Top view drawing / Placement of home circle

[mawa]

Hello,

I am almost finished with the assembly and have already mounted the machine to my table.

Now I am looking for a drawing with the dimensions where to place the uplooking camera hole, the home circle/dot and the PCB lower left corner.

Have I overseen something, because I can't find such a drawing nor a table with the - I suppose - relative coordinates from the lower left home position?

[mrandt]

I believe there is no such drawing - where you place the camera and PCB is up to you The actual locations can later be configured in software.

The homing mark needs to be near the camera location after homing X and Y mechanically (using the mechanical limit switches). It should be at positive coordinates, i.e. a bit top and right of the camera center after homing. I would wait until the machine is ready to move and place it afterwards using the down camera for reference.

For camera and PCB locations, it really depends. I put the camera about 10 cm from the front and as far to the left as possible while still being able to position the needle anywhere in the camera's field of view.

My PCB zero is currently next to the camera but I might move that around as needed.

Some considerations - list may not be complete:
- I want to be able to place component strips or trays around the PCB (i.e. on two or three sides in my case) so travel distance between component tape and PCB is minimized
- I want to be able to place larger PCB panels and still have enough room for components around it
- You want to reserve a small area for picking up individual / loose components
- I wanted the uplooking camera to be close to the PCB, assuming I will use it to align components, which means total travel will be from pickup to camera to PCB
- I left some space at the front-end of the table, maybe I want to put feeders there at some point in the future
- After homing, machine will always start around 0,0, so I wanted to reduce initial travel to camera

Hope this helps.

[mawa]

Thank you Malte,

I see there is quite a lot of design freedom in Juha's approach.

Therefore the up camera location could also be in the center.

Looking at some placer pictures on the web you see many with the up camera in the center close to the feeders and trays which IMHO makes more sense than placing it at the edge, when you intend to inspect a part.

[mrandt]

Yep, there is - and I think that is one of the best things about it

If you assume that you a) take parts primarily from feeders mounted to the front and b) all of these parts will need to be inspected by upwards camera it makes sense to put the cam in the middle of the table near the front edge.

Regarding a) the question is whether feeders are realistic in the near term... If not, one could argue that a location somewhere in the middle but closer to the rear end of the table would make more sense. Maybe 2/3 from the front? This way you could have component strips or custom trays left and right of it.

Regarding b) I assume that only a small subset of parts will require inspection and calibration using the upwards camera: loose parts picked up individually for sure, parts with many pins such as ICs or even BGAs (who knows?) and large parts where offset in center and rotation has a bigger influence.

So given this, I am still happy with my choice to place camera left of PCB - not saying you should put your's there as well