For any firm assembling SMT circuit board assemblies – OEM or CEM – there are two essential documents – workmanship standards and DFM guidelines. While most facilities use Workmanship Standards, surprisingly few have implemented Design For Manufacturability and Assembly Guidelines.
The Design for Manufacturability and Assembly Guidelines document is vital to optimized and high-yield assembly, and contributes greatly to product reliability. These guidelines can be used to establish a communications link between Design, Manufacturing, Quality and Procurement and set operational standards for board and assembly design, manufacture, inspection, test and rework. The Design for Manufacturability and Assembly Guidelines help established design practices so they match the operational parameters demanded by the production equipment.
Putting together a DFMA Guideline document can be an expensive, daunting and time-consuming task, yet it must be done. Each facility is different with regard to the equipment and processes used and thus, each requires its own set of DFMA Guidelines. (And a copy of IPC-782 on the reference shelf doesn’t quite cut it).
ITM Consulting has helped many of its clients compile and launch their own DFMA Guidelines. Based upon our experience and expertise, ITM has put together a product that will allow any SMT assembly facility to easily, expeditiously and economically produce their own DFMA Guideline document – the “Design for Manufacturability and Assembly Guidelines Template.”
ITM’s Design for Manufacturability and Assembly Guideline Template is a complete document – less the particulars of your company’s facility and line(s). You simply take this MS-Word™ document and fill in the blanks regarding equipment and their specifications (i.e. maximum and minimum board width handled by each machine, etc.), responsible personnel, and other process information – and in no time, your facility has a comprehensive DFMA Guideline document. The DFMA Guideline is also a “living” document that allows for changes in equipment, materials and process You simply modify or expand the tables and edit any other information.
If you are an OEM or a CEM, the ITM Design for Manufacturability and Assembly Guideline Template can now guide your supplier or your client on the necessity of designing printed circuit boards so the product can be assembled.
DESIGN FOR MANUFACTURABILITY AND ASSEMBLY GUIDELINES
TABLE OF CONTENTS
- ORDER OF PRECEDENCE
3.1. Purchase Order
3.2. Bill of Material (BoM)
3.3. Drawing Instruction
3.4. This Document
3.5. Industry Standards (e.g. IPC, EIA, JEDEC, etc.)
- AUTHORITY AND RESPONSIBILITY
- REFERENCE MATERIAL
5.1. PCB Supplier Specification
5.2. Rigid Printed Board Manual, IPC-M-105
5.3. SMEMA Fiducial Mark Standard, SMEMA 3.1
5.4. Surface Mount Land Pattern Design Standard, IPC-7351
5.5. Implementation of Flip Chip and Chip Scale Technology, J-STD-012
5.6. _____________________ Fab and Assembly Drawing
5.7. Implementation of Ball Grid Array and Other High Density Technology, J-STD-013
5.8. SMT Terms and Definitions, Phil Zarrow, ITM Inc.
5.9. Terms and Definitions for Interconnecting and Packaging Electronic Circuits, IPC-T-50
- TABLE OF CONTENTS
- PROCESS PROCEDURES
7.1. Application Requirements
7.2. Water Soluble (OA) Reflow Soldering Procedure
7.3. No-Clean Reflow Soldering Procedure
7.4. Repair and Secondary Operations Soldering Procedure
- EQUPMENT PARAMETERS
8.1. SMT Line 1
8.3. SMT Line 2
- DESIGN RULE SUMMARY:
- PRINTED CIRCUIT BOARD REQUIREMENTS
10.1. Schematic Generation
10.2. PCB Layout Requirements
10.3. Recommended Fabrication Drawing Notes
10.4. Recommended Assembly Drawing Notes
10.5. Workmanship Notes FOR RE-WORK, IF SO REQUIRED
10.6. PCB Construction
10.7. Conductor Layout
10.8. Plated Through Holes and Vias
10.9. Solder Mask
10.10. PCB Finish Options
10.11. PCB Dimensioning
10.12. PCB Legend and Marking
10.13. PCB Fabrication Drawing
10.14. PCB Panelization
- PRINTED CIRCUIT BOARD COMPONENTS
11.1. Component Selection.
- PRINTED CIRCUIT BOARD COMPONENT PAD GEOMETRIES
12.1. Spacing and Orientation
12.2. Component Land Patterns