Continuous Flow Manufacturing

Continuous Flow is a type of manufacturing process that builds items beginning to end in one production line without scheduled interruptions. It is a type of materials processing where the material undergoes mechanical, thermal, or chemical treatment continuously.

This method has been used in chemical and materials manufacturing for decades and has recently been introduced to the pharmaceutical industry.

Key Takeaways

  • Faster & more efficient (i.e. leaner) than batch production

  • Higher level of integration for smoother Smart applications

  • Reduces waste but also requires higher startup costs

Before we get into the nitty gritty, here’s a helpful chart comparing continuous flow and batch production that highlights the biggest differences between the two:

conceptual continuous manufacturing vs batch manufacturing process

[image courtesy of FDA US website]

Challenges of Continuous Flow

The biggest challenge of continuous flow manufacturing is that all necessary steps of production must be in the same location, working seamlessly and uninterrupted. This kind of workflow coordination requires a very strong culture of organization and clear levels of command between team leaders.

Here are more challenges of adopting continuous flow manufacturing:

  • Operators need extensive training
  • Lack of coordinated industry regulations
  • Not modular and cannot be easily repurposed
  • High cost of buy-in
  • Harder for customization within production
  • Higher difficulty coordinating scheduled maintenance
  • Production occurs 24/7, requiring fewer workers overall but more overlapping shifts

Because the automated systems required for continuous flow production are so specifically integrated with each other, it is difficult, if not impossible to repurpose equipment for other types of production, such as batch production.

Continuous flow systems are indeed systems, not individual machines stacked end-to-end. This means that as well as being largely difficult to repurpose, continuous production systems also cannot easily be scaled to different production cycles of the same item, such as batch processing.

In other words, manufacturers who rely upon continuous flow do not have the option of making “extra” and keeping it in inventory. They also cannot respond to lack of demand by making “just a few” products at a time.

There is a bigger buy-in for this type of manufacturing because it is not as modular as batch production. The technology for a fully integrated continuous flow manufacturing system is still fairly new.

It is true that there is a lack of coordinated regulation for continuous flow, but the reason for that is that it is not widely used outside of materials and chemicals processing. Now that continuous flow systems can be oriented for pharmaceuticals, industry standards are sure to catch up.

Moreover, the labor challenges with continuous flow manufacturing are a major point of concern because of the current labor shortage and skills gaps within the manufacturing industry.

Operating continuous flow systems may save on labor costs in the long run, but in the short run, manufacturers should expect a high cost of investing in training and education for their shop floor workers.

Benefits of Continuous Flow

There are numerous benefits of adopting a continuous flow style of production:

  • More ‘Agile’ than other production processes
  • Can produce smaller quantities of product with less waste
  • Much shorter production times
  • High level of compatibility with IIoT
  • Reduces the possibility of human error
  • Safer for employees when handling dangerous or unstable chemicals
  • Saves energy costs by not having to power up and down machines constantly
  • Streamlined process with no unnecessary steps costing time and labor
  • Uncovers quality issues that may be hidden within inventory
  • Production occurs 24/7 with little to no downtime

With all of the integrations built into a continuous flow model, such as sensors for measurement and preventative maintenance, the Smart Factory is an excellent candidate for adopting such a system of production.

Because continuous flow models need to move in harmony with great precision, most of the human labor required in traditional production processes is eliminated.

While this reliance upon automation saves money on labor costs, it is balanced out by the extensive training required to operate the machinery.

Overall, Smart sensors and other technologies can minimize the waste produced in a continuous flow production line: alarms will sound if there is an error, allowing workers to immediately fix the problem, rather than waiting for a quality check at the end of the production process like in batch processing. In the latter scenario, if a defect is found, then the whole batch may need to be discarded.

The same issue of waste is prevalent in the pharmaceutical industry, where drugs produced in batches and then stored for shipping or later processing can be contaminated or lose potency over time.

vaccines produced using continuous flow manufacturing

The Future of Continuous Flow

Continuous flow manufacturing has historically been used for chemical processing plants. This is ideal because in this type of manufacturing, raw materials undergo massively fluctuating temperatures and pressures in order to undergo chemical reactions.

Here are some of the industries that make heavy use of this type of production:

  • Pulp and paper
  • Power stations
  • Fertilizer
  • Oil refineries
  • Synthetic fibers
  • Natural gas
  • Wastewater refineries

These examples help show why continuous flow is the standard of manufacturing: rarely are waste or oil refineries producing items “to order”. Since these materials and processing procedures are continuously in demand for basic living conditions and almost every area of commerce, it makes sense to keep these plants open 24/7.

Additionally, because these plants refine materials under massively intense conditions (like the heat levels needed to melt steel), it would be a huge waste of resources – energy, time, money, and labor – to start and shutdown the mechanics every day on a 9-5 schedule. It makes much more sense, as well as being safer for workers, to keep these machines on 24/7.

Nowadays, the pharmaceutical industry is taking pointers from these classic materials manufacturers. Even though medication in tablet or capsule form seems like a “smaller” type of production, many pharmaceuticals undergo the same intensity of chemical reactions.

In today’s modern world, especially as we continue to move through the Fourth Industrial Revolution, the constant supply of basic medication – like Ibuprofen – is just as critical as the supply of metallurgical resources – like iron – for example.

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