Homebrew PCBs

Hi Derek,

Thanks for the very informative message below.

I am finishing the CNC retrofit of my China made ZAY7032 Milling Machine and can try the method you did for the Solder Paste dispensing.

I will get in touch with you then if and when I need additional info.

Again, my thanks.

Weedy

  ----- Original Message ----- 
  From: Derek Barger 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Thursday, September 21, 2006 1:41 AM
  Subject: Re: [Homebrew_PCBs] SolderPaste dispenser and Pick and Place.


  Hi Weedy,
  It has been awhile since we have done this so if I get some details
  wrong I will correct them latter. The solder paste is easier than than
  the pick and place. We got some supplies from a manufacturer. The
  needles and the O ring syringe cap with black hose.
  CNCed the bracket to hold the solder paste syringe.

  The controls are relatively simple a microprocessor or lots of timers
  are need to control the solder paste and Pick a place. We used a
  portable air tank the type that you air up tires with that full you
  can run quite a few boards before refilling. Less noise in the
  basement. The air goes through a pressure regulator that is set to the
  recommend pressure for the solder paste being used. I believe we set
  this to about 10psi for this particular type. Next is a air solenoid
  that is controlled by the microprocessor. At the right time the Mach2
  sends a signal from the DenverCNC controller to the microprocessor to
  fire the solenoid. The micro controls the timing in how long the air
  solenoid is on. You can hear the second air solenoid release the
  pressure after the first is closed. Mach2 will wait until the solder
  has been dispensed then move to the next g-coded pad. If the pad is
  very large it will double or triple shoot the pad for the proper
  amount of solder.

  By the way Steve was able to make a program that did most of the work
  locating the pad location from the Eagle file. There was some hand
  editing that still had to be done. Eagle doesn't do a very good job in
  the order it makes the pads. That is why it does a lot of rapids to
  other pads. If we had spent more time we could have optimized the
  code.

  The pick and place is more challenging. A vacuum and pressure is
  needed this required quite a few solenoids, vacuum pump and the
  portable air tank plus a 4th axis to position the surface mount parts.
  We made a tube and stepper bracket. The tube mounts to the stepper
  directly at the bottom the air/vacuum line is mounted the needle goes
  on the end.
  The stepper is used to orient the part to the board. It also functions
  in the centering of the part. The vacuum of course is used to is used
  to pick up the part then the air pressure from the tank is regulated
  to a few psi. This is pulsed at a milli second to get rid of the
  vacuum and push the part off of the needle. Miss alignment was not as
  big a problem as it was thought it would be. You do have to be careful
  moving the board to the hotplate some of the chip got bumped out of
  place. The solder paste will pull them back in to position if they are
  not out by very much. You can see the solder turn from a dull gray to
  a shiny silver when it melts.

  A lot of the parts where made from surplus. The vacuum pump was
  something we had laying around. Very noisy. Solenoids were surplus.
  Brackets and adapter were machined by us. Micro was an Atmel for some
  of the project. Mach2 was used to run the g-code. A macro in Mach 2
  was made to signal the Atmel. Overall it was a very sucessfull
  project. It is still used today for other prototype boards.

  You can contact me anytime by email.

  Thanks,
  Derek

  On 9/20/06, WT <pharmapack@...> wrote:
  > Hi, Derek.
  >
  > Nice solder paste and pick & place machine. Very interesting.
  >
  > Can I ask you to provide additional info and pictures of the solder paste machine? In particular, how the solder paste mechanism works. Also, details on what was used for the solder paste dispensing (needle, pump, motor, driver, software and timing control, etc.)?
  >
  > I intend to use it to make a DIY paste (glue actually) dispensing in a folding and gluing machine for making boxes. Can I communicate with you in private for additional info?
  >
  > Thanks in advance.
  >
  > Weedy
  >
  >
  > ----- Original Message -----
  > From: Derek Barger
  > To: Homebrew_PCBs@yahoogroups.com
  > Sent: Wednesday, September 20, 2006 9:13 AM
  > Subject: [Homebrew_PCBs] SolderPaste dispenser and Pick and Place.
  >
  >
  > I thought some might be interested to see a couple of video of a
  > homemade solder paste machine and Pick and place.
  > These were done on a Taig with DenverCNC controller using Mach2 and my
  > modular work holding system.
  > Steve and I did this along time ago but just recently got the video up
  > on Steve's site.
  >
  > http://www.ciciora.com/surface_mount.html
  > http://www.ciciora.com/picknplace.html
  >
  > There is also a hotplate video melting the surface mount after the
  > pick and place was done.
  >
  > Derek B.
  > www.hightechsystemsllc.com
  >
  >
  >
  >
  > [Non-text portions of this message have been removed]
  >
  >
  >
  >


   

[Non-text portions of this message have been removed]