Designing the Products On-Time. Lean Accounting for NPD – Blog #6

Designing the Products On-Time

Lean Accounting for NPD – Blog #6

Lean organizations do not put a great deal of stress on the traditional project planning methods that are so prevalent throughout traditional new product development. Here’s some reasons for this:

In simple terms, there are four steps in the design process for a significant product and/or service:

  • Voice of the Customer (VOC) is where the team gains deep knowledge of the customers needs.
  • Quality Function Deployment (QFD) is where the team converts the customers needs into features of the product, the production and delivery process, and other services that will best fulfill the customer’s needs. QFD is also where the price of the product is determined based upon the value created for the customer by the product features.
  • Questions. The selected design features will raise a lot of questions that need to be answered before the design can be completed. These questions may require experimentation and the development of new technical knowledge. Other questions will relate to how the product will be made and delivered to the customers. Other questions will relate to how the product will be marketed. There will also be questions related to the costs and lead time of the design process and the product when it goes into production. All these questions need to be answered before the product design can move ahead. How can this work be done without a detailed project plan connecting all the tasks together?
  • Design the Product.

Here’s an example:

The design team has completed the VOC and QFD for a new device that is used to securely support patients during radiation treatment. They have determined that 104 questions must be answered in order for them to have enough understanding to begin the design of the product. Some of these questions relate to the composite materials needed, others to the clinical requirements, and others related to design-for-manufacturing.

The design team has broken the questions down so that – as best they can estimate – each question can be answered with 2 days of work. This is a key issue of Lean NPD. To establish a “cadence” for each of the tasks and work to have every task broken down to the same cadence; in this case 2 days.

The total lead time for the delivery of the design is 10 weeks in order to meet the customer’s schedule, and the design team need to complete the question phase in 5 weeks. This is depicted on a “Slope Chart”. The Slope Chart is a simplified version of a Cumulative Flow Diagram.

How many people are needed to complete these 104 questions?

Takt Time = 5 weeks / #Questions = (5*5) / 104 = 0.24 days

Cycle Time = The Cadence = 2 days

# People Needed = Cycle Time/Takt = 2 days / .24 days = 8.33

The team assigned 6 people for 3 weeks and then 12 people for the second remaining 2 weeks.

Tracking the Progress

As the weeks progress, the team reports each day the progress with answering the questions.

The green line shows the actual number of questions completed each day and how this is tracking towards completing on time.

This simple visual chart shows how well the work is progressing against the number of questions that are required to be answered. If the green slope falls behind, then the team will need to work out how to get the work completed on time. They may need to remove some questions, add some more resources, or extend the time. These decisions can be made using the simple decision-making tools described in the previous blog (blog #5).

It is common for additional questions to develop as a result of answering the initial questions. Alternatively, as the questions progress, the team may find that the number of questions reduces. When this happens, the team recalibrate the chart and the adjusts the capacity as required,

Moving into the Design Stage

This same approach is used as the team moves from the questions stage into the design and delivery stages of the projects. There are some variations on this approach to the scheduling and controlling of the design process. In many projects it is difficult to bring every task down to a single desired cadence. In which case it is common to assign “dots” to the tasks. A “1 dot” task is expected to take less that the cadence. A “2 dot” task is expected to take a cadence. And a “3 dot” task will take more than a cadence. While the team recognizes the variability and the difficulty of estimating the required time, this “dots” approach gives some flexibility to the process. The chart will no longer show the number of tasks on the y-axis, it will show the number of dots.

A second variation is to use a full Cumulative Flow Diagram. This is a more complex diagram and can be used for more complex processes. The cumulative flow diagram does not just show the number of tasks completed each day, but also shows the number of tasks being introduced into the queue of work each day. There are 3 lines on the chart. The plan line, the number of tasks introduced, and the number of tasks completed. This enables the team to control the queue and to ensure that they do not add too many tasks into the queue and extend the lead time of the project.


In the next blog (blog #7) we will discuss how the design team’s daily review is addressed.