Default orientation of a component, and representation of board origin in outputs

[zeedel]

Hi,

I am trying to submit my board to Eurocircuits for manufacturing and assembly, but am noticing that my components are misaligned and at times rotated incorrectly.


However, everything looks fine in the EDA software I am using - CircuitStudio.

Questions to help me address the above:
1) How do I determine the 'standard orientation' of a component, so I can orientate my footprints accordingly - i.e. to have my rotations in sync with PCB vendors?
2) How is the origin set in the EDA software (and used by pick and place file) represented in the generated manufacturing files? In other words, how does the pick and place machine know what origin the component coordinates are relative to?

Thanks

[robertferanec]

1) There are some standards - I could not find what standard Eurocircuits is using. More about the standards, have a look at my video here - there is a nice table: https://youtu.be/cMxXea16Hxc?t=6413

2) For SMT it is Center of gravity - usually middle of component (usually when you create footprint in Altium you set Edit -> Set Reference -> Center). If center of gravity is in a different place, it is usually mentioned in datasheet and then you may need to set it manually into that specific location.

Please, let me know what did you find out. It is interesting to know. Thank you.

[zeedel]

Thanks Robert,

Your feedback and link has been immensely helpful. The fact that there are multiple standards explains the discrepancies.

With the second question, what I am not sure is how the origin on the PCB is communicated in the manufacturing files. I use CircuitStudio, and set the board center as the origin, but can't find where this information is placed in the generated outputs. I assume the Pick and Place process would use this information to determine what components coordinates are relative to.

Thanks again!

[robertferanec]

You need to set the center in every single footprint, not in board.

[zeedel]

Thanks again Robert,

I think I am still missing something. In the attached snippet of a "Pick and Place" file, how does the assembly machine know whether the coordinates are relative to center or top-left or bottom-left e.t.c of the PCB it is placing onto? I am guessing it refers to another source, but can't figure what source this is.

[robertferanec]

Coordinates in PCB are based on PCB Origin and Component Reference. Here are some picture:

Origin set in PCB



Reference set in library

[zeedel]

Thanks for getting back Robert. So does the location of this Origin get embedded in the generated Gerber files - where the pick and place machine can read?

[robertferanec]

When you generate gerbers, you can specify where you would like to have origin (play with the settings, you will see the difference):

[zeedel]

Thanks Robert, it's starting to make sense now. You have been a great help!