Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Standard for automated placement & assembly, density etc.

Views: 4309

#65864

Standard for automated placement & assembly, density etc. | 17 February, 2012

I am planning a PCB design for automated assembly of all components, SMT. I have been told that the industry standard used at the assembly house is something called "88", and that the assembly house can do better "55" or even "44".

I’m not sure if this is referring to a certain standard or if this is a measure of the maximum achievable component density or inter-component proximity for placement or something else.

Is anyone familiar with automated assembly and knows what this is referring to ?

Thank you

reply »

#65867

Standard for automated placement & assembly, density etc. | 18 February, 2012

The 3-Tier PCB library concept was originally created by IEC (International Electromechanical Commission) in 1999 and introduced to IPC in 2000. The concept had to be created as a solution for high density packaging for hand held devices to ruggedized military applications and everything in-between. The IPC-7351 and the IEC 61188-5-1 SMT land pattern standards for were specifically created to introduce this new concept in 2005. Before 2005, the IPC-SM-782 was a 1-Tier land pattern standard developed in 1985 and released in March 1987. The pad size of the IPC-SM-782 land pattern, compared to the new IPC-7351, fell in-between the Most and the Nominal environments. The IPC-7251 land pattern standard for through-hole components is currently being developed. It also has a 3-Tier environment concept that apply to the hole sizes and annular rings. Three land pattern geometry variations are supplied for each of the device families; Maximum Land Protrusion (Density Level A), Nominal Land Protrusion (Density Level B) and Least Land Protrusion (Density Level C). Here are the definitions for the 3-Tier (or 3 Level) PCB library system for both through-hole and SMD technology. [T Hausherr]

reply »

#65869

Standard for automated placement & assembly, density etc. | 18 February, 2012

Thanks for the information. So Density level A corresponds to "88", B to "55" and C to "44" ? Im wondering why the difference in naming ? Thanks

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#65870

Standard for automated placement & assembly, density etc. | 19 February, 2012

Not sure how 88, 55 and 44 tie to other things, but if you talk IPC, you'll have a point of reference that's portable between suppliers

reply »


JAX

#65887

Standard for automated placement & assembly, density etc. | 21 February, 2012

I have never heard of the "88", "55", or "44".

Are you sure this does not refer to Trace and Space guidelines?

reply »

#65889

Standard for automated placement & assembly, density etc. | 21 February, 2012

You may be right. The assembly house also manufactures the PCBs. This might be referring to 8 thou trace width and 8 thou separation. Down to 5 and 4 thou. Could be...

reply »

Boundary Scan

ii-feed SMD Intelligent Feeder