IPC 7711A - 第20页

General Information and Common Proedures 1 General 1.1 Scope This document covers procedures for repair- ing and reworking printed board assemblies. It is an aggre- gate of information collected, integrated and assembled…

Component Additions

Procedure Description Illustration

Product

Class

Skill

Level

Level of

Conformance

6.3 Component Modiﬁcations and

Additions

R, F, W, C Advanced N/A

Flexible Conductor Repair

Procedure Description Illustration

Product

Class

Skill

Level

Level of

Conformance

7.1.1 Flexible Conductor Repair F Expert Medium

IPC-7711A/7721A October 2003

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General Information and

Common Proedures

1 General

1.1 Scope

This document covers procedures for repair-

ing and reworking printed board assemblies. It is an aggre-

gate of information collected, integrated and assembled by

the Repairability Subcommittee (7-34) of the Product

Assurance Committee of the IPC.

1.2 Purpose This document prescribes the procedural

requirements, tools and materials and methods to be used

in the modiﬁcation, rework, repair, overhaul or restoration

of electronic products. Although this document is based in

large part on the Product Class Deﬁnitions of ANSI/J-STD-

001, this document should be considered applicable to any

type of electronic equipment. When invoked by contract as

the controlling document for the modiﬁcation, rework,

repair, overhaul or restoration of products, the requirements

ﬂowdown apply.

IPC has identiﬁed the most common equipment and pro-

cess in order to affect a speciﬁc repair or rework. It is pos-

sible that alternate equipment and processes can be used to

make the same repair. If alternate equipment is used, it is

up to the user to determine that the resultant assembly is

good and undamaged.

1.2.1 Definition of Requirements The words must and

shall have no special meaning beyond that commonly used

in other IPC standards.

1.2.2 Requirements Flowdown The applicable require-

ments of this document must be imposed by each manufac-

turer or supplier on all applicable subcontracts and pur-

chase orders. The manufacturer or supplier must not

impose or allow any variation from these requirements on

subcontracts or purchase orders other than those that have

been approved by the user. Unless otherwise speciﬁed, the

requirements of this document are not imposed on the pro-

curement of off the shelf assemblies or subassemblies.

However, the manufacturer of these items may comply as

deemed appropriate.

1.3 Background Today’s PC boards are more complex

and microminiaturized than ever before. Despite this, they

can be successfully modiﬁed, reworked or repaired if the

proper techniques are followed. This manual is designed to

help you repair, rework and modify PC boards reliably. The

procedures in this document have been obtained from end

product assemblers, printed board manufacturers and end

product users who recognized the need for documenting

commonly used rework, repair and modiﬁcation tech-

niques. These techniques have, in general, been proven to

be acceptable for the class of product indicated through

testing and extended ﬁeld functionality. Procedures con-

tained herein were submitted for inclusion by commercial

and military organizations too numerous to list individu-

ally. The Repairability Subcommittee has, where appropri-

ate, revised procedures to reﬂect improvements.

Rework completed satisfactorily will meet the original

speciﬁcation and requirements of IPC-A-600 and IPC-A-

610. But, by deﬁnition, modiﬁcations and repairs do not

comply with the initial design or fabrication criteria. For

modiﬁcation and repair, the user must recognize that the

criteria in IPC-A-600 Acceptability of Printed Boards and

IPC-A-610 Acceptability of Printed Board Assemblies are

not necessarily applicable to the procedures herein. Modi-

ﬁcations and repairs should not compensate for the lack of

proper processes and quality controls. Ultimate cost effec-

tiveness is achieved using appropriate design, fabrication

and assembly techniques that minimize the need for modi-

ﬁcation and repair.

1.4 Controls Although modiﬁcation, rework and repair

procedures may be very similar, the control of such proce-

dures may not be the same, due to the conditions and

objectives involved.

1. Modiﬁcation

The revision of the functional capability of a product

in order to satisfy new acceptance criteria.

Modiﬁcations are usually required to incorporate

design changes which can be controlled by drawings,

change orders, etc. Modiﬁcations should only be per-

formed when speciﬁcally authorized and described in

detail on controlled documentation.

2. Rework

The act of reprocessing non-complying articles,

through the use of original or equivalent processing, in

a manner that assures full compliance of the article

with applicable drawings or speciﬁcations.

3. Repair

The act of restoring the functional capability of a

defective article in a manner that precludes compliance

of the article with applicable drawings or speciﬁca-

tions.

October 2003 IPC-7711A/7721A

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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Repairs are generally changes to an unacceptable end

product to make it acceptable in accordance with origi-

nal functional requirements. The control of repaired

products should be by means of Material Review

Board (MRB), or its equivalent, which may consist of

Design Engineering, Quality Assurance, and User rep-

resentatives. The MRB, with technical support, should

deﬁne the mutually acceptable repair method to be

used and take the action necessary to ensure that all

applicable procedures are adhered to.

Repair of a failure in the ﬁeld seldom includes an

MRB, and typically is done in accordance with a con-

tract, repair/service order or the user-activity mainte-

nance program requirements. The maximum number

of repairs per printed wiring board assembly should be

determined by the using activity or agency.

1.4.1 Classification The user of the product is respon-

sible for identifying the Class of Product. The procedure

selected for action to be taken (modiﬁcation, rework,

repair, overhaul etc.) must be consistent with the Class

identiﬁed by the user. The three Classes of Product are:

1. Class 1 – General Electronic Products

Includes products for applications where the major

requirement is the function of the completed assembly.

2. Class 2 – Dedicated Service Electronic Products

Includes products where continued performance and

extended life is required, and for which uninterrupted

service is desired but not critical. Typically, the end

use environment would not cause failures.

3. Class 3 – High Performance Electronic Products

Includes products where continued performance or

performance-on-demand is critical. Equipment down-

time cannot be tolerated, end-use environment may be

uncommonly harsh, and the equipment must function

where required, such as life support and other critical

systems.

1.4.2 Printed Board Types There are a variety of printed

board types that the procedures in this document apply to.

When selecting the appropriate modiﬁcation, rework or

repair procedure the printed board type being worked

should be considered. Select a procedure that applies to the

printed board type as listed on the procedure. Printed board

types include the following:

R. Rigid Printed Boards and Assemblies

A printed board or assembly using rigid base materials

only. These may be single-sided, double-sided or mul-

tilayered, and may be constructed from base laminate

material that spans all approved commercial grades of

laminate and includes glass fabric reinforced epoxy

and polyimide resin laminates.

F. Flexible Printed Boards and Assemblies

A printed board or assembly using ﬂexible or a com-

bination of rigid and ﬂexible materials only. May be

partially provided with electrically non-functional

stiffeners and/or cover lay. These may be single-sided,

double-sided or multilayered.

W. Discrete Wiring Boards and Assemblies

A printed board or assembly using a discrete wiring

technique to obtain electrical interconnections.

C. Ceramic Boards and Assemblies

A printed board or assembly using ceramic as the base

material with interconnections separated by dielectric.

The board layers are usually formed by alternate print-

ing or depositing of interconnections and dielectric.

The assemblies are either surface mount or die attach.

Usually multilayered, these may be single-sided or

double-sided.

1.4.3 Level of Conformance Level of Conformance pro-

vides the means for selecting an appropriate level of con-

formance to the original electrical, mechanical, physical,

environmental and visual product requirements. Each pro-

cedure lists a Level of Conformance that the product will

attain when successfully completed.

The Level of Conformance rating for each procedure is

based on the skill of the technician. The ratings are based

on long term industry experience and are not necessarily

backed up with testing data.

1.4.4 Levels of Conformance

L. Lowest Level – Signiﬁcant variance with the physical

character of the original and may vary with many of

the electrical, functional, environmental and service-

ability factors.

M. Medium Level – Some variance with the physical

character of the original and most likely varies with

some of the functional, environmental and serviceabil-

ity factors.

H. Highest Level – Most closely duplicates the physical

characteristics of the original and most probably com-

plies with all the functional, environmental and ser-

viceability factors.

Class 3 Products must use procedures rated Highest level

unless it can be demonstrated that a lower level procedure

will not adversely affect the product’s functional character-

istics.

Class 2 and 1 Products should use procedures rated High-

est level for assured safety and dependability but Medium

and Low Level procedures can be used if it has been deter-

mined that they are suitable for the speciﬁc product’s func-

tional characteristics.

Procedures in this manual are given a ‘‘Level of Conform-

ance’’ rating which is described in Table 1.

IPC-7711A/7721A October 2003

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

--``,``,-`-`,,`,,`,`,,`---