Now that we’ve locked in our design and ordered parts, we need to continue planning our manufacturing process for when the parts arrive. Earlier we talked about the key thoughts and principles about Lean Manufacturing by going through an example from Joe’s Garage. The key take a ways were:

  1. Reduce waste by minimizing inventory (Muri) by having a few interchangeable components available from local suppliers that quickly allow a prototype to be built and tested.
  2. Build custom jigs and careful processes at each station so that anyone can make a part, and only in the correct way.
  3. Having a pull through system to reduce unevenness in workload (Mura) where someone starts with a part that’s needed and follows it through to final assembly, creating a sense of ownership and pride, and allowing the number of workers on the assembly line to more easily scale with demand.

When combined with the principles of Kaizen (continuous improvement), and 5-S (Sort, Sweep, Systemize, Standardize, Sustain), we have a start to our Lean manufacturing system. The next step is ensuring that we build quality products. Let’s revisit Joe’s Garage:

The second volume in the Joe’s Garage series is about quality. Joe, now knowing the basics of Lean, decides to help is neighborhood build modular cat-scratching posts. Along the way, Joe learns a number of basics about manufacturing quality products. 

  1. Joe must first decide how to define quality. His options are:
    1. Quality is a flawless products that work every time.
    2. Quality is making the customer happy.
    3. Quality is meeting customer requirements.
    4. All of the above.
  2. Joe knows that customer requirements are important for the design. His neighbors are concerned about some of the glues he plans to use in the design and added a requirement that “Glues must be safe”. Joe should:
    1. Assure the clients that the glue is fine and used commonly in household items.
    2. Refer to government and standards organizations to ensure the glue is acceptable for use inside a house with furniture.
    3. Try it and see.
  3. Joe knows that to meet his customer specified requirements, he needs to design for those specifications and requirements. How does he know when he has satisfied a requirement?
    1.  Each customer requirement is directly connected to an un-ambiguous design specification to know when it’s met or achieved.
    2.  Joe has created a quick measure to determine whether each specifications is in compliance.
    3. Each layer of the manufacturing process (raw materials, to parts, to final assembly) has individual checks.
    4. All of the above.
  4. Joe is now getting ready to finalize the design for production. He knows he needs to make the design easy to produce right, and difficult to produce wrong. To do this he should (mark all that apply):
    1. Each part should be custom with a unique part number.
    2. Only use a minimum number of standard parts, stored in labeled bins, with similar or identical production processes.
    3. Prototype the process to ensure he has a minimum number of parts that can actually be assembled.
  5. To allow his neighbors to manufacture the parts on their own, Joe is making part documentation. He should (mark all that apply):
    1. Document every process in the design completely both graphically and in simple writing.
    2. Include all necessary steps, resource capabilities, and materials.
    3. Reference prior instructions rather than repeat the instructions.
    4. Have a checklist on the documentation to validate that all objectives are met and nothing is left out.
  6. During production, the neighbors begin fighting over whether some of the pieces are perpendicular or not. Joe should (mark all that apply):
    1. Make sure the production process is consistent with the inspection method at the point of production. He needs to go back to the part documentation and add in a check with a square or other standard agreed upon tool in order to finish the part.
    2. Make sure the tool is not arbitrary or a judgement call, it is marked when something is compliant or not.
    3. Assign a quality control person to check all of the parts.
    4. Make sure all parts are perfect.
  7. Joe thinks he’s close to finishing production but is unsure. He should:
    1. Go around and ask everyone if they are done.
    2. Yell at everyone to FINISH!
    3. Make a standard chart/poster that is completed/filled in when components meet specification.

(Answers: 1-4, 2-2, 3-4, 4-2,3, 5-1,2,3,4, 6-1,2, 7-3)

From all of this, Joe realized that 100% defect-free output requires either a controlled, error-proof process, or 100% inspection. Controlled processes are more efficient than inspection as they are less expensive, with less waste, and reduced cycle time.

So we’ve got some work to do to ensure that we cannot make mistakes with our production processes:

  1. What manufacturing steps do we have for each table?
  2. What documentation do we need for each step?
  3. What jigs do we need to minimize mistakes?
  4. How and when will we inspect to ensure we’ve satisfied our specifications?

For next time:

Theorists need to summarize the key manufacturing steps for the table.

Builders need to start constructing jigs so these steps can be done safely with minimum mistakes.

Pros need to develop a standard process checklist for each manufacturing operation.

Reporters need to add this information to the report.

Liaisons need to develop a build-progress poster/chart to track progress.