I got my sample of the Mega Electronics JetStar film this morning, and tried
it out on an existing PCB design, as promised. It worked very well!
My printer is an old Epson Stylus Photo 870, and I used a non-Epson ink
cartridge. The printer was set for Photo Quality Glossy Film, according to
the Mega data sheet, and max. print quality, black ink. I actually cut a
smaller piece off the supplied sheet and fixed it to a piece of ordinary
paper when printing with a strip of masking tape, as it's quite expensive.
The UV exposure time I employed was the same as I use with transparencies
printed on a laser printer, on the low-cost single-sided FPC 16
(fibreglass-paper composite) PCB positive resist material supplied by Mega.
Etching was in warm FeCl3, and took the usual 10 minutes or so, with
continuous agitation.
Examining the etched board with a lens showed that the tracks were ∗much∗
sharper than I've been getting with laser printer transparencies (those
always look a bit ragged at the edges). The board used a minimum track width
of 10 mils; 8 mils shouldn't cause any problems and I might be able to get
down to 6 mils, especially if I use the newer Premium Jet Star film (Mega
also sent me a sample of that to try).
JetStar is available from Mega, Farnell and Rapid Electronics, and costs
5.10 GBP for 10 A4 sheets. The Premium JetStar film costs 10.50 GBP.
I'll be using it from now on, for most of the boards I make. I will probably
continue to use tracing paper in my laser printer for simple designs with 12
mil tracks.
Leon
--
Leon Heller, G1HSM
leon.heller@...http://www.geocities.com/leon_heller ---
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