Reducing Excess Motion
One of the wastes inherent in manufacturing operations is the excess motion of employees. In a typical manufacturing operation, we often find people walking around the plant.
Executive Director, Center for Manufacturing Systems, New Jersey Institute of Technology
One of the wastes inherent in manufacturing operations is the excess motion of employees. In a typical manufacturing operation, we often find people walking around the plant. Recently, I was working in an assembly plant. It initially struck me that many employees were supposed to be assembling products, yet they were actually somewhere else. When I asked about this, I was told that the employees were getting materials; looking for work instructions; searching for tools; walking to first-piece inspection; or walking to the supply cabinets.
Excess motion is relatively easy to remedy by employing point-of-use-storage techniques. So what should be stored at the point of use? In short, everything possible, including tools, supplies, inventory, work instructions, reference material and samples, and test and inspection equipment. Let's examine each to determine the benefits and practicality of point-of-use-storage.
Tools: In past columns, I have discussed the advantages of shared tooling when compared to individually-owned tooling. One major objection is that "others" will steal (really meaning they won't return) these centrally located tools, so they won't be available when needed. From my experience, the reported "theft" of tooling is exaggerated; however, when this is a real concern, some type of marking on the tools can help. Painted handles or color-coded heat shrink tape will clearly identify tools. If each workcenter is assigned a color (or two colors if there are multiple workcenters in the plant), there is a greater likelihood that tools will remain in their assigned locations. After all, a blue/green tool showing up on a red/black toolboard will really stand out.
Supplies: As is the case with tools, storing supplies at workcenters requires discipline. Storing supplies in a size-limiting container will provide the benefits of immediate availability, without generating an excessive supply. I recently worked with a company that stored shop towels in each work area. The problem was that workers in each area tended to hoard these shop towels. In fact, it was not unusual to see ten or more boxes of shop towels in some areas, which represented about 2 months of typical usage. To combat this practice of hoarding, the company took away the cabinets where these shop towels were being stored and replaced them with dispensers sized to hold about 1 week's worth of shop towels. Whether you are dealing with shop towels, or any other consumable supply, point-of-use-storage in a carefully sized container can be helpful in reducing wasted motion, without breaking the supplies budget.
Inventory: When used in just one area, inventory should ideally be stored in that area. In most cases, space constraints prohibit large quantities of raw material from being stored at a workcenter, but this can actually work to a company's advantage. As with supplies, raw material and other inventory can be stored in the workcenter in a carefully sized location. A "dock-to-area-of-use" concept can be employed, with small quantities being delivered at frequent intervals. Although such a concept requires cooperation from suppliers, it offers the added benefit of improving cash flow, as less money is tied up in inventory. Companies also find their inventory reconciliation process is simplified, as the people using the inventory can more easily account for it during physical inventories or cycle counts.
Work instructions (reference materials and samples): There can be a benefit to keeping work instructions and reference materials at the point of use. However, the key to doing this successfully is proper control. It doesn't matter how you achieve this control, but this must be an integral part of your document management process. Any benefit you gain from saving time and motion by having work instructions at the point of use can quickly be erased if you find yourself using out-of-date or inaccurate documents. Fortunately, technology can help with document control. For example, the placement of printers at the workstation so that only the latest revisions can be generated, or placing more computer screens on the shop floor to reduce the need for hard copies, can provide control for point-of-use-storage of work instructions.
Test and inspection equipment: Today's operators are expected to be responsible for their own quality, so it is becoming more common for operators to be given the tools and equipment to check their own work. Keeping inspection and test equipment in assembly and machine shop areas reduces the amount of time that people and products move around the plant.
Everything cannot be stored where it is used. If you look at your own operation, you may find that more can be stored there than currently is, and your staff will spend less time moving and more time doing.