The centrality of quality management in medical device production cannot be overstated. For that reason, the production of medical devices is heavily regulated across the world, falling under the jurisdiction of various national and international bodies, such as the U.S. Food and Drug Administration and the European Commission. To help companies comply with this international patchwork of standards, the ISO (International Organization for Standardization) has published the ISO 13485, a guideline specifically intended for companies that manufacture medical devices.
Companies working in this field are well-advised to purchase the current ISO 13485, revised in 2016, and thoroughly familiarize themselves with it. However, knowing the guidelines isn’t the same as knowing how to carry them out. The necessary generality of the advice—broad enough to encompass the manufacturing of objects as dissimilar as tongue depressors and knee implants—tells companies to control, supervise, validate, and document their production process. But how is that done?
Following these guidelines comes down to developing a detailed, risk-based, verifiable plan for each product to be created, executing the plan with tools capable of meeting specifications, and recording the process and results. For companies using threaded fasteners in their medical devices, tools capable of controlling the amount of torque they deliver are the best way to meet design specifications. Some can even record the process automatically. Medical device makers using threaded fasteners can achieve ISO 13485 rigor in part by using high-quality torque control fastening systems.
Torque Control and the ISO 13485
The ISO 13485 standards for medical device production call upon manufacturers to have a specific engineering plan, follow it through, and document the results. For any device which includes threaded fasteners, like screws or bolts, torque tools are necessary for meeting engineering specifications in a reliable and verifiable way.
For each fastener, engineering specifications should identify a torque value to tighten to. This is to prevent fasteners and their assemblies from cracking, deforming, warping, or shearing under too much stress. It also prevents fasteners from working loose and falling under due to insufficient torque. The repercussions for either form of failure can be severe, especially in implanted devices.
Torque tools are hand or power tools designed to read and control the amount of torque they deliver to a fastener. Without these tools, there’s no measurable way to be sure that a fastener has been tightened to design specifications. This lack of verifiability in itself renders torque tools essential for ISO 13485 compliance.
Choosing Torque Tools for Medical Device Production
Medical devices typically use small fasteners, with narrow ideal torque ranges. Hand torque screwdrivers and wrenches are effective under these conditions, as are electric screwdrivers. For certain products, which must be manufactured in clean room conditions, specialty clean-room certified torque tools can ensure both torque and air quality specifications are met.
Given the need for specificity, the preferred hand tools for medical device manufacturing are break-over or cam-over wrenches. Break-over wrenches significantly deflect, or “break,” on a built-in joint once the desired torque value is reached. This prevents an operator from over-torquing and allows them to tighten until the breaking point, preventing them from under-torquing as well. Cam-over wrenches rely on an internal clutch mechanism to “slip” when the specified torque value has been applied, similarly preventing both under- and over-torque results. Hand torque screwdrivers also rely on an internal clutch.
Speed is the primary advantage of electric screwdrivers, but they can also help improve quality management as well. By connecting an electric screwdriver to a screw counter or automated control system, it’s possible to generate a real-time record of each fastener used in a device. This documentation helps verify that production specifications have been met and is important in order to satisfy ISO 13485 guidelines.
Medical devices vary widely and so will their production. But for each medical device which relies on threaded fasteners, meeting ISO 13485 quality management standards, as well as the national and international regulations, can only be accomplished using reliable torque tools.
