CNC solder paster dispenser - how do I approach this.

[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.?

[HankMcSpank]

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.?

My pneumatic dispenser can either be set to auto (in which case the length of 'dispense' time is controlled by a pot on the dispenser - triggered by a footswitch - or a relay under g-code control), or manual in which case it is controlled by how long the footswitch is held down. (or again a relay uinder g-code control). In other words the amount of dispense could be set by the dispenser itself or else by how long the g-code paused between on & offs.


Where it gets a little wearying is that for example, a SOT23-3 pad doesn't need anywhere near as much paste as a PLCC2 LED per pad. Therefore it'd need a bit of sorting pads into different 'dispense' runs.

If I had enough grasp of coding geometry then I could have an eagle ulp do this pad sizing decision for me....but I haven't so manual it is for now!