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By Brian Golden, Sales Director Americas, GN Thermoforming Equipment
Automation of the thermoforming process has been embraced in the medical packaging industry more quickly than in other markets. Originally this trend was driven by stringent quality requirements and the need for high levels of repeatability. Automation has also brought other benefits of strategic importance to medical packaging producers, including facilitating higher and more predictable throughput, as well as helping to address the challenges of attracting, training, and retaining a quality manufacturing workforce.
What is different about medical packaging?
Thermoformed medical packaging is designed to protect a wide variety of items ranging from implantable medical devices to surgical instruments, to disposable catheters and syringes. The selection of materials and the forming and sealing processes are crucial to ensuring that the integrity of the sterile barrier system is maintained during shipping and handling until the product is opened by the user.
Medical items are often delicate. Therefore, the packaging must protect the products from damage during shipping and handling, securely holding each item in place and separating multiple items packaged together from damaging each other. For sharp objects, such as needles, screws, and drills, the packaging must be designed to protect the safety of the people handling and opening the package.
Ensuring an effective and durable sterile barrier starts with material selection. PETG and HIPS are often selected for medical packaging applications. Polyethylene terephthalate glycol-modified (PETG) is created by adding a glycol modifier to PET making it slightly softer for tighter seals and also more suitable for withstanding high-temperature sterilization processes.
In addition to the polyethylene family of plastics, high-impact polystyrene (HIPS) is also commonly used for thermoforming in medical packaging. HIPS plastics are impact-resistant and clear and they have excellent hygienic qualities.
Strong Flange and Complex Geometries
The shape of the packaging typically differs for medical products. The entire package must withstand the temperature and pressure extremes of the sterilization process. The flange must have the required thickness and rigidity, and smooth surface, to accept and maintain a hermetic seal to the Tyvek lid. The sidewalls must also have adequate and consistent strength and thickness to prevent cracking and leakage during transport and handling.
The most challenging aspect of medical packaging design is often the complex geometries required to isolate individual items into separate compartments and to lock each item in place. When properly designed and manufactured, undercuts allow each part to be snapped into place and held securely.
Elimination of Airborne Particulates
Most medical packaging applications call for enclosing the thermoforming machinery in a protective enclosure to minimize exposure to airborne particulates that can cause gaps during the hermetic sealing process. It is imperative that measures are taken to eliminate static that will attract particulates and to ensure that the cutting process does not generate particulates that can migrate to the product.
Enclosing the machinery is important not only for protection against particulates but also for isolating the system from ambient air and temperature that cause fluctuations in the heating of materials and in the air pressure of pneumatic components.
These various special requirements for medical packaging have led to the wide-scale adoption of Form/Cut/Stack thermoforming systems. Simpler and less costly Contact Heat systems are suitable for only a small fraction of medical packaging applications because they lack plug assist capabilities required for complex geometries and the higher clamping forces that Form/Cut/Stack systems offer. Contact Heat systems are primarily used for simple package designs and low production volumes.
Form/Cut/Stack systems are usually enclosed in a protective envelope protecting the process and the product from airborne particulates and ambient temperature and humidity, and they can be more fully automated and therefore more precisely monitored and controlled, especially machines with 100% servo motors and drives.
Investment in automation offers many advantages in medical packaging manufacturing. More precision and control result in much higher repeatability, which means higher quality products as well as fewer defects and less waste. The process improvements achieve faster cycle times and predictable output, for higher throughput and scalability.
Precise control and repeatability are also critical to the calibration and production consistency required by the strict standards and government regulations for medical packaging, such as ISO 11607:2019 and Title 21 CFR Part 11. Automation may also include vision systems and other inspection technology that provide automatic, continuous real-time quality control. In general, the more automation, the greater the opportunity to collect data for process improvement and for traceability.
In addition to the benefits of better product quality and higher production quantity, another factor driving increased investment in automation is the increasing challenge of recruiting, training and retaining manufacturing employees.
Medical packaging manufacturing faces the same workforce challenges as all industries. The 2021 Deloitte and The Manufacturing Institute Manufacturing Talent study found that US manufacturing is expected to have 2.1 million unfilled jobs by 2030, a trend that began before the pandemic and has been accelerated since. The study also reiterated to obvious: “The pace of digital transformation in the manufacturing industry will likely continue to redefine work for humans.”
Traditionally, the operation of earlier generations of thermoforming equipment was often known as more of an art than a science, with operations acquiring a feel for what works after decades of experience. Veterans of the industry are moving on to other roles and retiring, and it is difficult to transfer these skills to new equipment operators, especially when employee turnover rates are high.
Ease of Operation
Automation addresses these workforce issues in several ways. Obviously, automated systems are less labor-intensive. Instead of requiring one or more operators per production line, a single operator can cover multiple lines. First of all, this requires that the machines autonomously perform the forming, cutting, and stacking processes with little or no hands-on engagement by the operator. For high volume production, robotics are increasingly employed to automatically perform downstream packaging and palletizing functions. But the autonomous operation of these functions is only one element of automation.
The procedures for changing tooling between SKUs and for replacing roll stock also need to minimize human error and effort. The right tooling needs to be installed in exactly the right way, for every production run, and roll stock can weigh 1500 lbs. Thermoforming equipment should be designed with procedures and tools for streamlining these processes and preventing errors and with ergonomic aids for lifting and correctly positioning heavy objects.
Moreover, the Human-Machine Interface (HMI) must be designed to be intuitive and easy-to-learn for new employees while also being very efficient and easy-to-use during production every day. The latest HMI systems employ large high-resolution displays that support multitouch gestures, taking advantage of the skills new employees now universally bring with their years of smartphone experience. Like smartphones apps, these new interfaces should require little training and no paper documentation.
The whole concept of a form/cut/stack thermoforming machine is to integrate and automate these multiple functions in a single system. Medical packaging manufacturers have been at the forefront of the trend toward automation, initially driven by the need for high quality, repeatability, and traceability. Automation also increased scalability and throughput. The third driver of automation is the need to address labour shortages and high turnover by making processes more productive and less labour-intensive, and easier to learn