8 deadly wastes. These are what lean practitioners are always looking for to identify the non-value-added activities and ways to eliminate those. Without getting into the weeds of lean toolboxes, we all know 6S (5S+Safety), standardized work, visual management, quality at the source etc. are all great lean tools to eliminate waste after identification. Even though there is no doubt in the value of these tools, one major source of all these wastes is overlooked quite often. Plant layout.
In this article we will address a few fundamental questions about lean layout planning.
What is a lean layout?
A lean plant layout is a layout that optimizes the overall material, people, and information flow in order to minimize the non-value-added activities.
When lean practitioners design a new layout, they usually start with the product family matrix. By developing this matrix, the optimized product families can be defined and the decision on how many product lines or value streams are needed can be answered. Then, depending on the product mix/ volume the types of the product lines can be selected. For instance:
In a low mix/ high volume (LMHV) environment, usually a linear product line with specific takt times, supported by line side sub-assemblies (as needed to support the takt time) could be a logical choice. In this model, each product goes through workstations linearly designed and each station has standardized work content equal to the takt time. Automotive manufacturers usually follow this model.
In a high mix/ low volume (HMLV) environment, usually a cellular production model can better support the customers everchanging demand. In this model, each workstation has a wide range and yet similar capabilities. This provides flexibility to switch between products as they are received. Generally speaking, this model is best fitted for job shops and parts manufacturers.
2 Immediate Impacts of a Lean Layout:
Waste reduction: Regardless of the product mix (LMHV or HMLV), the immediate benefit of a proper layout is to reduce waste. Minimized transportation, elimination of walking between workstations, reduced waiting time, correct inventory level, etc are just a few examples of lean layout. Some of the tangible results are listed below:
Shorter production lead time
Higher throughput
Better visual management and material presentation
Improved responsiveness to the production line issues
Improved quality: Every time a product (raw material, WIP and finished goods) is touched through material handling (with equipment or operations), there is a chance to create a defect. An ideal layout minimizes the material touch points resulting in less chance to cause a damage.
5 Steps to Implement:
Product family matrix: As stated in the introduction section, the starting point is to create the product family matrix, by definition, a product family is a group of district products that goes through a similar manufacturing processes/ equipment. Product family matrix, if designed correctly, provide a good picture of how many production lines are needed to support the operational goals and objectives.
Current State Mapping: The next step after development of the product family matrix is to overlay that on the existing product flow. This exercise effectively identifies the areas for improvement to support the offered product mix.
Future State Mapping: When the pain points are identified through overlaying the material/ operator and information flow on the existing layout, the next step is to develop the ideal state of the flow and the layout
Implementation: Now this is the time to start designing the workstations based on the product mix and offering and build the workstations.
6S and Visual Management: After building workstations and confirming that the flow meets the operations objective, the work areas needed to be as efficient as possible. A strong 6S program is one of the most effective tools to assure the workstation design minimizes the non-value added activities while the material is going through the line.
3 Don’ts:
Don’t build monuments
Monuments are enemies of flexibility. The equipment bolted to the building, don’t let the adjustment of the flows when needed. So, eliminate monument as much as possible whenever and wherever it’s appropriate. Cranes, Hoists, building constraints such as overhead doors, paint booths, etc are some examples of monuments. We cannot eliminate them all the time, but we need to be cautious about their long-term impact.
Don’t rely on forklifts
Forklifts are great material handling equipment and yet one of the major reasons for safety incidents in manufacturing environment. Ideally products should be designed to move in small quantities/ batches and containers. Working with vendors is another way to reduce the raw material packing to be moved by standard or special-built carts.
Don’t use 6S as a schedule for cleaning only
6S is the tool to maximize the efficiency of the workstations by designing the operators, material and tools interaction.