Following from the previous pick and place part 1 post we have completed the initial build on our semi automatic pick and place machine.
The air / vacuum supply nozzle was made on the lathe using a section of 10mm steel and has a 4mm hole approx 3/4 the length in the middle and a smaller 2mm hole at the end where the needles fit. The vacuum is supplied via a side hole in the shaft and uses O rings to seal against the body.
The top place was machined from 10mm sheet aluminium and the stepper motor was fitted using M2 bolts
The stepper control circuit, valve control relay and selection switches are driven by a PIC processor and a Pololu A4988 Stepper Motor Driver Carrier + Voltage Reg from www.technobotsonline.com
The two switches on the left turn the stepper motor by 90 degrees either left or right and the third button releases the component by switching the valves to shut off the vacuum and allow air in via the second valve.
The control boards fitted in the box and cables fitted.
The cables and vacuum pipe were run along length of E-Chain ® from www.igus.co.uk which cost only £59 including postage.
A pair of 12V vacuum valves were sourced from eBay for £6 each and these switch between the vacuum pump and optional compressed air or open air to release the component.
The basic Chinese vacuum pen kit I got from eBay for £22 was supplied with a single needle size and had a optional rubber end for picking larger components. We machined a small needle holder from a section of 4mm flat aluminium with a 1.6mm channel and then milled slots for the needles.
The needles are easily changed when in use by gently pushing down on the needle required and then sliding out of the holder.
The completed machine ready to use once our new reflow oven arrives.
Total cost so far to build is approx £444
|All Alumimum materials
|Air control Valves
|Rails and Bearings
|Other bearing races
|Stepper motor and controller parts
|Misc nuts and bolts
|Perspex for base
|Air hose and fittings
At the moment we are going to be using the manual component feeder mounted on the left of the machine but are looking into different options to make automatic feeders.
The image below shows how the pick and place needle assembly is connected to the vacuum pump and can rotate without loss of suction: