What info is needed to designate location for PCB assembly process?

[OgreVorbis]

So there are some other questions similar to this, but none of them talk about how to designate the placement of components for the manufacturer.

I use a pretty uncommon piece of software for designing my PCBs (sprint layout), so I can't just send the project file because they won't be able to open it.

I have done PCB manufacture before without assembly. All I have to do is send the company the gerber and drill files.

Now to do a pick and place, I also have to provide a BOM; this I understand.

What I don't understand is how they program the machine to place the components at the right location. Do I need another file for this? Is it good enough to just have the component numbers on the silkscreen layer and have them figure it out themselves, or is there some type of other file I have to include to tell them the exact location to place the components?

[Rerouter]

what they need is either:

A. Reference designators and a pin 1 marker on the relevent chips, markings for diode orientation, polarity markers for caps, etc on the silk scren

B. A fabrication layer with all that information

In both cases, you will have supplied a BOM which will generally make clear what the chip markings are, but in doubt, put it on a fabrication layer.

[DerekG]

so I can't just send the project file because they won't be able to open it.

Are you saying that your CAD software cannot export a Bill of Materials (BOM) in either comma separated or Excel format?

Are you saying that you CAD software cannot export a pick & place file that specifies the exact location of the components on the PCB?

[RomDump]

What I don't understand is how they program the machine to place the components at the right location. Do I need another file for this? Is it good enough to just have the component numbers on the silkscreen layer and have them figure it out themselves, or is there some type of other file I have to include to tell them the exact location to place the components?

A Centroid data file is used for the Pick and Place machine. See if your CAD package can generate it. If not you may be able to create one from the Gerber file.

[ThomasDK]

According to the sprint website it can:

Each component can manage some additional data, so called “Pick+Place” data. With these additional data, Sprint-Layout can export Pick+Place files, which are necessary for the automated placement of SMD components on a board.

[xaxaxa]

Yes, most (all) PCBA houses require a centroid file; it is a de-facto standard format and you can find specifications for it if you look it up. It's simply a text file that lists the x,y coordinates and rotation values for every component.

The caveat is that some EDA packages don't generate centroid files properly even if it is claimed to be supported (gEDA is one of them, and I had to write my own software to parse the PCB file and output a centroid file). Be sure to manually check a few components of various rotations and compare the value in the generated file against the spec, especially for components on the bottom side of the board (gEDA fails here).