In the aerospace manufacturing industry, the required reading is somewhat dry; there isn’t a lot of consideration of the human factors involved, i.e. the people who make the planes and who fly in them. As such, conscientious industry employees may want to pick up a copy of Arthur Miller’s book All My Sons and flip through the pages. A tragic play, it imagines an aircraft manufacturer in World War II shipping out faulty parts, ultimately leading to the deaths of 21 pilots. Though a fictitious cautionary tale, it serves as a serious reminder: In aviation, people’s lives depend on the quality of your products.
Building a single, perfect example of a product isn’t enough when you’re manufacturing components for the aerospace industry. Instead, you must build a perfect product time and time again. To ensure in-flight safety—and to comply with Federal Aviation Administration (FAA) regulations—you must design a manufacturing process that produces components exactly as designed. To do so, it’s imperative to work from the correct design specifications. This includes torque specifications for all critical fasteners. Designs must also be executed accurately, which requires investment in torque-sensitive tools for your assembly operators or robotic operation.
Your operation depends on being able to consistently create product after product, article after article, year after year. Sure, the torque tools you invested in were accurate to the ounce-inch when you first introduced them to your assembly process. But, five months later, are they still delivering the right torque? If not, then you may find yourself asking some of the scariest questions in aviation manufacturing: How many components did we produce with incorrect torque values? And, where are they now?
Primary Solutions for Testing Torque
Every pilot checks their aircraft before powering up and lifting off; it’s equally important for aircraft manufacturers to check their tools before constructing aviation products. To test the calibration of their torque tools, manufacturers essentially have two options. They can:
- Ship their tools to the original equipment manufacturer or an accredited third-party laboratory for testing and certification, or
- Invest in their own in-house torque testing equipment.
Sending torque tools into a laboratory for testing has both benefits and disadvantages. One of the benefits is that the quality and precision of the torque testing will be exemplary. Further, as a standard part of the calibration process, the laboratory will document the tool’s original condition, any adjustments made, and all other relevant information in order to provide critical certification which can be presented to the FAA, as required.
The disadvantage to outsourcing your torque testing to a laboratory, however, is that the transit, testing, certification, and return transit of the tool may take one to two weeks, possibly even longer depending on the laboratory and your location. During this period, your tool will be out of production. When you consider that each of your torque tools must go through this same testing process every six months to a year, this adds up to a significant amount of production downtime.
Additionally, finding out after a six-month interval that your torque tool has not been in calibration raises those scary liability questions again. How long has this tool been off calibration? How many products may have been shipped with incorrectly torqued fasteners during that time? What if someone gets hurt?
The Basics of In-House Torque Testing Equipment
Manufacturers who wish to reduce their testing downtime, while simultaneously increasing oversight of the calibration of their tools, should consider investing in their own array of torque testing equipment. The capability to test tools in-house enables manufacturers to eliminate shipping delays, ultimately increasing production ability and profit.
Another benefit of in-house torque testers is that they allow manufacturers to increase their tool testing frequency. With ready access to torque testers, tools used for critical applications can be tested daily—or even continuously throughout the day. Constant monitoring reduces system downtime and significantly augments the quality assurance process by allowing technicians to detect incorrectly torqued products long before they leave the factory.
If you need this level of torque oversight to feel confident in the quality of the aerospace components you produce, what equipment is required to test your torque in-house? There are two basic components of torque testing equipment:
- Torque sensors
- Torque analyzers
Torque sensors are the eyes and ears of your torque calibration equipment; the physical mechanism that tests the torque output of your tool. If sensors are the eyes, then torque analyzers are the brain. They record and compile information from multiple torque sensors and communicate this information to their operator. While the sensor detects your tool’s torque, the analyzer determines if that torque is within specifications.
Choosing the Right Torque Sensors and Analyzers for Your Operation
The right torque testing equipment for your operation depends on your specific needs. For small operations producing a limited array of aircraft components with hand tools, the most efficient testing option may be a number of simple torque testers. For larger operations working with hand tools, it may make more sense to invest in a few torque analyzers, which can work with many torque sensors at the same time.
For operations working with power assembly tools, it’s best to use a combination of a torque analyzer and a rotary torque sensor. Rotary torque sensors attach to the end of your tool and detect the torque it uses during an actual application. This is the most effective way to measure and verify the torque output of power tools.
Investing in torque testing equipment can increase process oversight and reduce system downtime. However, just as torque tools need to be occasionally tested, it’s not enough to merely invest in torque testing equipment and assume it will function without error indefinitely. At regular intervals, you must test your testing equipment itself, often by returning the equipment to the original manufacturer or sending it to an accredited third-party laboratory.
While this may at first glance appear to be simply swapping one nuisance for another, there is a significant difference in scale that softens this requirement. In a large operation, dozens, or even hundreds, of torque tools may be consistently shipped out for testing. That same size operation would need to send in only a few torque sensors and analyzers over the same time period, offering a reduction in system downtime. By investing in redundant testing equipment, it’s even possible to eliminate testing downtime almost entirely. As such, in-house testing equipment still represents a significant improvement in production ability and system oversight compared to relying on outside laboratories for testing torque tools. With the system oversight allowed by in-house testing equipment, you’ll never again have to wonder if one of your fasteners is coming loose somewhere over the Pacific.