Screws are the central component when it comes to any kind of permanent connection. Only screws can guarantee a permanently firm hold that can be taken apart and put back together as often as one pleases. Screws are so common that their manufacturing process is hardly ever though about. Thereby, the production of screws is a very complex process that requires several machines.
Screws are made out of steel wire or steel bars. These are cut into the desired length and then the required head is formed. The development of the thread undertaken using a special forming technique with rollers. The forming of the head and development of the thread is all done at room temperature. This "cold process" ensures high strength. However, this strength can be increased even more. Depending on the requirement of the strength of the screw, a subsequent hardening process can be applied. The screw is heated up until it glowing point and then cooled in cold oil. These types of screws are used with particularly high tensile loads. These types of screws can be used for high torsional moments, such as for cylinder heads of vehicles.
The raw material used for the production of screws (steel bars or wire) is delivered to a loading unit and this is the first step in the production process. With the wire, an electrically operated reel is used. Steel bars are moved along a conveyor.
The lengthening and production of the head is done with a special machine. The transportation from one machine to another is conducted by ribbon and vibratory feeders. The thread is produced using a thread rolling machine. The optional hardening process is undertaken in a furnace and a hardening station.
The production of screws is widely automatic and a very quick process. Transportation and loading are the only tasks that could be done manually. It is important during this process to ensure high quality control. The extensive discharge rate of screw production results in high levels of rejection rates if quality control is neglected. Therefore, a quality monitoring system is essential for any screw production process. Trained workers can randomly enter the actual values of the screws. If the defined tolerances are exceeded, a qualified machinery officer can correct these using appropriate measures.
An assembly line for the production of screws can be built from various manufacturers. Thread rolling machines are available from ORT, EW MENN, WMW and ROLLFORM. Vibratory feeders are offered by DEPRAG, WEBER and RNA. Screw presses are manufactured by KUHNE MASCHINENBAU and SACMA.
Well maintained used machinery for producing and processing srews can regularly be found in our numerous industrial auctions. Fort further assistance don't hesitate to contact the Surplex Customer Care.