UV Exposure units

[Trevor Rymell]

Dear All

Can anyone recomend a small, good quality UV Exposure unit suitable for small PCBs - maximum size say, 12" x 9" preferably with a built-in timer? I dare say I could make one but prefer to buy off the shelf.

I'm surfing around and there seem to be a large number of products available. I just wondered if there was a particular make/model or type that I should look for. I know nothing about the specs of these devices such as light output or whatever.

Any advice would be valued.

Trevor

 

[zachtheterrible]

I just use a halogen desk lamp with the UV filter removed. Works great.

As for timer I dunno . . .

 

[Oznog]

Cheap blacklights- the flourescent kind, not the purple light bulbs.

The key is getting the mask mated up closely with the board. If not there are areas of partial shadow on either side of the edge of the features rather than the desired states of completely exposed or completely masked.

 

[Trevor Rymell]

Thanks for the replies. I decided to have a go and make one a UV box after all.

I would have preferred to buy a ready made one for the sake of the professional finish but the cost of units such as the Farnell or Kinsten products seems to be way over-the-top. Low volume I suppose.

Anyroad, I bought 4 x 8 watt "blacklight" tubes and will put a darkroom timer in the front of the box. Should look and work ok.

I take the point about making sure the artwork is in close contact with the copper.

One question I have though is that I read a post saying that the "glass" platten should be Plexiglass (Perspex?) as mineral glass is not UV transparent enough. Can anyone comment on that?

Cheers

Trevor

 

[samcheetah]

have a look at **broken link removed**

im sorry if im late in giving u this link. but even if you have decided your own plan for the exposure box, this link might help

 

[Screech]

Here's mine again.

 

[sgoum]

Ive made an exposure unit using an old scanner as a case
4 UV lights for pc modding
and an old ATX ps

 

[mstechca]

Here's mine again.

wow, that's alot of bulbs. You are lucky they are not touching the ground.
You must be getting high hydro (electricity) bills.

All I use is just a desk lamp with a halogenbulb in it, and have it about a foot away from the board.

I lay the design on top of the photoresist and cover everything with glass. I expose it for 60-90 minutes. Anything less will make the design not appear as well, and if exposure time is too small, the entire design will rub off.

and another thing I do, since I mainly deal with boards less than 3 inches square, is use a quarter cup of water, and about 10 squirts of developer. YES, I said 10 squirts, because the bottle of it is expensive, and each squirt is better than each cup!

It takes about 10-15 minutes for the developing action to work, but it is to my advantage, because it allows me to buy the developer much later than I need to.