pick and place files

hello

for pick and place files can any one explain to me the following:

to witch refer "the component's user-defined reference point", does this value used by the pick and place machine?

for altium designer, and a footprint that i make my self, does the - coordinates for the component's center point- calculated by altium, or is it difined by

the user when making the footprint.


should the footprint refers to a standard pakaging?

thank's

For all the footprints that you define in Altium, you can always set reference. To set reference for a particular footprint that you are editing in pcb footprint editor, you can issue one of the following commands from following menu:

Edit > Set Reference > Pin 1

Edit > Set Reference > Center

Edit > Set Reference > Location

The first command "Pin 1" will make pin 1 of the component as reference point
The 2nd command "Center" will make center of the component as reference point
The 3rd command "Location" will allow you to make any location to be the reference point

It is good practice to draw a cross hair (+ sign) in mechanical 15 layer for reference mark in all your footprints. It facilitates you in knowing where is the reference point for any footprint. Altium own library use this convention.
You can also always change reference for any footprint at any later time, but you must update the footprint from library to pcb by issuing following command:

Right click the part in PCB Library view and select : update pcb with <footprint name>
Please note that this command will change the location of your footprint in your pcb therefore you should understand the consequences (for example updated reference overlaps the component over other components etc)

The pick place file always use reference mark defined for each part in pcb library for the component's 0,0. However assembly houses can edit the reference marks for any component for their machine requirement.

Hope this helps!