Hi All,
Spray painting your own pcb material is much cheaper than pre-coated
photo resist board. The pre-coated also has a lifetime.
My US$0.02 worth or with the dropping NZ currency NZ$0.03
Cheers,
will,
ZL1TAO
On 10/12/14 06:57, Camillus
camillus_blockx@... [Homebrew_PCBs]
wrote:
>
>
> why using the paint, this should also work with the presensitised clad
> boards. If you use a UV laser in the right wavelengt of the photoresist.
> I have being pondeingr over this myself, but never though to have a
> suitable beam that can be controlled in width from let say 0.1 to 0.5
> mm. I was even thinking of making my boards myself, by submerging the
> board completely in UV cureable photoresist, and then centrifuge it with
> high speed, so that the centrifugal force would make the layer of resist
> so equal as possibe. A brushless motor from old drive would be good for
> this, just have to make a reliable holder to keep the board from flying
> away...LOL.
>
> If you have more information about laser control, specialy the focus
> part, then please would you care to send it to me or post it here?
>
> thanks.
>
> Camillus
>>
>> On 12/9/2014 7:25:07 AM, Howard Chester howard.chester@...
>> [Homebrew_PCBs] <homebrew_pcbs@yahoogroups.com> wrote:
>>
>>
>>
>> Jeff posted,
>> >I’m mentally exploring the idea of spray painting copper clad with
>> spray paint and drawing traces in the paint >with a laser. After the
>> laser, the board is then placed in etchant and the copper exposed by
>> the laser is >etched away. I understand this is possible with 20W
>> CO2 lasers by Youtube videos but has anyone >explored this with a
>> laser diode? Is the abundant ebay 445nm, 1W laser or the 808nm, 3W
>> laser up for >the task paint ablation?
>>
>> >Jeff
>>
>> Hello Jeff,
>> Just a few words of my musings...
>> Why not try to replace the high power LASER with a 400nm Ultra Violet
>> Soild State Laser Diode combined with a CD/DVD optic sled unit to
>> expose a UV resist PCB?
>>
>> A few advantages;-
>> 1) Lower power equals safer working enviroment
>> 2) Ease of use, the CD/DVD has a constant correcting focus control
>> loop. This would probably allow tracks in the sub mm range(0.2mm?). As
>> the visable red dot shining through the prism bounces back from the
>> PCB, mixing the nearly invisible UV beam on the opposite side of the
>> prism assembly by delivering the beam via a short lenght of cladded
>> fiber through the unpopulated side of the prism.
>> 3) A secondry advantage of the visible red dot is easy and accurate
>> registration when doing double sided PCB's.
>> 4) By tapping into the beam control(constant amplitude loop that
>> monitors the reflected beam power to compensate for impurities on
>> CD/DVD's (analog available at the red laser diode Anode-Cathode as a
>> varying Current through the red Diode)) would allow for a "Resist
>> thickness vs stepping motor delay" as well as slaving the UV LASER
>> drive current.
>> 5) Modern Micro-stepping Motor drive IC's would maximise the
>> resolution of the optics, unless you use the optics of the "sled"
>> control. In which case the resolution could be in the micro/nano meter
>> range.
>> 6) Cost, a UV LASER Diode module costs about 45 Bucks vs BIG bucks for
>> a large LASER, Drive Electronics and the delivery optics.
>>
>> / have pondered this concept for a while now but declining health has
>> force my early retirement/ and as such, my access to the nessessary
>> engineering tools.
>>
>> As stated, just my musings...
>> Good-luck with you project, chester
>>
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