Pick and place file formats

[uer166]

I'm trying to have PCBs assembled, but due to lack of requirements, and maybe my misunderstanding, the pick and place files generated by Diptrace seem to not be suitable for the assembly house. If anyone is familiar with these, can you compare good.txt with bad.txt?

Seems like they want the following format:
Mid X         Mid Y         Ref X         Ref Y         Pad X         Pad Y      Rotation

While Diptrace only exports X,Y,rotation, and place area width and height...

[jmelson]

I'm trying to have PCBs assembled, but due to lack of requirements, and maybe my misunderstanding, the pick and place files generated by Diptrace seem to not be suitable for the assembly house. If anyone is familiar with these, can you compare good.txt with bad.txt?

Seems like they want the following format:
Mid X         Mid Y         Ref X         Ref Y         Pad X         Pad Y      Rotation

While Diptrace only exports X,Y,rotation, and place area width and height...

I'm no expert, I do my own assembly.  But, it seems to me that for almost all standard parts, the X and Y centroid and the rotation is all they should need.
The Ref XY is, I think, the coordinate of pin 1.  I have no idea what Pad XY is, maybe the outer dimensions of the part.  That might be helpful for setting up the vision.

Jon

[SMTech]

Like jmelson I don't know what they are used for, someone must, ref X/Y is a user defined coordinate for the package and so will usually be the same number as mid X/Y, Pad X/Y is the co-ordinate of pin 1.

Presumably if a fab house is requiring they be supplied exactly like that it is because they have developed tools/scripts sufficiently inflexible that they can only cope with that format.

Different machines have different ways of being programmed, sometimes requiring a 3rd party piece of software that stiches centroid & BOM together with machine data to create a file it then uses. Our Essemtec (as do many others) requires the centroid to contain part numbers or values, when people send us centroid data without that I can either use my own tools or an old abandoned but very useful piece of freeware called SMT Maestro that can re-organise columns as required, expand BOM lines and merge them with the centroid file. This bascially means I don't care how you send your files, and frankly neither should they, it is trivial text manipulation they could do in excel/calc or with scripts.

[mrpackethead]

Pad X/Y is the co-ordinate of pin 1.

I've seen it a hundred tims, but never knew what 'Pad' actually was.. ( and have never used it myself... )  Mmm.  very handy!

[uer166]

Yeah I'm honestly at a loss right now. I've asked for a detailed spec of file format and what they expect, but it's pretty confusing so far. House it just AllPCB, so if anyone has experience with them that would be a lot of help.

It's an interesting situation though, since $$$ was already paid, who eats the cost if they can't manufacture it?

[Smallsmt]

RefDes   Pattern         X (mm)   Y (mm)   Side   Rotate   Value   Width (mm)   Height (mm)
____________________________________________________________________________________________

C1       CAP_0603        19.118   72.938   Top    270      1u              2.8          1         
C2       CAP_0603        13.823   75.851   Top    180      2.2u    2.8          1     

Copy your X/Y value to Mid X/Y and Ref X/Y position, RefDes to Designator, Pattern to Footprint, Value to Comment, Rotate to Rotation and set TB to T = Top Side.
Pad X/Y is not needed I think but need to have value so you need to fill these 2 columns too.

[Mattylad]

Do an assembly drawing that shows the polarisation of polarised components.
What your CAD system calls a rotation is only in reference to how it was created in your library.

Unless you create them at the same zero rotation that the components are as presented to the placement machine then your rotations will be wrong - which is where a good drawing is used to check it. 

[mrpackethead]

This is a great reference with regard how to set up your component librarys.  Its based on IPC-7351/IEC 61188-5-1.  Its the best way to get started.

Its not the full picture, because Some manufacturers will not pack parts this way. :-)



https://ohm.bu.edu/~pbohn/__Engineering_Reference/pcb_layout/pcbmatrix/Component%20Zero%20Orientations%20for%20CAD%20Libraries.pdf

[SWR]

I'm in the process of setting up my CAD libraries according to IPC7351B (see attached).

On the P&P I'll set up the rotation according to the orientation on the tape.
According to the P&P software manual the P&P will automatically compensate for reel position on the west, north or east side of the machine.

Best regards
Soren