Original Date: 10/14/1988
Revision Date: 01/18/2007

Manufacturing Process Instructions (MPIs) are used to amplify engineering process specifications with specific instructions for controlling individual part processing and for assuring a documented, repeatable process. MPIs are written within the limits of the associated Bell Helicopter Textron, Inc. (BHTI) process specification. In addition to the advantages listed above, they provide clarification of the procedures and additional process detail that eliminates interpretations on the shop floor that could result in lack of control and repeatability.

MPIs generally fall into two categories. They are either a principal procedure for general usage or a specific procedure for a specific part. Examples of principal procedures are MPIs for equipment, tools and facilities, tool preparation, material preparation and control, fabrication of kits, trimming of uncured material, thermocouples, debag and cleanup operations, and subassembly and assembly. Examples of specific procedures are MPIs for lay-up, compacting, debulking, hot drape forming, bagging for cure, and cure cycle.

MPIs also allows for changes in procedures without having to rewrite the engineering process specification. MPIs are written and controlled by manufacturing development personnel. As long as changes are below the level of detail in the manufacturing specification, they are approved and signed by only the Manufacturing Development Department, the Engineering Methods and Materials Laboratory, and the Manufacturing and Product Assurance Department.

To assure the smooth operation of the MPI practice, BHTI has established a departmental instruction for the preparation, release, maintenance and control of MPIs.

For more information see the Point of Contact for this survey.