Configuration Management

Transcription

1 Configuration Management (CM) is the organized control of engineering change involving the proposing, approving and incorporating of design changes into product development documentation. Although CM can seem laborious, if not employed, the results can be devastating to a project in terms of product quality, cost and schedule. Project activities in which configuration management is useful: From the point the first document or drawing is created to the retirement of a product Other tools that are useful in conjunction with configuration management: Requirements Management Introduction Almost every product design project inevitably involves changes along the way. These changes may be due any number of reasons including changes in product scope, customer request, product enhancement, or error correction. Regardless of the source, these changes need to be carefully presented and evaluated, and if approved, subsequently incorporated into the necessary documentation and distributed in a timely manner to persons requiring the information. CM needs to be applied for even the most trivial seeming changes. What may seem to be a small, insignificant change may affect other areas of the design that the initiator of the change did not consider. For example, a carpenter decided to locate the dishwasher in a home directly next to the dinette believing that this would make the process of stacking the dishwasher faster. The building contractor later had the carpenter move the dishwasher near the sink so that it was in close proximity to the plumbing and also, would easily permit the homeowner to rinse the dishes before stacking the dishwasher. A unilateral ad hoc decision that initially seemed to be a good idea resulted in schedule and cost overruns, and embarrassment for the carpenter. Application of Configuration Management Document Baselines The first official or controlled release of any design document, be it a written document (e.g., specifications, bill of materials, parts lists, technical notes, etc.) or drawing (e.g., layout, detail, assembly, etc.), forms the initial baseline for the document. So that these documents can be easily monitored and controlled, they require a form of identification. There are a number of identification methods that can be used, each with associated pros and cons, however the most important aspect of any method is that it is easy to use, employed consistently and followed scrupulously. Configuration Management.doc Page 1 of 7 V0.0

2 Assignment of Identification It is important that each document receives a unique identification and that two documents are never given the same identification. Therefore, it is suggested that identifiers be obtained from a single source. This source may be a single person or department that has the responsibility for identifying and maintaining a current list of active and superseded documents or it may be an electronic or manual database from which the originator of the document retrieves the next appropriate identifier in series. Identification of Written Documents There are a number of methods for identifying written documents. A simple method that is employed by many engineering firms involves three or four components: Project/program this may be a number, or a name or acronym Document type - specification (product, process, material), bill of materials, technical note, etc. Identification number from a project/program series (e.g., each project s documents start with 1000, 1001, etc.) or assigned from a company wide series (i.e., every new document receives a unique number) Revision number or letter each revision is given the next number or letter in series. For example, the initial release of a document would receive the revision identifier A or 1. A subsequent release would be identified as B or 2. Some companies will use a two level numbering system where a whole number indicates a significant or Class I revision (e.g., 1.0 to 2.0) while a 1/10 th increment identifies a minor or Class II/III revision (e.g., 1.1 to 1.2). More information will be provided on classes of changes. For example, a product specification for a new GT2000 series bike may have the identifier: Doc Type Rev GT E B Project I.D.# Configuration Management.doc Page 2 of 7 V0.0

3 Identification of Drawings As with documents, there are a number of methods for identifying drawings. The main methods include: Non-significant Drawings are assigned a serial number in the order that they are created. Although a straightforward method, there is an associated risk of human error in transposition, duplication, etc. with this method. Format Size (partially significant) This method includes a letter that corresponds with a standard drawing size (e.g., A for 8-1/2 x 11, B for 11 x 17, etc.). A drawing number for a 22 x 34 drawing may be D1234. While this method helps with filing, it provides little other significant information. Project Identifier (partially significant) This prefaces the drawing number with a project code. For example, GT Significant This method incorporates a significant amount of information in the drawing number. This information can include the project, product type, model number, and drawing type depending on the size and needs of the engineering organization. While this system conveys the most information, it may be overly complex for smaller or simpler organizations. Document and Drawing Reviews Every document and drawing should be reviewed by at least one party other than the creator prior to release. The process for this review will depend on the practices of individual organizations that in turn will be influenced on size and organizational structure. In hierarchical organizations, it is often the engineering or program manager that will approve documents for release. In the case of drawings, the drafting manager may provide the final approval. In team based organizations, documents may require the review and approval of a number of identified speciality disciplines. This approach divides the workload and increases the comprehensiveness of the review. In some cases, a combination of the two processes is used where the specialist will review and approve the document before it receives a final approval by management. Distribution of Documents and Drawings The distribution of documents requires more attention that first thought. More than one company has proceeded with the development of a product with an outdated version of a drawing or specification because of the unawareness of a newer version. Configuration Management.doc Page 3 of 7 V0.0

4 Depending on the size of the organization, documents and drawings are either distributed by the originating department or by a central registry that controls distribution for the entire company. Regardless of who is responsible for distribution, it is important that careful records are kept concerning what is the most current version of the document, and who has received a copy and what version is currently in their possession. Although originals of all documents should be kept, when a new version of a document is released, it is advisable to collect and destroy all copies of the preceding version. Change Control Classification of Changes Changes range from major to minor and it is helpful to categorize these changes such that they can be addressed appropriately. Although some organizations have developed their own classification system, many have adapted the one devised by the U.S. military. These adapted systems generally classify engineering changes into one of three categories: Class I normally impact form, fit or function may have impact on contractual requirements such as performance, hardware interchangeabiltiy, reliability, safety, interfaces, etc. may require reidentification of a part or assembly may require review and sign-off by the customer implementation of changes must usually be expedient and carefully controlled Class II covers most other changes does not affect contractual requirements typically can be approved and resolved entirely in-house implementation of changes can usually be made on the basis of cost or convenience Class III addresses changes that involve corrections to documents does not involve changes to design Class III changes should be reviewed to ensure that they are not misclassified Class II changes Configuration Management.doc Page 4 of 7 V0.0

5 Initiation of an Engineering Change Although anyone can identify the need for a change, the engineer(s) or department responsible for the design of the product typically initiate engineering changes. This allows the engineer to do an initial review of the validity of the change. At the same time, it places responsibility on the engineer to seriously investigate each request. Engineering Change Notice Once the need for a change has been identified and confirmed, the details of this change need to be communicated to others in the organization. A document entitled Engineering Change Notice or ECN is typically used. The actual name, contents and specific format of this document may be different for each organization. Most ECNs generally contain the following information: ECN serial number project involved part, assembly or, in some instances, the document involved brief statement of why the change is needed technical description of the change impact of the change (e.g., parts list, work in progress, inventory, manuals, field units, tooling, etc.) approval signatures including that of the initiating engineer Additional information may accompany the ECN to facilitate informed decisions. This information may include: sketches, descriptions, part list revisions, etc. listing of affected drawings and documents, and their required changes (Note: some companies require that drafts of actual changes be included with the ECN. While this may expedite the implementation of a change, it may be wasted work if the ECN is modified in the approval process) assessment on the effects of changes on other areas Review and Approval of Engineering Changes There are a number of different methods that can be employed to review and approve engineering changes. A simple method is to have the engineer that initiated the change approve it for implementation, however a review by more than one person is generally favoured. Another approach is to review and approve the changes in the same manner as the original documents, either by a single manager or by a number of persons representing different disciplines. Configuration Management.doc Page 5 of 7 V0.0

6 Change Control Board Many organizations employ a Change Control Board (CCB) which is responsible for reviewing and approving engineering changes. This board is usually made up representatives from different disciplines and has the authority to approve engineering changes. There may be a single CCB for the entire company or each project may form its own CCB. The frequency with which a CCB will meet usually depends on the number and urgency of ECNs. In some cases, a CCB will meet daily and in other cases, weekly. The engineers that have initiated ECNs will generally attend the CCB to present the proposed change to the Board and answer any questions. Often, it is the chairperson on the CCB who has the final authority on approving the changed based on the input of the other CCB members. Therefore, the chairperson is often one of the most senior persons in the organization or, for a project specific CCB, the project or program manager. Implementation of Engineering Changes There are three approaches to implementing engineering changes and distributing the updated versions of affected documents and drawings. The first approach is to complete the necessary changes to the documents then have them distributed. This approach works well if timing is not crucial. Another approach is to complete a draft of the change to be submitted with the ECN, then finalize and distribute once the ECN has been approved. A final approach is to distribute a copy of the approved ECN to those that need to be aware, and advise them when the updated documents will be available. This approach allows action to be taken immediately if required while the appropriate documents are being updated. As documents and drawings are being updated, it is essential that only the changes covered in the ECN be made. If other changes are required, they should be addressed in another ECN. Note of Revisions Every time a document or drawing is revised, it is important to note the changes that have been made. This maintains a history of changes as well as helps those reviewing the documents to identify the changes quickly. The revision notes should also include the date of the revision, the revision number or letter, and the author and/or approver of the revision. Especially on drawings where there is often limited real-estate, it may not be possible to list the details of a revision. In these situations, a very brief explanation and an identification of the applicable ECN is acceptable. Often, attaching a copy of the ECN to the document or drawing is useful. Configuration Management.doc Page 6 of 7 V0.0

7 Escrow Companies are often contractually required to keep certain engineering documents in the possession of a third party, typically a legal body. These documents may include specifications, drawings, and in the case of software, the actual code. The purpose of escrow is to protect both the customer and the supplier. If the supplier ever ceases to exist, the customer has access to the necessary design information to continue supporting the product. The supplier is protected in that the documents in escrow reflect the product as delivered which can be compared illegally made changes or copies. References Burgess, John A., Design Assurance for Engineers and Managers, Marcel Dekker, Inc., New York, U.S.A., pp , 77-83, ISBN X Configuration Management.doc Page 7 of 7 V0.0