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Joseph Hebert
05/02/12 11:47
Read: 1048 times
Okemah, Ok
United States


 
#187286 - solder mask and legend
Responding to: Mahmood Elnasser's previous message
Hi Mahmood,

Both solder mask and legend are photoimagible 2-part epoxies from LPKF. There are others out there. I've heard of a solder mask that can be machined, but I've never actually seen it. Pretty much everything I've seen, whether film or liquid, is photoimagible. You'll pretty much need to set up a UV source and you'll need to do the chemical developer. I like LPKF's because the only disposal issue I have is the developer, and it comes with a neutralizing conditioner that makes it compliant for sewer disposal.

I can and will tell you this. If you are going to do fine pitch SMT, a solder mask is necessary in the most practical sense. It's not just about making the board look good. With the larger formats, the ones where you can use a pneumatic dispenser to apply solder paste to the pads (e.g. 0805, or even the 0.050" pitch soic parts if your hand is steady enough), solder mask looks good but isn't really necessary. On the other hand, once you get down to the 0.025" pitch parts, solder mask starts to become important for it's functionality, keeping the solder in its place during reflow. And you simply aren't going to put down a CP2102 without solder mask.

Legends, I must admit, are handy but not abosolutely necessary. It's nice to be able to just look at the board and know which header pin is 5V, which is GND and which is data, but I could just refer to a printout if I had to. In truth, I only include the legend because I'm already set up to do the process (for solder mask), it doesn't really add much to the cost of the board, and it looks better when I'm finished.

Good luck,

Joe

List of 74 messages in thread
TopicAuthorDate
CNC      Mahmood Elnasser      04/14/12 10:43      
   Enjoy :)      Oliver Sedlacek      04/16/12 04:14      
      Having fun      Mahmood Elnasser      04/17/12 13:53      
   Congratulations      Joseph Hebert      04/16/12 09:42      
      We looked at buying one of those      Jez Smith      04/16/12 14:09      
         Me Either!      Joseph Hebert      04/16/12 14:17      
            We use a variety      Jez Smith      04/17/12 00:50      
               do not be lazy,Mr.Smith      Stefan KAnev      04/17/12 11:28      
               prototype cost and turnaround      Joseph Hebert      04/17/12 13:31      
                  I'll find the ads      Erik Malund      04/17/12 14:14      
                     googled      Erik Malund      04/17/12 14:22      
                        Ebay deal      Steve M. Taylor      04/17/12 15:08      
                           What about this one then...        Robert Revens      04/25/12 12:59      
                              Follow up on prototype board shops      Joseph Hebert      06/22/12 08:41      
                                 international pcb houses      Mahmood Elnasser      06/22/12 14:13      
                                    PCB Houses      Joseph Hebert      06/22/12 16:55      
            working out of town      Erik Malund      04/17/12 07:20      
      CNC bits      Mahmood Elnasser      04/25/12 06:37      
         answering      Joseph Hebert      04/25/12 11:38      
            it happens      Mahmood Elnasser      04/25/12 14:51      
               what other tools required?      Mahmood Elnasser      04/25/12 15:00      
                  a new trick zeroing Z axis      Mahmood Elnasser      04/26/12 12:26      
                     Z ref      Steve M. Taylor      04/26/12 13:10      
                        Collet type      Mahmood Elnasser      06/22/12 14:27      
                        Z axis reference      Mahmood Elnasser      07/02/12 01:40      
                           Vacuum      Per Westermark      07/02/12 02:35      
               this sort of thing happens often, from my experience      Richard Erlacher      05/01/12 07:38      
                  ctrl+A, crtl+C, submit      David Brown      09/19/12 01:34      
         tools      Joseph Hebert      04/26/12 14:11      
            holding the PCB      Mahmood Elnasser      04/27/12 00:27      
               Holding the PCB      Joseph Hebert      04/27/12 14:06      
                  Carbon steel?      Per Westermark      04/27/12 20:16      
                     Not tungsten carbide      Joseph Hebert      04/28/12 16:37      
                        Just carbide is a bit lazy slang for tungsten carbide      Per Westermark      04/28/12 21:41      
                           If you say so.      Joseph Hebert      04/28/12 22:30      
                  Plate through holes      Mahmood Elnasser      04/28/12 11:05      
                     plating holes      Joseph Hebert      04/28/12 16:46      
                     plated through holes cont.      Joseph Hebert      04/28/12 22:37      
                  2 point registration system      Mahmood Elnasser      04/30/12 14:27      
                     Need not be exactly in middle.      Per Westermark      04/30/12 16:05      
                        is it that simple?      Mahmood Elnasser      05/01/12 00:27      
                     2-pin registration      Joseph Hebert      04/30/12 23:40      
                     Fine pitch milling      Joseph Hebert      05/01/12 23:54      
                        Solder Mask      Mahmood Elnasser      05/02/12 10:28      
                           solder mask and legend      Joseph Hebert      05/02/12 11:47      
                              too much work      Mahmood Elnasser      05/02/12 15:54      
                                 Much work      Joseph Hebert      05/06/12 15:50      
                                    My CNC      Steve M. Taylor      05/07/12 06:57      
                                       Is That...      Michael Karas      05/07/12 10:30      
                                       which cad did you use?      Mahmood Elnasser      05/07/12 15:58      
                                          Limit Switches      Michael Karas      05/08/12 00:22      
                                             Will do      Mahmood Elnasser      05/08/12 10:55      
                                                Little Plates      Michael Karas      05/08/12 16:40      
                                             MEchanical limit switches      Steve M. Taylor      05/11/12 12:50      
                                       Your project      Joseph Hebert      05/10/12 06:18      
                                          This:      Steve M. Taylor      05/11/12 12:38      
                                             very cool!      Joseph Hebert      05/11/12 13:29      
                                             Funnel      Michael Karas      05/12/12 12:37      
                                                Funnel !      Steve M. Taylor      05/13/12 13:04      
                                                   Lawyer or Solicitor - Not ! !      Michael Karas      05/13/12 15:43      
                                                      RIght      Steve M. Taylor      05/14/12 12:16      
                                    vacuum pick and place tool      David Brown      09/19/12 01:29      
            90 degrees bits      Mahmood Elnasser      09/14/12 04:22      
               Z-axis depth control      Joseph Hebert      09/15/12 22:53      
                  stepper       Mahmood Elnasser      09/16/12 06:34      
                     z-axis control      Joseph Hebert      09/16/12 15:37      
   oiling      Mahmood Elnasser      09/29/12 14:49      
      lubrication      Joseph Hebert      10/01/12 10:41      
      Lube      Steve M. Taylor      10/05/12 14:47      
         ballscrews      Mahmood Elnasser      10/06/12 00:21      
            Ballscrews      Steve M. Taylor      10/06/12 14:00      
               Sometimes it's useful for controlling dynamics      Richard Erlacher      10/06/12 14:08      
            ballscrews & table slides      Joseph Hebert      10/06/12 15:15      
   LINUXCNC      Mahmood Elnasser      10/19/12 02:08      

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