Volume 7 Issue 6 June 2006
Wasting Away to Nothing
Getting Leaner Through Waste Reduction
by Kevin Zuege
Let’s not be wasteful here and get right to the point. Less waste means a leaner manufacturing operation.
Cut the fat, and you’re left with the minimum of people, time, equipment, materials, parts and space required to add value to your product. Anything above these minimums is considered waste.
The lean manufacturing approach identifies and eliminates waste through continuous improvement. This process helps insulating glass (IG) and window fabricators reduce costs and improve service and quality. To succeed, fabricators should reduce the following common forms of waste:
Defects: In IG and window fabrication, defects often arise from materials or processes that create the need for repairs or reworks. For example, if a manufacturing process leaves excess sealant around the perimeter of an IG unit (IGU), the unit may stick to a handling cart and break when removed with force. Here, one defect–the process–leads to another–the broken unit.
Motion: Any extra motion required to stage materials, parts or finished units is considered waste. Systems with fewer components require less motion for materials to be brought to the workspace. Fabricators can reduce wasted motion by choosing systems that allow grid insertion in line, move completed IGUs directly to a glazing line and do not require a separate IGU cooling area. Systems that limit handling through the use of power conveyors and butterfly topping stations also reduce motion.
Conveyance: Extra effort spent to transport materials, parts or finished goods into or out of storage or between processes indicates conveyance waste.
Reducing secondary processing will limit some conveyance needs. For example, a single-component spacer system will require less conveyance of raw materials from the warehouse to IG production areas compared to a multiple-component system.
Fabricators may consider a different plant configuration to address conveyance waste, such as adding work cells that group machines in a tight sequence to permit single-piece flow and flexible deployment of labor.
Overproduction: Producing more finished products–or parts–than are needed before they are needed is another form of waste. For example, producing stock glass creates a Work-in-Process (WIP) situation. In other words, the glass is a part of a complete IGU, and it will need to be stored WIP until that size unit is ready for production.
Batch producing IGU sizes may also lead to overproduction. Fabricators should try to run at the same pace as customer demand. Otherwise, they end up with the next form of waste.
Inventory: Transportation and storage costs associated with maintaining excess inventory of raw materials, parts or finished goods creates unnecessary waste. Storing WIP and unsold units from overproduction leads to extra conveyance. Fabricators can limit additional conveyance needed for storing excess raw materials by streamlining order purchasing.
Over-processing: Processing waste occurs by doing more work than necessary. For instance, single-component IG spacer systems are ready to glaze, while multiple-component systems may encounter additional processing time to clean up excess sealants. Extra finishing work, such as edge deletion of low-E glass for spacer and sealant compatibility, may not be needed with an alternative system.
Waiting: Any non-work time spent waiting for tools, supplies, parts and other inputs is considered waste. Waiting arises from gaps in input flow from station to station. Reduce waiting by minimizing the number of working parts in a system, balancing work at each step of the process and choosing systems with the fewest possible process steps and number of components to be staged.
Companies may engage in several activities to identify and eliminate waste. We’ll address some of these activities in a future column. To do so here would just be wasteful.
Kevin Zuege is director of technical services and an efficiency expert for TruSeal Technologies Inc.
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