Register now or log in to join your professional community.
The Seven Wastes were first developed into a clear set of principles and rules nearly50 years ago by Toyota Chief Engineer, Taiichi Ohno.
The Seven Wastes of Production:
Over production
Waiting
Transportation
Inventory
Motion
Over processing
Defective Units
1. Over production
Over production involves producing goods over and above the amount required by the market at a given time. This consumes extra raw materials, labour and storage space, increasing the chance of damage to goods, excess handling and builds production queues which extends the lead time of goods on order. By limiting over production we can reduce lead times significantly and improve production flexibility and costs.
TIP: Over production can be avoided by using smaller batch sizes.
2. Waiting
Waiting involves periods of inactivity for people and product. Production lead time is tied up in waiting and queueing for the next sequence in the operation, typically when the flow of material, and information, people or equipment is poor. In a ‘batch and queue’ style process much of the time is attributed to waiting.
TIP: By improving material and information flow, optimising setups and changeovers and reducing the distance between work centres, productivity increases as the manufacturing cost decreases.
3. Inventory
There are many costs associated with holding excess amounts of inventory. This includes the direct costs of raw materials, work in progress (WIP) and finished goods stores, as well as extra handling costs, increased space requirements, more paperwork and possible product obsolescence.
TIP: To reduce inventory levels we can manufacture in small batches and introduce ‘pull systems’ to link production to consumption rates.
4. Transportation/Materials handling
Transporting product between processes is often viewed as “just part of the job”, however it adds no value from the customers’ perspective. Rather than improve the method of transportation the focus should be on the minimising or eliminating it from the process. Significantly, the number of material handling operations is directly proportional to the likelihood of damage to a product. Factory layouts are often the fundamental cause of excess transportation.
TIP: When a factory layout is carefully planned, through the use of mapping product flows and process relationship charts, it not only reduces transportation waste but can also reduce WIP and time.
5. Motion
The waste of Motion refers to any excessive movement by people or machines. For example, walking to and from tool boxes to retrieve items that could be stored at the point of usage, or bending to retrieve commonly used tools from an uncomfortable location. In CNC equipment cycles, sloppy programming can lead to the machine making unnecessary returns to maximum elevation during traverses or slow traverses even when not in contact with the work part.
TIP: Awareness of ergonomics (eg. bending, stretching) within the process has direct economic benefits. Analyse and redesign jobs with excessive motion with the involvement of plant personnel.
6. Over processing
Many organisations fail to ask what the customer actually values. As a result they perform work deemed unnecessary or even detrimental. The most common examples of this is unnecessary packaging, over-finishing parts, or specifying unnecessarily accurate tolerances.
TIP: By determining what it is that the customer is seeking and communicating this to staff with clear standards, inappropriate processing can be eliminated.
7. Defective Units
Processes not capable of producing the required specifications or quality are an obvious source of waste. The idea is to focus on preventing the occurrence of defects instead of finding and repairing defects.
TIP: Quality is improved through the use of standard work, training,5S and continuous improvement tools.
Every organisation can benefit from a ‘Waste Hunt’. This involves creating awareness and understanding of the Seven Wastes within a Blitz team who identify and categorise wasteful activities that occur in the workplace. Once identified, they develop an action plan to address the most significant wastes and reduce or eliminate them altogether. Until you take the time to stop and objectively analyse the operations, you will never truly know how much opportunity exists.
also by implementing SMED to reduce if there is an over-time during setup
OEE Factors introduces Availability, Performance, and Quality...the metrics that you will use to measure your plant's efficiency and effectiveness
Availability takes into account Down Time Loss, which includes any Events that stop planned production for an appreciable length of time (usually several minutes – long enough to log as a trackable Event). Examples include equipment failures, material shortages, and changeover time. Changeover time is included in OEE analysis, since it is a form of down time. While it may not be possible to eliminate changeover time, in most cases it can be reduced. The remaining available time is called Operating Time.
Performance takes into account Speed Loss, which includes any factors that cause the process to operate at less than the maximum possible speed, when running. Examples include machine wear, substandard materials, misfeeds, and operator inefficiency. The remaining available time is called Net Operating Time
Quality takes into account Quality Loss, which accounts for produced pieces that do not meet quality standards, including pieces that require rework. The remaining time is called Fully Productive Time. Our goal is to maximize Fully Productive Time.
Availability = Operating Time / Planned Production Time
Quality = Good Pieces / Total Pieces
OEE = Availability x Performance x Quality
be sure the maintenance schedule of the m/c done on the time.
be sure your labor are trained enough to satisfying the production p[lane.
making bonus if your plane was done
be sure the machine capacity are calculated actually not theoretically
use the right person in the right place
