Improving your process improves your profitability. In assembly, accurate torque tools enable companies to tighten their fasteners correctly, preventing product failures on the line and after delivery. If torque tools slip out of calibration, however, that may affect production. By developing a calibration plan and investing in the right tools to carry it out, companies can avoid costly dips in product quality and any resulting liabilities.
Calibration plans vary from company to company depending on the type and number of torque tools you use, the products you assemble, and any industry regulations. Companies using a low volume of torque tools may find it cost-effective to ship their tools in rotation to a certified laboratory for calibration. However, companies which rely on their torque tools more heavily or in higher numbers often find that procuring their own torque wrench calibration tools makes better fiscal sense.
Choosing the Most Effective Torque Wrench Calibration Tools
Different types of torque calibration tools are best suited to different styles of torque tools. However, all torque testing equipment functions in a similar way. One component, a transducer, senses the amount of torque a tool provides. Another component, the analyzer, interprets and displays the results of the test for a technician to see. Some calibration devices include both the transducer and the analyzer in the same housing.
Choosing the right calibration tools for your tool inventory comes down to understanding the calibration needs of your equipment. Identify:
- The torque output of your tools
- The allowable tolerance of your assembly
- Whether you’ll be testing hand tools or power tools
- Whether joint conditions require simulation
Different torque sensors are capable of reading different ranges of torque. A sensor that is calibrated to measure torque in lbf.ft won’t accurately register tools delivering ozf.in of torque. Conversely, a sensor designed to measure ozf.in may be damaged or destroyed by a tool delivering lbf.ft.
Tolerance allowance varies between industries and between torque calibration tools. Companies producing highly sensitive products, such as internal medical devices, have more stringent tolerance requirements than companies manufacturing products with less critical applications, like dishwashers. When choosing torque calibration tools for your operation, it’s essential to know how much tolerance is allowable and whether the tools you’re considering are accurate enough to provide useful measurements.
Torque Calibration for Hand and Power Tools
Power tools don’t necessarily produce more torque than hand tools—a worker with a large click wrench can create far more force than most electric screwdrivers. But power tools and hand tools do have different torque application profiles. Power tools can be difficult to repeatedly measure with standard torque sensors due to the force of their impact and the irregularity of their peak output. Manufacturers relying on power torque tools can mitigate this by investing in run-down adapters, which interface between the power tool’s driver and the sensor’s transducer. These adapters account for the different torque profile of power tools, providing accurate and repeatable results.
Sometimes joint conditions themselves—such as odd angles or the presence or absence of lubrication, gaskets, or washers—can affect the amount of torque a tool actually applies to a fastener. In these situations, tools which register the correct amount of torque on a standard sensor can deliver insufficient torque to the joint. Rotary torque sensors, which are mounted in-line between a tool’s driver and the joint, detect the amount of torque truly applied to the fastener. This helps workers adjust their tools to deliver the appropriate amount of torque.
Maintaining Calibration Tool Accuracy
Calibration tools provide a return for companies in improved process control and reduced lost product. Finding the right calibration tools for your company comes down to understanding your calibration needs and choosing a manufacturer you trust. Over time, however, calibration tools themselves may slip out of alignment and begin to return inaccurate results. Fortunately, this can be prevented by regularly sending your calibration tools to a certified laboratory or testing them against a fixed standard.
Deciding whether to ship calibration tools out for service or test them in-house with certified dead weights returns to the question of cost and efficiency. Sending tools to the laboratory can cost more money, especially when considering the amount of time your torque testing equipment will be out of service. If your industry requires routine testing, it may be more efficient to test in-house with calibrated dead weights. This allows for a higher testing frequency at a lower cost.
In addition to increased productivity due to improved process control, investing in effective torque calibration tools provides companies with peace of mind. Knowing that the products your assembly operation sends out into the world will perform according to design removes the worry of liability and reputational damage.
