Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?

Edit: Good to see Stack Overflow never changes - no we cannot "drop the CM4", this question is specifically about aligning those connectors in production; how it's done (or not done), how much it matters, direct experience of doing this or similar, not on the merits of whether this design is "stupid" or the Raspberry Pi is a bad solution to whatever you imagine we are doing with it.

Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?

Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?

Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?

Edit: Good to see Stack Overflow never changes - no we cannot "drop the CM4", this question is specifically about aligning those connectors in production; how it's done (or not done), how much it matters, direct experience of doing this or similar, not on the merits of whether this design is "stupid" or the Raspberry Pi is a bad solution to whatever you imagine we are doing with it.

Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?

Apologies if this seems like a duplicate of this question but the eventual "answer" to that seemed somewhat anecdotal at best - and there's been a LOT more of these used since 2012 so things may have moved on.

Basically I'm looking at a very similar situation - specifically mounting a Raspberry Pi CM4 module using the two Hirose DF40HC(3.0)-100DS-0.4V(51) connectors. (Manufacturer web page)

Edit: These connectors do NOT have any locating pins or other features, they are what's specified (and used by) the Raspberry Pi foundation for their CM4 and its IO board, so obviously they are being aligned in mass production by them.

My experience with prototype units using these connectors (professionally hand soldered) was that a small misalignment made the module hard to plug in and it concerns me that that's putting undue stress on the connector or the PCB traces.

Best I can find in the datasheets are a line that says "Keep connector warpage within 0.02 mm in connector longitudinal direction" which is pretty darned tight, although later they claim "Guide ribs utilizing dead space ensure 0.33mm of self-alignment" but don't really specify in which direction(s).

So - the question is, is there some proper way to ensure alignment in production (reflow) or do these things really self-align accurately enough when placed on the standard footprint and run through an oven?