For every OEM like Toyota, there are thousands of small-to-medium manufacturers (SMM) whose operations simply do not match those of an assembly line. Most SMMs tend to be HMLV (high-mix low-volume) custom manufacturers, or worse, they operate like job shops. The Toyota Production System (TPS) is not the complete solution for these HMLV (high-mix low-volume) manufacturers because many of the revolutionary operational strategies of the TPS are primarily suited for assembly line production. The majority of the popular Lean tools were never designed to handle the operating conditions and constraints of high-mix low-volume (HMLV) manufacturing facilities, as shown in Table 1.
Table 1 TPS/Lean Tools to Use or Avoid for HMLV Manufacturing
TPS/Lean Tools to Use for HMLV Manufacturing |
TPS/Lean Tools to Avoid for HMLV Manufacturing |
Strategic Planning |
Value Stream Mapping |
Top-Down Leadership |
Assembly Line Balancing |
Employee Engagement |
One-Piece Flow Cells |
5S |
Product-specific Kanbans |
TPM (Total Productive Maintenance) |
FIFO Sequencing at Workcenters |
Setup Reduction (SMED) |
Pacemaker Scheduling |
Error-Proofing (Poka-Yoke) |
Inventory Supermarkets |
Quality At Source |
Work Order Release based on Pitch |
Visual Controls/Visual Management |
Production based on Level Loading (Heijunka) |
Product and Process Standardardization |
Mixed Model Production with Takt Time |
Jidoka |
Right-sized Machines |
Standard Work |
It is essential that HMLV manufacturers embrace the philosophy and principles of Lean. But, they must also carefully select a manufacturing strategy that suits them. In turn, their choice of manufacturing strategy will force them to significantly change the methods and tools they use to implement that strategy. Today, there is a clear-cut need for a viable production system model that could be implemented by the thousands of small-to-medium (SMM) high-mix low-volume (HMLV) manufacturers in the US alone!
Advancing Lean to High-Mix Low-Volume (HMLV) Manufacturing
JobshopLean is essentially a modification of the five-step process for implementing Lean proposed by James Womack and Daniel Jones in their bestseller book published in 2003, Lean Thinking. Unfortunately, while the Womack-Jones process for implementing Lean may be universally applicable in bits and pieces, many of the Lean tools that are used to implement that process are unsuitable for HMLV environments. In the case of any HMLV manufacturer, such as a CNC machine shop, fabricator or custom forge shop, the TPS/Lean tools are incapable of implementing the three major steps in the Womack-Jones process for implementing Lean:
How JobshopLean Differs from Lean
JobshopLean is similar to, but also differs from, Lean as follows:
Additional Reading
Please click here to listen to a seminar JobshopLean vs. ToyotaLean: Why the Toyota Production System is Unsuitable for Jobshops.
Please click here to access the article The Robust and Reliable Job Shop: Going Lean Requires More than the Traditional Lean Tools.
Please click here to access the article Adapting Lean for high-mix low-volume manufacturing facilities. Gear Technology, (2012, August), 10-12.
Please click here to access the report Recession-Proof your Shop the Lean Way.