Screws must be super familiar to everyone. They can be seen everywhere in life, but small things are very useful, from mobile phones and watches to airplanes and high-speed trains. There are thousands of bolts to fasten or link structures.
Do you really understand the small screws that can be seen everywhere?
Today, I will briefly share with you the knowledge about screws.
1. The history of screws
Screws and bolts come from the force of a screw, and the screw was first proposed by Archimedes in Europe. The Archimedes spiral is a spiral in a wooden cylinder that can lift water from one level to another.
In the Middle Ages, carpenters used wooden nails or metal nails to connect furniture to wooden structures. In the 16th century, nail workers began to produce spiral nails, which were able to connect things more firmly. That is a small step from this type of nail to a screw.
Around 1550 AD, the first metal nuts and bolts that appeared as fasteners in Europe were all hand-made on simple wooden lathes.
In 1797, Mozley invented an all-metal precision screw lathe in London. The following year, Wilkinson built a nut and bolt manufacturing machine in the United States.
In 1836, Henry M. Philips applied for a patent for the screw with the cross recessed head, which marked a significant progress in the screw base technique.
2.classification
There are many ways to classify screws in modern commodities, but in terms of specifications, there are English and American systems.
From the perspective of form and purpose, we can roughly have the following types:
Micro screw, fine thread screw
Self-tapping screws, touch screws, high-tech screws
Drilling screws
Hexagon bolt type
Thin head bolts
Through hole bolt
Stop screw
Full thread type,Stud bolt
Plastic screws,ceramic screws
Eye screw
U-bolt for piping
Anti-drop screw
Precision screws
3.screw production method
(1) Use roll forming method to manufacture screws
Screw roll forming is a process of forming thread teeth through plastic deformation. A cylindrical screw blank is placed on a thread rolling die for rolling to form thread teeth on the surface of the blank.
Compared with the cutting method, this process does not produce chips, saves material, and has high mass production efficiency.
Secondly, the tooth bottom where the stress of the rolling screw is concentrated is work hardened, the surface is smooth, and the strength is better than that of the cutting screw.
When manufacturing bolts, cold forging is used for the head and roll forming for the screw, so no chips are generated.
Taking aluminum alloy bolts as an example, the following four processing combinations are used to form: front extrusion, upsetting, rear extrusion, and screw rolling.
(2) Using cutting method to manufacture screws
a)Self-tapping screw processing and die processing
Self-tapping screw processing
Processing tools include manual hand taps and automatic tapping machines. These are special tools for internal thread processing.
Tapping has the meaning of "internal thread cutting = internal thread production" and tap dance, that is, light tapping.
b)Die processing
Die processing is the processing of cutting external threads on round bar materials.
Cutting with threaded turning tool
This method generally uses a combination of thread turning tools, lathes, and NC processing machines to perform thread cutting.
Generally used for thread processing in areas that require high precision and cannot be processed by rolling.
Milling with thread milling cutter
At present, CNC cutting using a machining center (a machining method that uses a computer to control multi-directional moving cutting tools for reasonable cutting) and a thread milling cutter are combined, and screw cutting is performed using spiral interpolation (moving the tool along a spiral shape). processing methods.
In this method, a machining center is used to automatically process molds under CNC control, and screw processing can also be performed under CNC control.
Qisheng Metal is a professional manufacturer of screws and nuts and other fastener products integrating R&D, production, processing and sales. Specializing in the production of special precision screws and nuts of various standards such as national standard GB, Japanese standard JIS, British BS, American ANSI, ISO and so on. Our equipment is advanced, the smallest screw diameter that can be produced at present is 0.4mm, the shortest is 0.4mm, and the longest is 300CM. The materials used are stainless steel SUS304/SUS410/SUS 430/SUS620, etc., red copper H95, brass C2700, aluminum 6061, titanium TI 04, etc. Look forward to working with you!
