030070104 Cebrail Yıldırım 4th week

Poka(Baka)-Yoke(new&better) [Mistake proofing Method]

      Poka-Yoke method has been implemented in one of the companies of automotive industry. This organization shall have two main production sectors: manufacture and assembly gearboxes and manufacture of engines for factories belonging to its own group. The organization currently employs around 700 employees.

     The main purpose is the manufacture of these elements of high quality, which meet quality standards in accordance with the principles processes continuous improvement (Kaizen). One of the ways of realization the improve strategy is to use Poka-Yoke techniques. Taking into account that the engine shall consist of approximately 310-350 part, they are very useful in just such as companies concerned with putting together of elements and manufacturing of parts. The produced elements must have a large precision therefore should be to minimize in the processes possibility of appearance a large risk omissions "something" or errors.

      By introducing techniques Poka-Yoke company guided by the following principles:

following principles:

 Defects arise most as a result of human errors. The following types of errors committed by people have been distinguished:

 1) Although the worker is aware of the mistake he makes, he continuous to do the same,

 2) The errors due to the misunderstanding,

 3) Incorrect identification,

 4) Forgetting,

 5) Lack of training,

 6) Good intentions but improperly implemented. All errors arising in the company are recorded and then analysed. Most of them can be prevented by using techniques Poka-Yoke.

7) Poka-Yoke techniques are a kind of response to errors in the short term. The reaction to obtain the information of the formation error must be immediate. Poka-Yoke must be exactly in the place where the error occurred or which may occur. It is also important that seek to provide, where error may arise.

 8) Use of Poka-Yoke causes, that the frequency of errors is less.

 9) Techniques used are simple, does not require the intervention of engineers, are cheap and effective.

(M. Dudek-Burlikowska, D. Szewieczek, The Poka-Yoke method as an improving quality tool of operations in the process, vol.36, 2009)

Baka-Yoke (Fool-Proofing) (previous)

To produce quality products 100 percent of the time, innovations must be made to tools and equipments in order to install devices for the prevention of defects. This is called baka-yoke, and the following are examples of baka-yoke devices:

1. When there is a working mistake, the material will not fit the tool.

2. If there is irregularity in the material, the machine will not start.

3. If there is a working mistake, the machine will not start the machining process.

4. When there are working mistakes or a step left out, corrections are made automatically and machining continues.

5. Irregularities in the earlier process are checked in the later process to stop the defective products.

6. When some step is forgotten, the next process will not start.

(Öno T., Toyota Production System: Beyond Large-Scale Production, 1978, pg.122)

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Line Balancing (new&better) [Operation optimization]

Line Balancing (LB) is a classic, well-researched Operations Research (OR) optimization problem of significant industrial importance. Assembly Line Balancing, or simply Line Balancing (LB), is the problem of assigning operations to workstations along an assembly line, in such a way that the assignment be optimal in some sense.

LB is a classic Operations Research (OR) optimization problem, having been tackled by OR over several decades. Many algorithms have been proposed for the problem. Yet despite the practical importance of the problem, and the OR efforts that have been made to tackle it, little commercially available software is available to help industry in optimizing their lines. In fact, according to a recent survey by Becker and Scholl (2004), there appear to be currently just two commercially available packages featuring both a state of the art optimization algorithm and a user-friendly interface for data management. Furthermore, one of those packages appears to handle only the “clean” formulation of the problem (Simple Assembly Line Balancing Problem, or SALBP), which leaves only one package available for industries such as automotive. This situation appears to be paradoxical, or at least unexpected: given the huge economies LB can generate, one would expect several software packages vying to grab a part of those economies.

(Emanuel Falkenauer, Line Balancing in the Real(International Conference on Product Lifecycle Management) World, n.d.)

Line Balancing (previous):

Given a target production rate and the number of working hours available, the planner calculates the work content of the process and breaks it into meaningful work assignments. In this way, the required number of operators and workplaces is determined, along with the flow of materials between them. Assumptions or calculations must be made to establish the time that will be lost to breaks and to nonvalue-adding tasks such as material handling, housekeeping, and the like. The formal name for this process is “line balancing”. A good line balance achieves the desired production rate with the minimum number of operators and minimal idle time. (Hwaiyu Geng, Manufacturing Engineering Handbook, p. 52.7)

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Data Model (new&better)

The data model is a relatively small part of the total systems specification but has a high impact on the quality and useful life of the system. Time spent producing the best possible design is very likely to be paid many times over in the future. The database is specified by a data model, describing what sort of data will be held and how it will be organized.

(Graeme C. Simpson, Graham C. Vitt, Data Modelling Essentials, pg. 4,10)

Data Models (previous): 

 IEC defines a wide range of data models. Before a variable can be used, it must be declared as one of the data models. Data models include the following;

SINT, INT, USINT, UINT, REAL, LREAL, TIME, DATE, TOD, STRING, BOOL, BYTE, WORD, LWORD, DT ...

(Computer Aided Manufacturing, 2nd Edition, Chang T.C., Wysk R.A., Wang H.P., 1998 Page: 202

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Foundry(new&better) [Casting Field]

Foundry engineering deals with the processes of making castings in moulds formed in either sand or some other materials. Castings have several characteristics that clearly define their role in modern equipment used for transportation, communication, power, agriculture, construction and in industry. Cast metals are required in various shapes and sizes and in large quantities for making machines and tools, which in turn work to provide all the necessities and comforts of life.

The main design advantages are the following:

·         Size (from a small wire of 0.5mm diameter to 200 tonnes weight parts)

·         Complexity

·         Weight saving (Less wasting of the raw material)

·         Production of Prototypes

·         Wide range of properties and versatility

·         Low cost

·         Dimensional Accuracy

·         Versatility in production

(P. L. Jain, Principles of Foundry Technology, 2009)

Foundry(previous)

A foundry is a factory equipped for making molds, melting and handling metal in molten form, performing the casting process, and cleaning the finished casting.

(Groover M.P., Fundamentals of Modern Manufacturing:Materials, Processes and Systems, pg.207, Kayra Ermutlu)

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Thermoforming (new&better) [Manufacturing Process]

Thermoforming is an industrial process in which thermoplastic sheet or film is processed into a new shape using heat and pressure. The process is neatly segmented into four steps:

·         Heating the sheet

·         Stretching the sheet

·         Cooling the sheet on the mold surface and

·         Trimming the part from its surroundings.

This manufacturing technique has a number of advantages as follows:

*  Low Equipment Costs

*  Low Tooling Costs

*  Economical to produce at low volumes

*  Timeline from design to prototype

*  Large Surface to thickness ratios common

*  Wide variety of plastics available

*  Decorating and printing

*  Multi-Layer Parts

(Peter Klein, Fundamentals of Plastics Thermoforming, 2009, pg. 1,2,3,4)

Thermoforming (previous)

Thermoforming is a process in which a flat thermoplastic sheet is heated and deformed into the desired shape. The process is widely used in packaging of consumer products and to fabricate large items such as bathtubs, contoured skylights, and internal door liners for refrigerators.
Thermoforming consists of two main steps: (1) heating and (2) forming. Heating is usually accomplished by radiant electric heaters, located on one or both sides of the starting plastic sheet at a distance of roughly 125 mm (5 in). Duratio n of the heating cycle needed to sufficiently soften the sheet depends on the polymer—its thickness and color. The methods by which the forming step is accomplished can be classified into three basic categories: (1) vacuum thermoforming, (2) pressure thermoforming, and (3) mechanical thermoforming. In our discussion of these methods, we describe the forming of sheet stock; in the packaging industry, most thermoforming operations are performed on thin films.

(Mikell P. Groover, Fundamentals of Modern Manufacturing, Materials, Processes and Systems ,page 293)