PCB expousre

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Chris

Chris

Member
Joined 2001
The work is done.......

This weekend I tried to develop my first PCB boards using UV light and boards with positve fotoresist. I placed the tube ca. 8 cm above the board and exposed it for 4.5 min (after testing first). And the result was great..................

:D :D :D :D :D

Happy new year:)
 
Devil_H@ck

Devil_H@ck

Member
Joined 2003
members.lycos.nl/anthonyvh
I have some little problems lately. While the PCB's themselves get better and better, it's the drilling that causes troubles.

When I drill a hole in a small trace, the copper around it gets lose from the board. I didn't use the have this. Could this be because my drill bit is worn down? It's a real pain, because very short traces (eg. between 2 resistors legs that are very close together) almost dissapear from the PCB and I have to bend the legs underneath the board to connect them together that way.

What's my problem?
 
Chris

Chris

Member
Joined 2001
Devil_H@ck said:
I have some little problems lately. While the PCB's themselves get better and better, it's the drilling that causes troubles.
Click to expand...

Hi

What size bits do you use? I use 0,1 to 1,0 mm size. The bit must be centered properly or else the drill hole will be bigger. I also put ordinary scotch tape on the board. This stops the "wandering" of the drill, before it starts to penetrate the surface. I also use a dremel tool for the drilling.

Happy DIY

:) :) :)
 
jackinnj

jackinnj

Member
Joined 2002
tech-diy.com
drill sizes

the problem is that your drill bit may be worn in which case it's heating up the pad and loosening the adhesive which binds the copper layer to the fiberglas. if you find that the pads are disappearing consider drilling before you etch -- as has been pointed out before -- this might result in some of the etchant creeping into the pad and making the hole unpretty -- but you can stop this by applying a little wax or nail polish over the hole.
 
Devil_H@ck

Devil_H@ck

Member
Joined 2003
members.lycos.nl/anthonyvh
Re: drill sizes

Chris said:
What size bits do you use? I use 0,1 to 1,0 mm size. The bit must be centered properly or else the drill hole will be bigger. I also put ordinary scotch tape on the board. This stops the "wandering" of the drill, before it starts to penetrate the surface. I also use a dremel tool for the drilling.
Click to expand...
I also use a Dremel and the bits I use are 0.8 mm which is just right for most parts. I'll try the scotch tape thing. I didn't have this problem 2 weeks ago, only with the last 3 boards I did I had this problem. I made a JLH board 2-3 weeks ago with a new bit I bought then and all holes on it are near perfect.

jackinnj said:
the problem is that your drill bit may be worn in which case it's heating up the pad and loosening the adhesive which binds the copper layer to the fiberglas.
Click to expand...
I think this is my problem, however, I only have bought the drill bit 2 weeks ago and have since drilled maybe a maximum of 100-150 holes. Is it normal that the bit is worn out after that? These things cost 2.5€, so I expect they should last a bit longer. Also, are there more than one type of these? So, could it be that I have a 0.8mm drill bit for wood, where I need one for iron?
 
AuroraB

AuroraB

Member
Joined 2001
Low quality drill bits will wear very rapidly. Use only good quality HSS drill bits, or at best - the tungsten-carbide bits specially made for PCBs. These comes with a standard 1/8 inch shaft and fits the Dremel perfectly. They should be appx. 3USD ( or Euros) each,- but beware- they are extremely brittle and breaks easily, particularly with just a twich of sideways pressure. Run the Dremel at full speed and feed gently.
 
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