Topic outline

  • Design Work Cells

    • Product Family Grouping

      Cells are the first level grouping of individual machines. There are different approaches to creating cells, but the main approach is to group products that need to be produced into families such that each family can be produced fully within one or a few cells. This means that we have to take into account the characteristics of the product to determine how to fit them together. This video focuses on some common criteria that can be used to make product groupings.

      • Compound Similarities 
      • Machines used
      • Demand per product
      • Machine Capabilities 

      Once we know what happens in the cells we can determine the material flows going into the cell and finished or intermediate products flowing out of the cell. This will be important information for the layout. 

       

       

      Layout Planning and Methods

      Most layout methods use one or more of the PQRST data (Product, Quantity, Routing, Operation sequence, Services, Timing). There are other factors the affect flow patterns, such as, exploded view, assembly chart, Operation Process Chart, Flow Process Chart, Demand Volume Variety. Products can be classified based on their technical characteristics, and from that different methods can be used- How to classify products:

      • Intuitive Grouping
      • Production Flow Analysis
      • Code-based Grouping

        

        


      Quantifying Flow Characteristics. 

      This video explains the Flow Dominance Measure (FDM). In complex situations with many parts and many different operations sequences it can be very helpful to obtain a general idea whether a dominant flow exists or not. This can be determined using the flow dominance measure. FDM considers operation sequence and yearly demand.

       

       

      Examples of Flow Dominance Measures

      This video follows up from the previous about Flow Dominance Measure (FDM). In complex situations with many parts and many different operations sequences it can be very helpful to obtain a general idea whether a dominant flow exists or not. This can be determined using the flow dominance measure. We will be applying the FDM to some examples.

       

       



       

      • Little's Law

        Little’s law is a tool that can help with determining how long job/parts have been waiting, when timestamp data is not readily available. This law explains that the work in process equals the throughput (so the number of products going through the system), multiplied by the total time it takes.

        Part 1

        This video explains the basics of Little’s Law. This law is a basic description of the relationship between the duration of a job, the amount of time the product orders spends on the queues and the throughput.

         

         

        Part 2

        This video goes through a simple example of a single server and the use of Little’s Law formula.

         

         

        Part 3 

        This video explains applications of Little’s Law when there are multiple parallel servers.

         

         

        Part 4

        This video goes through an example with multiple parallel servers and the use of Little’s Law formula.

         

         


        • Kingman's Equation

          Part 1: Introduction

          The Kingman’s Equation provides an approximation of the mean waiting time of the components for a single process based on its utilization and variance.

          This video will introduce the equation. Later videos will expand this formula multiple servers.

           

           

          Part 2: Effect of utilization or the magnifying effect.

          This video describes a part of Kingman’s equation related to the utilization of processes. The higher the utilization, the higher the impact of variation, this has as result longer waiting times and high WIP. Rajan Suri calls this "the magnifying effect".

           

           

          Part 3: Influence of Variation

          This video will focus on the direct effect on waiting time. Previous video explained the basics of the equation.

           

           

          Part 4: Utilization

          This video will explain the basics of the Utilization of a process, machine or service. It is used for many calculations, for example, for the Kingman’s equation or in combination with the Little’s Law.

          No Variation is assumed to understand the basics of the Utilization concept. Variation is considered in the last video of this series: Kingman’s Equation: Influence of Variation.

           

           



          • Designing POLCA cells

            This video concerns the design of a modular cellular layout that can be controlled by means of the POLCA planning and control system. The aim is to design cell that can realize short throughput times. In addition, various Layout types are explained. 

            A POLCA layout is a modular layout where dependent cells are created.  Each cell can produce some of the operations needed for products.  Cells are connected by means of the goods flow.  In case of POLCA the interfaces between cells are coordinated by POLCA cards, so the interfaces are standard, which makes the layout modular. 

             

             


            • Additional Content on Little's Law

               

               


                

                

              • Additional Content

                Lean Work Cell Design