The development of spring processing technology

At present, the processing equipment and processing production line of mechanical springs are developing towards the depth and breadth of numerical control (NC) and computer control (CNC). However, with the change of spring materials and several new forms, the processing technology has also been developed.

1) Variable spring outer diameter, variable pitch and variable wire diameter (three-variable) suspension spring to achieve non-molding processing. Since the development of the three-variable spring, the conical steel bar has been wound on the CNC lathe, but the yield and price are not ideal. Now it is changed to the heating state through the spring coiling machine, control the roll speed and drawing force, obtain the required cone shape, and quench with processing waste heat.

2) The hollow stable spring rod is rolled and welded with low carbon boron steel plate.

3) The torsion bar is made of high-purity 45 steel, which obtains high surface hardness and large residual compressive stress after high-frequency quenching, thus improving fatigue life and anti-relaxation ability.

4) Sheet springs widely used in electronic products are basically formed by stamping and automatic bending. At present, it is mainly to develop the bonding technology of composite materials.

(1) Cold forming process of spring

1) One-time automation capability of cold forming process. The cold forming machine has been developed to 12 claws. The steel wire in the range of (0.3 to 14) mm is basically formed at one time in the 8-claw forming machine. At present, the development direction of forming process equipment: ① to improve the forming speed, the main development trend is to improve the forming speed of the equipment, that is, the production efficiency; ② Improve the durability of equipment by improving the precision of equipment parts and strengthening the heat treatment effect; ③ Add the length sensor and laser rangefinder to automatically control the manufacturing process of the CNC forming machine.

2) Cold forming process range capability. At present, the maximum specification of the large diameter spring coiling machine can reach 20mm, =2000MPa, and the winding ratio is 5. The cold forming process of Minic-Block springs and eccentric springs with reduced or equal diameters still has limitations.

(2) Hot forming process of spring

1) Hot forming process speed ability. At present, China's forming on the (9~25) mm specification only CNC2 shaft hot coil spring machine, the maximum speed of 17 pieces per minute. Compared with developed countries, there is a big gap.

2) Large spring hot forming process control ability. Because only CNC2 shaft hot spring coiling machine, so the shape control less three direction action, poor accuracy; Moreover, there is no automatic bar rotation control and adjustment mechanism, so the forming process level and ability of hot coil spring are low. Therefore, the precision level and surface oxidation and decarburization level of the spring are also low.