Equipment/PCB etch station

Etch station

Important Warnings

• Do not put any water in the spray wash tanks at the moment : it will flow straight onto the floor.
• Do not run any heater unless the tank is full of liquid. It should blow a thermal fuse before melting the tank, but that may involve replacing the heater. Keep unused heated tanks full of plain water until we have disabled the heaters.
• Do not etch anything except copper (other metals will pollute the etchant).
• Do not drink the contents, even when there's no beer.
• Do not allow children or drunken hackers to play with the tanks.
• Check the power has been turned off after use.

Status

There's some spilt etchant on the cupboard floor. Please keep a careful eye on this in case it's actually a sign of a leak.

We are currently planning on fixing-up the unit and working out how it should be configured:

From a quick test it appears to have no major faults : it heats all the tanks, it bubbles, the spray wash solenoids click, and the tanks don't appear to leak. And the cupboard turned out to contain some developer and tin plating crystals!

The tanks are currently full of water - very polluted by the previous contents. Don't expect it to etch ! The intention is to soak off the old contents, clean them out and then refill.

The bench should be usable in the simplest form as soon as we've checked it out, but there are some things we can do to make the best of it. There's a need for a handful of plumbing and electrical accessories.

Todo

Soon

• Scrub out sink
• Connect waste pipe on back of cabinet. There are some random plumbing fittings in a bag in the cupboard and may be some more in the space, possibly under the lab 24 sink. In particular a rodding tee that was fitted to the outlet, and a new swept tee. Check under the hangar 23 sink for a spot to link in using that swept tee or some other fittings. A length of 1 1/4" pipe will be needed and maybe a few other fittings. A short flexible section or something easily disconnected would be a good idea.
• Connect cold water to wash tanks. This can probably be done using the tap just above the tank, if the pipes are long enough. BUT DON'T DO THIS UNTIL THE WASTE IS CONNECTED!!
• Build splashback if possible.
• Connect cold water to tap. Might be possible using a Y connector on the same supply as the wash tank, but a neater solution would be to add washing machine fittings to the side of the existing sink unit. Unfortunately there's a water heater in the cupboard just where you need to work.
• Connect hot water to tap. Probably not really needed since there's an adjacent sink, but would complete the job.

Usage configuration

• Since it's already stained there's no problem in putting ferric chloride in it if we have some available (it needs 5 litres but 3 or 4 would do).
• We can use a spare tank to start brewing the cupric chloride if we want to do that
• There were some chemicals in the cupboard - developer, tinner, stain remover.
• I (artag) have some date-expired mask stripper we can try in a strip tank

Placement

• We need water and waste connections for the rinse tanks. These are simple washing machine fittings but we may need adapters for the supply pipework and a waste hose. I do have some plumbing fittings but we may need more.
  • Depending on when you need these, I could go out and get these on Fri/Sat. -- Elliot
  • I think we'll need at least one cold fitting, ideally another cold and a hot too, and a way to get 1.25" waste into the sink plumbing - possibly just a length of pipe, possibly some joints. May be easiest to put things in place and then find exactly what's needed.
• Where do we put it ? I suggested replacing the unit 23 sink, but short-term it could simply go next to it. Tools may need moving, though. Or it could be installed in the unit 23 toilet. Or it could be integrated into a darkroom build. Discuss ..
  • I think it can fit next to the sink in the place of the metal cabinet that is there currently - it may be a bit longer and deeper but that shouldn't be a problem. Ideally it'd be nice to keep the sink for other chemical type experiments. If we can avoid talking about the darkroom then we can save ourselves a lot of hassle :-) -- Elliot.
• It would be nice to have power without using the extension lead. The existing ring main might be extended fairly easily to put sockets on the wall near the sink.
  • Again, depending on when electrical stuff is needed, I could go out and get conduit/socket/back box/etc. on Fri/Sat. -- Elliot
  • I see there's a bit of conduit near #23 back door. Needs a socket plate and probably some more 2.5mm wire to link into the ring. Could be patched up but a better plan might be to look at fixing a couple of electrical jobs and buy the bits at the best price rather than in small pieces.

Model

• Make: Mega Electronics
• Model: PB710S - PCB 7 tank production line with sink

Controls

The leftmost button on the control panel is mains power. If you see it lit up when no-one is using the tank, please turn it off (but if someone _might_ be waiting for it to warm up, please check first!). Probably a good idea to switch off at the mains as well.

Each tank and rinser then has a control section. Working from left to right, these are:

• Developer - Heat button and 'heater active' light. Set to about 28°C. Heating not normally required.
• Developer rinse - Spray button activates spray bar. Not yet available as it requires plumbing in.
• Etch - Heat button and 'heater active' light. Set to about 48°C. Takes about 15-20 minutes to get hot.
• Air bubbler button - only active when heating is also on.
• Etch rinse - Spray button activates spray bar. Not yet available as it requires plumbing in.
• Photoresist stripper - Heat button and 'heater active' light. Set to about 50°C. Optional.
• Stripper rinse - Spray button activates spray bar. Not yet available as it requires plumbing in.
• Tinning - Heat button and 'heater active' light. Set to about 50°C. Optional.

Instructions

The tank was previously in a school and there is a laminated sheet with usage instructions. It may not be applicable to our use but is worth looking at.

• Manufacturer's instructions (local copy)
• Heater and bubble bar Maintenance - also see Mike's posting on mailing list.
• Ferric Chloride
• Stain remover
• Fine etch crystals - we don't use this at present but it's been suggested.
• Photoresist stripper
• Tin plating - We have a small tub of this, possibly unusably old.
• All Mega MSDS and data sheets