The “Forever” Rule An attribute of Product Realization

Forever means forever until death do us part. Similar to marriage so should it be with your production processes. If we follow the methodology inherent with Product Realization or the former APQP (Advance Part Quality Plan) we can quickly see the power of adopting the Forever Rule. However, many front-line operational managers will chose to defy or ignore the power of the rule.



Changing machines or a process will add variability to your products and to your process. It may seem minor but to the end customer it could provide significant consequences. As Lean Practitioners, we are always in pursuit of achieving the perfect process. A perfect process that delivers a repeatable product with no variation.


Let us review the traditional 5 steps used for Product realization and how the forever rule plays into our design methodology.


Phase 1 – Program Definition and determining Commercial Viability

During this gate check, the organization looks at the request to quote to determine if it fits the organization’s Mission Vision, Process, and technical capability. If program seems to have merit, we proceed to phase 2.


Phase 2 – Product Definition

Ending with another gate check …we allow the engineers to play with all their toys to create a product or service that the customer is willing to pay for. Hopefully, the engineers are applying some Lean Thinking to minimize part count, make sure tolerances required can be achieved with current technology and that the product can be produced competitively and provide the customer a significant edge.


Phase 3 – Process Definition

My experience has shown me that the use of Value Stream Map during this process step is not only valuable but can be very powerful. Here is where we define how the product will be produced, the product flow through the facility, how much inventory will be required through-out the process and at what stages. Additional tools that can and should be employed during this phase include Process FEMA (Failure Evaluation Mode Analysis) to predetermine potential failure modes, the triggers, and potential corrective actions. Your summary of this phase will conclude with a Control Plan … this is where the forever rule comes into play. You will clearly define the process by machine number and routing … even if you have multiple options, you must select one specific to this process.


Identical machines have different souls and subtle different characteristics … do not let anyone else tell you different. Based on usage, machines and internal components wear at different rates, hence defining their specific attitude. As you create your control plan you will need to run in the background of your system a dynamic Capacity and Staffing modeler to see what the impact of additional through-put will do to the capacity of your process.


Phase 4 – Validation

Here is where we finally convert our definitions into a tangible product. Typically, Validation can occur through 3 phases

  1. Prototype where we make the product using whatever means necessary and probably not using production equipment of tooling.

  2. Beta Production, our first part using production tooling and finally

  3. Trial Run mimicking our standard production methodology and batch size to validate that our run-at-rate estimates can be achieved. Typically, in the automotive world, this where PPAP (Pre-Production Part Approval Process) and PSO (Production Sign-Off) activities are accomplished.


An excellent tool to be employed during the validation phase is the “Problem Follow” sheet which allows for documentation of problems or difficulties operators experienced building the product and how the problem was rectified. This document becomes a powerful resource tool later if a problem during production surfaces.


Phase 5 – C.I. & Feedback

Feedback should be constant and always ongoing. However, at minimum annually, you need to conduct a complete review of the process. Again, the use of Value Stream Mapping will allow the team to conduct an in-depth review of the process. Comparing the “Current State” map to the control plan will allow the team to identify any additional process steps that may have been added, why and are you getting the proper compensation for the additional value add … or should they be eliminated. Is the process running to the planned Value Stream or have we allowed for excess inventory to creep into the Value Stream and why? This is also a good time to review the Visual Standard Work Instructions to determine if they reflect the current best practice or is there a better, safer easier way to conduct the process.


The Forever Rule …

If you enforce the forever rule if you become capacity constrained it will require immediate attention to find methods to increase through put at the constraint. It may require the organization to improve up-time capability of a particular machine.


It will also eliminate “silo” thinking where a department is focused on meeting their numbers for through-put and delivery performance without thinking of the value stream as a whole. What may be good for that particular department today could play havoc further in the value stream … but, hey, out of sight … out of mind, not in my books. If the forever rule is going to be broken … make it an organization wide decision and truly understand the consequences, you make invoke on your team and potentially your customer.


Really … it is common sense and you do not need 6 Sigma to figure this one out.

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