China
Africa
Explore chapters and articles related to this topic
Metal Forming III—Sheet Metal Forming
Published in Zainul Huda, Manufacturing, 2018
Roll forming involves continuous bending of a large sheet metal by using opposing rolls to produce long sections of formed shapes. Roll forming is an ideal process for making components with a consistent profile running the entire length of the part, in which coiled sheet metal is passed through a horizontal series of rotating dies to produce a uniform cross-sectional shape. In roll forming, each set of rolling dies makes an incremental change to the sheet metal until the desired profile is achieved. Finally, the bended piece is cut to the specified length of the final part.
Sheet Metal Parts—I
Published in Godfrey C. Onwubolu, Introduction to SOLIDWORKS, 2017
Roll forming is a continuous bending operation in which a long strip of metal (typically coiled steel) is passed through consecutive sets of rolls, or stands, each performing only an incremental part of the bend, until the desired cross-section profile is obtained (see Figure 18.2). Roll forming is ideal for producing parts with long lengths or in large quantities.
General aspects
Published in A. Ghersi, R. Landolfo, F. M. Mazzolani, Design of Metallic Cold-formed Thin-walled Members, 2001
A. Ghersi, R. Landolfo, F. M. Mazzolani
The process of cold-rolling is shown in Figure 1.4. It is widely used for the production of individual structural members and corrugated sheeting. The final required shape is obtained from a strip which is formed gradually, by feeding it continuously through successive pairs of rollers which act as male and female dies. Each pair of rollers progressively forms the strip until the finished cross-section is produced. The number of rollers that are used depends on the complexity of the final shape as well as thickness and strength of the strip used. The completed element is usually cut to required lengths by an automatic cut-off tool, without stopping the machine.Cold-formed profiles manufactured by roll-forming are essentially uniform in cross-section and can be held within very close dimensional tolerances. The main advantages of cold-roll forming, when compared with other methods of fabrication, are: (1) the high production capacity; (2) the ability to maintain fine surface finishes during roll-forming operations. The latter benefit is particularly important where pre-galvanized steel or steel pre-coated with plastic are utilized.
Manufacturing a telescopic tube screw using a hydroforming process
Published in Materials and Manufacturing Processes, 2019
Hui Seok Jeong, Jae Hyun Ra, Sang Wook Han, Young Hoon Moon
Screw threads and threaded pipe joints have been widely used in heat exchangers, petroleum, mining, and civil structures.[12–15] A telescopic tube screw is a device that can provide an adjustable length feature and has been used in various applications for a secure and perfect fit. A variety of forming methods have been established for fabricating threaded and spiral parts. The screw is typically formed from a solid piece of material into desired rough shapes, and then machined into precise final desired shapes. Certain alternative methods, including roll-forming,[16,17] multi-stage cold forming,[18,19] and cross-wedge rolling of tubes,[20,21] have been used to form threaded and spiral parts. Table 1 compares different manufacturing processes to form threaded parts. As shown in the table, each manufacturing process is characterized by its own strengths and weaknesses, and because the formed product is significantly influenced by the manufacturing method, a reasonable compromise between process efficiency and product quality is required. The fabrication of threaded screw parts by using THF has been investigated due to its advantages of high efficiency, dimensional accuracy, and significant cost savings.
Classification and selection of sheet forming processes with machine learning
Published in International Journal of Computer Integrated Manufacturing, 2018
Elia Hamouche, Evripides G. Loukaides
Metal sheet forming is the process of transforming flat metal sheets to desired 3D geometries through mechanical means. In these processes, the sheet is reshaped without adding or removing material, and its mass remains unchanged. The material undergoes plastic strains to achieve the transformation. These often result in more uniform mechanical characteristics of the final workpiece when compared to contemporary processes such as machining and additive processes (Lange 1985). Sheet metal is used heavily in major industries such as the automotive and aerospace sectors. Example parts include car and lorry bodies, building roofs, engine covers, aeroplane fuselages and wings. Various processes are used to form rolled sheet metal using tools such as dies, rollers and jigs. Common processes include deep drawing, bending, stretch forming and roll forming (Swift and Booker 2003).
Impact properties of thermoplastic composites
Published in Textile Progress, 2018
Ganesh Jogur, Ashraf Nawaz Khan, Apurba Das, Puneet Mahajan, R. Alagirusamy
Many manufacturing methods/techniques are available to fabricate thermoplastic composites (semi crystalline/amorphous) in a wide array of profiles, dimensions, and quality. Some of these are thermo-forming, autoclave moulding, diaphragm forming, roll forming, filament winding, and pultrusion (a process for forming laminates of particular cross-section in a very reproducible manner by pulling filaments, precisely positioned by guides and impregnated with resin, into a die where the assembly is moulded into the required shape). In these methods, processing temperature must be above thermoplastic polymer’s melting point, i.e., a temperature ranging from 260° to 370 °C (500°–700 °F) for high-thermal-stability thermoplastics. The pressure required for thermoplastic processing varies; it may be as high as 34 MPa for stamp moulding to as low as 0.7 MPa for thermoforming. Finished thermoplastic parts can be joined by various methods like ultrasonic welding, infrared heating, vibration, hot air/gas, and adhesives [56]. In addition to commodity thermoplastic materials such as PP, PE or PA, there is another family known as high-performance thermoplastic polymers. High-temperature thermoplastics are effectively used in structural engineering applications where composites need to be exposed to both high mechanical and thermal loadings. They generally offer enhanced mechanical properties and retain their physical properties even at high temperatures and show good thermal stability for a long time [6]. Both commodity thermoplastics and high-performance thermoplastic polymers are discussed briefly in this section. Table 1 shows important properties of a range of useful thermoplastic polymers.