When it comes to packaging challenges, medical devices pose unique challenges. Among them: odd shapes, tacky services, complex electronics, cost constraints, and condensed timetables. In response, continuous motion automation systems are providing the accuracy, delicate part handling, and uptime device that manufacturers need.

What exactly is continuous motion? Simply put it involves multiple processes that occur without interruption for every cycle, effectively overlapping. The tooling never loses contact with individual components, ensuring that exact part alignment is maintained during assembly.

Other benefits:

• Outputs as high as 1,000 cpm—with higher numbers possible depending on the number and complexity of components.
• Positional accuracy as good or better than any other automation solution.
• Machine footprint up to 10 times smaller than other technologies.

Root cause

These benefits are directly related to fundamental difference between indexing systems and continuous motion technology.
The tooling of an indexing system completes a task on one component, pauses while the next part is aligned, then completes the same task on that component. These intermittent motion systems are therefore subject to the constraints of the desired output speed. In other words, if the desired output is 60 parts per minute, then the tooling has 1 second to complete all the required tasks on each component, plus index the next part into position.

Contrast that with continuous motion, where the process never stops. Multiple, longer processes can be automated on one machine. One component moves through the system from one task to the next—a smoother process that prevents damage to both the packaging and the machinery.

The result is not only significantly lower maintenance costs, but also higher speeds and a greater ability to perform testing and inspection to the precise standards sought by medical device manufacturers. Because the continuous motion system is not constrained by the available dwell time on indexing systems, individual tasks performed by the system can be calibrated to meet more demanding requirements.

Consider a leak test for any given medical device. Returning to the same 60 ppm indexing system example, after accounting for movement and stationary time of the tool, a maximum of two-thirds of a second might be available to perform this test.

On the other hand, the same test on a continuous motion system using a rotary dial could be expanded to whatever the test requirements and output dictate by just devoting more radial space on the machine to perform the task. It’s a matter of sizing the continuous motion equipment so that each operation has the appropriate amount of time.

Thorough and efficient Inspections

A continuous motion system’s ability to accommodate lengthier tests and inspections is particularly beneficial to the medical device industry.

Due to regulatory, liability, and patient safety issues, packaging assembly for medical devices requires redundant, precise inspections. Machines can be designed to check for extremely accurate assembly heights, missing components, and disfigured piece parts to ensure quality.

Continuous motion systems allow these tests to occur without lowering the output speed.
Inspection capability also can be applied as a failsafe against operator error for medical devices. Even for simple changeovers that require no adjustment, manufacturers often want to perform an inspection to verify that each changeover has been completed correctly before proceeding. Again, continuous motion system can accommodate this requirement.

Application examples

With proper planning and design, continuous motion systems can handle the challenging parts and materials typical of medical devices, including difficult-to-automate, tacky materials such as silicone and irregularly shaped pieces and tubes.

Some examples of successful continuous motion applications for medical device packaging:

Irregular shapes such as complex curves and parts that only travel in a straight line. These are best dealt with in the orientation of the parts to the assembly machine. Once the parts are presented by the feed system and are in the machine, the parts can be mechanically repositioned or even placed on a carrier to create ideal control features from the carrier to the part and from the carrier to the machine.

Tacky surface parts such as silicone. Best dealt with by keeping tooling centerlines as close as possible to part spacing, and by designing tooling geometry so that parts flow from feed system to the machine at the most consistent speed. The goal is to minimize the percentage of piece part speed variation. This will minimize the effect of tacky surface parts. Low-friction tooling coatings are also utilized.


Fluids that must be applied to a part (e.g. adhesives and solvents used as bonding agents). These can applied either by dispensing from individual nozzles on each station or by transfer of fluid from reservoir to tooling tip.


Processes involving heat to modify the part or transfer another material. Continuous motion because the continuous motion technology allows more time for the operation than an indexing application whose cycle time would be dictated.



Future of continuous motion

The need for greater reliability and lower labor costs have driven demand for increasingly sophisticated, yet easy-to-use automated continuous motion assembly systems.

As a result, advanced controls—designed to enable a small labor force with minimum skills to operate machinery flawlessly and consistently—have become a major focal point of technical development in the industry.

In general, as demands increase for faster speeds and greater quality, automated continuous motion systems offer the potential to meet ever more stringent requirements in the coming years. �