Author Topic: DIY pcb anyone?  (Read 6868 times)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
DIY pcb anyone?
« on: September 08, 2013, 10:46:08 AM »
Just tried to knock off a couple of boards but its all gone PT....

Firstly my developer was too strong.....

...but I'm not sure if my exposure time is too short ...around 3 mins...
Any tips or pointers?


eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8966
  • Country: gb
  • East Sussex, UK
Re: DIY pcb anyone?
« Reply #1 on: September 08, 2013, 11:12:26 AM »
John,

Before I moved (about 6 years ago) I had a full development  lab pcb production line set up, with developing tank, rinsing,etching tank, washing, and tin plating - it was one of the things that got sold to reduce volume for storage. About 18 months ago another similar one flitted by me on eBay and I reached out and grabbed it - its like this one:

http://www.megauk.com/pcb_labstation.php

I've installed it, plumbed it in, replaced a faulty heater, and got all the chemicals but not yet filled it up. I used pre-coated boards, exposed through overhead slide film printed on my laser printer, developed using mega developer, and etched with ferric chloride. I would let the developer tank temperature stabilise for a while, then put the board in and examine it every 30 seconds or so until it looked right. Actual time of course varies with the strength of the developer and and its temperature.

Lots of hints and tips on the Mega site
Andrew Mawson
East Sussex

Offline Bluechip

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 1513
  • Country: england
  • Derbyshire UK
Re: DIY pcb anyone?
« Reply #2 on: September 09, 2013, 01:20:20 PM »
Just tried to knock off a couple of boards but its all gone PT....

Firstly my developer was too strong.....

...but I'm not sure if my exposure time is too short ...around 3 mins...
Any tips or pointers?

PT in what way , John ???
 
I have a MEGA UV unit. I only expose for 2 mins ... UV tubes are little used though, so I suppose they are fairly good emission. Need to be warmed up first for 10 mins as MEGA recommend.
 
Dave BC
 
 
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: DIY pcb anyone?
« Reply #3 on: September 09, 2013, 02:08:43 PM »
Dave,
I'm using pre coated board with ohp films and a 4 tube uv unit.
I exposed the board for 3 mins,then developed using a proprietary solution.
The board appears to develope ok but then etches poorly...Fresh ferric chloride solution used...
Not sure if the board is past it's sell by date tbh....(I've had the board for a umber of years stored in a cool dry environment)
My methodology has been fine uptil now.....

I'm thinking the board isn't exposed long enough......?
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Bluechip

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 1513
  • Country: england
  • Derbyshire UK
Re: DIY pcb anyone?
« Reply #4 on: September 09, 2013, 03:12:54 PM »
John
 
I assume it's not removing the copper in places. ??
 
I only use MEGA stuff, odd bods I know who do pcb's warned me about 'pick 'n mix'  sometimes not working properly, but if you've used it all before that should not be an issue.
 
Could be the board, I believe it does have a shelf life.
 
I get mine from CPC, I think it is MEGA sourced.
 
Only time I got  other than MEGA was some board off an ebay seller .... cheap ... and not without good reason it turned out...  :bang:
 
All the resist had the 'spray' lines across it ... utter rubbish. Fortunately I only got 2 A5-ish sheets to see what it was like. 
 
I reckon I could put the resist on better myself with a stick ... :(
 
Dave BC
 
 
 
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: DIY pcb anyone?
« Reply #5 on: September 09, 2013, 03:20:05 PM »
Dave,
It appears that the exposure/developing process is the issue.....

The FeCl3 solution doesn't etch too quickly....but the developer seems to remove too much of the resist making me think that it isn't exposed for long enough or it is past it's sell by.....

I'll try another piece of board and expose for longer......
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Bluechip

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 1513
  • Country: england
  • Derbyshire UK
Re: DIY pcb anyone?
« Reply #6 on: September 09, 2013, 03:34:17 PM »
That's what I had with the crappy board. The machine or  whatever sprays the lines of resist on was going too fast or something ?? There was very little resist in places. The traces were narrowed every 1mm or so.
 
You got Skype going ??? Summat has to be better than banging a k'board ....
 
I'm on now if you want a better explanation.
 
bchip_s7
 
 
Dave
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: DIY pcb anyone?
« Reply #7 on: September 10, 2013, 03:37:01 AM »
Dave,
Yes I have Skype....Sorry didint read this 'til this morning...Hope you werent waiting for me... :coffee:

I have a couple/3 of options..
a)Buy some new board
b) Buy a tin a spray resist and clean all of my boards
c) ermmmm.....Something else  :scratch:

I may get back to this tonight....but need some time in the 'shed' got things to do  :dremel:
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Bluechip

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 1513
  • Country: england
  • Derbyshire UK
Re: DIY pcb anyone?
« Reply #8 on: September 17, 2013, 10:01:28 AM »
So what's happened then ??
 
 
Nowt ???
Some of us are all agog.
Some have no gogs at all I expect ...
 
Dave
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline Chuck in E. TN

  • Hero Member
  • *****
  • Posts: 572
  • Country: us
  • USAF Retired
Re: DIY pcb anyone?
« Reply #9 on: September 17, 2013, 10:05:33 AM »
I have finally had sucess with the laserjet toner transfer process. Just have your art printed on glossy paper on a laserjet printer. Use a domestic iron to transfer the laser toner to plain copper board. Etch with ferric cloride.
Chuck
Chuck in E. TN
Famous TN last words: "Hey ya'll, watch this..."
MicroMark 7x14, HF X2 mill, Green 4x6 saw. Harbor Freight 170A mig

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: DIY pcb anyone?
« Reply #10 on: September 17, 2013, 01:45:07 PM »
So what's happened then ??
 
 
Nowt ???

 
Dave

Yup.....nothing nada.....

I've just got another generator to repair..... :zap:
So this has gotten in the way.....

I'll get back to the board soon, but need to tidy up the shop, got visitors coming on Saturday

eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr