中国国际医疗器械设计与制造技术展览会(Medtec China)2021

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Medical Packaging: Automation of Thermoforming Processes

2022-09-19

The medical packaging market has quickly embraced the use of automation for the thermoforming process. Automation has enabled adherence to stringent quality requirements and has addressed the need for high levels of repeatability. Automation has also facilitated higher and more predictable throughput.

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.

CONSIDERATIONS

Material Selection. Ensuring an effective and durable sterile barrier starts with material selection. Polyethylene terephthalate glycol-modified (PETG) and high-impact polystyrene (HIPS) are often selected for medical packaging applications. 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, 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 a 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 can cause fluctuations in the heating of materials and in the air pressure of pneumatic components.

INCREASING AUTOMATION

All of these special requirements for medical packaging have led to the widescale 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. They can be more fully automated and, therefore, more precisely monitored and controlled, especially machines with 100 percent 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.

EASE OF OPERATION

Automation addresses 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. 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.

INTUITIVE HMI

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.

LOOKING FORWARD

The whole concept of a form/cut/stack thermoforming machine is to integrate and automate 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 labor shortages and high turnover by making processes more productive and less labor-intensive and easier to learn.

Article source: Medical Design Briefs