Taiichi Ohno’s devised the seven wastes as part of the Toyota Production System. There are 7 categories of the major wastes typically found in mass production. Here we list a basic synopsis but it should be noted that the explanations and waste examples are far from exhaustive. Also note that the wastes can be applied to any environment.
Muda Meaning
-Futility
-Uselessness
-Wastefulness
Two Types of Muda
Muda Type I: non value-adding, but necessary for end-customers. These are harder to eliminate, as non-value adding, they may still be necessary.
Muda Type II: non value-adding and unnecessary for end-customers. These contribute to waste, incur hidden costs, and should be eliminated.
Waste can be avoided by identifying which activities add value and which do not, then progressively work to improve or eliminate them.
Transport
This is the movement of resources further than necessary, from one location to another, that doesn’t add any value, such as: parts, products, people, tools, inventory, equipment. Unnecessary transportation adds no product value and the customer should not pay for it.
-Transportation takes time.
-Can lead to damage and defects.
-A wait for product to be delivered due to delays.
-Extra resource costs incurred.
-Addition of unnecessary process steps.
Inventory
Inventory is having more than the minimum stocks necessary for a precisely controlled pull system. Holding far more goods and services before the customer wants them using a Just in Time (JIT)“ system; and conversely having a ‘waste’ ‘Just in Case (JIC)” inventory system.
-Too much inventory drives up costs.
-Capital invested in producing or purchasing the inventory.
-Inventory must be stored, managed, moved, and insured.
-Obsolete inventory must be disposed of.
-Moving inventory causes injuries, extended production time and more.
Motion
The waste in motion includes any unnecessary movement of people, equipment, or machinery. Motion refers to the damage and costs inflicted on what creates the product.
Motion within a process should be minimised to also reduce Muri, overburden on workers.
-Lowering work efficiency.
-Wear and tear on equipment.
-Repetitive strain injuries for workers.
-Shuffling files to get to the right one.
-Looking for parts, tools, documents, etc.
Waiting
Whenever the product is not in transportation or being processed. When goods or tasks are not moving, the waste of waiting occurs. It is the act of doing nothing or working slowly whilst waiting for a previous step in the process.
-Time required to perform work.
-Operators standing idle as machines cycle, equipment fails, needed parts fail to arrive,
-Staring at the hourglass on a computer screen.
-Cost of the time spent waiting will come direct from profit.
-Unbalanced, unreliable processes causing delay.
Over-Production
Waste is anything that the customer is not willing to pay for and producing more means the customer’s demand has been exceeded. Over-production occurs any time an upstream process produces more than a downstream process can use right away.
-The worst form of waste because it contributes to the other six.
-Leads to excessive inventory (more waste).
-Big batches in the process instead of single or limited batches.
-Using a ‘push’ production system instead of a ‘pull’ production system.
-Hiding defects inside the work in progress (WIP).
Over-Processing
Any unnecessary steps or processes that do not add value to the end product or service. Doing more to a product than is required by the end-customer results in it taking longer and costing more to produce. Adding work that is not required.
-Adding extra features to a given product that nobody is going to use.
-Performing unnecessary processing, typically from poor tool or product design.
-Using components higher quality than absolutely required.
-Generating more detailed reports than needed.
-Running more analysis than needed, over-engineering a solution.
Defects
Defects occurs when the product is not fit for use. In most cases, this shows up as a product or service not conforming to a specification. Defects are when products or service deviate from what the customer requires or the specification.
-Cause additional inspection, rework and scrap.
-Rejects and rework add additional costs to the operations.
-Incorrect service or parts either in house or delivered to the customer.
-Lost customers who will take their custom elsewhere.
-Defects are the undesirable results of an error in a process.