Whether you’re producing large volumes of products or small batches with low or no tolerance for failure, repeatability is king. Of course, in an imperfect world, perfect repeatability is easier aspired to than achieved. So, what’s the solution? Testing your tools as often and as accurately as you’re able.
The electric and pneumatic tools you use to fasten screws and bolts in your products must be tested regularly in order to ensure they continue to deliver the amount of torque your fasteners demand. But the lab isn’t the factory floor. In order to accurately reproduce production conditions, manufacturers must rely on joint simulations for torque tool repeatability measurement. Here’s how it works.
Joint Simulations Allow for Accurate Torque Tool Testing
A joint simulator, otherwise known as a run down adapter, is a device used during torque testing to measure the repeatability of a power tool. Typically, power torque tools, like electric or pneumatic screwdrivers, are tested using a torque sensor or torque tester, which measure the tool’s torque output.
A run down adapter is a third, separate, device, which is no less integral for accurate measurements than the sensor or analyzer. The run down adapter is inserted into the drive of the torque sensor or torque tester. To use it, the operator applies torque until the run down adapter is finished and the power tool shuts off. Then, simply note or save the readings using the torque analyzer.
You’ve heard it before: for every action, there is an equal and opposite reaction. Which means that when your electric or pneumatic screwdriver exerts force on a screw, that screw exerts the same force on your screwdriver. Simply put, it’s easier for your screwdriver to turn in the air, against no resistance, than it is for it to turn in the joint, against the resistance of the screw. Depending on the amount of torque—or radial force—the screw’s threads need to reach the ideal compression, the force the screw returns can significantly affect how hard your screwdriver has to work to achieve the ideal torque.
While it’s certainly harder to turn the receptacle in a torque sensor than it is to spin it in the air, that doesn’t mean the torque sensor’s resistance is equal to the resistance of the actual joint your tool needs to fasten. So, if you’re testing your screwdriver with the sensor alone, you won’t get the same results as you would with the actual joint and it could even damage the sensor. This difference can lead to fasteners which are too loose or too tight. And preventing fasteners from being over- or under-torqued is the whole reason you’re using torque tools in the first place.
In addition, rotary torque sensors are ideal torque-auditing tools for measuring the actual amount of torque that is being applied during the torque fastening process. By connecting a rotary torque sensor between an electric or pneumatic tool and the fastening application, you can monitor the torque being applied to the fastener or blt. The rotary torque sensor works well with torque testers for this type of testing application.
The Importance of Accurate Torque Tool Testing
Why are we using torque tools again? Because improperly torqued fasteners can fail, and those failures can cost money or even lives. Not enough torque, and the fastener can rattle loose and fall out. Too much torque, and the fastener or the materials it’s holding together can warp, deform, shear, or otherwise fail.
For companies manufacturing large amounts of less sensitive products—like consumer electronics or comfort or style components for the automotive industry—these failures increase the rate of lost product. And the higher the lost product rate, the lower the profit margin. Post-delivery failures can lead to reputational damage, returns, and decreased future sales.
For companies manufacturing sensitive or critical products—like satellite components, implantable medical devices, or operational assemblies for the automobile or aviation industries—fastener failures can cause serious harm. Not only can these failures cost a serious amount of money—think of the price tag of a failed communications satellite—but they can also pose a serious risk to the lives of customers. To prevent these sorts of mistakes, you should test torque tools often and in conditions as close to their production environments as possible.
Which brings us back to joint simulations. Using a run down adapter will help your tool testing regimen return accurate results and enable you to verify your tools correctly. Improperly calibrated tools can cause expensive and dangerous product failure. Fortunately, joint simulations can help ensure safety and accuracy, thereby enhancing quality assurance and mitigating product risk.
