A shoe factory in Bandung has 200 workers, but 40% of their working time is spent waiting: waiting for delayed raw materials, waiting for machines in line, waiting for inspections that are not yet completed. Their daily output could actually be achieved by 120 people if the flow is improved. This is not a matter of worker skills or motivation. It is a systems issue. And Lean Manufacturing was born precisely to address problems like this.
Lean Manufacturing is rooted in the Toyota Production System (TPS) developed by Taiichi Ohno and Eiji Toyoda after World War II. At that time, Toyota had to compete with American automotive manufacturers with far more limited resources, so they could not play in volume; they had to focus on efficiency. The result was a production system that changed the way the world views manufacturing: not how much can be produced, but how much value can be delivered without waste.
8 Wastes That Quietly Kill Productivity
Lean identifies 8 types of waste that must be eliminated: Transportation (unnecessary movement of materials), Inventory (excess stock tying up capital), Motion (unproductive worker movements), Waiting (waiting time at each stage of the process), Overproduction (producing more than needed), Overprocessing (excessive processes that do not add value), Defects (defects requiring rework), and Skills (underutilized human resources). The acronym TIMWOODS helps to remember all eight.
In practice, the most often unnoticed wastes are overproduction and waiting. A factory that prides itself on 100% machine utilization but has finished goods piling up in the warehouse for 3 months is actually engaging in massive waste. Lean teaches to produce only what is needed, when it is needed, in the amount that is needed—a principle known as Just In Time (JIT).
Value Stream Mapping and 5S: From Theory to the Production Floor
Value Stream Mapping (VSM) is one of the most powerful Lean tools. VSM visualizes the entire value flow from raw materials to products in the hands of customers, including all information and materials that flow. With VSM, managers can visually see where bottlenecks occur, how long inventory waits at each station, and what percentage of time truly adds value.
5S (Seiri/Sort, Seiton/Set in Order, Seiso/Shine, Seiketsu/Standardize, Shitsuke/Sustain) is often underestimated because it appears to be a “cleaning program.” In fact, 5S is the foundation of a sustainable Lean system. A well-organized workplace reduces the time spent searching for tools, facilitates the identification of abnormalities, and creates visual standards that allow anyone to detect abnormal conditions in seconds. Toyota factories around the world start their shifts with 5S not as a ritual, but as an operational discipline.
Takt Time, Heijunka, and Kaizen: Perfecting the Production Rhythm
Takt Time is a key concept in Lean: how often a unit of product must be completed to meet customer demand. If customers need 480 units per 8-hour shift, the Takt Time is 1 minute per unit. All workstation designs and machine capacities should be aligned with this Takt Time, not with the maximum machine capacity, which often far exceeds actual needs.
Heijunka (production leveling) and Kaizen (continuous improvement) complement Lean as a living system. Heijunka ensures that fluctuating demand does not create waves of workload that burden operators and machines. Kaizen ensures that improvements do not stop after one project is completed, but continue as part of the operational DNA. In the Indonesian manufacturing environment, which often faces variations in demand and limited human resource capacity, both concepts are highly relevant for gradual implementation.
References:
- Ohno, T. (1988). Toyota Production System: Beyond Large-Scale Production. Productivity Press.
- Rother, M. & Shook, J. (2003). Learning to See: Value Stream Mapping to Add Value and Eliminate Muda. Lean Enterprise Institute.
- Womack, J.P. & Jones, D.T. (2003). Lean Thinking: Banish Waste and Create Wealth in Your Corporation. Free Press.