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Manufacturing Processes for Small Weapon Components
Published in Jose Martin Herrera Ramirez, Luis Adrian Zuñiga Aviles, Designing Small Weapons, 2022
Jose Martin Herrera Ramirez, Luis Adrian Zuñiga Aviles
Big forging machines are available for hammering large components. The process is known as hammer forging, and it can be done either by swaging or radial forging. Both processes are used to reduce the diameter of a tube or solid rod [2]. The difference is that in swaging the dies rotate around the workpart, whereas in radial forging the workpart rotates as it feeds into the hammering dies. Hammer forging is most often used to manufacture symmetric parts, such as gun barrels [6]. It can be performed as hot or cold working and the number of hammers to be used can be three, four, or six. The machines used for forging large gun barrels are of a horizontal type and can size the bore of the gun barrel to the exact rifling that is machined on the mandrel. Most mandrels are made from shock-resistant tool steel and high-speed steels; they are hardened, ground and polished, and sometimes plated with chromium to improve wear resistance and surface finish on the inside diameter of the barrel. Tungsten carbide mandrels are used for superior wear resistance when production volume justifies their increased cost; a mandrel can be used to rifle 1000–2000 barrels depending on its quality [5]. Workparts produced by this process often have improved microstructural and mechanical properties compared to those produced by other techniques like broaching, button rifling, or even investment casting.
General Information About Electrical Heating Elements
Published in Thor Hesborn, Integrating Electrical Heating Elements in Appliance Design, 2017
The presently used automatic coiling machines (Kanthal, Oakley, and Platt) are all based on the same principle: The wire is wound round a short rotating mandrel (about 10 mm long) and continuously pushed off it. The mandrels are often made of a hard material such as tungsten carbide. During the coiling process the wire is pressed in a radial direction against the mandrel and its shoulder by one or two rotating rolls, as shown in Figure 3.10. The speed of the rolls can be adjusted, and their circumferential speed should be about the same as for the wire on the mandrel. Their axes may or may not be parallel to the axis of the mandrel. The rolls can be made of tungsten carbide, of steel, or of plastic. The guiding rolls for the wire may be made of nylon.
Fabrication Processes
Published in Manas Chanda, Plastics Technology Handbook, 2017
In the filament-winding method, continuous strands of glass fiber are used in such a way as to achieve maximum utilization of the fiber strength. In a typical process, rovings or single strands are fed from a reel through a bath of resin and wound on a suitably designed rotating mandrel. Arranging for the resin impregnated fibers to tranverse the mandrel at a controlled and predetermined (programmed) manner (Figure 2.49) makes it possible to lay down the fibers in any desired fashion to give maximum strengths in the direction required. When the right number of layers have been applied, curing is done at room temperature or in an oven. For open-ended structures, such as cylinders or conical shapes, mandrel design is comparatively simple, either cored or solid steel or aluminum being ordinarily used for the purpose. For structures with integrally wound end closures, such as pressure vessels, careful consideration must be given to mandrel design and selection of mandrel material. A sand-poly(vinyl alcohol) combination, which disintegrates readily in hot water, is an excellent choice for diameters up to 5 ft (1.5 m). Thus, a mandrel made of sand with water-soluble poly(vinyl alcohol) as a binder can be decomposed with water to recover the filament-wound part. Other mandrel materials include low-melting alloys, eutectic salts, soluble plasters, frangible or breakout plasters, and inflatables.
Long-term viscoelastic properties of carbon fiber/epoxy composites using tow prepreg strand specimens
Published in Advanced Composite Materials, 2023
A composite material macroscopically consists of two or more constituents and has better properties than when each constituent is used alone. Carbon fiber reinforced plastic, representative composite materials, uses carbon fiber as reinforcement and polymer as a matrix. There are many manufacturing processes for making composites, such as filament winding, resin transfer molding, vacuum bag molding, etc. Each method has advantages and disadvantages, so the best choice is selected according to the geometry and purpose of the structures. A prepreg is an intermediate material that is partially cured. It is mainly used in high-performance and reliable parts, which require precise control of fiber volume fraction and orientation [1]. Prepregs are mainly made in the form of sheets or tows. The sheet prepreg is usually laminated and cut into the desired shape. Tow prepreg is in the form of a strand wound on a bobbin for filament winding. Filament winding is a method of winding fibers on the mandrel and is used to manufacture cylindrical structures such as pipes and pressure vessels. There is an advantage of good material efficiency because there is no wasted material to be cut and discarded [2]. There are many processing parameters, such as winding angle and pattern, which directly affect the performance of the structures. Therefore, it should be designed to satisfy the purpose, and the lifespan and performance of the structures should also be predictable [3,4].
Effect of shape on depth profile Nuclear Magnetic Resonance data of multilayered composite structure
Published in Nondestructive Testing and Evaluation, 2023
Sanjaya K Sahoo, Srinivas Kuchipudi, Ch. Sri Chaitanya, R Narasimha Rao, Manoj K Buragohain
A cylindrical shaped (220 mm diameter, 5 mm thick and 250 mm long) and flat shaped (300 mm X 200 mm, 4 mm thick) composite structures were manufactured using filament winding method. The glass filaments are impregnated in a bath with epoxy resin as they are wound on to the mandrel. Once the mandrel is completely covered to the desired thickness, the component is sent for curing in an oven. After the component is cured, the mandrel is removed by cutting from the template using a lathe machine. Cured glass epoxy composite structures realised from the process described above were later adhesively bonded with rubber (a copolymer of acrylonitrile and poly-butadiene) liner material (2 layers of 2 mm thick rubber material). The material then coated with carbon black based adhesive liner and hydroxyl-terminated poly-butadiene (HTPB) based composite solid propellant to obtain the final multilayered composite structure used for the testing as shown in Figure 1. NMR testing was done on composite structure adhesively bonded with the rubber, composite with rubber and coated adhesive liner and composite with rubber, adhesive liner and propellant.
Buckling of helically wound composite cylinders under uniform external pressure
Published in Ships and Offshore Structures, 2023
Xinlong Zuo, Jian Zhang, Wenxian Tang, Ming Zhan, Yongsheng Li
Many experimental studies have been devoted to filament wound cylinders because the continuous strands offering reinforcement can be oriented in any direction. Filament winding is the main process for manufacturing composite cylinders in which a series of continuous fibres are applied to a rotating mandrel (Rosenow 1984). To validate design results, multiple hydrostatic pressure tests were conducted on filament-wound cylinders(Hernández-Moreno et al. 2008; Javier et al. 2018; Bozkurt et al. 2019). To quantify small deformations caused by buckling, the group of Pan presented an experimental approach in which the strain and buckling responses are employed to evaluate and monitor the buckling modes and load capacities of composite cylinders. They discovered that the buckling of composite cylinders precedes their collapse (Shen and Pan 2021). Studies have also been conducted on composite cylinders that have fibre reinforcements arranged at ±55° to the longitudinal axis (Al-Salehi et al. 1989; Mistry et al. 1992; Carroll et al. 1995; Graham 1995). For instance, Kaddour and coresearchers tested ±55° glass–epoxy composite cylinders under biaxial compression (Liu et al. 2005) because the ±55° angle plies were considered optimal for closed-ended cylinders subjected to uniform external pressure (Kaddour et al. 1998).