How to do strength torque test for combination screws?
SEMS screw is the use of the physical and mathematical principles of the beveled circular rotation and friction of the object, in a step-by-step manner to fasten the object parts of things. In the use of often occur between the teeth and teeth can not be close, too hard to lock the combination of screw head broken off, or bad teeth pattern lock not tight, etc. failed to reach the conditions of use, are quality of precision questions. So today the screw manufacturer to talk to you about the combination of screws is how to do the strength torque test.
SEMS screw strength torque test:
1、 Turning force test: the changing force of a commodity is to show its ability to resist being changed into two halves. Various specifications have rules for self-tapping combination screws to change the minimum requirements of the force, the test is the combination of screws clamped in a tapping center cutting collet on the force test apparatus, and then use a torque wrench to apply force until the combination of screws twisted off. If the torque does not exceed the minimum requirements of the rules, test the product failed. Failure to show that the combination of screws are too soft or the thread diameter is too small.
2、Lock test: This test is to lock the combination of screws to a test plate, this plate has the rules of hardness / thickness and aperture. If the combination of screws locked through the test plate, but the thread deformation, the product failed. Failed to show the combination of screws hardening treatment on the surface is too shallow or too soft.
3、Locking torque test: this test as long as the screw rolling combination screws only need. When performing the locking test, observe the minimum locking torque of the test plate. If the torque exceeds the normative value of the rules (the normative value is based on the size of the combination of screws / appearance of the treatment), the product fails. Failure to show the appearance of the hinge screw does not have sufficient lubrication, or the thread is not properly formed and requires more torque.