Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
04/28/12 22:46
Read: times


 
#187267 - plating holes
Responding to: ???'s previous message
Hi Mahmood,

The short answer is, no. There is no easy way to do plated through holes. But there are ways it can be done.

Obviously you can set up to do electroplating. But if you do you need to know a couple of things. First, you'll need an "activator" to make the holes platable. That's why it's important not to use dull bits that just burn their way through the FR4. You need clean holes for the activator to work. Basically, activator is just carbon particles in liquid. You dip the board in the liguid and squeegee it off the surfaces. As the liquid dries from the holes it leaves behind a layer of carbon which can be plated.

The second thing you'll need to know is a technique called reverse pulse plating. Espeially if you have high aspect ratio holes (l >> d), you need to read up on this.

Of course, you'll also need to know the various chemistries you'll use, plating solutions, etc., but that stuff is easy enough to find.

It happens that, as we speak, I am doing the ground work to start plating my through holes. Since I recently finished building a lamination press and can now produce multi-layer boards, I need to make the change. I've been using a conductive epoxy to "plate" my through holes. It's a paste that you smear over the panel while a vacuum table sucks the paste through the holes. Then you bake the panel at 160°C for a half hour and you've got continuity.

The problem is that the paste is very expensive, and it only works well for 2 to 4 layer boards. You might be able to get a 6-layer done, but I wouldn't take any bets. If you're only going to do 2-layer boards this is a good alternative. If you're going to do multi-layer boards, go ahead and set up to electroplate.

One more thing. Whether you electroplate or use conductive epoxy, you will need to put a stop, a protective membrane, on the surfaces of your board before you drill the holes. I use a clear plastic that I buy from a library supply store. It comes in rolls 18" wide (just wide enough to cover both sides of my 9" x 12" panels) with adhesive on one side. It's intended to put on the covers of books to protect them.

Good luck,

Joe

List of 74 messages in thread
TopicAuthorDate
CNC            01/01/70 00:00      
   Enjoy :)            01/01/70 00:00      
      Having fun            01/01/70 00:00      
   Congratulations            01/01/70 00:00      
      We looked at buying one of those            01/01/70 00:00      
         Me Either!            01/01/70 00:00      
            We use a variety            01/01/70 00:00      
               do not be lazy,Mr.Smith            01/01/70 00:00      
               prototype cost and turnaround            01/01/70 00:00      
                  I'll find the ads            01/01/70 00:00      
                     googled            01/01/70 00:00      
                        Ebay deal            01/01/70 00:00      
                           What about this one then...            01/01/70 00:00      
                              Follow up on prototype board shops            01/01/70 00:00      
                                 international pcb houses            01/01/70 00:00      
                                    PCB Houses            01/01/70 00:00      
            working out of town            01/01/70 00:00      
      CNC bits            01/01/70 00:00      
         answering            01/01/70 00:00      
            it happens            01/01/70 00:00      
               what other tools required?            01/01/70 00:00      
                  a new trick zeroing Z axis            01/01/70 00:00      
                     Z ref            01/01/70 00:00      
                        Collet type            01/01/70 00:00      
                        Z axis reference            01/01/70 00:00      
                           Vacuum            01/01/70 00:00      
               this sort of thing happens often, from my experience            01/01/70 00:00      
                  ctrl+A, crtl+C, submit            01/01/70 00:00      
         tools            01/01/70 00:00      
            holding the PCB            01/01/70 00:00      
               Holding the PCB            01/01/70 00:00      
                  Carbon steel?            01/01/70 00:00      
                     Not tungsten carbide            01/01/70 00:00      
                        Just carbide is a bit lazy slang for tungsten carbide            01/01/70 00:00      
                           If you say so.            01/01/70 00:00      
                  Plate through holes            01/01/70 00:00      
                     plating holes            01/01/70 00:00      
                     plated through holes cont.            01/01/70 00:00      
                  2 point registration system            01/01/70 00:00      
                     Need not be exactly in middle.            01/01/70 00:00      
                        is it that simple?            01/01/70 00:00      
                     2-pin registration            01/01/70 00:00      
                     Fine pitch milling            01/01/70 00:00      
                        Solder Mask            01/01/70 00:00      
                           solder mask and legend            01/01/70 00:00      
                              too much work            01/01/70 00:00      
                                 Much work            01/01/70 00:00      
                                    My CNC            01/01/70 00:00      
                                       Is That...            01/01/70 00:00      
                                       which cad did you use?            01/01/70 00:00      
                                          Limit Switches            01/01/70 00:00      
                                             Will do            01/01/70 00:00      
                                                Little Plates            01/01/70 00:00      
                                             MEchanical limit switches            01/01/70 00:00      
                                       Your project            01/01/70 00:00      
                                          This:            01/01/70 00:00      
                                             very cool!            01/01/70 00:00      
                                             Funnel            01/01/70 00:00      
                                                Funnel !            01/01/70 00:00      
                                                   Lawyer or Solicitor - Not ! !            01/01/70 00:00      
                                                      RIght            01/01/70 00:00      
                                    vacuum pick and place tool            01/01/70 00:00      
            90 degrees bits            01/01/70 00:00      
               Z-axis depth control            01/01/70 00:00      
                  stepper             01/01/70 00:00      
                     z-axis control            01/01/70 00:00      
   oiling            01/01/70 00:00      
      lubrication            01/01/70 00:00      
      Lube            01/01/70 00:00      
         ballscrews            01/01/70 00:00      
            Ballscrews            01/01/70 00:00      
               Sometimes it's useful for controlling dynamics            01/01/70 00:00      
            ballscrews & table slides            01/01/70 00:00      
   LINUXCNC            01/01/70 00:00      

Back to Subject List