Process for Manufacturing a SCUBA Tank

PROCESS FOR MANUFACTURING A SCUBA TANK
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Introduction
A SCUBA is a pressure vessel designed for to hold liquids or gases at a pressure that is different
from the ambient pressure. The pressure vessels can either be thick walled (where the diameter is
less than ten times the wall thickness) or thin walled ( where the diameter is more than the wall
thickness). SCUBA tanks are made from various materials that include steel, aluminum, polymers,
carbon fiber, and other metals. Manufacturing the SCUBA cylinder is an engineering process that
begins with a drawing or diagrammatic representation of the cylinder and determining its
dimensions, components, and materials to be used in its manufacture. The diagram is then
converted into a real cylinder, following a general engineering process consisting of various specific
tasks and steps. There are four basic processes in manufacturing technology, especially with regards
to engineering and these include casting and molding, machining, joining, and shearing and forming
(Nordmeyer 2017). This article describes the steps involved in the production of a SCUBA cylinder
tank, detailing the various steps involved and what each step achieves/ accomplishes. Before
describing the processes specific to the SCUBA manufacture, the general engineering processes are
discussed and then expanded to fit the manufacture of SCUBA cylinder tanks
The Process
Casting and Molding: The casting process is used for producing items with a specific shape that
can be difficult to achieve if any other means is used. Casting is a process that entails pouring liquid
material, for instance molten metal, into a hollow mold cavity and allowing it to solidify. After its
set (hardened), the casting is removed: examples of products made through molding include engine
blocks and household goods (Nordmeyer, 2017).
Machining: This entails cutting a material piece into its desired shape, in the process removing
some parts of the material, a subtractive manufacturing process. It entails using machine tools like
milling machines and drill presses together with tools for cutting.
Joining: This entails brazing, welding, mechanical joining with fasteners such as pins , adhesive
bonding, and soldering. Joining is important if a product cannot be made as a single piece
Shearing and forming: This is done to get a material of a specific size and shape, using piercing,
punching, blanking, or trimming and cutting. Forming can also be achieved by forcing a metal
through a die. Forming includes operations like extruding, roll bending, spinning, and drawing
(Nordmeyer, 2017).
Having understood the basic manufacturing processes, the processes specific to manufacturing a
SCUBA cylinder tank are discussed in detail next. In brief, the processes entailed in the
manufacture of SCUBA tanks include forming, pressing, spinning, bending, welding, post-weld
heat treatments, assembly, and finally, painting. These key processes are discussed in detail in the
following sections. The processes assume that the cylinder tank already has been designed using

appropriate tools, such as using Auto CAD and the specific materials or alloys for its manufacture
selected.
Forming
Forming is a particular process for material manufacture that utilizes suitable stresses such as
tension, compression, combined stresses, or shear: these result in plastic deformation of materials
producing the desired shapes. Metal is used mostly in forming processes due to a plethora of uses
for it, although forming can also be applied to other materials such as plastics. There is no remove
of materials during the process of forming. Forming has various process examples that include
extrusion, forging, rolling, thread rolling, rotary swaging, sheet metal working, electromagnetic and
explosive forming (Hosford & Caddell, 2014). For the cylinder, forming can be achieved through
hot forming, where the temperature of fabrication exceeds the temperature of recrystallization for
the material. Warm forming can also be used, where the temperature of fabrication is above the
room temperature, although below the material recrystallization temperature. Cold forming can also
be used in which case the temperature of fabrication is significantly below the material
recrystallization temperature. Recrystallization is a process through which deformed material grains
are replaced by new grains that are undeformed. Recrystallization temperature pertains to the
minimum temperature where complete recrystallization occurs (Banabic, 2014).
Pressing
Pressing is also known as stamping in cylinder manufacture: it a process where flat sheet metal in
either coil or blank form is placed in a stamping press where a die surface and a tool form the metal
into shape. Pressing is a stamping process used in sheet metal forming processes, such as punching
with a stamping or machine press, embossing, blanking, coining, and flanging (Lim, Venugopal and
Ulsoy, 2013). This is done through a series of stages until the desired net shape is achieved. During
stamping, friction is generated by the tribology process, hence a stamping lubricant is used to
protect the die surface and tool from galling r scratching. The stamping process produces the
desired shape, such as the semi circular or circular shape for the general cylindrical shape of the
tank (Halimahtun and Alan, 2011).
Spinning
This is a process that follows the pressing process and is also termed as metal turning or spin
forming. It is a process in metal working where a tube of metal or a metal disc is formed into an
axially symmetric part by rotation at high speed. This can be achieved through the use of a CNC
Lathe machine and does not entail material removal; instead, the metal is molded over an existing
shape. The spinning process is used for shaping the end of the cylinder (the head) and is done after