Quote Originally Posted by Doddy View Post
Okay, I have more questions (and more challenges) with what you say - but I think you know your own mind. An hour soldering under a stereo mic is enough for me and my back - so I appreciate your intent. Despite this, progressing this will be a project no matter what.

If I was looking to do this within the use/cost constraints you say, I'd pick up the most physically robust of the GRBL-based machines and look to adapt the firmware or integrate with the control software a joystick/joypad controller. The mechanical builds are... appropriate for your use-case (and it pains me to say that). You're not going to get fantastic placement speeds - imagine 5 seconds traverse speeds in the working area. but that gives you time to think. I've since read that the thread pitch on at least one of those machines is 5mm, so that's higher resolution (but lower speed) than I mentioned earlier.

It's a project no matter how you look at it. It's do-able, I wish you luck. Personally - mic, a pot of of tweezers, soldering pencil and frequent breaks. But I rarely go north of a 100 components on the occasional board.
Yes this will be quite the project as it is which is why I am being careful about not trying to design anything I can already buy and to avoid features that are too complex for what the intent is and just keep reminding my self that this is to be a relatively simple aid not full automation.

At the moment it's taking over a minute per passive, some of that I can reduce with a hand held sucker tool if it works as a lot of time is spent trying to get parts up the right way having tipped them out of their tight tape pocket. So a 5s movement time is fine really. The few 300x180mm machines that state an accuracy say 80-100µm which is not bad and the controllers seem easy to work with. I spend several seconds as it is entering the part designator into the PCB software to locate where the part goes so in less than that time a machine can just go to the location and in less time than I spend carefully rotating the PCB around and "getting into position" the Z axis can lower and await my confirmation after any minor adjustment. At the moment to deal with rotation I rotate the entire board as I have to go in from the side that the location is closest to and be very careful about not knocking anything else. My last board was 175x90mm so most parts had to go in from two sides rather that all 4.

The PCB design software will output a part position file. I use KiCad so I can add my own fields to parts (and I am sure other programs do it too) as I create them which I am doing a lot of at the moment. So I can put into the bill of materials columns for things like the height of the part in the tape and on the PCB so that the Z axis knows how far to travel and stop at pickup before confirmation and on confirmation. I can put in the pitch of the tape. So if I load the BOM and position file into a program I will have all of the information it needs about the part to pick up and where to get more after the location of the first is known and where on the board to move to.

So yes if I use one of those off the shelf systems I can then concentrate on the picker head and software as the one thing I am not equipped to do is start making CNC beds. I can do a controller that over a serial to USB adapter will talk to a PC so that apart from the 3 axis's that the basic bed comes with I can also issue from the same USB port commands to control the rotation stepper motor, pump, pump solenoid and anything else I need. The only other USB port I will need is for the camera that I will have to look into and should be available off the shelf that sits on the picker mechanism to give me a nice big picture on screen of what my picker is doing. I think that is as simple and functional as I can make it without trying to do the impossible.

For example rather than relocate to an origin on each operation if I have to manually correct I can decide to tell it that it made a permanent positioning error and to use the corrected location as the new true location so all of the position offsets can be recalculated on the fly if it drifts.