EtchingBox: Difference between revisions
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=The Idea= | =The Idea= | ||
Build a portable / mobile PCB etching workstation that fulfills these criteria | Build a portable / mobile PCB etching workstation that fulfills these criteria | ||
* waterproof | |||
* able to etch 100x160mm double sided boards with 8mil precision | |||
* low cost | |||
* diy approach, mostly laser cut plexi and easily sour cable materials | |||
* fits in a RAKO Box | |||
Some guiding ideas | Some guiding ideas | ||
* use very little but always fresh chemicals | |||
* good heat management: etching has to be done at 45-50 degrees celsius, developer has to be kept at >20 degrees as well (in my workshop, temperatures can easily drop below 16 degrees and developing is a pain). | |||
* all material and chemicals travel in the box. liquid waste can travel in the box as well until it can properly disposed of. | |||
=The Project= | =The Project= | ||
Revision as of 17:05, 3 May 2014
The Idea
Build a portable / mobile PCB etching workstation that fulfills these criteria
- waterproof
- able to etch 100x160mm double sided boards with 8mil precision
- low cost
- diy approach, mostly laser cut plexi and easily sour cable materials
- fits in a RAKO Box
Some guiding ideas
- use very little but always fresh chemicals
- good heat management: etching has to be done at 45-50 degrees celsius, developer has to be kept at >20 degrees as well (in my workshop, temperatures can easily drop below 16 degrees and developing is a pain).
- all material and chemicals travel in the box. liquid waste can travel in the box as well until it can properly disposed of.
The Project
Components
Power Supply
should be able to provide at least 2 x 2 Amps for heating, 1 Amp for lights and a bit more for micro controller, displays and stuff so at least 12V / 6-8 A, 72W - 100W
Master Controller
Gnusbuino based? Controls -relais/FET for UV lamps
UV Exposure unit
Slot loading, double-sided UV exposure: put PCB and overhead slide between two glass plates. The mechanism presses glass plates together. Exposure starts when assembly is fully inserted. You can stop exposure anytime by retracting the assembly. Otherwise it will stop at a predefines time interval.
First tryouts with UV fluorescent lamps seemed promising - you can get DULUX S style UV lamps for nail polish hardening on ebay for about 2.50 Euro. But two bulbs, 8cm apart, 6cm distance from PCB don't give an even enough light to expose a full 160x100mm PCB - 3 minutes exposure seems to overexpose the center while the corners still don't get enough light. You can put 2 Dulux S on one ballast, so adding a third lamp per side means 3 ballasts if I want to stick with double sided exposure.
UV LEDs?
LEDs would be much easier to control, they are low voltage DC, safer to operate in a potentially humid environment. You could put plenty of leds dispersed on a eurocard size PCB and achieve a much more even lighting. Just found and ordered these suckers: