Today’s automation capabilities are helping manufacturers improve consistency, quality and delivery, while also reducing costs.
Chris Tellers, Trelleborg Healthcare & Medical
For a variety of reasons, including quality, delivery, cost and safety, medical device component manufacturers are increasingly adding automation to their processes, especially when it comes to the molding of silicone and other materials.
Silicone’s versatility and biocompatibility make it the material of choice for many medical devices, and automation is key to the silicone molding process delivering consistency and high-volume output for the applications that need it.
Automation helps overcome potential manufacturing issues, such as short shots (underfilling the cavity), voids in parts due to air trapped in the cavity, and parts that are out of tolerance — either too large or too small. Automated manufacturing lines can be carefully calibrated to produce parts with amazing accuracy and speed, and to minimize the possibility of distortion and tearing as parts are removed from molds.
Automated manufacturing is the first step toward Industry 4.0, the industrial Internet of Things (IIoT). Sensors located on critical production equipment alert operators in real time to even fractional changes in critical processing parameters. These alerts prevent the manufacture of hundreds or, in some cases, thousands of incorrect parts.
Today, alerts prompt human intervention to diagnose and fix the problem. Soon, sensors will notify the equipment’s programmable logic controller, which will make the necessary adjustment without human involvement. In the future, even more sophisticated systems will employ preventative maintenance to analyze trends that indicate something is likely to slip out of spec within minutes or days and make an adjustment before incorrect products are produced.
Companies manufacturing products at quantities too low to justify full automation can still take advantage of this technology. For example, product inspection and verification can be automated using cameras or automated pressure tests.
A second major reason to add automation to medical device manufacturing is its ability to improve delivery. For example:
- Automated manufacturing has a constant cycle time. It does not slow down due to worker fatigue or distraction.
- It allows shop-floor personnel to focus on process improvement and efficiency because they’re freed from repetitive tasks.
- It can feed into analytical systems, such as overall equipment effectiveness (OEE).
OEE measures availability, performance and quality. Thus, an OEE score of 100% represents perfect manufacturing — manufacturing only good parts, as fast as possible, with no downtime. OEE dashboards, like the one in Figure 1, can be created or purchased and give manufacturing engineers and others involved in manufacturing an accurate way to gauge how an automated cell is performing. Having real-time OEE enables those with an in-depth knowledge of the manufacturing process to identify the root cause of deviations and slowdowns.
OEE and other analytic systems can also be used on semi-automated lines, with adjustments made for the type of downtime expected on such a line.
Automated manufacturing makes financial sense for many processes used in medical device manufacturing because it can usually run faster than manual operations and has very little downtime. Maintenance, however, plays a vital role in the long-term success of any automation project, and it requires a robust and well-trained maintenance team.
The increased throughput enabled by automation can be significant, even when upgrading from a semi-automated cell to a fully automated one. For example, the number of parts produced per hour can increase by double, triple or more.
If needed, manual operations include multiple fail-safes to protect operators and so are generally safe. However, automation lessens the need for manual intervention during the manufacturing process and so is inherently safer than non-automated processes. Sharp objects used to slit silicone, hot molds and other possible dangers are common in medical device manufacturing. Even simple automation, such as a conveyor belt to transport heavy objects or boxes, can prevent a significant number of back injuries.
Design for manufacturability
Finally, as engineers work to improve quality and delivery and reduce overall costs, design for manufacturability (DfM) should be in place. Quite often, a simple change to a part design will have no impact on the final piece’s performance, but a large effect on the cost and time to manufacture it.
For example, sharp corners should be avoided in many part designs because they require high-injection pressure that can lead to more internal molded-in stress. Rather than adding venting to prevent a short shot being formed in the corner, redesigning a sharp corner to be more rounded increases the material flow. This reduces the injection pressure and minimizes the likelihood of a short shot.
A strong DfM practice combined with a close partnership with your injection-molding vendor can improve consistency and quality on a medical device production line as well as the overall device performance.
When evaluating molding partners, medical device manufacturers should consider the suppliers’ existing and planned automation capabilities, capacity, in-house technical expertise, quality performance, certifications and ability to add value to the product and the development process.
Selecting the right molding partner with experience in automation can improve production efficiencies and quality while reducing the total cost of ownership and reducing the time to market, especially when that partner is engaged early in the development process. So, medical device manufacturers should do their research and ask questions. The upfront time spent evaluating suppliers will pay dividends later as products are scaled up to high-volume production.
Chris Tellers is director of engineering at Trelleborg Sealing Solutions. He has over 20 years of experience in manufacturing, tool making, product development, information technology and automation.
The opinions expressed in this blog post are the author’s only and do not necessarily reflect those of Medical Design and Outsourcing or its employees.