Push Principle

The Push Principle Concept/Term refers to a production system where material and products are manufactured and moved along the production line based on a predicted demand, rather than actual demand. This system operates under the assumption that the customer demand can be accurately forecasted and the production line can be appropriately scheduled to meet that demand.

However, the Push Principle often leads to negative impacts on operations. One of the main problems with this system is the assumption of accurate demand forecasting. In reality, customer demand is highly unpredictable and can fluctuate rapidly, leading to overproduction and inventory buildup. This excess inventory creates significant problems such as storage and handling costs, obsolescence, and potential quality issues.

Additionally, the Push Principle often results in an inefficient utilization of resources. The production line is designed to produce a set amount of product, regardless of actual demand. This can lead to idle time and equipment, increased energy costs, and reduced production capacity. The production process is also disrupted by production line breakdowns, worker absences, and equipment failures, resulting in increased downtime and decreased efficiency.

Another negative impact of the Push Principle is that it can lead to a lack of focus on customer needs. The emphasis is on meeting a predetermined production schedule, rather than meeting the actual needs of the customer. This can result in an overproduction of products that are not needed, as well as a lack of flexibility to adapt to changing customer demand.

To mitigate these negative impacts, Lean Management experts advocate for the implementation of the Pull Principle. The Pull Principle is a system where production is based on actual customer demand, rather than a predicted demand. This system allows for a more flexible and efficient utilization of resources, as well as a greater focus on meeting the actual needs of the customer.

In a nutshell, the Push Principle can lead to negative impacts on operations such as inventory buildup, resource inefficiency, and a lack of focus on customer needs. Lean Management experts recommend the implementation of the Pull Principle as a more efficient and effective alternative. By focusing on actual customer demand, organizations can achieve greater operational efficiency and meet the needs of their customers.

Push vs Pull Principle

The pull principle is one of the main blocks in lean manufacturing > pull manufacturing. The customer demand determines which good will be produced and in which quantity. Max/Min inventory levels are agreed with suppliers and customers. This gives you the opportunity to limit overproduction.

In a pull process a workstation or process step is only being triggered when the downstream processes are free to take the output. This means that only when the customer initiates a need the value adding is started. By this a customer can be seen as internal as well as external one. This is lovely as you make sure that only what you will sell will be produced.

Pull is always to prefer against push. As it allows you to manage the WIP and inventories in between workstations which has a straight impact on your lead time. To successfully install a Pull System you have three choices, it is either the well known continuous flow installed, sequential pull or the replenishment pull.

All three types of connection will help you to achieve different levels of Pull in your environment.

No matter what it always comes down to three factors in your system:

1. Having max one piece of inventory between two process steps

2. Having a fix production sequence

3. and having a max number of parts waiting

Thinking about the three types of a Pull System, the continuous flow system has the highest level of Pull, as all three factors are highly involved. Only One Piece at the time and in between two process steps which means a fixed sequence as well as max one part waiting for the next process step.

If you have several workstation linked in one main manufacturing process working on one final product you have a work cell or simply a production line, depending on the shape you can call it e.g. U-cell.

With the sequential pull system you will have the second best choice of a pull manufacturing. It will have a fixed quantity, the sequence of production is defined but with a max number of WIP allowed between process steps. Basically you will allow buffers in your manufacturing. This can typically be seen in FiFo lines (First in First out).

Last but not least we have a look on the Replenishment Pull. This is in other words your supermarket in the production and your third and last option of implementing pull. The supermarket has a maximum number of components, parts or products waiting to be worked or processed on. But it is not known which one will be next. This type of inventory is usually steered or controlled using the Kanban systematic.

To put it in a nutshell - the following table should be fine to give you an overview: