As you surely know, it is more efficient to produce larger quantities. This is the economy of scale. In a recent post I talked about the Power of Six, a rule of thumb for the relation between lead time and cost. In this post I will show you a rule of thumb for the relation between quantity and cost. Credit for this rule goes to Juan Carlos Viela.
In my previous posts I explained how POLCA works and discussed the pros and cons of POLCA. In this post I will explain how to calculate the number of POLCA cards. While POLCA is overall a feasible method, I do have some critical comments on the method to calculate the number of POLCA cards.
In my previous post I described how POLCA (Paired-Cell Overlapping Loops of Cards) is supposed to work. Now let me look at the advantages and disadvantages of the method. Overall POLCA is a valid method of managing job shops. If it is the right one for you depends very much on your production system.
POLCA stands for Paired-Cell Overlapping Loops of Cards with Authorization and was developed by Rajan Suri around 1990. It is sometimes mentioned alongside kanban and CONWIP as a production control system. Let me explain to you how POLCA works. In my next post I look at the pros and cons of POLCA. In my last post of this mini-series, I will show you the calculation for the number of POLCA cards, including some critical comments.
The similar-sounding word Polka is also a Czech dance music and textile pattern, hence the colorful illustration of the polka dots on the left (don’t worry, more technical diagrams will follow below).
Lean has a bunch of advanced but good tools for material delivery, like Just in Time, Just in Sequence, and Ship to Line. Using them is much easier on short distances and with short delivery times. Yet, sometimes you just don’t have the option of short delivery times. This blog post deals with the issues related to long lead times and delivery times.
SMED (Single Minute Exchange of Die) is a very useful tool to reduce changeover time. Reducing changeover time will free up time for other uses. Western management often wants to use this time to produce more goods. However, the rule of thumb at Toyota is to use this newly available time to do more changeovers rather than more products. This increase in changeover has the potential to significantly reduce the lot size, which often has much larger benefits than the additional work time. In this blog post I want to look in more detail at this relation between changeover duration, productivity, and lot size.
In this post I will look at the effects of theft and give you some industry examples.
A famous step toward perfection in a lean production system is a lot size of one. However, few people realize what enormous effort and rigor Toyota applies to achieve this goal. During my visit to a Toyota plant and the APMS conference in Tokyo in 2015, I saw quite a few stunning examples of this quest. Let me show you …