Applications of Group Technology
1.0 Introduction
Nowadays, the global economic of the world is getting increase and improves. All of the countries, nations and citizens are developing in a fast growing trend. Now the manufacturing processes also have to improve to such a way that produce and manufacture a good quality product with lower costs. Therefore a term group technology has been introduced. Group technology actually refers to a kind of technique which classifies the manufacturing part (sometimes named as family part) according to the size, shape, process or length. Some companies may group in according to other criterion such as the product’s function as long as it makes the company’s works easier. Actually, this group technology really can help to reduce the production costs. This is because grouping the part together (group of the part can be known as family part) can help to save the transportation costs, time of production and all this consequently increase the productivity, therefore, group technology definitely will be very useful to many of us.
Actually people start using group technology since the 1920s. People start using group technology in manufacturing process during that moment. We are also able to see the example of group technology in our daily life. For example, when we go to the library in our school, all the book will be classify according to the faculty and the title of the books. This method is not only makes the works of the library staff easier but also enables the students or lecturer to find the books that they need easily.
During the past decades, people normally used group technology to reduce the cost of production in manufacturing process. However, now the situation has changed, group technology has now become an important strategy for most of the manufacturing processes. It is an important aspect to improve the productivity and cause the company to develop in a better way.
2.0 Method to develop family part
In order to use the concept of group technology, the companies have to think of the way to classify the group. The first step will be classifying the part of the products (family parts) according to two different attributes which will be based on the geometric characteristics and production process characteristics.
In geometric characteristics, the products will be classified according to the size, shape and length. However, if the products are being classified according to the operation process, then the machine used for production, method of processing and tools used to hold the products will all being take into consideration. This actually is a method to group the part based on their attributes. Therefore, the company should observe their own product and determine the best way to classify the products.
For example, for those company that actually own a factory that produce screw or bolt nut, the best method of classification will be geometric classification since the products may varies in shape and size. However, if the company is actually a health care company, and they are producing body shampoo, toothpaste and mouthwash then the better way to classify the product will be the operation processing classification. This is because the products produced are actually all the same in term of size and shape, but they may be varying in flavor and smell. This is causing the operation process to be different from each other.
Then, the next step will be determining the method to form part families. Normally, the company will use three different methods to form the part families. The methods include coding and classification, manual visual inspection and production flow analysis. Different product may have different method to form the part families. The company should find the best way to group them and obtain the best result.
2.1 Classification and coding
Classification is a process to group all the related parts into a group and sometimes can be known as part families. Wherease, coding is means that the part families are being assigned with a symbol. People will be able to obtain the information of the particular product based on the code. Each character of the code also carries the information of the previous character. This is the most effective and accurate method to classify group technology among these three methods.
Nowadays, there are almost more than 100 types of classification and coding are available in the world. Besides, the coding system may vary from one company to another company. Many company had hire some experts to improve the coding system but there is no any universal acceptance until now. Some of the people may think that coding is just a simple task and can be easily done. However, it is actually a very difficult complex problem. Many time and energy have to be spent in order to find the best coding system that suitable for the company.
As stated above, there are about 100 kind of coding system available in the world. However, all of the classification and the coding systems are actually can be grouped into three different kind. That will be Hierarchical (monocode), Attribute (polycode) and Hybrid (mixed code).
Hierarchical (monocode)
Hierarchical (monocode) is actually a coding system which the each character being used will need to depend on the meaning and carry along the information of the previous character. This kind of system also will show a tree structure pattern. The benefit of using this coding system will be the coding system is seem to be more apparent and all the information will be able to obtained based on the code itself. Hierarchical (monocode) is very useful in many ways especially when the products are differing in shape, size or other geometric characteristics.
Forming a good hierarchical system can be very difficult. However, there are some hints for those companies who wish to form hierarchical system. When forming the codes, the company should ask themselves some questions. The answers collected from the choices will enable them to form an effective coding system.
The benefits of this kind of coding system will be enables us to obtain many information within a single few digits code. Furthermore, this kind system makes some part of the part can bring along some useful abstracting information to the company. However, the disadvantage will be it is quite impossible to produce a perfect hierarchical system. The other disadvantage will be the existence of sub group can lead to many different sub-sub group, this cause some position having blank code.
The figure above is an example of hierarchical (monocode) system and we can see that there is some imperfection in this system due to there is some empty coding exists. There some researches being done in order to improve and increase the efficiency of this hierarchical system.
Attribute (Polycode)
The attribute code system sometimes can be known as polycode and chain code system. This code is different with the monocode in term of their digits. In this polycode system, the digits within the code are all carrying different information. Each digit represents each different attribute of the part.
The advantage of this attribute (polycode) system will be very easily understood. This is due to each character is independent from one another. The company can know the details exactly after they saw the code. Unlike hierarchical code, the character has to depend on the previous information. Therefore, only the users who are familiar with the process can read the exact details. But this kind of coding system also did show a very significant disadvantage. This will be the code formed will be very long and large.
The figure below will be an example of attribute code system. From this table, we can clearly see that each character actually represent different attitude of the products. For example, if we obtain a product with a code of ‘32123’ that it will represent that this product actually has the characteristics of, boxlike in external shape, center hole in internal shape, do not have any number of hole, the type of hole will be cross and the gear teeth is actually an external spur.
Digit
Class of feature
Possible value of digits
1
2
3
4
1
External shape
Cylindrical without deviation
Cylindrical with deviation
Boxlike
…
2
Internal shape
None
Center hole
Brind center hole
…
3
Number of holes
0
1-2
3-5
…
4
Type of holes
Axial
Cross
Axial cross
…
5
Gear teeth
Worm
Internal spur
External spur
…
…
..
…
…
…
…
Hybrid (mixed code)
The final category of coding system will be the hybrid (mixed code). This is a kind of code system which most of the company prefer. This system combines the advantage from the Hierarchical (monocode) and Attribute (polycode) system. People may define this is an advanced system code. The example of this code will be ‘A12131B120’. The first alphabet ‘A’ is actually represents the type of part such as gear or screw. The next 5 digit used to represent the attribute of the part. Then the ‘B’ in the code above represents another subgroup such as the material or design. The following digit will be explaining the attitude of the subgroup stated. This clearly shows that this system did rely on the precious digit but also have some digit are independent which are able to show the attribute by itself.
Actually there are also some organizations and company use a special kind of hybrid (mixed code) system. They are known as DCLASS or MICLASS code and contain up to 8-12 digits in a particular code. However, there is only some specific organizations such as (The Netherlands Organization for Applied Scientific Research) are using this special kind of hybrid (mixed) code system.
Manual visual inspection
Manual visual inspection will be one of the methods used to classify part families. Actually, this method is not accurate enough compared to coding and production flow analysis. This method is actually classifying the products based on the physical appearance. Sometimes, there will be some companies or organizations are classifying the products only based on the photograph and arrange them based on their feature. Therefore, we can conclude that this is one of the most inaccurate methods of grouping part families.
However, there are actually some organizations are suitable to use this kind of coding system for their group technology. There is one company in United State successfully save their company from being backrub by using this manual visual inspection to classify their group technology. Actually, all of the method will be effective as long as it is suitable for the production of the company.
Production flow analysis
The other method to determine the part families will be the production flow analysis. This kind of classification system will mainly focus on the production process. The products that need to be manufactured by the same working process will be classified as a part families and then being processed by using a single kind of machines. The machines that used to manufacture part families are known as cells. Cellular manufacturing is referring to the manufacturing process when the part families are being manufacture by cell machine. The advantage will be this production flow analysis system need less effort compared to coding and classification system.
When classifying products by using this system, we need to form a matrix. This matrix actually did bring along some special meaning. This actually is a machine-component chart and it is also a M * N matrix where M = number of machines and N = number of parts. The 2 figures below show the production flow analysis. The grouping will be based on the operation process and find the optimum solution for it. For example, there is a duplicate D in production flow analysis. This is because machine D need to produce too many parts. If only single machine to be used, group 1 and group 2 have to be combined but they have too many dissimilar routings,
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
A
1
1
B
1
1
1
C
1
1
1
1
1
1
D
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
E
1
1
F
1
1
1
1
G
1
1
1
1
1
H
1
1
1
1
I
1
1
1
1
1
J
1
1
K
1
1
Figure above is the component machine chart
2
11
1
10
16
18
12
6
3
4
7
8
9
14
15
19
5
13
17
H
1
1
1
1
D
1
1
1
1
1
(Group1)
F
1
1
1
1
A
1
1
B
1
1
1
E
1
1
D
(Group 2)
1
1
1
1
1
1
1
1
1
1
C
1
1
1
1
1
1
I
1
1
1
1
1
G
1
1
1
1
1
J
(Group 3)
1
1
K
1
1
Figure above is the production flow analysis
3.0 Flow Chart in forming group technology
Group Technology
Advantages and disadvantages of group technology
Group technology will play an important role in the future production plants although now it still does not achieve the widespread application. Using group technology strategy is definitely beneficial to all of us. This strategy is not only beneficial to the company but also beneficial to the citizen or users.
The advantages of group technology toward the manufacturing process will be the production process can be improved. For example, the part control can become tighter, the physical layout of the machine group can be improved and the ordering tied toward the production also can be improved when group technology is being used. The other advantage will be a more systematic design and redesign can be produced. This will consequently lead to reducing on the planning time of the process and the setup time. The other advantage toward the manufacturing process will be the purchasing cost of the material can be reduced due to the materials are purchase in a very large quantity. This can also improve the accuracy of cost estimation of a certain companies or organizations. All these will definitely bring to an improvement toward the company and causes company or organizations to develop faster.
The improvement also can be clear seen on the product itself when group technology is being used. We can clearly see the quality of the products being improved. This is because the number of completely new design can be reduced and this causes the workers more familiar with the part. This leads to a production of better quality products.
The advantage that brings to the customer or users is the cost of the product is reduced when group technology being introduced. This is because the transportation fee to tr
