Hey,
I realise lots of people will post pics of their diy boards but I'm after some constructive criticism.
I made this CPLD (TQFP48-0.5mm pitch) - DIP adapter as a real test to see just what toner transfer can do. Materials used:
-Software: Eagle 4.12.
-Printer: Cannon LBP200i @ 600DPI.
-Paper: Stock printer paper. Tried magazines (thick and thin pages), glossy (for inkjet and laser). Every one but the standard cheapo printer paper caused severe smearing/smudging, and the staples photo basic wouldn't even come off after 24 hr's in soak. I'll try proper toner transfer paper (the blue stuff) later.
-Copper clad. Stock SRBP (FR2). Good enough for these circuits, and won't destroy my drill bits after a hundred holes.
-Etchant: Amonium persulphate 100g disolved in 500ml of warm water.
-Drill: Dremel 300, with HSS 0.8 (blunt) and 1.0mm (new) bits. PZ541 drill stand.
Results? well, considering the pads for the TQFP part were 0.5mm in pitch and 0.34mm wide..thats a gap of 0.16mm. Getting the paper out of these 'trenches' was tough, and meant that three of the gaps did not etch away properly, leaving shorts corrected by a craft knife. Some areas where the toner didn't stick too well were touched up with an etch resist pen. Which was crap and was quickly eaten away by the etchant within minutes.
I think I got the drilling down, despite some off-centre holes, and the ironing seems to require NOT the highest heat as that causes smudging but a pretty high heat, as qwell as a preheated board. But can anyone recommend some decent paper? Preferably stuff that DOESN'T smudge the toner, but comes off without 30 minutes of rubbing and swearing? God knows why people recommend glossy paper, every type I tried results in small pads becoming one large patch of toner.
Suggestions welcome! Next time, I'll try some photoresist, with washing soda as developer
Blueteeth
I realise lots of people will post pics of their diy boards but I'm after some constructive criticism.
I made this CPLD (TQFP48-0.5mm pitch) - DIP adapter as a real test to see just what toner transfer can do. Materials used:
-Software: Eagle 4.12.
-Printer: Cannon LBP200i @ 600DPI.
-Paper: Stock printer paper. Tried magazines (thick and thin pages), glossy (for inkjet and laser). Every one but the standard cheapo printer paper caused severe smearing/smudging, and the staples photo basic wouldn't even come off after 24 hr's in soak. I'll try proper toner transfer paper (the blue stuff) later.
-Copper clad. Stock SRBP (FR2). Good enough for these circuits, and won't destroy my drill bits after a hundred holes.
-Etchant: Amonium persulphate 100g disolved in 500ml of warm water.
-Drill: Dremel 300, with HSS 0.8 (blunt) and 1.0mm (new) bits. PZ541 drill stand.
Results? well, considering the pads for the TQFP part were 0.5mm in pitch and 0.34mm wide..thats a gap of 0.16mm. Getting the paper out of these 'trenches' was tough, and meant that three of the gaps did not etch away properly, leaving shorts corrected by a craft knife. Some areas where the toner didn't stick too well were touched up with an etch resist pen. Which was crap and was quickly eaten away by the etchant within minutes.
I think I got the drilling down, despite some off-centre holes, and the ironing seems to require NOT the highest heat as that causes smudging but a pretty high heat, as qwell as a preheated board. But can anyone recommend some decent paper? Preferably stuff that DOESN'T smudge the toner, but comes off without 30 minutes of rubbing and swearing? God knows why people recommend glossy paper, every type I tried results in small pads becoming one large patch of toner.
Suggestions welcome! Next time, I'll try some photoresist, with washing soda as developer
Blueteeth