Electronics > Manufacturing & Assembly
Are these the right UV tubes for pcb dry film photoresist exposure ?
BravoV:
Bought these at local brick & mortar approx. $ 1.5/pcs, are these suitable for the job ?
Also I made a thread asking how to power these -> Here
Balaur:
Those look like "BLB" (i.e. blacklight/night clubs) with wavelength peaks at 350-370nm.
Most pre-coated PCBs have a good response for a 350-450nm spectrum. While "white" UV tubes or LEDs are recommended, your tubes may work.
You will have to do some trial runs of course, not only to account for the tube characteristics but also to cover the specifics of your box/toner/film, etc:
- build your UV exposure box
- print a testing pattern consisting in several traces of variable length
- cut several pieces of PCB
- expose them individually while protected by the test foil for a few reasonable intervals of time
- do finer tests around the best performing combination
While you are certainly perfectly aware of all this, and with the risk of appearing pedantic, I would really like say that it's important to have a repeatable procedure to minimize later disappointing and loss of materials.
The procedure is a combination of:
- quality pre-coated PCB material. I had significant issues with that and it's better to find something that works good and stay with that
- uniformity of UV exposure
- good media
- correct UV exposure duration
- quality developer (i.e. not sodium hydroxide) and developing time
Mike's site it's a very good reading.
Best regards,
Dan
carloscuev:
If you're into dry-film, basically we only can get thru ebay 2 types of dry film:
Dupont Riston Series Dry-Film: (http://www2.dupont.com/Imaging_Materials/en_US/assets/downloads/datasheets/mm500series.pdf)
eBay: http://www.ebay.com/itm/171012338332
Hitachi Chemical Dry-Film: (http://www.hitachi-chem.co.jp/english/products/pm/)
eBay: http://www.ebay.com/itm/390414280019
And AFAIK they both work best with 365nm which is arguably the center of the UVA range.
I was going to make a black light tube box, but then I stumbled upon this 11Watt 365nm LED from LEDENGIN: http://www.ledengin.com/files/products/LZ4/LZ4-00U600.pdf its $99.88 USD in Mouser-USA, however it costed me $127.24 USD from Mouser-Mexico (I also recommend buying this Ohmite brand heatsink: SA-LED-176E and this LEDENGIN brand lens: LLNF-1T06-H) and it works very good, the light output is parallel so you have sharper exposure, practically that means it's easier to achieve thin traces :)
BravoV:
Dan, thanks for the long & detail reply, really appreciate it. :-+
Missed that Mike's site, apparently these BLB are not the best, have to admit I didn't do much reading & research 1st before buying those tubes, it was a spontaneous buy cause they're so dirt cheap. All my pcbs were made using laser toner transfer method, this UV photoresist is new to me and planning to use the film instead of pre-coated pcb.
I will definitely do trial runs at small pieces 1st, and I guess a it over exposed wont hurt to if the tubes is emitting the right wavelength.
Now, next step is finding the suitable exposure box as Mike suggests or make one. :P
@carloscuev,
Thanks for pointing out the uv led, unfortunately I'm just a hobbyist and that led you suggested is not justifiable, I will try these tubes 1st and see how they perform.
Btw, looking at different types of these photoresist films, the one I have is blue color, I guess its made by Hitachi, while the Dupont's is green.
Any experience that you could share on both ? Which one is better ?
poorchava:
Look at auction sites for manicure uv lamps. They usually contain either one or four 9W tubes. Those emit mostly in 360-385nm range, which seems to be perfect for this application (and they are cheap as hell - I bought from mine from auction used for something like $5.5 :) )
Navigation
[0] Message Index
[#] Next page
Go to full version