The document discusses assembly lines, emphasizing their role in manufacturing efficiency and productivity through sequential addition of interchangeable parts. It highlights advancements in assembly line methods, including just-in-time manufacturing, and addresses the system's complexities and dependencies that affect overall production. Additionally, it mentions the application of assembly line principles beyond manufacturing, such as in project development through Joint Application Development (JAD).

1. A parts assembly station on a production line exhibits a severe vibration problem. A simplified
schematic representation is shown in Fig. 4.26. Two large tables of mass m_1 and m_2 are each
mounted to a sliding metal plate on resilient rubber mounts with shear stiffness K_1 and K_2, as
shown. The tables are each subjected to a vibrational excitation force, F_1(t) and F_2(t). The
plates are able to slide viscously on a second pair of deformable rubber mounts, with shear
stiffnesses K_3 and K_4. The viscous sliding coefficients are B_1 and B_2. The two plates are
coupled by a shaft with longitudinal stiffness K_5. Draw a linear graph for the system using the
two forces F_1 and F_2 as inputs.
Solution
An assembly line is a manufacturing process in which interchangeable parts are added to a
product in a sequential manner to create an end product. In most cases, a manufacturing
assembly line is a semi-automated system through which a product moves. At each station along
the line some part of the production process takes place. The workers and machinery used to
produce the item are stationary along the line and the product moves through the cycle, from
start to finish.
Assembly line methods were originally introduced to increase factory productivity and
efficiency. Advances in assembly line methods are made regularly as new and more efficient
ways of achieving the goal of increased throughput (the number of products produced in a given
period of time) are found. While assembly line methods apply primarily to manufacturing
processes, business experts have also been known to apply these principles to other areas of
business, from product development to management.
The introduction of the assembly line to American manufacturing floors in the early part of the
twentieth century fundamentally transformed the character of production facilities and businesses
throughout the nation. Thanks to the assembly line, production periods shortened, equipment
costs accelerated, and labor and management alike endeavored to keep up with the changes.
Today, using modern assembly line methods, manufacturing has become a highly refined process
in which value is added to parts along the line. Increasingly, assembly line manufacturing is
characterized by "concurrent processes"—multiple parallel activities that feed into a final
assembly stage. These processes require sophisticated communications systems, material flow
plans, and production schedules. The fact that the assembly line system is a single, large system
means that failures at one point in the "line" cause slowdowns and repercussions from that
point forward. Keeping the entire system running smoothly requires a great deal of coordination
between the parts of the system.
Computer power has enabled tracking systems to become more sophisticated and this, in turn,

2. has made it possible to reduce the costs associated with holding inventories. Just-in-time (JIT)
manufacturing methods have been developed to reduce the cost of carrying parts and supplies as
inventory. Under a JIT system, manufacturing plants carry only one or a few days' worth of
inventory in the plant, relying on suppliers to provide parts and materials on an "as needed"
basis. Future developments in this area may include suppliers establishing operations within the
manufacturing facility itself or increased electronic links between manufacturers and suppliers to
provide for a more efficient supply of materials and parts.
VARIATIONS IN ASSEMBLY LINE METHODOLOGIES
The passage of years has brought numerous variations in assembly line methodologies. These
new wrinkles can be traced back not only to general improvements in technology and planning,
but to factors that are unique to each company or industry. Capital limitations, for example, can
have a big impact on a small business's blueprint for introducing or improving assembly line
production methods, while changes in international competition, operating regulations, and
availability of materials can all influence the assembly line picture of entire industries. Following
are brief descriptions of assembly line methods that are currently enjoying some degree of
popularity in the manufacturing world.
As new assembly line methods are introduced into manufacturing processes, business managers
look at the techniques for possible application to other areas of business. One such application is
called Joint Application Development, or JAD. It is a process originally developed for designing
a computer-based system. It brings together those working in business areas and those working
in the information technology area into a single workshop. The advantages of JAD include a
dramatic shortening of the time it takes to complete a project. The JAD process does for
computer systems development what Henry Ford did for the manufacture of automobiles (a
method of organizing machinery, materials, and labor so that a car could be put together much
faster and cheaper than ever before—the assembly line).
In a similar way the fundamentals of assembly line theory have been applied to business
processes with success. These new methods of organizing work all share the common goal of
improving throughput by reducing the amount of time individual workers and their machines
spend on specific tasks. By reducing the amount of time required to produce an item, assembly
line methods have made it possible to produce more with less.