It’s easy to recognize waste when you think of unused scrap or parts left over from the manufacturing process. They might be piled in a heap, taking up valuable space on the shop floor; the material will go unused, and the money spent on it will also be lost. This type of production waste isn’t hard to identify.
But what about other, less obvious kinds of waste? Like the waste of time and capacity that happens when you’ve finished one process and are waiting to begin another? Or the waste of movement that happens when you repeatedly find a tool out of easy reach and have to walk across the room to grab it? Or the waste of untapped human skill that could be put to valuable use? One of Lean’s greatest benefits is that it assists us in identifying – and eliminating – waste in the forms and places that we often don’t think to look.
In Lean, there are eight forms of waste:
1. Overproduction – Often considered the worst of all wastes because it creates conditions for other kinds of waste, overproduction is making too much or producing too quickly for customer demand.
Solution – Produce only what is needed by the customer, and only as much as you have the capacity to process downstream. Stacks of inventory waiting in queue is a sign of overproduction waste. Focus on “pull” rather than “push” production, which means you let customer demand, not your own production capacity, establish the rate and quantity of production.
2. Waiting – idle time while waiting for material, people, information or machines is all a form of waste.
Solution – Review or revise standardized work processes so that gaps between steps are minimized. Find ways of adding value to production during downtime.
Tooling Solution – As much as possible, utilize tooling that allows you to minimize downtime due to machine maintenance. Choosing tooling with a longer grind life will keep your machines productive for longer stretches of time, limiting waiting and downtime. Also, implementing flexible tooling solutions such as an adjustable V die in your press brake, or staged bending limits the downtime that occurs during tooling changes.
3. Transport – any form of transport that isn’t a necessary part of the production process is waste. Relocating materials to a temporary location or conveying them further than necessary fits the definition of Lean waste.
Solution – Locate sequential production steps as close together as possible and create an automated process for any part transport that can’t be avoided. Eliminate overproduction so conveyance to a temporary holding location isn’t needed.
Tooling Solution – Where possible, implement tooling that allows for maximum machine flexibility, so you are not transporting tooling between machines. For punching operations, tools that allow you to bend or stamp in a turret like Opti-Bend® or an in-machine tapping tool serve this function.
4. Overprocessing – This is considered the most difficult of wastes to identify. Overprocessing means you are putting more work or effort into a part than the customer needs or will pay for.
Solution – Overprocessing requires gaining a clear understanding of customer expectations and making sure your part matches those requirements without additional, unnecessary elements. It’s also important to make sure your part is well designed, so that the least amount of processing is required to manufacture it.
Tooling Solution – Order a special tool that is designed to optimize efficiency in your application. Make use of tools that take away the need for secondary or finishing applications, such as Wilson Wheel® tools, which don’t create burrs or nibble marks.
5. Inventory – Excess stock of anything is wasteful. It takes up space that can be put to valuable use and can also be a safety hazard. Furthermore, if that part stops being needed, the excess inventory will be useless.
Solution – Evaluate your process to make sure that you aren’t producing more than the customer demands. Review standardized work to make sure that processes are being followed, and make adjustments as needed. Make sure employees are comfortable with flowing just one piece or a small lot of parts at a time.
Tooling Solution – Decrease inventory backup by making sure tool set-ups are as short and efficient as possible. For press brake operations, utilizing quick clamping systems will decrease inventory waste by making tooling changes fast.
6. Motion – Any movement of people, material, paper, information or other resources that does not add value to the product is wasteful.
Solution – Layout the shop floor in such a way that movement is minimized. Organize tool storage close to machines so that tool loading and unloading does not require much walking on the part of the operator. Make sure that each machine has its own set of peripheral tools (such as measuring tools, hand tools, etc.) needed for operation, so workers don’t need to go looking for them around the shop. Always return tooling to its designated place.
Tooling Solution – Tooling cabinets such as the Xtreme Storage Cabinet make it easy to store tooling next to the machine. They can also be labeled so tools can be easily located and returned after use.
7. Correction (of defects) – Waste from correcting errors or defects involves both the processes and materials that created the defective item, as well as those needed to correct it. Defective production results in additional time, materials, energy, capacity and labor costs.
Solution – Go to the source, so the defects don’t happen: find out if there are common defects and identify what is causing them. If it’s the same problem that continues occurring, alter your process so that those defects don’t happen anymore. Build “error-proofing” steps into your process that prevent defects from occurring.
Tooling Solution – The Express Crowning™ system corrects deflection, or the “bowing” of parts by straightening the beams of the press brake. This solution stops defects before they happen.
8. Underutilization of People – This waste is not always included in the list of lean wastes. The underutilization of people occurs when you don’t make use of an employee’s full skills, knowledge or abilities.
Solution – Orient company policies so that employees are empowered to implement and suggest new improvements. Make sure employees are trained to employ best practices, and encourage cross training.
While these less obvious forms of waste may seem insignificant, when you add up the seconds of time or cents of dollars lost due to these small inefficiencies, you will be surprised by how much your organization is losing over time.
Lean’s definition of “waste” is anything that adds cost or time without adding value.
Given that definition, it’s almost impossible to get rid of waste in its entirety. However, it’s important to be able to identify it, and to create processes to minimize it wherever possible. Most lean organizations are dedicated to "continuous improvement" of their processes so that they are always on the path to better elimination of waste.
Wilson Tool has provided lean solutions to sheet metal fabricators for decades. Don’t hesitate to contact your Wilson Tool sales engineer for assistance with making your operation leaner.
* Information for this article provided by The Lean Pocket Guide: Tools for the Elimination of Waste! MCS Media, Inc. 2007.
January 09, 2019