IPC Standards Committee Reports: Assembly/Joining, Process Control, Flex Circuits, Rigid Printed Boards

These standards committee reports from IPC APEX EXPO 2014 have been compiled to help keep you up to date on IPC standards committee activities. This is the third in a series of reports.

Assembly and Joining

The 5-11c Electronic Assembly Adhesives Task Group is approaching final draft status for a new document, IPC-HDBK-4691, Guidelines for Design, Selection, Application, and Reliability of Adhesives and Associated Processes Used for Electronics Assembly Purposes (working title).

The 1-13 Land Pattern Subcommittee and 5-21a IPC-7070 Task Group met jointly to consider component mounting issues being addressed in two IPC standards: IPC-7070, Component Mounting: Issues and Recommendations and IPC-7351, Generic Requirements for Surface Mount Design and Land Pattern Standard. IPC-7070 will address component placement issues, while IPC-7351 will address board design, land pattern and through-hole pad issues. Since the board actions in IPC-7351 combine the existing standard with a proposed through-hole standard (IPC-7251), the committee decided to circulate a survey to ensure that all previously involved committee members are informed of these potential actions.

The 5-21g Flip Chip Mounting Task Group prepared revision A to IPC-7094, Design and Assembly Process Implementation for Flip Chip and Die Size Components. The new revision will contain new semiconductor packaging concepts of 2.5 and 3-D package configurations. A change in direction was proposed to develop a separate document for the 2.5 and 3-D package configurations.

The 5-21k IPC-SM-817 SMT Adhesive Task Group re-formed and opened IPC-SM-817, General Requirements for Dielectric Surface Mounting Adhesives, for revision A. This task group will be modify the standard accordingly in the coming months.

The 5-22a J-STD-001 Task Group reviewed more than 80 open action items and comments on IPC J-STD-001F, Requirements for Soldered Electrical and Electronic Assemblies. This task group met a second day to resolve comments on criteria common to both IPC J-STD-001 and IPC-A-610, Acceptability for Electronic Assemblies. IPC staff is now preparing J-STD-001 revision F for ballot.

The 5-22arr J-STD-001/Conformal Coating Material & Application Industry Assessment Task Group discussed the current status of round robin testing and made a number of revisions to measurement protocols.

There were three J-STD-001 related committee meetings. The 5-22as Space Electronic Assemblies Task Group continued work on the addendum used for electronic assemblies that need to operate in micro-gravity, micro-atmosphere environments with extreme temperature excursions and very high mechanical shock and vibration during launch.

The 5-22f IPC-HDKB-001 Task Group had an initial meeting to develop a roadmap to update the handbook to incorporate Revision F changes. In addition, the 5-22bt J-STD-001 Technical Training Committee met to share ideas for improvements to the training program for Revision F. This committee also reviewed the new IPC Certification Quality Initiative that provides uniquely scrambled exams and electronic training reporting.

The 5-22h Thermal Profiling Guide Task Group held its first meeting and focused on revision A of IPC-7530, Guidelines for Temperature Profiling for Mass Soldering (Reflow & Wave) Processes. The group discussed missing definitions and modification of what thermal profiles should be covered, including special applications of laser, inductive soldering, hot bar and hot belt. The group also discussed development guidelines, calibration, process control and process guidelines.

The 5-23a Printed Circuit Board Solderability Specifications Task Group completed work on IPC J-STD-003C, Solderability Tests for Printed Boards. This group is discussing a replacement for the solder float test which has been proven to be unreliable. An amendment with typographical corrections and some clarifications will be published in later this month.

The 5-24b Solder Paste Task Group began review of all test methods originating with the group.

Process Control

The 7-23 Assembly Process Effects Handbook Subcommittee addressed problems, probable cause, and actions taken in troubleshooting assembly processes and updated the original IPC process effects handbook, IPC-PE-740, Troubleshooting for Printed Board Manufacture and Assembly, with new information. The group reviewed each of the 15 sections of the draft document and solicited additional information/pictures. In addition, subcommittee members requested the document be finalized and released for comment before the Fall Standards Meetings in Rosemont, Ill.

The 7-24 Printed Board Process Effects Handbook Subcommittee pushed for completion of a companion document, IPC-9121, Printed Board Process Effects to IPC-9111, Printed Board Assembly Process Effects. This document will incorporate a new process effects or troubleshooting guide and syllabus for an advanced troubleshooting PD class under development. The handbook will provide printed board anomaly illustrations with possible cause and solution explanations and will be more closely tied to IPC-A-600 acceptability criteria.

Flexible Circuits

The D-12a UL 746F and UL 796F Task Groups discussed the UL 796F flexible printed wiring standard. The group circulated a questionnaire on the type of materials and applications for guarding against EMI using shielding techniques.

The D-13 Flexible Circuits Base Materials Subcommittee continued revising IPC-FC-234, PSA Assembly Guidelines for Single- & Double-Sided Flexible Printed Circuits. The group also evaluated a new potential material from DuPont that could be used as both a covercoat material and bonding material for the IPC-4203. Some properties are yet to be determined, but this effort is in process.

The D-15 Flexible Circuits Test Methods Subcommittee completed the final draft of TM 2.4.9E and awaits comments from the 7-11 Test Methods Subcommittee prior to having it incorporated in TM-650, Test Methods Manual. The subcommittee revised TM (Insulation and Moisture Resistance, Flexible Base Dielectric) to its C revision.

Rigid Printed Boards

The D-31b IPC-2221/2222 Task Group worked on the first working draft of IPC-2221C, Generic Standard on Printed Board Design, including minimum electrical clearances for conductors, requirements for internal plated layers in sequential builds, conductive anodic filament (CAF) issues, and hole-to-copper spacing.

The D-33a Rigid Printed Board Performance Task Group reviewed comments on the final draft of IPC-6012D, Qualification and Performance Specification for Rigid Printed Boards. The group focused on comments related to requirements for blind and buried microvia structures. The task group will continue to meet by way of web conferences held twice a month throughout the spring and summer of 2014. Publication is anticipated for December 2014.

The D-35 Printed Board Storage and Handling Subcommittee discussed revision to IPC-1601, Printed Board Handling and Storage Guidelines. The subcommittee plans to develop an Appendix that provides samples of industry packaging requirements for board fabricators and also plans recommendations for the shelf-life of various printed board surface finishes.

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