Homebrew PCBs

None of the standard Inkjet inks that I tried would even stand up to water much less etchant.

Epson 1520, Epson C80, HP 1000C, Lexmark Waterproof, Generic HP refill, Generic Epson refill.

None of these would withstand ferric chloride or ammonium persulfate etchant. 

A shocking thing I found out is that Sharpie ink which I've used for years to touch up boards when etched
with ferric chloride just floated away in my ammonium persulfate etchant.

later,
Larry E.

  ----- Original Message ----- 
  From: crankorgan 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Saturday, September 14, 2002 3:32 PM
  Subject: [Homebrew_PCBs] Re: Inkjet printing PC boards


  Larry and others,
        If you print onto a sheet of plastic with an inkjet and
  put it into the acid for us. I am out of acid right now. Let us
  know if the inkjet ink holds up! If it does then the idea is 
  valid. I remember a guy from Texas asking me about printing directly
  onto copper. I am overwhelmed with projects right now and it has been
  too hot this summer. I burned out trying to finish the Morph!

                                                Cranky




  --- In Homebrew_PCBs@y..., "Larry Edington" <ledington@a...> wrote:
  > The problem with scratch and etch is the same as milling. Users 
  must have a toolpath calculation program to 
  > generate the outline toolpaths. In practical terms, that's 
  expensive for robust software that can do small trace
  > pitches. 
  > 
  > Outline paths also have the problem of "islands" of varying sizes 
  which can cause a lot of problems
  > for high speed boards. I don't think you could practically route a 
  differential trace pair with isolations. There would
  > be an enormous amount of rubouts required to clear all the copper 
  between the traces but keep the traces at the 
  > proper spacing and width for the correct impedence. One tiny hair 
  of copper running along between your traces
  > can really mess up the signalling. I wouldn't even try an LVDS bus 
  with isolation.
  > 
  > Sure, Eagle can do outline paths but not everybody uses Eagle. T-
  Tech's Isolator Pro does excellent toolpaths
  > but is expensive!. KellyCam generates pretty good toolpaths but 
  sucks as a CNC controller. I always used Isolator
  > Pro for toolpaths when I did mechanical etching.
  > 
  > I played around with "scratch and etch" too for a while. I also 
  plotted directly to copper using modified drafting pens
  > filled with acrylic floor polish. The smallest pen I have found 
  locally is a .18 mm tip technical pen. That produces a trace
  > of .0070866 wide. So it's a 7 mil trace. I successfully plotted and 
  etched some 48 pin TSOP to 48 pin DIP adapter
  > boards so I could read some flash roms on my programmer. But it was 
  SLOW!  Also filled areas like pads
  > had concentric circles in them where the carbide pen tip scratched 
  into the just layed down path of resist.
  > 
  > However, using Inkjets produces solid fills with no voids. No 
  special software is needed either. All you need is 
  > something that can print your gerber files to a standard printer.
  > 
  > Modern inkjet printers are fast and are accurate enough to do some 
  very small trace widths and spacings.
  > 
  > You could also lay down solder mask and the component identifiers 
  using the same modified printer.
  > 
  > While I agree that the scratch and etch idea is great, and has some 
  benefits over direct resist application, the biggest 
  > downside I see is the problem of the toolpath generation for the 
  average user.  Also, the tool must be tightly controlled
  > to produce the necessary isolation path widths. For me the perfect 
  width would be a 5 mil tool. But will a tool that is 
  > .005 wide cut a clean swipe through the bluing without splintered 
  edges?  If your tool has a very sharp tip, then you'll 
  > need multiple passes to get a 5 to 10 mill isolation path. I never 
  got a clean enough path through the resist. "furry" 
  > or jagged edges on traces also cause lots of noise problems on high 
  speed circuits.
  > 
  > The market for these products are not just hobbiests. There are a 
  lot of us guys out there that make their living in the 
  > electronics industry that would LOVE to have something to quickly 
  make a board without having to send it out!
  > Lots of corporations would buy them for the EE labs!
  > 
  > I just wish someone would run with it and work out all the bugs so 
  I could just buy one. I want to make boards not
  > tools to make boards.
  > 
  > later,
  > Larry E.
  > 
  > 
  > 
  >   ----- Original Message ----- 
  >   From: crankorgan 
  >   To: Homebrew_PCBs@y... 
  >   Sent: Saturday, September 14, 2002 6:41 AM
  >   Subject: [Homebrew_PCBs] Re: Inkjet printing PC boards
  > 
  > 
  >   Larry,
  >         I sell plans for a PCBmill (Brute) and I just finished a 
  >   machine that will mill or draw simple boards. (Morph)
  >         Months ago I brought up the idea of Scratch and Etch. This
  >   idea is not dead. First I developed a super simple CNC plotter. 
  Now
  >   I have a machine strong enough to drag a scribe through the 
  blueing.
  >   Several people tried Scratch and Etch With good results. Coating 
  the 
  >   whole board and then scribing and isolation between pads for 
  etching 
  >   seems easier.
  > 
  >                                              Crankorgan John 
  > 
  > 
  >   --- In Homebrew_PCBs@y..., "Larry Edington" <ledington@a...> 
  wrote:
  >   > This is a copy of a reply I just posted in 
  sci.electronics.design. 
  >   I thought I would
  >   > post it here as well for you folks to pursue if you are 
  interested 
  >   in it. Maybe
  >   > Crankorgan John could go work up some plans for it. It's 
  promising 
  >   technology
  >   > but I like working with boards more than belts and gears.
  >   > 
  >   > 
  >   > > >Has anyone every tried putting Etch resist  Ink in a 
  BubbleJet 
  >   or InkJet
  >   > > >printer and printing a PCB design directy onto the copper 
  side 
  >   of a PCB.
  >   > 
  >   > As a matter of fact I have. I thought about turning this into a 
  >   commercial product, but
  >   > I just don't have the time. Too many other projects to do. I 
  even 
  >   went so far as to 
  >   > turn an inkjet into a flatbed plotter. The problem there is 
  >   converting the stepper motor driven
  >   > motion of the platten roller into linear motion with the 
  stepper 
  >   using belts or gears or
  >   > electronic gear ratio reduction for the steps. All three 
  methods 
  >   work but I like the 
  >   > belt and gears method best.
  >   > 
  >   > I tried modifying printers to feed a board through as is, but 
  that 
  >   was just too much trouble.
  >   > Some would feed thin stock just fine but others wouldn't. The 
  flat 
  >   bed approach solves that.
  >   > Plus the flat bed approach with some simple guide pins lets you 
  do 
  >   double sided boards with
  >   > accurate side to side registration.
  >   > 
  >   > For ink, I found two things that work well standing up to the 
  >   etchant.
  >   > 
  >   > Acrylic Floor Polish.  
  >   > Shellac 
  >   > 
  >   > Floor polish ( sometimes called wax ) ( I used the Future 
  brand ) 
  >   works well and won't gum
  >   > up the printheads as easily as Shellac does.
  >   > 
  >   > Floor polish is removed with Ammonia.
  >   > 
  >   > Shellac with Denatured Alcohol. 
  >   > 
  >   > I used three different types of printers. A Lexmark where the 
  head 
  >   is built into the cartridge,
  >   > an HP where the printhead is separate from the cartridge but 
  still 
  >   uses thermal "bubble" jet
  >   > technology and an Epson which uses piezoelectric technology.
  >   > 
  >   > The winner was the Lexmark. Easy cartridge to refill and cheap 
  >   enough to replace.
  >   > 
  >   > The problem in all this is that to use straight "ink" that is 
  very 
  >   water ( and then etchant ) proof
  >   > is, it will dry on your printhead orifices. The solution to 
  that is 
  >   a valve. One path to ink, one path
  >   > to a flushing fluid. Before you print the board, run a cycle 
  >   of "ink" to clear out all your flush fluid.
  >   > Once you have finished printing, run a cycle of flushing fluid 
  to 
  >   purge all your "ink".
  >   > 
  >   > Ammonia diluted with water works great on the acrylic polish 
  ink. 
  >   You can even put a little regular
  >   > inkjet ink into it to color it so it's easier to see on the PC 
  >   board blank.
  >   > 
  >   > Once you get the "ink" on the board and have etched it, you can 
  >   clean it off with just a quick spray of
  >   > Windex or other ammonia based cleaner.
  >   > 
  >   > I have no idea as to the benefits or problems with acrylics as 
  >   conformal coatings but I plan to try it 
  >   > some day on a finished board. Just dip it in Future polish and 
  see 
  >   what happens!
  >   > 
  >   > Another thought I had was a PVA ( poly vinyl alcohol ) based 
  ink 
  >   but the PVA I had on hand didn't
  >   > thin out well to run in an inkjet. The acrylic ink worked well 
  >   enough so I didn't really pursue PVA much.
  >   > 
  >   > Now go have fun......
  >   > 
  >   > later,
  >   > Larry Edington.
  >   > 
  >   > 
  >   > [Non-text portions of this message have been removed]
  > 
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