The objective of Lean waste reduction in manufacturing is to reduce the 3Ms in order to achieve a business’s improvement in terms of performance. These 3Ms come from three Japanese terms, Muri, Mura and Muda, which are believed to contribute to a company’s inefficiency – and potential downfall.
Muri means over-burden but also refers to absurdity and unreasonableness. Avoiding Muri is to standardise work.
Mura refers to unevenness, looking into the inconsistency of a company in terms of physical matter.
Muda means waste and is relatively the most important term of the three. Reducing waste is perceived to increase the profitability of a business.
When focusing on Lean waste reduction within production and manufacturing processes, the Seven Wastes are used to help assist in identification of the types of waste found. They are non-value added (NVA), absorbing time and costs, and must be seen as the enemy.
The seven wastes are abbreviated to the acronym “TIMWOOD”: T – Transport, I – Inventory, M – Movement, W – Waiting and delays, O – Over-production, O – Over-processing, D – Defects.
Transportation of product and work in progress is necessary, but it must be controlled in terms of times and distance. Each turn a product is moved, it stands the risk of being damaged, lost, delayed, and so on. More critically, the longer a product moves around, the longer there is no value being added to it, as it is not being physically transformed. Transportation does not make any transformation to the product that the consumer is supposed to pay for.
Producing something to sit around and wait for the next process which doesn’t start straight away is non value added. The product is waiting and not adding value sitting on a job rack somewhere. The problem is, the more inventory the worse the situation is, as this can be in the form of work in progress, raw material or finished goods.
This is similar to transportation, but movement refers to movement of operator and equipment. Again, think of the fact that it cannot be adding value when operators move around to search and find things. It’s the same with equipment: if you are spending time lumping equipment around, you cannot be using it to add value and make money, plus there is an increased chance of damage.
When work in progress and goods are not being worked on, they sit there waiting – waiting for the next process.
This is typical of traditional “batch and queue” methods. Waiting means that product is costing the company money and not adding value.
This is the worst of the seven wastes as it incorporates all the other wastes as well. Overproduction occurs when processes are not efficient. If change-overs are too slow, one would overproduce; if quality is poor, again, one would overproduce – just in case. The problem is thinking, for instance: “the customer may want 10 parts, but we will produce 20 parts and store them…….”
If you don’t know exactly what the customer wants, how can you align your processes to what the customer needs? Overprocessing is about completing work which is more than the customer really wants. Think of mowing your lawn: would you cut each blade of grass with a pair of scissors and then measure it with a ruler? Of course not. Mowing the lawn with the mower is sufficient.
You can’t add value twice! If you scrap a complete job, you wouldn’t go to your customer and ask for an extra £5,000 (or whatever the cost may be) to reprocess a job that you couldn’t do right first time! Your customer would think you are mad and go elsewhere!
Every bit of scrap costs money and time: money for the resources to pay staff, lighting, etc, to do it again, but also means that you have to push another planned job back in the queue in order to get the rework out. It’s all cost and less cash for the business.
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