High mix – low volume

11-01-2019 by Marian Wijnen.

In the pharmaceutical industry, we notice a growing need for high mix–low volume production (HMLV). HMVL means that medication and medical devices are presented to the patient more and more personalized (thus targeted): multiple medical products are combined in small quantities.

For the packaging process, this means adapting to new requirements. The process has to be 100 percent reliable and must be fitted with a balanced degree of automation. Especially biomedical producers face these questions. The graph below shows the expected exponential growth of the demand for smaller batches at biomedical companies.

Predicted trend at a biomedical company: the growth of batch sizes compared to the number of orders

To ensure a 100 percent reliable HMLV-packaging process, we have to look further than just machines. Here, logistics, processes and costs also play a relevant part. With this article, we will clarify some considerations.

HMLV and logistics

In manufacturing and packing of small batches, flows of goods and quality checks must be carefully arranged from the start. If not, operators will spend a lot of time checking products and errors will occur easily.

A code is connected with each batch of products, and access to these products is allowed only to those using this code, ensuring no ‘mix-up’ will take place. Each step in the process uses the same code for the same batch. Once the batch is completed, a new batch with its own code can be processed. This way, batches will never be in the same room at the same time. By applying this thorough process, operators will only have access to the products they need for a specific batch. Other products, not related to that batch, will be inaccessible at that time. That’s what we call ‘Good Manufacturing Practice’ (GMP).

The flow of the components is made very clear by applying this approach. Most errors are usually made by operators and at change-overs of machines. These are both prevented with a clear method and routing. A clear logistical plan is essential with HMLV.

HMLV and processes

Processes of a high speed machine that already have been fully validated and equipped, can be fully adopted into the design of a HMLV machine. Any vision check can be built in and any security measure can be incorporated into the HMLV machine. A feature like for example, when a high speed machine cannot remove anything after a syringe is added to a product, but instructions still have to be added, can also be installed on the HMLV machine.

This process is organized in such a way that 100 percent reliability is guaranteed, despite working with operators and upping the number of changeovers of the machine. With HMLV, it is all about adopting existing techniques and safety of the original high speed production line and translating these into manual or low-speed production, while still meeting the same requirements for quality, safety and validation.

HMLV and machines

We translate the techniques of a high speed production line to a manual or low speed machine. High flexibility is ensured with easily exchangeable molds and tools. The parts are designed poka yoke and can be interchanged quickly. Where operators are active, avoiding human errors and safety are of utmost importance.

In the machine builing industry, co-bots or collaborative robots, have been around for many years. These robots replace human action in a safe manner, without requiring any screens of fences around machines. Robots will automatically stop upon touch, preventing anyone getting hurt. GTE-engineering applies this principle to the construction of HMLV machines. Speed is often less important than the interaction with an operator. The operator has to be able to produce or package products easily and safely. We can achieve safety by using low powered HMLV machines. They only use the necessary (low) amount of energy, not posing any danger to operators. Fencing is made obsolete. An example of such a HMLV machine can be found at

HMLV and costs

When does setting up a HMLV environment for smaller numbers of batches become more interesting than producing those batchs on a high speed line? The answer lies within the cost and time required. When looking at required time, the diagram below shows that HMLV machines and processes are more interesting for batches just over 1,000 pieces.

But when manufacturing smaller batches on a automated high speed production line, the machine has to be stationary for 7 hours because of change-overs, leaving only one hour for actual production time.

When looking at costs, take into account:

  • The costs of the machine
  • Operator costs
  • Costs of floor space at factory

The graph below shows production costs for a HMLV line are lower than a high speed line for batches up to 2,800 pieces. With bigger batches, the high speed line becomes more interesting. These calculations can easily be made for each product and HMLV machine or HMLV process, offering medical companies better insights into production time and costs. Based on these two elements, decisions can be made.

The production of a biomedical product, based on the costs of an operator, the machine and required floor space.

For many companies, now is the time to study the trend of high mix – low volume, given the exponential growth of batches with small numbers in the coming years. High speed production lines are not efficient for smaller batches because of time needed for changeovers. This is especially true when dealing with a large variety of batches. By optimizing the HMLV production, the transformation to high mix – low volume, can proceed smoothly.

Marian Wijnen

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