame

Process

We tried to put shredded CD cases in the hot press to see the result, unfortunately it went not fully transparent because most of the plate inner structure ended up being amorf. I don’t know exactly the good parameters to make it. We put 220º on the press for one hour, and when the temperature was more or less there we put inside the frame and we fill it with flakes. We distributed the plastic evenly and left one mountain in the middle and 4 small ones near by the corners. After 1 more hour of compression we turned off the machine. and at the following day we had the result. We noticed that maybe it was too much time with the heating on since few yellow spots due to burning plastic appeared. see pics below.

Conclusions

– Not fully transparent, still need iteration in terms of Tº, timing and pressure (maybe?)
– Less than one hour needed since it was slightly burnt.
– Still some wrinkles characteristic from the hot press (teflon sheets).
– The frame deformed a little bit in the middle because of the pressure the ended result is not a perfect rectangle but a little bit rounded sides.

Attachments:
starter
13/12/2018 at 22:03
0

this is some cool news. you guys work really fast.

Please be carefull working with PS on 220 deg. you hardcore geeks. keep on the great work!

starter
19/12/2018 at 20:09
0

hello,

very interesting work.

perhaps a stupid question: regarding the cold press model, what would happen if you didn’t press it and simply let it cool down in the mold?

i assume the surface facing upward would be uneven and have some bumps and perhaps a few bubbles. but would it be a cohesive sheet which e.g. water wouldn’t penetrate?

helper
24/12/2018 at 01:33
0

Have you guys tested the strength properties of these yet? I’ve been working on my own sheet press and can make some very attractive, uniform, void-less HDPE and PP sheets, but they tend to be brittle. They have a lot of strength for bearing weight, but sharp impact with a hammer shatters them like glass – especially the PP. My most recent HDPE was pretty tough though.

According to academic literature, cooling speed seems to be the biggest factor – the faster you cool them, the less crystallization that happens, resulting in lower strength, but higher toughness.

I’ll keep experimenting with it all and eventually start my own thread.

dedicated
27/12/2018 at 06:09
2

What if you use teflon coated baking sheets and weights in the cold press method?

 

I found these on Amazon, but they are available all over the world.  Even in the Philippines at department stores and the markets

Attachments:
helper
28/12/2018 at 03:05
0

@btmetz, this is how I’ve been experimenting and it works just fine. However, these sheets are far too small for what they’re trying to achieve. Also, the teflon will eventually wear off, so something else is necessary. Vaseline doesn’t really work well. Some form of silicone is probably the way to go.

dedicated
28/12/2018 at 03:36
0

@nick  I can get teflon coatings made here in Manila at the same place that does anodizing and powder coating.  It lasts a long time on cookware.

 

Also have you also considered high temperature RTV silicone gasket material as the metal coating?

 

For my compression oven I use silicone mold release spray in mild steel molds

new
11/01/2019 at 19:16
0

Hi Varella, could you share like blueprints and electronic to us?

starter
17/01/2019 at 02:48
0

Hi there! I´m Juan Pablo, starting to think of building a sheet press. My first Question about sheets is if anyone has ever tryed to make a PET sheet. Hope to hear from anyone soon!

Viewing 16 replies - 1 through 16 (of 16 total)

You must be logged in to reply to this topic.