Product and production development have to be in sync. Initially the product defines the production design, but further into the project maturity of the production design limits the flexibility. Late product changes may cause expensive production redesigns and may delay start of production. To avoid this there has to be a solid communication between both groups starting with the digital prototype, and an agreement on design freezes.

A 3 stage approval process may be suitable:
  • process approval:
This approval freezes the general production process. Product breakdown structure, joining technologies, joining steps and product materials are set. All joining points are descibed. Production depth, productivity (output per day), layout and takt are fixed. Part dimensions may deviate only to a limited amount afterwards. The goal is to provide a solid foundation for detailed design, without the risk of expensive changes later on.
  • tools approval:
Some production line components take a longer time to manufacture. This may be due to physics of production (press moulds, hemming beds etc.), complexity and market constraints (i.e. robots) or upfront preparation needs (like building changes, steelwork, conveyors, media supply).
Moulds and beds are hardened and have limited surface flexibility. Adding or removing a few mm may lead to a complete replacement with larger delays and extended costs – and should be avoided. Robots and other components are build to order. There are limited sources. Expect lead times of several weeks or months.
The production field has to be ready for construction of machines. Working on two levels above each other is not possible due to security reasons so building facilities have to be finished in time.
Tools approval is used to limit further product changes to stay within bounds of the already planned production line.
  • final approval:
This is the general design freeze. Manufacturing of short lead components starts. Most changes beyond this point will be expensive and several might pose a risk for your start of production. Change management will become key and implications have to be discussed: is there urgent need of implementation (i.e. product security or homologation issues like failed crash tests or electrical hazards) ? Is it possible to integrate after start of production ? Quick and easy or with high effort ? Will it cause delays or need for extra resources ? Priorities have to be set.
Shift of priority:
Prior to process approval product design has priority over production interests. Production planners will be informed and check for ability of production. But unless there are severe issues changes will be accepted. Between process and tools approval priority starts to shift. Product and production designers become partners working on the same level. After tools approval priority moves to production design. They have to OK any change prior to commitment. With final approval done many changes will be delayed until after start of production.
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