Opinions sought on cheap desktop PCB milling machine

[saxonhawthorn]

Hank, you're right on all counts. Fresh developer each day is a must (prepared the night before to stabilise), though I've found I can usually go on using ferric chloride until it's spent. But temperature control is very critical, and it took me a lot of experimentation to get it right. I was making boards for production then, not just prototyping, and scrap costs money.

Another nice thing about milling has just ocured to me: there's a big price difference between plain copper boards and pre-sprayed photo-sensitive boards (NB to anybody thinking of doing it: use Fotoboard 2. Don't even think about spraying your own photo-sensitive stuff on. You've got to spray it evenly with no missed bits, bake it dry at the right temperature, and never let it see daylight until you use it. You really don't want to go there).

A pick-and-place m/c for SMD is next on my list after PCB-making. Sounds as though you and I are travelling the same road. Are you using an "Archimedes Screw" device to dispense solder?

Ian

[HankMcSpank]

Another nice thing about milling has just ocured to me: there's a big price difference between plain copper boards and pre-sprayed photo-sensitive boards (NB to anybody thinking of doing it: use Fotoboard 2. Don't even think about spraying your own photo-sensitive stuff on. You've got to spray it evenly with no missed bits, bake it dry at the right temperature, and never let it see daylight until you use it. You really don't want to go there).

I use from SRBP copper boards (not so much nasty glass fibre dust in the air, they're easier on the tools & they're fine for protos)...

http://www.rapidonline.com/Tools-Equ...f-e2e6ffd711d1

....for 100pcs it works out about 36p inc vat & delivery for a 6" x 4 board" (cheapest I know of but I'm happy to be corrected!) ....the cheapest fotoboard of the same size I was ever able to source worked out at about £2.00 delivered per board, so yes a lot cheaper! (and the board I'm milling with are so cheap that it doesn't ruin your day if you screw up!)

re your comment...

2. Don't even think about spraying your own photo-sensitive stuff on. You've got to spray it evenly with no missed bits, bake it dry at the right temperature, and never let it see daylight until you use it. You really don't want to go there).

been there done that...bought some foto spray from Farnell & was appalled that they could even sell this stuff - complained to Farnell "This stuff truly sucks & you should remove it from your product range asap" ...they re-credited me for it!

Still got the can - doub't I'll ever use it....it's twatful stuff.

[saxonhawthorn]

Still got the can - doub't I'll ever use it....it's twatful stuff.

Maybe it works as fly spray?

I'd be interested in details of your solder paste dispenser (apologies if you have already posted them somewhere - I've been away from this site for quite a while). What air pressure do you use? Is the amount dispensed repeatably accurate? I admit to a prejudice against pneumatic control of such small amounts of thick and gooey (and expensive if lead-free) stuff, but I'd be very happy to be proved wrong.

Ian