Configuration Management
Definition
Configuration Management is a management system which:
- Identifies and documents the functional and physical characteristics of an item or a system
- Controls the changes to such characteristics
- Records and reports the change and its implementation
- Audits items to verify conformance to requirements.
For example, drawings and parts lists (Bill of Materials) contain information on the materials used to assembly hardware. However, in the field, this information may not be readily available.
It is true that Lead Free solder joints have the following characteristics:
- Grainy dull appearance
- Do not wet as well as SnPb solders
While an inspector or engineer may become tuned to the differences between Lead Free and SnPb solders visually, outside of testing the metallurgy of the solder joint, there are no methods where one can reliably predict what solder alloy is used.
Component and Solder Identification
The electronics manufacturer shall implement a methodology to identify component finishes, board finishes, and solder alloys used on deliverable hardware. This methodology shall be compliant to the requirements of the program stakeholder and customer.
There are several potential methods to identify the type of solder used to manufacture hardware:
- Date Coding would identify when the hardware was built. It assumes that Lead Free production would start after a specific date or serial number.
- Assembly Identification can be used to determine the types of solder used. For example, SONY uses a green leaf to identify products that are manufactured with Lead Free solders. Assembly drawings and the parts lists (Bill of Materials) routinely identify component and board finishes. It may be possible to identify the type of solder used on an assembly.
One important consideration is the customer requirements for Configuration Management control. For example, the typical consumer has minimum interests in when hardware is built nor their assembly records. However, Aerospace and DoD customers are extremely interesting in the assembly records for a system. This is due to the contractual obligations between the supplier and the Aerospace and DoD customers.
Industry Standards
The electronics manufacturer shall be compliant to the following industry standards:
- IPC-1066: Marking, Symbols, and Labels for Identification of Lead-Free and Other Reportable Materials in Lead-Free Assemblies, Components, and Devices.
- JESD 97 – Marking, Symbols, and Labels for Identification of Lead (Pb) Free Assemblies, Components, and Devices.
Bill of Materials Database Management
Electronic manufacturers are using Manufacturing Resource Planning (MRP-II) relational databases to support Configuration Management functions. The following is a strategy to use relational databases to identify solders and component finishes.
Configuration Management Control Via Relational Databases Example
It is feasible to apply these practices into current configuration management procedures. As an exercise, the codes to identify solders and component finishes were utilized on a battery re-charger assembly developed for the US Army, as shown in Figure 1. As Table 1 illustrates, the component finishes were identified from the various component manufacturers, using the codes within IPC-1066 and JESD-97 documented in Table 2. Properly inserted, these codes can be used in relational databases which support manufacturing systems such as Manufacturing Resource Planning (MRP-II), Enterprise Resource Planning (ERP) and Strategic Production Inventory Optimizing System (S-PIOS).
Figure 1A. Battery Re-charger Assembly
Figure 1B. Battery Re-Charger Assembly
Table 1. Battery Re-charger Assembly Parts List with Lead Free Solder inputs
Solder Alloy / Component Finish Coding |
Conformal Coating Finish |
Board Resin |
Database
Code |
IPC Classification |
Database
Code |
IPC Classification |
Database
Code |
IPC Classification |
1 |
e1 – SnAgCu |
E |
ER – Epoxy Resin |
H |
Halogen Free Board Material |
2 |
e2 – Other Sn alloys (ie. SnCu, SnAg, SnAgCuX, etc.)
(No Bi or Zn) |
U |
UR – Urethane Resin |
<Blank> |
halogen-containing base resin and reinforcement
matrix is assumed |
3 |
e3 – Sn |
A |
AR – Acrylic Resin |
- |
Not Applicable |
4 |
e4 – Precious metals (ie. Ag, Au, NiPd, NiPdAu, but
no Sn) |
S |
SR – Silicone Resin |
|
5 |
e5 – SnZn, SnZnX (no Bi) |
X |
XY– Paraxylylene |
6 |
e6 – Contains Bi |
|
7 |
e7 – Low temperature solder (<150°C) containing indium
but no bismuth |
Table 2. Component characteristics coding based on IPC-1066 and JESD-97
When compared to PMI’s definition of a Configuration Management System, this strategy:
- Will identify and documents the functional and physical characteristics of an item or a system. The properly coded documentation will reside within the manufacturing system for every component and assembly within a deliverable end item.
- Controls the changes to such characteristics. Manufacturing Systems which employ relational databases require discipline to maintain. Therefore, the control of changes to the hardware will be established.
- Using manufacturing systems can automatically record and report changes to the bill of materials and component characteristics, and track its implementation.
- Audits items to verify conformance to requirements. In conjunction with component finish identification techniques, such as X-Ray Fluorescence (XRF), this strategy can assure compliance to component finish requirements.
Configuration Management Relational Databases System Caveats
An important feature of this strategy is that it utilizes the capabilities of existing manufacturing systems. It would not be beneficial or cost effective to develop a stand-alone system to track component and assembly characteristics. Properly implemented, the relational database can be used to track electrostatic discharge (ESD) sensitivity levels and moisture sensitivity levels. Some aerospace manufacturers have implemented tracking component ESD and moisture sensitivity levels within their manufacturing systems. Tracking component finishes and solders would be the next logical evolution.
Manufacturing Systems relational databases should be considered to include characteristic data of components and assemblies, as part of the configuration management process. Its implementation will be dependent on specific Manufacturing Systems used. There are caveats to using this strategy. Data entered into the manufacturing system must be accurate to reflect part and materials characteristics. During this exercise, component manufacturers that supplied the component to the Battery Re-Charger were contacted. It was determined that component manufacturers were not consistently identifying component physical characteristics. Over 36% of component manufacturers did not provide this information.
