What is your experience with "first run capability" as an ongoing process metric?

"First run capability" is a relatively simple concept with a direct method of calculation. The concept is reflected in the statement below:

"If you loaded the process inputs with enough raw material and parts to produce, say, 10,000 parts, how many would be produced if there were no repairs or other corrections to the process?"

If 9,000 parts were produced, your first run capability would be 90%. The objective then is to track first run capability and use the data to improve the process.

To further illustrate the concept suppose there was a 3 step process. Each step in the process passed 90% of the work presented to it. Then your first run capability would be 72%. (0.9 x 0.9 x 0.9). The 28% that is lost represents waste and/or added cost to repair. There are added quality concerns about the 28% the deviate from the straight-through process.

Comments and/or experiences with this metric?

Outside audits

What is your experience with outside audits (i.e. ISO/TS)? How helpful are these audits in ensuring your company meets the true intent of it's policies and procedures?

Optimizing a process

A recent small assembly job was reviewed for the potential to optimize the profit. There were 3 manufacturing operations all performed by one person. After Op #1, this person turned around and walked 3 steps to Op #2. He then walked to his left 5 steps to Op #3. To pack the part, there were 3 more steps, plus 3 more steps to return to op #1.

Total cycle time was 80 seconds with 14 seconds devoted to walking (17% of the time). The job elements were broken down by Operation number and various theoretical cycles were generated by utilizing a 2nd head for portions of the process. Finally, a new process was developed in which a 2nd person performed all operations after Op #1 and still had some time (inherent delay) to prep material for Op #1. A significant factor was that the time to walk station to station was utilized by the inherent delay (extra time) in the 2nd person's tasks.

A financial analysis of the new process showed that the cost of the added person was more than off-set by the increased revenue due to reduced cycle time.

Conformance to Specification vs Target Value

One view of manufacturing quality is that all measured characteristics must be within the specification or tolerance ranges. There is another view that value of the average of a number of measurements should be as close to a specified "Target Value" as possible. I am a strong proponent of the Target Value system for a lot of reasons.

What system do you favor and why? Is there an opportunity for readers of this blog to initiate a dialog on this topic?

Kick off

All areas within manufacturing and quality are open for discussion. Once we get a critical mass of knowledgeable men and women, we should be able to become a valuable resource for visitors to this blog.

To start off, here is a list of areas which we could discuss:

Manufacturing planning
New equipment approval
Machine capability
First run capability
Process optimization
Capability determination
Quality monitoring
Quality control charting
Statistical analysis
Target Value
Design for Manufacturing
Design of experiments
DFMEA
PFMEA
Design guides
Failure analysis
Group problem solving (8D)
Cost reduction and TQCM

This list is not limiting and other topics are welcome; however the above items are areas where I have varying degrees of experience.