one approach to creating engineering bill of materials
DESCRIPTION
Bill of Materials (BOM) is a list of materials and components of a product. BOM is a basis forproduction planning in a company. BOM in various forms can be applied to companies which are notrelated with production. Good design and optimizing BOM directly affects to the productivity ofcompanies with no change in capacity of production facilities. The BOM can be roughly divided intogeneric bill of materials (GBOM) and engineering bill of materials (EBOM). BOM is basis for advancedlists of materials. GBOM is BOM adjusted for data analytical and EBOM is BOM adjusted for engineers.This paper presents the basis of the methodology for creation GBOM and influence EBOM on thefunctioning of BOM trough their implementation through the database.TRANSCRIPT
SRMA 2011
ISBN 978-86-82631-59-0
*Faculty of Mechanical Engineering, Belgrade, Serbia, [email protected]
One approach to creating engineering bill of materials
Miroslav Gojić, Faculty of Mechanical Engineering, Belgrade
Mentor: prof. dr Slobodan Radojević, Faculty of Mechanical Engineering, Belgrade
Bill of Materials (BOM) is a list of materials and components of a product. BOM is a basis for production planning in a company. BOM in various forms can be applied to companies which are not
related with production. Good design and optimizing BOM directly affects to the productivity of
companies with no change in capacity of production facilities. The BOM can be roughly divided into
generic bill of materials (GBOM) and engineering bill of materials (EBOM). BOM is basis for advanced
lists of materials. GBOM is BOM adjusted for data analytical and EBOM is BOM adjusted for engineers.
This paper presents the basis of the methodology for creation GBOM and influence EBOM on the
functioning of BOM trough their implementation through the database.
Keywords: bill of material, generic bill of material, engineering bill of material, database,
production planning.
I. INTRODUCTION
BOM includes all the elements of structural,
technological and operational production data,
which define the product structure and
technological process of production. BOM task
is to control and manage of complex ways for
obtaining assemblies from sub-assemblies,
while is the calculations of required quantities
for launch of the work order less important.
BOM development is significantly influenced
by computer science that allow quickly
obtaining BOM of final product in the most
diverse variants, with a large number of
connections between data that are incurred in
the production. Instead of requests for materials,
BOM has become the basis for planning and
managing resource in production.
Engineers based on the BOM can analytically
evaluate the quality of the product, and directly
affect on the speed for getting new product. The
study of BOM is a complex problem because it
is a multidisciplinary field in which, with the
computer is applied a simple tree data structure
and easy calculation, and with engineers the
problem is expressed by large amount of data
that has been developed by the creation of new
BOM for new products.
Design of the basic BOM is a key activity in the
definition of data for design and realization of
the production process. The lowest element of
the BOM, known as leaf, is material, while the
highest element, known as root, is the finished
product, and between them are materials, parts,
subassemblies and assemblies that make up a
product.
Presentation of the actual data in databases is
done through entities and relations. The data
what are stored in a database, first must be
processed (normalized) in order to save more
effectively.
By properly defining the database tables and
relationships between tables, we can get a very
efficient system what can accept the BOM in a
modified form suitable for storing in the
database. BOM stored in the database is not
acceptable for use by the human; we must have
a mediator, like query, who will create BOM list
of product that can be readable by human.
In this paper, it is shown on way of forming
GBOM through the arranged couples, parent
and child Fig.4.
Adding attributes important for engineers we
get an engineering bill of materials. Through the
examples it is presented the work of pseudo-
functions for formation EBOM on the base of
defined GBOM.
I. BOM ADDOPTION FOR DATA-
BASE
For example on Fig.1 it is shown Bill of
Materials (BOM) with one root and five levels.
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First international symposium for students with papers from mechanical engineering
One approach to creating engineering bill of materials
Fig. 1 Bill of Materials (BOM)
This BOM it show's set of leafs {3, 6, 7, 8, 9}
and a, leaf three one time, leaf six two times,
leaf seven three times, leaf eight three times and
a leaf nine one time. Analyzing the given BOM
we can see that is made from a leaf three {3}
and two sub-BOM (sBOM).
Fig. 2 Example of two sBOM, each sBOM is
new BOM
In Fig.2 we show that there are sBOM which
are part of both, the now BOM. In complex
BOM, finding common sBOM is very difficult;
in more complex BOM it is practically
impossible.
Each BOM it is represent of finish product, an
each sBOM in BOM as complex sub-assemble.
Seeking for com's sBOM is primary task in
Material Requirements Planning (MRP).
Using computers it makes ease to improve
BOM and lead to more developed finish
products. This is achieved when the BOM is
based on two level bill of materials or Modular
Bill of Materials (MBOM).
MBOM is sBOM based on two levels, which
according to Fig.1 and Fig.2 have the form
shown in Fig.3.
Fig. 3 MBOM as sBOM
For the realization of a BOM which can be
observed by computer is necessary to define a
Generic Bill of Materials (GBOM), Fig.4.
Fig. 4 Basic table field
Fig.4 also defined tree structure, which is
assumed that is acyclic. In this definition we can
simply add all the other attributes that
characterize the Engineering Bill of Materials
(EBOM). Fig.5 presents the Fig.1 through
GBOM definition.
Fig. 5 BOM in data structure notation
Given data in Fig.5 we can pass through the self
recursion pseudo-function r( ) defined in Fig.6.
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First international symposium for students with papers from mechanical engineering
One approach to creating engineering bill of materials
Fig. 6 Self recursion pseudo-function r( )
As we see the function seek (arg1, arg2) has
two arguments. The first argument arg1 is the
name of the table with MBOM. The second
argument arg2 is a value that is found by index
in MBOM table. The results of function seek( )
is a list, which is a subset of EBOM.
If the function r( ) has already been called, the
result of the last call is added to previous result.
The pointer is set on the list, by default at first
element of a list that was last added. Also the
result of function r( ) may be an empty list
(NILL).
For example, Fig.7,
EXAMPLE(t) = seek (EBOM (t), 5)
is assuming it has been invited by arguments
seek(EBOM (t), 4).
Fig. 7 Results from execution
EXAPMLE(t) = seek(EBOM(t),5)
If on the result from Fig.7 we apply function
EXAMPLE(t) = seek (EBOM (t), 7) the result is
NILL, Fig.8.
Fig. 8 Results from execution
EXAPMLE(t) = seek(EBOM(t),7)
Fig.9 is a transformation of Fig.8, using the
function EXAMPLE(t) = seek (EBOM(t), 7).
Fig. 9 Results from execution
EXAPMLE(t) = seek(EBOM(t),7)
Function skip(arg1, arg2) has two arguments.
The first argument arg1 is the name of the list,
while the second argument arg2 is the integer
value. The result of this function is the same
list, but the pointer is moved for arg2.
Let's give an example, Fig.9, in which we use
skip(EXAMPLE(t), 1), then the result is given in
Fig.10.
Fig. 10 Results from execution
skip(EXAMPLE(t), 1)
II. CONCLUSION
GBOM it is introduced through a
database on the basis of ordered pairs
and represents the most general BOM.
By adding different attributes,
arrangement, we get the different types
of EBOM. For each of the obtained
EBOM it is necessary to make a
pseudo-function r( ) which generates
the appropriate database list, BOM.
Future studies are aimed at finding the
"standard" pseudo-function r( ) and
special functions required by the
engineer. One such function is the one
that gives results in probability of
making the product.
III. REFERENCES
[1] C. Todman, Design a Data
Warehouse, Cet Beograd, 2001.
[2] L. Welling and L. Thomson,
MySQL Tutorial, Mikro knjiga
Beograd, 2005.
[3] B. Meyer, Object-oriented Software
Construction, Cet Beograd, 2003.
[4] mr. S. Radojevic, Algorithms for
formation BOM in relations database,
Mechanical Faculty Belgrade, 1989.
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First international symposium for students with papers from mechanical engineering
One approach to creating engineering bill of materials
[5] mr. S. Radojevic, Forming BOM of
products by simulated recursion and
pointers in relations database,
Mechanical Faculty Belgrade, 1990.
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