Homebrew PCBs

On Tue, 13 Mar 2012 19:49:32 +0100, you wrote:

>Thanks for the info.
>
>I'll start my tests with through hole and a regular iron.
>Did anyone ever try to use a fuser unit from an old laser printer?
>I have an old Laserjet II I can sacrifice for that. It should have the 
>perfect temperature to transfer the toner. If I could get the speed down 
>there should not be any need for multiple passes.

I have one that's sitting there asking to be a project.  It's on the
list, that's all I can say.

I have a thermocouple controller, and I'll be using the original
heating element, providing a constant speed drive to the gearing.
Further than that, no ideas yet, although I think I will be perhaps
using aluminum, or something that is an insulator and easy to replace.

Down the road a bit.

Harvey

>
>Bert
>
>
>On 13/03/2012 15:22, Harvey White wrote:
>>
>> On Mon, 12 Mar 2012 09:48:12 +0100, you wrote:
>>
>> >Hi all,
>> >
>> >After a hiatus of many years I'm getting back into electronics (robotics
>> >in particular). I have made a couple of PCBs using the photo transfer
>> >method.
>> >I am now venturing into SMD components and want to use the toner
>> >transfer method as I have discarded my UV lightbox.
>> >So I'd like to know what methods you guys use to get very thin traces
>> >reliably.
>>
>> clean board, good paper, good laminator.
>>
>> >What are the limits of this method?
>>
>> I find that 10 mil traces are reliable, but somewhat picky to get
>> right. 0.5 mm spacing on a VQFP-100 flatpack is about the limit for
>> me, and the board still needs a bit of hand rework at times.
>>
>> >What are the things to look out for to get reliable thin traces?
>>
>> clean the board well. proper temperature and pressure in the
>> laminator. For large (5x7) boards I run through 8 to 10 times with
>> the laminator I have. You will need to experiment. Green foil helps
>> a lot, but I have had instances where it simply does not adhere at
>> all, ever. Then it may ruin the board. Odd. Best boards have green
>> foil done properly. Photoresist is actually a better process when
>> done with a good negative.
>>
>> You will need a laser printer with 1200 DPI, dense toner, and one that
>> the toner softens at the proper temperature (that of the laminator).
>> 600 DPI does not work for fine traces.
>>
>> Harvey
>>
>> >
>> >Thanks.
>> >
>> >Bert
>>
>> 
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>
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