Hakan YORULMUŞ 030070111 1.ST WEEK

1) Optimized Production Technology; (Manufacturing method) 
Optimized Production Technology (previous)
Optimized production technology (OPT) is an approach to scheduling, which places the primary focus upon the "bottleneck" process or processes. Bottlenecks are an everyday concept. Motorway roasworks and super market chechouts are bottlenecks at busy times of the day. They restrict the flow of work through the operation. Processes may be bottlenecks because either their capacity is less than the level of demand or because their capacity is used in an inefficient manner. Once bottleneck processes are identifiedi supplying processes are backward scheduled from the bottleneck. At all of the bottleneck processes, therefore, operations are activated on the basis of delivering products just in time for their linked downstream processes. OPT is a computer-based scheduling system. The more bottlenecks a system contains, the more complex the scheduling task becomes and a computer is essential.
OPT is based on the view that the goal of the operation is to make money. It was developed for manufacturing, however some of the principles of OPT are applicable to all organizations.
(Azhashemi M., Galloway L., Rowbotham F.,Operations Management in Context, 2nd Ed., pg.259, Kayra Ermutlu)


Optimized Production Technology (new)

OPT’s objective is to schedule production so that the production output is maximised.

The key distinctive feature is its ability to identify and isolate bottleneck operations,

then to focus on these bottlenecks to determine production plans and schedules for the

entire shop. This simple idea could lead to the better utilisation of manufacturing

resources, resulting in greater productivity and lower costs.

Evans [1993] perceives that OPT can be viewed form several perspectives. These

being: as a philosophy for scheduling, as a language for modelling manufacturing

operations, as a software system for manufacturing resource planning, or as a tool for

co-ordinating the efforts of marketing, engineering and manufacturing to realise the

common goals of the organisation. Moreover, Hill [1991] describes OPT as a sound

aid to achieve the only goal in any manufacturing organisation, and that goal is to

make money.

 The ten rules of OPT.

To achieve this goal, Hill [1991] goes on to suggest that there are three important

factors that have to be carefully considered. They are throughput (rate at which the

manufacturing system generates money through sales), inventory and the operational

expense (amount in which is spent to turn the inventory into sales). These in turn feed

into the ten rules of its philosophy [Hill, 1991]:

1) Balance flow, not just capacity: Capacity and a smooth flow of materials should

be considered and maintained simultaneously, which is similar to the JIT

approach.

2) The level of utilisation of a non-bottleneck is determined not by its own potential
but by some other constraint in the system: The throughput (rate of which the
manufacturing system generates money through sales) of a system is limited bythe bottleneck (a resource whose capacity is equal to or less that the demand placed upon it). Therefore, it is necessary to control the inputs into the system
since it should be the bottleneck that dictates the throughput of the system. If nonbottlenecks resources produce more than bottlenecks can absorb, or more than the
demand dictates, then inventory builds up and operating expenses are increased.
3) Utilisation and activation of a resource are not synonymous: This rule defines utilisation as the degree to which a resource should be used in order to achieve the strategic goal of profitability, and activation as the degree to which the resource can be used.

4) An hour lost at a bottleneck is an hour lost for the entire system: Bottleneck resources should be utilised 100% at all times: breaks should not occur and set-up times must be reduced.

5) An hour saved at a non-bottleneck is just a mirage: Bottleneck resources limit the

capacity of the system, hence, saving non-bottleneck time does not effect the efficiency of the system.

6) Bottlenecks govern both the throughput and the inventory in the system: Inventories can be controlled where the bottlenecks are located, and which determines the throughput.

7) The transfer batch may not, and many times should not, be equal to the process batch: The transfer batch is the amount of product transferred from one operation to another, and the process batch being the amount processed at any operation between transfers. The numbers should be flexible, since it is essential for the flow of product from raw material to the finished goods.

8) The process batch should be variable, not fixed: When there is a different number

of parts to an object that are to be manufactured on different equipments, the

process batch needs to be varied in order to maintain a smooth and rapid flow, and

hence reducing inventory.

9) Schedules should be determined by looking at all constraints simultaneously.

Lead-times are the result of a schedule and cannot be predetermined: Lead-times

depends upon the sequencing (the sequence in which different parts, with different

processing times are being loaded), and so cannot be determined in a capacity

bound situation unless the capacity is considered.

10) The sum of the local optima is not equal to the optimum of the whole: OPT seeks

to measure the performance of the plant as a whole based on its raw material input

and the final product output.

(A Study of Production Management (Manufacture) , Lee Angela ,University of SalfordResearch Unit, (January 1999), page 9-10)

New answer is better it is more simple and it has more information.

2)Production Activity Control (Manufacturing method)

Production Activity Control (previous)

There is a widely perceived gap within the domain of scheduling for manufacturing systems, namely, many of the methods employed by production supervisors are quite different from those developed by researchers. In a sense, this inconsistency highlights the important fact that much scheduling research has failed to win approval where it matters most, namely, within the manufacturing system.

In this article, we argue for a practical approach to scheduling for manufacturing systems, one that we believe can narrow, and possibly bridge, the gap between theory and practice. This approach is based upon a well-defined and modular architecture for scheduling, termedproduction activity control. This architecture is the foundation of our proposed solution to scheduling, since it provides a coherent blueprint for the synthesis of information technology and scheduling strategies. The result of this synthesis is a design tool for production activity control, which allows for detailed and disciplined experimentation with a range of scheduling strategies in a controlled and simulated environment. Due to the unique modular property of the design tool, these strategies may then be implemented live in a flexible manufacturing facility, hence narrowing the gap between scheduling theory and manufacturing practice. Our overall approach is tested through an appropriate implementation in a modern electronics assembly plant.

(Internal Journal of Flexible Manufacturing Systems, Volume 4, Number 1, p. 79-103)

Production Activity Control (New)

Operational production management system issues take the tactical schedule outputs and

manage the manufacturing system to meet those requirements. Production Activity Control

(PAC) describes the principles and techniques used by management to plan in the short term

and to control and evaluate the production activities of the manufacturing organisation [2].

PAC architecture is a self contained series of tasks which control a specific cell within a

factory. The aim of PAC is to reduce complexity and uncertainty in task execution and

improve the co-ordination of decision making. With an SME their size should help them to

deal with PAC more easily, but in a study by Stahl [7] it was found that the SME was

constrained by a lack of access to knowledge and skills. It found that they lack the capacity

to define real training needs and they were unable effectively to plan, organise and implement

training. Further, the external training market did not meet the specific needs of an SME and

the tight financial margins and small number of employees made it very difficult to attend off

site training programmes. Larger companies with greater access to technical resources, such

as dedicated vendor planners, buyers and supervisors are better able to manage the PAC

process. Not surprisingly the cynical view is that the larger company, normally the customer

has the planning skills but is dependant on the smaller company, the supplier who has to

deliver against short term plans with limited knowledge and operational planning skills. The

planning process in both large and small companies may be the same, but the SME’s

effectiveness is constrained by shortcomings in understanding and executing basic planning

discipline and control.

(PRODUCTION ACTIVITY CONTROL FOR SMALL AND MEDIUM SIZED ENTERPRISES, SMEs WITH LESS THAN 500 EMPLOYEES; Neil Towers; Manchester Metropolitan University)
New definition is better than previous one


3)Production Planning (Manufacturing method) 


Production planning (previous) and control are the manufacturing support functions concerned with logistics problems in manufacturing.Production planning is concerned with planning what products are to be produced, in what quantities, and when.It also considers the resources requried to accomplish the plan.

(Mikell p.Groover,Fundamentals of modern manufacturing second edition ,page 928)


Production planning (new)
Manufacturing planning and control address decisions on the acquisition, utilization and
allocation of production resources to satisfy customer requirements in the most efficient
and effective way.  Typical decisions include work force level, production lot sizes,
assignment of overtime and sequencing of production runs. Manufacturing planning and control entails the acquisition and allocation of limited resources to production activities so as to satisfy customer demand over a specified time horizon. As such, planning and control problems are inherently optimization problems,
where the objective is to develop a plan that meets demand at minimum cost or that fills
the demand that maximizes profit.  The underlying optimization problem will vary due to
differences in the manufacturing and market context.

(Manufacturing Planning and Control; Stephen C. Grave; Massachusetts Institute of Technology
November 1999)
New answer is better it is more simple and it has more information.

4)Turbucharger (product)
Turbocharger: (previous)
The purpose of supercharging is to increase the mass of air trapped in the cylinder of the engine, by raising air density. This allows more fuel to be burnt, inreasing the power output of the engine, for a given swept volume of the cylinders. Thus the power to weight and volume ratios of the engine increase. Since more fuel is burnt to achieve the power increase, the efficiency of the engine cycle remains unchanged. A compressor is used to achieve the increase in the air density. Two methods of supercharging can be distingused by the method to drive the compressor. If the compressor is driven form the crankshaft of the engine, the system is called "mechanically driven supercharging" or often just" supercharging". If the compressor i driven by a turbine, which itself driven by exhaust gas from the cylinders, the system is called "turbocharging". The shaft of the turbocharger links the compressor and turbine, but is not connected to the crankshaft of the engine. Thus the power developed by the turbine dictates the compressor operating point, since it must equal that absorbed by the compessor.

(Diesel engine reference book, Second edition, p. 29-Edited by Bernard Challen and Rodice Baranescu)


Turbocharger: (new)
Turbochargers are precision pieces of machinery which operate at high speed, using heat of expanding
exhaust gasses to “boost” intake manifold pressure. Turbochargers increase performance and decrease
exhaust smoke through improving an engine’s volumetric efficiency.

(Technician Turbocharger Guide for the Powerstroke Engine; International Truck and Engine Corporation; September 2003 Rev. 3)




New definition and old definition is good. 


5) Euro Emission Standart (Standart) 
Euro Emission Standart (previous)
I can not find the previous answer

Euro Emission Standart(new):
Before a new vehicle can be approved for sale in the EU it must meet certain standards for
exhaust emissions as specified by EU directives.  These standards are vehicle type specific and for
petrol fuelled vehicles are sub-divided into passenger cars and light-duty vehicles.  The
passenger cars are further sub-divided according to their laden weight (below or above 2.5
tonnes) and the number of seats they have, whilst the light-duty vehicles are sub-divided into
three different categories by vehicle mass.
For all petrol vehicles the regulatory test cycle involves starting the engine when cold followed
by driving a cycle simulating urban and sub-urban driving (ECE 15 + EUDC).  The emissions
are monitored for the whole cycle and, after dividing by the cycle’s length (11.007 km), the
emission standards are expressed in grams of pollutant per kilometre.

(Appendix 1EU Emission standards for petrol vehicles; AEAT/ENV/R/0679 Issue 3)