Job shop production system final

Job shop production system is described. the meaning of production, systems and production systems and job shop are explained

1. JOB SHOP PRODUCTION SYSTEM
Production
Production can be explained as an act of either manufacturing or mining or growing of
goods (commodities) generally in bulk for trade.
Production is a method employed for making or providing essential goods and services
for consumers. It is a process that puts intangible inputs like ideas, creativity, research,
knowledge, wisdom, etc. in use or action. It is a way that transforms (convert) tangible
inputs like raw-materials, semi-finished goods and unassembled goods into finished
goods or commodities.
System
System is an arrangement or assembly of inter-dependent processes (activities) that
are based on some logic and function. It operates as a whole and is designed (build)
with an intension to achieve (fulfill) some objective or do some work. Huge systems are
often a collection (assembly) of smaller sub-systems.
Definition of production system
Production system may be defined as,
"The methods, procedure or arrangement which includes all functions required to
accumulate (gather) the inputs, process or reprocess the inputs, and deliver the
marketable output (goods)."
Production system utilizes materials, funds, infrastructure, and labor to produce the
required output in form of goods.
Meaning of production system
Production system consists of three main components viz., Inputs, Conversion Process
and Output.
1. Inputs include raw-materials, machines, man-hours, components or parts,
drawing, instructions and other paper works.
2. Conversion process includes operations (actual production process).
Operations may be either manual or mechanical or chemical. Operations convert
inputs into output. Conversion process also includes supporting activities, which
help the process of conversion. The supporting activities include; production
planning and control purchase of raw-materials, receipt, storage and issue of
materials, inspection of parts and work-in-progress, testing of products, quality
control, warehousing of finished products, etc.
3. Output includes finished products, finished goods (parts), and services.

2. The three components of a production system are depicted in this diagram.

Hence, we can say that, production system is a union or combination of its three main
components viz., Inputs, Conversion Process, and Output. In short, everything which is
done to produce goods and services or to achieve the production objective is called
production system.
Examples
The examples of a production system are as follows:
1. Tangible goods: Consider an example of a manufacturing industry like a Sugar
Industry. Here, sugarcane is first used as an input, and then the juice of
sugarcane is processed through a conversion process, finally to get an output
known as a refined sugar (used for mass consumption).
2. Intangible goods: Consider an example from a service industry that of a
software-development firm or company. Here, initially, written program codes are
used as inputs. These codes are then integrated in some database and are
provided with a user-friendly interface through a conversion process. Finally, an
output is made available in form of an executable application program.
Production system is a result of arranging inputs, their conversion process and output
based on some logic and functions. Production system fails if any such arrangement
made doesn’t give a desired level of outcome.
Types of Production Systems

The types of production processes / systems are classified on the basis of
 –Product / Output Variety and
 –Product / Operations / Output Volume

They are broadly classified as:

 Continuous Production Process

 Process / Flow Production

 Mass Production

3.  Intermittent Production Process

 Batch Production

 Job Shop Production




A job shop is a type of manufacturing process structure where small batches of a variety
of custom products are made. In the job shop process flow, most of the products
produced require a unique set-up and sequencing of processing steps.
Job shops are designed to manufacture a wide variety of products with small lot sizes in
order to achieve maximum flexibility.
Products have usually different operation sequences and operating time for each
operation could vary significantly in job shop manufacturing. Products are released to
the job shops in batches also called jobs.
General purpose machines are suitable in job shops because they are capable of
performing many different types of operations and thus capable of producing a wide
variety of products with small lot sizes. Machines which perform similar function
grouped together: lathe machines in one department, milling machines in another
department and so forth. A job shop layout is also called a process or functional layout.

4. Here, in jobbing production flows, company accepts a contract to produce either one or
few units of a product strictly as per specifications given by the customer. The product is
produced within a given period and at a fixed cost. This cost is fixed at the time of
signing the contract.
Examples of such jobbing production flows include, services given by repair shops,
tailoring shops, manufacturer of special machine tools, etc.
When is Job Shop production system used??
Job Shop Production Process is used when there is a need for:
 High variety of products with low volume
 Use of general purpose machines and facilities
 Highly Skilled Operators who take up each job as a challenge
 Large inventory of materials, tools and parts
 Detailed planning is essential for sequencing of each product Capacities for each
work centers and order priority
CHARACTERISTICS OF A JOB SHOP
1. Layout
The layout is designed to minimize material handling, cost, and work in process
inventories.

5. 2. Routing
Jobs often travel in a jumbled routing and may return to the same machine for
processing several times. This type of layout is also seen in services like
department stores or hospitals.
3. Employees
Employees in a job shop are typically highly skilled craft employees who can
operate several different classes of machinery. These workers are paid higher
wages for their skill levels.
4. Information
Information is needed to quote a price, bid on a job, route an order through the
shop, and specify the exact work to be done. Information begins with quoting.
5. Scheduling
A job is characterized by its route, its processing requirements, and its priority. In
a job shop the mix of products is a key issue in deciding how and when to
schedule jobs.
Advantages of job shop manufacturing
1. Better utilization of machines
In job shop manufacturing, all machines are fully and effectively utilized thus fewer
machines are required to manufacture a wide variety of products. Thus job shop
manufacturing needs lower investment because of comparatively less number of
machines. Also purchasing cost of general purpose machines becomes lower.
2. Greater flexibility
Both a varied quantity and a varied mix of products can be manufactured because
there are not dedicated machines. This leads to greater flexibility in job shop
manufacturing.
3. More effective supervision
As the machines are grouped into departments on the basis of functions performed
by them, the specialized knowledge of supervisors about their departments ensures
the specialized and more effective supervision. Supervision task becomes more
effective because each supervisor has to supervise limited same types of machines
functioning in his/her department.

6. 4. Develop high skills & knowledge in operators
Each operator is working in a single department. This develops high skills and
knowledge in operators to perform various tasks in their departments. Management
can also take advantages of capabilities of operators in order to execute
manufacturing activities more effectively and efficiently in each department.
Disadvantages of job shop manufacturing
1. High material handling cost
Material/parts must be moved from one department to another department. If
machine in another department is not ready to accept a job or worker is unavailable
then materials need to be stored and protected there. Status & location of materials
are difficult to track and control. Thus cost of moving, storing, protecting and
controlling materials becomes high in job shop manufacturing.
2. High material flow distance
When the processing of a part has been completed in one department in the job
shop manufacturing, it usually must be moved to next department travelling a large
distance. Material flow distance is high in job shop manufacturing because every
parts may have to travel through the entire shop to complete all of the required
operations.
3. High production lead time
Each part in a batch must wait for the remaining parts in its batch to complete
processing before it is moved to the next stage of production. This causes high
production lead time and low production rates in job shop manufacturing.
4. High levels of work in progress inventory
Level of work in progress inventory is high in job shop manufacturing because of
high production lead time.
5. High production cost
A production cost in job shop manufacturing is high because of high material
handling cost and high material transportation cost.

7. INPUT CONTROL FOR JOB SHOP

1. Forecasting
This is the first and foremost step in a job shop production input control. The
future demand for the products is estimated.
2. Order Acceptance
Orders from customers are taken as per their forecast.
3. Production Planning
Production planning determines the appropriate levels of shop capacity and
aggregate production to meet demand and minimize i nventory and
manufacturing costs. The production is planned accordingly based on the
capacity and capability of both firm and machines.
4. Production Schedule
A master production schedule (MPS) is a prepared according to the plan to be
produced in the time period such as production, staffing, inventory, etc. It keeps
in mind the end item requirement. It specifies the due dates of scheduled orders
of individual end items
5. MRF
The MPS is the input to the Material Requirement Planning (MRP) function.
Using planned lead times for each component, MRP explodes the bills-of-
materials of the end items to determine when to release purchase orders for raw

8. materials and work orders for make items. MRP does not use capacity
information while performing these calculations. This fact, coupled with the often
optimistic delivery schedules set by the program managers, leads to uneven
loading of the shop, overloading of the bottleneck resources and, as a
consequence, high work-in-process inventory (WIP), long cycle times, and poor
on-time delivery performance.
6. Shop floor scheduling
Shop floor control comprises the methods and systems used to prioritize, track,
and report against production orders and schedules and then the finished good is
produced.
Conclusion
A job shop production system is a production system where the products are to be
tailormade according to the customer requirements within a fixed time frame. General
type machines are used as they can be used for multi purpose. The employees will be
highly skilled and many type of products can be produces. It’s a very challenging type of
production since products may vary largely. Job shop production process is used in
wood working shops, metal fabrication shops, etc. It may require an inventory of a few
type of the raw materials but, here the largest percentage of the inventory is Work in
Process (WIP).Work in Process is the inventory that accumulates in between process
stages.
Bibliography
1. Input control for job shop manufacturing, Principal Investigators: Jeffrey W. Herrmann,
Ioannis Minis –Research paper
2. Reference for business.com
3. Slide share
4. Wikipedia
5. Quora