1. Terms related to screws
●The difference between screws, screws, bolts and fasteners.
●Definition of thread: a thread is a shape with uniform spiral lines on the outer or inner surface of a solid.
2. The role of thread
●Tightening and connection function: suitable for most screw products at this stage.
●Transmission function (displacement function): such as a micrometer used for QC check size.
●Sealing function: such as the connection of pipelines.
3. The history of thread development
Machine Screw→Self Tapping Screw→Self Drilling Tapping Screw.
●Machine thread: When assembling, drill holes and taps on the assembly first, and the inner teeth of the tapping are the same as the outer teeth of the screw. Use a smaller torque to assemble.
●Self-tapping thread: When assembling, drill holes in the assembly first, without tapping the internal teeth, use a larger torque for assembly.
●Self-drilling thread: directly used on the assembly, the screw is drilled and tapped once.
4. Screw processing method
●Turning: By removing the material, the material reaches the desired shape.
Advantages: high processing accuracy, no mold restrictions.
Disadvantages: high production cost and slow processing speed.
●Forging: Extruding the material by external force to deform it to achieve the desired shape.
Advantages: fast production speed, low cost, suitable for mass production.
Disadvantages: Molding is limited by molds, and mold costs for complex products are high.
5. Cold heading process
●Cold heading: is the process of using a mold to squeeze and deform the metal wire with the help of external force when the metal wire is not heated.
●The cold heading process is only one of the forging processes.
6. Raw materials commonly used in manufacturing screws
●Metal and non-metal.
●Metals: iron Fe, copper Cu, aluminum AI.
●Iron: Carbon Steel, Alloy Steel, Stainless Steel.
●The shape of the raw material (wire and bar).
●The processing technology of raw materials.
●Current source of metal materials: Japan/Korea, Taiwan, Mainland China.
7. Screw standard
●National standard: GB-National Standard, BS-British Standard.
●Industry standards: SAE-American Society of Automotive Engineers, AISI-American Iron and Steel Institute, JCIS-Japanese Camera Industrial Standard, DIN-German Industrial Standard JIS-Japanese Industrial Standard.
●Enterprise standard: GE-General Motors Standard, IBM Standard, SONY Standard