Case Study of Brass Terminal Screw
As a kind of connector, the terminal is an important component in the electrical industry. And each terminal must be fixed with a screw, screws are mainly used in various terminals block.
With the beginning of my country's 3C certification system, the country has put forward higher requirements for the safety and electromagnetic compatibility of electrical products. Like barrier terminals are mainly used in: power supplies, relays (especially double-layer terminals), frequency converters and air conditioners.
The requirements of this series of terminals are that the torque requirements of the screw are high, when the wire is pressed, and the distance from the screw to the highest position should be greater than the maximum pressure range. For the terminals with long digits, there should be no warping deformation, and the corrosion resistance of screws is required to be high.
So how to produce high quality terminal screw?
The first important is material. From one of our customer the material they request brass CuZn37(Brass H63), and the torque request is Thread Should Withstand, When the Screw is Tightened & Loosened for 12 times(1mm 2 wire- 1 time + 2.5mm 2 wire 11 times)with torque of 0.8 Nm(minimum) as per BSEN 60669 with its Mating Part. When sample finished doing torque test, found the screw is soft, torque test results failed.
After discussed with customer, we decided to use brass H65 material to produce, finally the brass H65 terminal screw sample had passed torque test.
Secondly production machine, usually the terminal screw we use single cold heading machine forming, but due to the customer is strict requirements for chamfer of screw end. For first time sample we use single cold heading machine to produce, the chamfer of screw end not reach customer’s request. Then our company decided to use Multi-station cold heading machine(3 Mold 3 Punch) to manufacturing this kind brass screw, forming directly on the mold.
The terminals screw seemingly simple production, some customers who do not have such high requirements for products, and they will compare the price. But like we always said screw is small, safety is big. We need strict customers, so that we will produce more strictly.