The secret to reducing throughput times lies in the efficient design of the value chain. The basic principle here is the reduction of waste. As is well known, its origins date back to the beginnings of the Toyota production system in the 1930s, which is why the principle has also become known in Europe and North America under the Japanese term "muda", which can be translated as "waste" or "activity without benefit".
A company avoids such activities without benefit by coordinating all stages of value creation. In production, this means above all
- the integration of suppliers to reduce transportation times,
the shortening of idle times or the reduction of waiting times by focusing on just-in-time production and
the
- a consistent reduction in set-up times.
These measures have a number of consequences: Reducing idle times in the warehouse allows the warehouse to be downsized, which reduces costs. And the increase in throughput time enables orders to be processed much faster, thereby increasing productivity. Both increase the effectiveness of production processes and thus ultimately the competitiveness of the company.
I formulate the principle of avoiding waste in the production process by coordinating the stages of the value chain as follows:
Only when companies have truly understood the vision of one-piece flow do they strive for maximum efficiency. No matter whether in the direct or indirect areas. The principles have the same effect everywhere.
These principles are concretized and systematized in lean management. This is based on a specific sequence of implementation. One prerequisite is the reduction of waste in the workplace. Once this has been achieved,
- it is possible to set up processes that are free of disruptions,
- to get the production process flowing,
- to calculate the so-called "rhythm" and
- to introduce only the suction or the "pulling principle".
Production sites are always socially defined places where people work together. In order to organize production in line with lean management, it is therefore also necessary to create an understanding of the strategy among employees. Below you can find out what this means in detail and how it can reduce throughput times:
1. Avoid waste in the workplace
The first step in reducing throughput times is to avoid waste in the workplace.
This requires
- an ergonomic workplace design,
- optimized material provision,
- optimized set-up time at the machine, e.g. through processes such as . E.g. through processes such as SMED, as well as
- an optimal technology
for the respective process. These goals can be achieved in various ways. I would like to mention two methods here:
One is so-called Cardboard engineering, in which employees model their workplace on a one-to-one scale using cardboard. Only when they are satisfied with the design is it converted into aluminum profiles or similar.
The other method for designing the workplace is 5S or 5A method, which consists of sorting out what is not necessary at this workplace, tidying up, i.e. arranging work equipment ergonomically, keeping the workplace clean, making the arrangement the rule, and finally complying with and improving all points.
How you realize those goals is not important. What ultimately matters is that workstations are set up in such a way that they enable efficient work.
2. Ensure disruption-free processes
The set-up of disruption-free processes is the second step in optimizing production processes and reducing throughput times. Various known methods are also suitable for this, such as
- Jidoka to detect and fix defects during the production process,
- Poka Yoke to avoid mishandling being reflected in the final product, or
- TPM for the maintenance and continuous improvement of all areas of the company with the aim of eliminating losses.
All methods have slightly different focuses and corresponding advantages and disadvantages. Which method you use therefore depends on the concrete situation on site and should be carefully considered, if necessary with the support of an external consultant. Ultimately, the decisive factor is the goal: trouble-free process flows and the avoidance of unnecessary throughput times.
3. Get the production process flowing
After optimizing the individual processes, you can implement the flow principle and get your production process flowing, so to speak. This means eliminating bottlenecks and avoiding stops in the form of temporary storage or buffer stocks.
As soon as production or the individual steps of the production process are coordinated in such a way that they form a gap-free chain, the control system can also react quickly, flexibly and in line with orders. Essential for this
- is the minimization of inventory and
- the introduction of a value stream design.
Minimize inventory in production
As the inventory of goods directly influences the throughput time in production, one of the most important steps in process optimization is to minimize this work in process. This is because stock and throughput time are proportional: the smaller the stock, the shorter the throughput time. And as soon as there are no more goods, the parts flow with minimal throughput time.
Introduce a value stream design
Use a value stream design to gain transparency about the actual material flows. This method offers a powerful lever for increasing value and eliminating waste. This is because classic, order-related individual or small batch production is often carried out according to the workshop principle: The same operating resources are grouped together in certain workshops, for example CNC machine tools for parts production in machining. However, this can lead to a cluttered material flow for multi-stage products, as components have to be repeatedly transported back and forth between the individual workshops - an obvious muda from a lean management perspective, which has a negative impact on throughput time.
To minimize waste in a production area, you should therefore, if possible, arrange the machines optimally and interlink the processes accordingly. The material flows can be visualized well with the help of spaghetti diagrams. Of course, the linking of processes cannot always be realized in one big step. One possible intermediate step towards flow production with minimal throughput time is production in decentralized structures, i.e. on production islands, in production segments or production cells as well as in fractals and the like.
4. Calculate the rhythm for your factory
Once you have succeeded in converting your production according to the flow principle, you can calculate the rhythm for your factory, i.e. the customer cycle. The customer cycle can be calculated by dividing the working time within a period by the customer demand within this period.
A simple example: The period is 1 year, the number of working days is 250, and the working time (without breaks) is 8 hours, while the customer demand per year is 5.000 machines.
Customer cycle =〖(250×8×60min )/5000〗 = 120,000/5,000 min/machines=24 min/machine
This means that a machine would have to leave the factory every 24 minutes. The processes must be aligned with this.
5. Introduce the pulling principle
The final step in optimizing your production processes is to introduce the so-called pull or pulling principle.
To do this, you need to set up Kanban racks at all production units or machines and systems that have not yet been integrated into the production flow. These shelves or - in lean management jargon - supermarkets create a kind of pull by collecting materials or components and thus drawing them in - a pragmatic solution for the missing integration of a production unit. But the fact that a Kanban shelf or a supermarket still represents waste is something you should always raise awareness of and communicate.
After all, the ultimate goal is always to perfect productivity by establishing a one-piece flow. And the criterion for this remains the shortest throughput time, which results from the sum of the processing times of the parts in batch 1 on the individual machines and systems. Anything else indicates activities without benefit and waste.
6. Create an understanding of the lean philosophy in your company
Major transformation projects will only succeed if everyone involved understands and comprehends the purpose of the project. And, of course, this also applies to optimizing productivity by reducing throughput times.
Before you tackle this topic, you should therefore make sure that you take the affected and involved employees along on this journey and provide them with intensive training: Waste can be learned to see.
I will show you how to do this.
