Aside from the potential risk of injury or death, bolted joints that fail can slow down or stop your production line. You could temporarily change to new screws to get things going again but that does not provide a permanent solution.
To prevent future problems, you need to uncover the root cause of the failure, which can include the following.
- Change of friction conditions. An increase may damage the fastener. A decrease may separate joints.
- The tightening torque may be too high, which causes the fastener shank to fail or strip bolt threads. The tightening torque may be too low, which prevents joint tension from meeting design requirements.
- Loss of preload due to a setting change, which loosens fasteners and separates joints.
- Corrosion, such as rust, due to the environment or the use of inadequate materials, which damages the fasteners.
- Operation loads that stress the fastener because they are higher than what the joint was designed for.
At Bossard, we can rely on our test laboratories to uncover the root cause through extensive failure analysis. Only then can we work with you in defining a solution that prevents future failures. Among the many Expert Test Services that we can provide during such analyses are the following:
- Bolted Joint Analysis: By directly measuring the clamping force in a bolted joint while monitoring the torque and angle of the fasteners, or measuring bolt stretch with ultrasonic equipment, we can define the torque/tension relationship to determine what is going on in your assembly and use this information to recommend solutions.
- Joint design calculation can determine the load and stress on bolted joints by calculating such factors as friction variation, contact surface pressure, assembly method, and expansion coefficient. The MDESIGN tool is what we base our calculations on.
Find out more about how we can test your joints before manufacturing by contacting us at ProvenProductivity@bossard.com.Why It's Important to Test Your Fastener Joints Before Manufacturing by Bossard