Silk Screen printing for etching boards.

[TheWinterSnow]

I am in the process of slowly "mass producing" constant amounts of circuits and boxes.  After doing some research I figured I could save a lot of money in the long run to (powder coat the enclosures) silk screen print not only my enclosures but bakelite boards as well.  Then I could do my own soldermaks which I need as I have had trouble with short circuits in the past.  I would imagine that it would speed up the time to build multiple units in bulk.

Since I need the table on the silk screen printer that can be adjustable for the enclosures and eventually guitar amp chassis, I am going to make my own printing machine.

What all would you need to start silk screen printing for enclosures and boards?  Right now I have this list minus the machine:

Mesh (going to make my own screens)
Emulsion (Plastisol compatible)
Scoop Coater
Enclosure Ink (Opaque Plastisol)
PCB Ink(s) ()
Squeegee
Developing UV light source

I am also curious as to what mesh should be used for either powder coated enclosures or PCBs, I heard 120 being used and the results turned out good for the PCB, but I am not sure about the enclosure.

Also, where can you go to pickup inks for developing/etching boards that are removed via caustic soda and the soldermask epoxy?  I have been looking all over the internet and cannot seem to find an ink that states that it is made for such purposes.

[Earthscum]

This thread might be a good read for ya: http://www.diystompboxes.com/smfforum/index.php?topic=98385.0

I use the same lacquer as etch resist with FeCl, even using the sponge-wipe method (which I do once the inner parts start to etch completely through using the sit and soak method). The lacquer cleans up real nice with, obviously, lacquer thinner, with no cracking on anything I've used so far. If you want a lighter solvent, you can clean it up with denatured alcohol, then brush to a shine with a 000 steel wool.

Here's a good example where I use the lacquer as a pad mask:

Scruffy's layout of the One Chip Chorus




After soldering, the lacquer pulls back and exposes the copper. I have been eyeballing some of the MG chem coatings. The ones my local shop carry are a bit thin, but with a tighter mesh, shouldn't be a problem. I would just consider not even doing a flood, or you'll probably undercut thin seperations when you lift your screen to place your material.

[TheWinterSnow]

Did I get you right, are saying that you use the same ink for the solder mask as you do for etching the board?  I was just worried about finding an ink that had little to no reaction to FeCl, but came off easily with NaOH, and an ink that could stand up to the heat of solder when used as a solder mask.  I found a video where a guy had ink that was resistant to FeCl but came off with NaOH, but everything was done by a native Spanish speaker with the the detailed site in Spanish.  I could not find what types of inks where used or where to get them, because it made it seem like it would be no different from my current presensitized/developing method, expect I would paint the ink where I wanted to keep copper.  This to me would seem faster to to multiple boards back to back.

Again I looked all over the internet looking for inks, but could only come across "order from china" solder mask epoxy.

So are you using the 7200 Lacquer for ecthing and solder mask?  And if so, where are you buying it, I cannot seem to find where to pick it up at the site you posted, at least on the internet.  The only thing I could gather is that I would have to order it from a distributor, which my nearest distributor doesn't seem to care much in the screen ink department and the don't seem to sell to anyone who isn't an "established business".

[darron]

if you already have the UV light development box then save yourself a lot of headaches and just use photosensitive boards (:


or you can buy photosensitive spray and developer. it comes in positive and negative resist.


you print an image on clear film and then use that like a stencil to block the UV reactive with the chemicals on the board. then you quickly dip it in a developer and it wipes off the stuff you dont want. then you have your acid etch resist.



silk screaning is a bit of a pain... i've always been happier to try new things when i use it.