LibreSilicon - User contributions [en]

GloveBox

2022-08-25T11:46:59Z

84.113.89.176:

This is a low cost solution for having a clean room environment for handling dies and other components which require a clean room environment.

While there are commercial solutions available for sale, they typically cost several thousand dollars, while our BOM, even for the big variant, is typically below thousand dollars.

The design was originally based on the premise that the whole goal is just to have some quasi-airtight enclosure of some kind, where a circular airflow can be achieved which is purified by pumping the air through multiple stages of HEPA filters, while accessing the objects to be handled by using gloves fixed to the enclosure.

For obvious reasons, a glove box only makes sense when the material to be handled is visible, so acrylic glass was chosen as material for the enclosure.

During the development process it turned out, that just using glue isn't sufficient for holding the sheets of acrylic glass together in a box shape, because the weight of the material, puts too much stress onto the glue, which compromises the isolation and lets external dust enter, additionally, after a while the glue gives up under the mechanical stress, and the box falls apart.

For this reason additional aluminum extrusions are being used, for giving the whole box more stability.

This only increases the cost minimally because the main cost of the BOM ironically is in the acrylic glass.

For the airflow cheap 120mm PC fans like the ones found on AliExpress (https://www.aliexpress.com/item/1005003980506458.html) can be used.

{| class="wikitable" style="margin:auto"
|+Tools
|-
!Name
!Description
!Details
|-
|Screwdriver
(sonic or normal)
||Used to screw in the screws
||(and potentially fighting against Daleks and Cybermen, in case it's actually a sonic one)
|-
|A soldering station
||Well... it's used to solder stuff
||I've got this one, it's awesome! -> https://www.aliexpress.com/item/32969863227.html
|-
|A 3D printer
|Seriously, why not?
|Check out the Ender 3 Pro, it's only a few hundred bucks!
|-
|}

For making sure, that there's no dust entering the enclosure through the space where the acrylic glass touches down onto the aluminum, we've got to use some single sided silicone tape like this one:
https://www.aliexpress.com/item/1005003961444166.html

=General airflow fan assembly=
Below you can see a picture of a 4x4 array of 120mm, 12V fans, as used in the glove box air circulation system:

[[File:FPYT6ZQI03OBHCG.png|400px]]

When wiring the fans together into a common 12V power rail, you should keep in mind, that each fan draws around 2 Watts, which means that your wire, you're using to provide power to the fans can drive at least 160mA (milli amps), per fan.

<p style="color: red">
'''WARNING'''

Do not use too cheap wire, which might go up in flames, use a wire diameter which actually can drive the current
</p>

It makes sense to combine only 4 of the fans onto a single power rail at first, and then distributing it onto multiple rails of the power supply you're using.

Any common ATX PSU can be used for providing the required 12 volts, as long as the PSU rails are rated for that kind of power output.

=Air filtration=
Depending on what you wanna use your glovebox for, you might be able to get away with relatively low cost filters, for instance for a class 100 aka. ISO 5 clean room environment, you can find inexpensive filters on - let's say - AliExpress.

A quick look at a website giving us some classes filters which can produce a class 100 clean room gives us a hint on what to look for: https://isocleanroom.co.uk/blog/iso-5-defining-cleanroom-classification-guidelines

Looking for ULPA and HEPA online makes us realize that if we'd go for an ULPA filter we'd have to pay up to 400 Euros for a single filter, while for a HEPA H14 filter we only have to pay between 14 to 30 bucks, like for instance for this cheap vacuum cleaner replacement filter: https://electropapa.com/en/vacuum-cleaner-hepa-filter-replacement-for-nilfisk-107409854-elite-h14-filter

Like with any clean room, the direction of the laminar flow is important, it's usually from top to bottom, like shown in this image:

[[File:Non-unidirectional-airflow-cleanroom-e1620825297344.jpg|200px]]

Make sure your fan array points into the right direction

=Large box=
The large box

[[File:Screenshot_20220823_165351.png|200px|thumb|FreeCAD design: Large box]]

{| class="wikitable" style="margin:auto"
|+BOM
|-
!Component
!Amount
!Price per Piece
!Price Total
!URL
|-
|Gloves
||4
||9,89€
||39,56€
||https://www.manutan.pt/pt/map/luvas-em-neopreno-com-manga-comprida-ultraneo-450-a169336
|-
|12 volt fans
||64 (2*32, top and bottom)
||0,64€
||40,96€
||https://www.aliexpress.com/item/1005003980506458.html
|-
|Acrylic glass 50cm x 50cm
||2
||15,99€
||31,98€
||https://www.leroymerlin.pt/Produtos/Madeiras-acrilicos/Vidro-acrilico/Acrilico-vidro-sintetico/WPR_REF_81902623
|-
|Acrylic glass 100cm x 100cm
||1
||54,99€
||54,99€
||https://www.leroymerlin.pt/Produtos/Madeiras-acrilicos/Vidro-acrilico/Acrilico-vidro-sintetico/WPR_REF_81902578
|-
|}

=Small box=

{| class="wikitable" style="margin:auto"
|+BOM
|-
!Component
!Amount
!Price per Piece
!Price Total
!URL
|-
|Gloves
||2
||9,89€
||19,78€
||https://www.manutan.pt/pt/map/luvas-em-neopreno-com-manga-comprida-ultraneo-450-a169336
|-
|12 volt fans
||32 (2*16, top and bottom)
||0,64€
||20.48€
||https://www.aliexpress.com/item/1005003980506458.html
|-
|Acrylic glass 50cm x 50cm
||4
||15,99€
||63,96€
||https://www.leroymerlin.pt/Produtos/Madeiras-acrilicos/Vidro-acrilico/Acrilico-vidro-sintetico/WPR_REF_81902623
|-
|Perforated floor
||
||
||
||https://www.leroymerlin.pt/Produtos/Ferragens/Perfis-chapas-e-grelhas/Chapas/WPR_REF_11118485
|-
|}

R&D challenge

2022-04-09T06:34:17Z

84.113.89.176:

This side holds projects for which we welcome external help to contribute man power and machine access.

==Polysilicon==
Polysilicon is currently only done by using silane gas, which is highly poisonous and unfeasible for small scale manufacturing setups.
We welcome the help from material science students and labs to come up with alternative recipes which require less poisonous gases or
provide alternative chemical recipes for alternative gate materials with similar resistivity and temperature tolerance as polysilicon.

===Requirements===
* Liquid material deposition
* Can be done with lab furnace (preferably around 1200 degrees Celsius)
[[File:Labfurnace.png|500px]]
* No chemicals which get your garage SWATed
* Etching method should be provided which can be done in a garage

===Possible Solutions===
* Can we use https://futurezone.at/science/computerchips-honig-memristor-washington-state-university-neuromorphes-computing/401967797 instead of polysilicon?

Security Concept

2022-03-07T15:29:23Z

84.113.89.176:

The Libresilicon Security Concept:

Status: DRAFT

Threat Model:

1. Chemical recipies could be modified causing chemical hazard

2. Malfunctions / Crashes of the control system could leak chemicals

Requirements:
1. Chemical recipies must be correct, tamper-proof / tamper evident

2. We have to ensure that valves are closed in case of malfunction

Security Concept:
1. To avoid bit-errors, we SHOULD use Hashes on the Recipies

1. We need air-gaps for security-critical control systems

1. To avoid bit-errors, we MUST use ECC RAM wherever possible

1. The usage of Majority-Voting for failsafe control systems has been deemed unnecessary.

2. We need a failsafe system: The Fail-Safe state is to close the valves.
-> All Valves of dangerous chemicals must be monitored (with potentiometers or switches) and alerted in case the valve is open in a situation where it should not be open
-> Preferably a system that can actively close all valves in case of a safety alert.
-> Safety-Alerts should either be done by pressing a button, or by a watchdog that monitors the liveness of control system

Security Concept

2022-03-07T15:26:47Z

84.113.89.176: Created page with "The Libresilicon Security Concept: Status: DRAFT Threat Model: 1. Chemical recipies could be modified causing chemical hazard 2. Malfunctions / Crashes of the control syst..."

The Libresilicon Security Concept:

Status: DRAFT

Threat Model:

1. Chemical recipies could be modified causing chemical hazard

2. Malfunctions / Crashes of the control system could leak chemicals

Requirements:
1. Chemical recipies must be correct, tamper-proof / tamper evident

2. We have to ensure that valves are closed in case of malfunction

Security Concept:
1. To avoid bit-errors, we SHOULD use Hashes on the Recipies

1. We need air-gaps for security-critical control systems

1. To avoid bit-errors, we MUST use ECC RAM wherever possible

1. The usage of Majority-Voting for failsafe control systems has been deemed unnecessary.

2. We need a failsafe system: The Fail-Safe state is to close the valves.
-> All Valves of dangerous chemicals must be monitored and alerted in case the valve is open in a situation where it should not be open
-> Preferably a system that can actively close all valves in case of a safety alert.
-> Safety-Alerts should either be done by pressing a button, or by a watchdog that monitors the liveness of control system