CNC solder paster dispenser - how do I approach this.

[JAZZCNC]

The paste goes on the PCB not the ICs!

I was refering to finding the centre of the chip not paste.! With a jig to hold the chips he would know the exact centre coord.

[HankMcSpank]

Thanks for the input.

Jonathan....re Z move triggering ....but I need those Z moves too?

Sequence will be like this...

1. Machine moves to first coord
2. Z lowers
3. Once Z is at +0.2MM abovez0 (or similar), the 'trigger' happens.
4. Z raises

rinse repeat.....so I don't see how I can link the solder paste dispense to a z move, else the paste would be dispensed as the z plane is descending.

Jazzcnc ...not sure I'll be using mach3 (I'm warming to the CNC software called USB CNC...and will likely jump over to that .that software allows scripts though, I've coded pics in PICBASIC, so it should be within my ability to lash something up). Not sure I'm understanding you point about the smd components and the reel...I'm not doing pick & place, I just want to get a dab of paste at the centre of each smd pad.

[JAZZCNC]

rinse repeat.....so I don't see how I can link the solder paste dispense to a z move, else the paste would be dispensed as the z plane is descending.

This is easy with a brain just tell it to watch Z Axis DRO and while ever equal to 0.2 then turn on dispenser.! . . could easily be done with a VBscript as well using something like a While-wend loop.

Not sure I'm understanding you point about the smd components and the reel...I'm not doing pick & place, I just want to get a dab of paste at the centre of each smd pad.

Ok didn't realise that.! . . . If theres something to probe against then It's very easy to find the centre of a square or circle.

[HankMcSpank]

Ok didn't realise that.! . . . If theres something to probe against then It's very easy to find the centre of a square or circle.

There's no need to auto probe to get the cnc machine to find the SMD pad centre , my pcb software can either give me those coordinates or I can export the smd pad as a gerber file & import into a cad program & get the cad software to mark the centres of each SMD pad. (which I can then use cam software to use this coords with)

Ok so using this brain melarkey....my z plane lowers & once at say 0.2mm, a trigger happens....but what is the output here? Mach 3 has control of the printer port, presumably once the 0.2mm threshold is breached a nominated pin will change state?

[JAZZCNC]

Ok so using this brain melarkey....my z plane lowers & once at say 0.2mm, a trigger happens....but what is the output here? Mach 3 has control of the printer port, presumably once the 0.2mm threshold is breached a nominated pin will change state?

Yes the brain or script watch's the designated Axis DRO and while ever it's at the commanded position it will trigger the pin state of which ever pin you choose, So say output pin 11 will turn ON and activate the dispenser or relay that controls it. Then when axis starts to move the pin state changes back OFF untill it reaches the commanded height again so on and so forth.

The script or brain can be as simple or complex as you want and really for safety sake you would want it to do some simple error checking IE: only change the pin state if the X & Y axis are not moving etc but in it's simplist form it's a very simple thing to do. Go to the artsoft site and watch the vids on scripts and brains it will give you a quick run down and idea just how simple.

[HankMcSpank]

Ok, thanks I'll go have a read.

The video I was referring to earlier was this one...

http://www.youtube.com/watch?v=HdqVt..._order&list=UL

[JAZZCNC]

The brain approch would work perfect for this because you won't need to do anything inside the G-code, It will just monitor the Z axis and activate/deactivate the pin at the correct height.

While watching I could hear an air solenoid firing then read that he use's a pnuematic dispenser connected to a 555 timer and 3 way valve to control over dispense. The Brain and Mach could be made to act as the timer but how would you control over dispense.?