Convert a delta 3d printer to specialized pick & place

[Pierre Poulpe]

Good evening folks!

Let's make a quick yet efficient introduction :

I'm working on a project where I need to produce for a first batch 100 boards. More to come if everything goes fine.
53x54mm, 26 SMT parts, smallest is a SOT23-5, all passives are 1206. Biggest part is a ESP8266 module.

I already have a small (20x15x6cm) 3D CNC router (very precise - quite slow (cartesian)), and a delta 3D printer, 180mm diameter, fast and pretty precise (strong build).

To avoid having an additional machine in my workshop, to save a few coins, and -maybe the deep motivation- because it's kind of fun, I'd like to use and convert one of these machines.

My idea is to keep specialized for this board design. It means :
I could dispose my parts already in the good orientation, and avoid adding a C axis?
I could 3D print a support to have the PCB hold in a precise place, and cut tapes also in a precise place...

To begin playing, I got inspiration from this BOM, and I bought a small vaccum pump and two solenoid valves from aliexpress.

For the nozzles, I have the idea to hack syringe and needles, did a quick try with the house vacuum, and it works great.


Question : What about the camera?

What is its exact purpose? compensate wrong position? Is still necessary if I work correctly in positionning PCB and parts and that I don't have very small part?

I saw on the BOM  1MPixels - 6mm lens.
Is 6mm the best choice?
Here I have a large choice from 2.1mm to 16mm.

Many thanks! Pierre

[Michael Anton]

You may want to take a look at this pick and place head for a delta printer project: https://hackaday.io/project/45404-arcus-3d-p1-pnp-for-3d-printers that another person on this forum is working on.

The pockets on the tape that the SMT parts are in, can be pretty large, and as a result the parts can not always be located well enough without a camera.  So, we use cameras to make sure we know what the part alignment is after it is picked up, so that it can be placed more accurately.  I think since you are using fairly large parts that this might not matter in your case, so you may not need to use a camera.

[Marek T.]

Looking on the fact that parts in tape sockets are not kept tight, so even if your parts are relatively large I don't think you'll get good results without after-pick allignment by camera (or by mechanical jaws what is more complicated to build).

But you can try without camera then add it if occurs necessary.

Better take 2Mpx. Price difference is small and 2M will be better for future, you never know what may be needed. Later changing is calubrstion again. 6mm lens is rather much too narrow however it depend on distances camera-part. But probably typical 3.6mm will be more universal if you're not sure.

6mm probably perfect for upper camera for fiducials checking.

Br
Marek

[Marek T.]

1Mpx for fiducials perfect choice.