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Meanwhile, the life goes on. We’ve been making some of the wall clocks in the background and selling them on the Bazaar and through local channels. Currently the business model looks like – sell as many wall clocks as possible. At the current production rate, we barely cover the monthly garage rent. A switch towards workshop based activities is required and also developing local group of volunteers is a must. Machine development is somewhat frozen at the moment to maximize the production.
If you have any tips about the workshops, give us a shout!
(resource efficiency will help us become type 1 civilization 🙂 )
Well, the first thing you actually need to change is the base of the shredder. If you say that after some time shredding the screws start to move a bit it means it is not secure and stable especially with a 2+kw motor. For your case it has got to be metal base.
Hopper itself should be doing well in any condition apart from when there is a lot of vibrations and shredder box / hopper base twisting. This is also cured by a solid metal base.
In terms of operation you better cut big pieces into smaller chunks as it would be way easier to throw them into the hopper.
Hope this helps,
Update N.28 – Wall clock making
Today I’ll post about the wall clock making. The 3d model version of the mould is shown in Pic.1.
It comprises of a square bottom plate with pieces of flat bar welded to the sides that act as walls. Then in the middle there are two plates with circular cuts that set the shape of the wall clock. We wanted them to be perfectly round, so we ordered that from laser cutting. The lower plate is thin (2mm) and the cut is 250mm in diameter. The one above it is more thick (5mm) and the cut is 245mm in diameter. This can be clearly seen from Pic.2.
The reason as follows:
Thinner plate is below the thicker one. It shapes the number plate of the wall clock. In case there is not enough plastic in the mould (operator error), the thin area would still be filled all the way.
Another plate goes on top just to compress the plastic. For the moment, we compress plastic separately from the oven.
More pictures will show different steps in making the item, please also take a look at the short pdf presentation attached here.
EDIT: A quick note that although the thinner plate cut is ø250mm, the overall shrinkage of the wall clock results in it being ø245mm. Consider this as well!
Update N.27 – Garage party
We decided to address all those requests to see the workshop we got, see the machines and get to know us through a garage party. We arranged a set of speakers, related electronics, a fireplace with some marshmallows and so on. Inside the garage itself we set up a wee wall clock exhibition. On the table – traditional
food coasters. In one of the corners people also played table football, France won.
In order to get into the workshop people had to pay in plastic bottle caps. The number of caps had to be at least 1. Total amount after the event was about 600 caps. Between all the people who gave caps, we ran a raffle/lottery and the lucky winner got our designed wall clock as a prize.
The whole evening I personally spent telling people what’s up and sharing some ideas about the best or better practices they should consider using/doing.
Please check the photos, give us some questions to ignore (that is a joke) and follow us on Instagram.
We did some coke can plastic melting test. The results described in our topic here.
If you just scroll to Weekly update number 11 you’ll see the result for just taking a can and filling it with PP and placing in an oven. This could definitely be machined to meet the product design specs (and also cheap and easy to make)
Update N.26 – Great success story v3
To continue the
success stories, here is another one:
During the production of wall clocks, we came to the point when the plates needed to be marked with material type. For those who don’t know what it is, please refer to Precious Plastic FAQ and/or Google.
Our first attempt using PP brass coins failed, so did the second (Photo 1).
Then we referred to our own technique – using specially designed paperclips with unique handwriting (Photo 2) – a limited edition btw
Look at the result (Photo 3)– now it is perfectly clear what material it is. To heat up the wire we used a simple candle. So here is high-tech solution everyone needs now!
On a bit more serious note, the results shown in the first image are most likely due to:
– PP brass coin temperature (overheated with candle, hard to control)
– No silicone spray is applied to the surface – no mould release – failure
– Plastic itself is a bit burned, somewhat laminated and might have different properties on different layers.
More about the wallclocks later. Boom!
This result of using the PP coins for marking material type is not always like that. Our result shows that we need to optimise our process if we want to use them. Coins themselves mark well if used properly.
Update N.25 –
Great success story v2
Hello people. Today we’ll continue with some difficulties with the keychain mould
success story shown above. After drilling the sprue (injection hole) to 8mm diameter, the results started to shine!!
But not for long.
Photo n1 shows why.
As you can see, the mould hook is made of a plate, where the hook is created with straight cuts. This allows for shearing under applied load.
In our case, over cycles of opening and closing the mould, the hook got deformed badly, see photo n2. The hook was strengthened by some welding under it, but unfortunate location of the hole in the plate (photo n3) does not give the weld much of a base, so it doesn’t help at all.
What we did > we added max amount of weld that would fit in the latch, both sides, so it won’t be a problem anymore.
Update N.24 –
Great success story
Oh hi there,
Recently we got an aluminium mold from the headquarters, for some time to test and see how it goes. We wanted everyone to know that behind all the fancy looking product photos, there are lots of trials and errors, mistakes and failures.
We got the first two keychains made well and the rest of them, moulded another day, you can see below.
What are we going to do?
Well, melting temp is high enough, no chance of going higher. We’ll try to warm up the mould itself. This will allow slower plastic solidification. Also injection itself should be controlled a bit better.
One suggestion would be to may be increase the mould temperature, to have plastic to cool slightly slower.
Another thing: how do you know the temperature of plastic? Could you may be share a photo / sketch of the orientation of the heating elements + the thermocouple location. It could be that your reading is taken from the heating element and that doesn’t represent actual plastic temp.
I usually do it by weight. You know the average density of the plastic type you use. For items that are more complex than a regular plate I tend to make a 3d model and get its weight from the program. Then add something like 10% and see how it turns out. If it is not enough, you need to analyze the reasons for it and then add a bit more.
R.I.P. <HTML> editor,
I will miss you.
Update N.23 – Still mess
Some compression machine building photos. Of course I had to add a cheeky photo of myself holding the oven door (about 10kg). The magic box we’ve built is going to host a platform like in a regular compression machine. But also in one of the oven configurations it will have a rotomoulding unit inside. It will be a 2-axis rotomoulding thingy, similar to this.
🌎Update N.22 – Mess
For those of you who wanted to see how messy our garage is – this is ‘relatively clean’ state. Not much can be otherwise said apart from that we’re building a custom compression machine, photos soon to follow.
*panoramic photo stiched by a trial version of Autopano Giga. Quite a good software, in case anyone asks.
From the experience of working with these materials:
PS is brittle at small thicknesses, will sustain low number of bending cycles and will quickly break.
PVC when thin and deformed becomes white at the folds and later if deformation is removed stays that colour, which is not great for the aesthetics. Not to say that is should be phased our of everyday use at all (as PS to be honest)
HDPE and LDPE used a lot in bags as you know. I can only imagine that due to the softness it will be hard to make a thread from these like from PET, so these materials better be used in sheet form.
The search function is at the bottom of the page on this forum.
The answer for your question would be: Yes, you need to wash off any dirt that might compromise the structure of the plastic product you plan on making. If it is clean, it also allows further recycling..
there is almost 50,000 registered users on this forum..
11k have 2-2400 points
9k have 1 point, which is at least one forum login.
30k have ZERO points and hence have never logged into their accounts after registering
while it is a lot, some of the users are here for the Phonebloks and Storyhopper