Scholarly article on topic 'Software Tool for Planning and Analyzing Engineering Changes in Manufacturing Systems'

Software Tool for Planning and Analyzing Engineering Changes in Manufacturing Systems Academic research paper on "Computer and information sciences"

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Abstract of research paper on Computer and information sciences, author of scientific article — R.C. Malak, J.C. Aurich

Abstract Companies are facing an increasing number of engineering changes (ECs) in manufacturing systems (MS). The planning of ECs becomes a continuous task. It has to be proceeded properly in order to identify the efforts of the implementation and to reduce the risk of production shutdowns. Tools of the digital factory are able to support the planning and analyzing procedure. In order to improve the handling of ECs, an approach for planning and analyzing is presented. It starts with a systematic description of ECs. This systematic description initiates modules to analyze the impacts on MS and to automatically generate plans for the implementation. The planning and analyzing procedure is implemented in a software demonstrator which enables an intuitive navigation for the planning engineer. This software demonstrator provides direct feedback based on planned ECs. Its functionality is demonstrated and validated by a use case.

Academic research paper on topic "Software Tool for Planning and Analyzing Engineering Changes in Manufacturing Systems"

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Procedia CIRP 12 (2013) 348 - 353

8 CIRP Conference on Intelligent Computation in Manufacturing Engineering

Software tool for planning and analyzing engineering changes in

manufacturing systems

R.C. Malaka *, J.C. Auricha

aInstitute for Manufacturing Technology and Production Systems, University of Kaiserslautern, P.O. Box 3049, 67653 Kaiserslautern, Germany * Corresponding author. Tel.: +49-631-205-4282; fax: +49-631-205-3304. E-mail address: malak@cpk.uni-kl.de._

Abstract

Companies are facing an increasing number of engineering changes (ECs) in manufacturing systems (MS). The planning of ECs becomes a continuous task. It has to be proceeded properly in order to identify the efforts of the implementation and to reduce the risk of production shutdowns. Tools of the digital factory are able to support the planning and analyzing procedure. In order to improve the handling of ECs, an approach for planning and analyzing is presented. It starts with a systematic description of ECs. This systematic description initiates modules to analyze the impacts on MS and to automatically generate plans for the implementation. The planning and analyzing procedure is implemented in a software demonstrator which enables an intuitive navigation for the planning engineer. This software demonstrator provides direct feedback based on planned ECs. Its functionality is demonstrated and validated by a use case.

© 2013 The Authors. Published byElsevierB.V.

Selection and peer review under responsibility of Professor Roberto Teti

Keywords: Planning; Digital Factory.

1. Introduction

Companies need to continuously adapt their manufacturing systems (MS) to keep up with shorter innovation cycles, competition, and a rapidly changing market. According to that, companies have to implement numerous engineering changes (ECs): This development requires a systematic and fast method for planning and analyzing ECs [1]. Inaccurate planning and analyzing of ECs lead to production shutdowns, time delays, and consequently cause high costs [2]. In addition to caused production shutdowns, ECs have to be re-planned and analyzed. This leads to postponed deadlines and cause high cost [3, 4].

The increasing number of ECs and the reduced available time for planning and analyzing them causes a dilemma (Figure 1). On the one hand, this leads to a decreasing quality in planning and analyzing, which in turn leads to the necessity of re-planning or to ineffective ECs. Financial restrictions and time pressure prevent a detailed analysis [5]. On the other hand, the

reduced available planning time leads to a reduced implementation of ECs. This leads to an increasing stock of required ECs._

! Possible solutions !

Additional resources ^^H Increased efficiency

Decreasing r \

quality Less time Less ECs are

of planning for planning implemented

.and analyzing, V y V >

C Increasing

number of ECs

Replanning and/or r N Decreasing Increasing „stock" of ECs

ECs are not , effective , productivity

Dilemma of ECs

Fig. 1. Dilemma of ECs

The decreased planning and analysis quality, as well as less implemented ECs, are reducing the productivity. This leads to further required adaptations in MS. There are two possibilities to solve that dilemma: additional

2212-8271 © 2013 The Authors. Published by Elsevier B.V.

Selection and peer review under responsibility of Professor Roberto Teti

doi:10.1016/j.procir.2013.09.060

planning and analyzing resources and an increased planning and analyzing efficiency. Additional planning and analyzing resources can be established, for example, through new personnel or external services. The efficiency of planning and analyzing can be increased through supporting software tools. They are able to accelerate the planning and analyzing procedure and enable a high quality. For this reason, software tools are required which support planning and analyzing ECs in MS by accelerating the procedure.

In this paper, we present a conceptual work for a software tool that supports planning, analyzing, and the implementation of ECs in MS. We implement this approach in a software demonstrator, programmed with JAVA 3D, and illustrate its application in a case study.

2. .State of the art

2.1. ECs in MS

The term EC originates from the area of product development. Additionally, ECs occur in MS and can be described as follows [6, 7]:

• reconfiguration of production objects, as for example machines and working places;

• addition, substitution, and removal of production objects, e.g. machines or tools;

• changes to the structure of interrelationships between production objects.

MS can be separated into the levels network, production site, system or segment, machine, as well as processes and tools [8]. ECs do not concern whole production sites or networks. They are related to the segment or system level (part production, machining, assembly, etc.)with machines and workplaces as subsystems. Compared to factory planning, ECs are not necessarily related to investment decisions. They are usually on the level of machines and workplaces. The system boundary is a manufacturing segment and doesn't consider the whole factory. ECs can be planned within departments or segments independently from other departments or levels.

2.2. Planning and analyzing ECs in MS

Depending on the described level, there are different approaches for planning and analyzing ECs in MS. Factory planning concerns the level of production sites and networks. The procedure is divided into different phases which are supported by methods and tools [3]. It is not suitable for ECs for the following reasons:

• continuous need for ECs,

• consideration of the running production,

• consideration of restrictions of the current production environment,

• partially small investment,

• partially less effort of implementation,

• etc.

Approaches for planning and analyzing ECs are the continuous improvement process (CIP) [9], process optimization [10], and reengineering [11]. Reengineering is the analysis of existing processes with the scope of dramatic improvements in critical, contemporary measures of performance [11]. Roessing presents an approach for combining ECs in manufacturing systems and processing them as EC projects [12].

2.3. Support by tools of the digital factory

The planning and analyzing procedure of ECs in MS can be supported by tools of the digital factory [13]. The digital factory is defined as a set of computer aided methods and tools to provide a virtual production model. They can be used for planning, experimenting and implementation [14]. Tools of the digital factory have the potential to support the planning and analysis of ECs in MS and accelerate the procedure. These software tools can be classified into [15]:

• modeling and visualization,

• simulation and evaluation, and

• data management and communication.

Modeling and visualization software is applied to rebuild and represent MS. Simulation and evaluation software is applied in order to analyze processes or object behaviors. The different type of data is managed and communicated by the third software category.

The idea of the digital factory is managing the usually isolated and separated tools to a whole [16]. But this is still a concept and unimplemented yet for many reasons. Tools of the digital factory do not offer all required functionalities and have a lack of interoperability [17]. Interfaces between the software tools are still required and the transfer between the tools has to be done manually [18]. Many interfaces and incompatibilities foreclose a seamless integration [19]. Changes in a 3D-model with CAD-Software are not directly considered in a material flow simulation for example.

However, it is not widespread yet, especially not in small and medium-sized enterprises (SME) [20]. One reason is the required software specific know-how [21]. It requires qualified personnel and training, which in turn requires financial resources. Additionally, the financial effort for acquiring these tools is very high, especially for SMEs [22]. Another important issue is the transfer of data and models into the tools and keeping them up to date [22]. These aspects have to be considered for the development of software tools.

3. Planning and analyzing algorithm for ECs

The planning and analyzing algorithm (figure 2) contains three main procedures: description of ECs, analysis, and EC implementation planning. The EC description is the initial part of the algorithm and described in detail in chapter 3.1. It is the basis for the analysis in chapter 3.2. EC implementation planning starts after the analysis in chapter 3.3. The algorithm ends with the implementation of ECs._

EC description

Adaption

Analysis

Layout

Process chain

Conflicts

Interrelationships

Planning EC

implementation

C^ EC implementation

Fig. 2. EC planning and analyzing algorithm

3.1. Description of ECs

The systematic description of ECs through defined characteristics is the basis for the analysis and the planning of the implementation. Therefore, the description is significant for the following steps.

For the systematic description, ECs are separated into several procedures named basic operations. With these basic operations ECs are described together with the involved machines. The basic operations for ECs are: addition, removal, and transport of machines as well as addition and removal of processes. The description of ECs consists of these basic operations together with relevant information considering the basic operations and machines (for example required area and position for adding a new machine).

3.2. Analysis

process chains are evaluated based on estimated production times (machining, transport, buffer, and handling). The impacts are identified through comparing the planned with the current cycle times of the process chain. Then, conflicts between machines are derived. Therefore, conflict initiating (for example heat emissions through ovens or vibrations through forming machines, etc.) and conflict affecting attributes (for example vibration for micro machines) are described for each machine. ECs have impact on interrelationships in MS and can interrupt them. This leads to production shutdown. All processes for each product have to be defined after an EC.

3.3. EC implementation planning

Based on the aforementioned basic operations and the machines, the implementation has to be planned. Therefore, tasks for the implementation are described in a solution database by two parts (figure 3): one part contains information for allocating the tasks and the other one for describing them. Information for allocating the tasks is: basic operations, phases, and machine classes. The machine classes are described by the relevant attributes and the considered boundaries. The tasks are specified by a description of the tasks, required resources, time, cost, risks, counter measures, etc.

Description

Machine Basic operation (BO)

[—► Projectplan

Implementation tasks

Prepare

Process

BO n Prepare _Z

Criteria for allocation

Task 1

Task 2

Task 3

Task 4

Task 5

Task p h/€

Time/ Cost

Information.

Link 2

Doc 12

Resource

Res. 1

Res. 3

Res. 3

Task description

Implementation plan

Task 1

Task 3

Task 4

Task 12

Time/Cost

Fig. 3. EC implementation planning

The analysis is separated into layout, process chains, conflicts, and interrelationships. The layout analysis considers, whether the requirements of the ECs are feasible in the layout. The requirements are classified into: fixtures, supply systems (pressurized air, water, electricity, chip conveyor, etc.), dimension (machine, workplace, buffer, etc.), load capacity of the floor, and special requirements (constant temperature, acid resistant floor, etc.). Additionally, the impacts on

As depicted in the figure, the implementation plan is derived from the implementation tasks. The storage of implementation tasks enables the collection and the reuse of experiences, gained through former ECs. A continuous improvement by managing the task descriptions provides a learning procedure.

The functions of the approach are implemented in a software demonstrator in order to provide the planning and analyzing procedure for ECs in MS.

Res. 2

Res. 1

Res. 1

4. Software implementation

The presented approach is implemented in a software demonstrator. The software demonstrator is programmed with Java 3D. Java 3D is able to process many data formats and is web ready. The software demonstrator is separated into three layers: user, kernel, and data base (figure 4).

Fig. 4. Software architecture

The user navigates and applies the software through a graphical user interface (GUI). The kernel contains the 3D environment of the MS and the corresponding data. The planning and analyzing algorithms are connected to the data management of the database. The database contains 3D objects, MS data, and implementation tasks. 3D objects are stored as OBJ files. The MS database and the solution database consist of CSV files.

4.1. Application of the software demonstrator

The application of the software demonstrator is illustrated in figure 5. The user describes ECs. The description of ECs initiates the planning algorithm, which changes the 3D objects and the data of the MS.

Fig. 5. Software application

The changed data is processed by the analyzing algorithms and the results are illustrated to the user. After deciding to implement the EC, planning algorithms chose the relevant implementation tasks out of the solution database and illustrate them to the user. The GUI is illustrated in figure 6.

A: Menu

B: 3D environment

C: MS data

D: Evaluation

Fig. 6. Graphical user interface (GUI)

The GUI is separated into the areas A to D:

• A is the program menu. Therein, the user can manage projects, change views, navigate, plan ECs, and view the process chain.

• B is the 3D environment.

• C illustrates data of machines, buildings, and interrelationships.

• D is the evaluation area. Therein, the results of EC analysis are illustrated.

4.1.1. Description of ECs

The user describes ECs over the GUI. Its activities are used by the planning and analyzing algorithms. It is possible to remove, add, or move machines in the 3D environment. Movements are executed with keyboard controls. Interrelationships between machines and products can be added and removed. If interrelationships are added, the user will be automatically asked for production times of the concerned processes. Through the described changes, the related data is also changed. Adding or removing objects means that objects are removed from the 3D environment or added from a library with 3D objects. The corresponding data of the objects are also added and removed. Removing an object induces a removal of all interrelationships between that object and the related products. A transport of an object in the 3D environment leads to a position change, which will be stored in the MS database. Removing and adding interrelationships, creates new or removes existing processes. The software demonstrator asks automatically for estimated production times, when generating new processes.

4.1.2. Analysis

Based on their description, ECs are analyzed considering the layout, the process chain, conflicts, and interrelationships. The aforementioned aspects in chapter 3.2 are analyzed and visualized in the software demonstrator. The impacts of ECs are immediately illustrated in the 3D environment and in the evaluation area.

4.1.3. Plan for EC implementation

Based on the description of ECs, the implementation is planned with the software. Figure 7 shows how an implementation plan is derived from the activities of a

Basic operation: Transport Machine: CNC turning i

• Attribut 1

• Attribut 2

Database with implementation tasks

Implementation plan

Fig. 7. EC implementation planning

The basic operations and the machines involved in the EC determine the required implementation tasks of the solution database. An implementation plan outlines all tasks that are necessary to implement ECs. With additional information like required resources, time, cost, risks, measures, etc. the user is supported. The implementation tasks of the solution database are easily managed through standard forms without any special software specific know-how. Deviations between the plan and the implementation can be stored in the solution database and are available in the future. Additionally, reasons and counter measures for time delays or budget overrunning are stored in the solution database and are automatically considered for future planning.

5. Use case

5.1. Initial situation

The use case originates from an industrial partner of the Institute of Manufacturing Technology and Production Systems. It is a manufacturer of exhaust treatment systems which has to reorganize its turbocharger production in order to manufacture increasing production volumes and to increase productivity. The considered area is the manufacturing of turbine wheels and shafts (figure 8). The turbine wheel is purchased and welded with a shaft. After that, the shaft is manufactured with turning, and two grinding processes. Then, the component is balanced and washed. The production is organized workshop oriented and partially contains older machines. The material flow is unstructured and contains many buffers and consequently high stocks.

I Turning | Grinding | Grinding 2 —i

Fig. 8. Manufacturing process of turbine wheel with shaft

In order to reorganize the production, following issues have to be proceeded:

• reorganizing the workshop oriented production to eight product oriented manufacturing lines,

• purchasing of new machines,

• stock reduction and decreasing the throughput time,

• and introducing "first in first out" (FIFO) principle. Implementing the ECs within the running production

is quite challenging. The restrictions of the facilities, the production equipment, and the running production have to be considered. The implementation of the manufacturing lines is proceeded iteratively in order to better plan the ECs. This gives the opportunity to learn from the ECs and to improve the planning and implementation process. In order to manage the reorganizing process and the required ECs the software demonstrator is applied.

5.2. Application

The objects and the attributes of the new machines are gathered from the machine suppliers and stored in the library of the software demonstrator. Then alternative ECs are described. The ECs are analyzed by the software demonstrator considering the layout, process chains, conflicts, and the interrelationships. After choosing a solution, the required tasks are gathered through a workshop. The identified tasks are stored in the solution database and an implementation plan is generated. The implementation plan is used to control the EC implementation. Deviations and their reasons are investigated. Then, countermeasures are identified and documented in the software demonstrator together with the risks for deviations. Consequently, the implementation of the following ECs can be planned more precisely and the risk of time delays and budget overrun can be reduced.

5.3. Results

With the software demonstrator the required ECs for reorganizing the MS can be planned with one software tool. The required analysis ensure the feasibility of the planned ECs and consequently avoid required adjustments, and thus time delays and budget overrun.

The automatic generation of implementation plans and the easy improvement of the data base with implementation tasks enable a reliable implementation planning and provide experiences of former ECs for the future.

6. Summary and outlook

In this paper, a software concept is presented which supports the planning and analyzing procedure of ECs in MS. The processes of describing, analyzing, and planning the implementation of ECs is provided by one software tool. The presented software demonstrator manages data from different databases, is easy applicable, and accelerates the planning and analyzing procedure.

In order to improve the software demonstrator and to increase the applicability in practice, there are still some issues to research. Initially, a concept is required to embed the software in existing IT infrastructure of companies. Therefore, the current IT infrastructure of companies has to be investigated and interfaces have to be defined. In order to enable a centralized planning and analyzing of ECs for production sites in other locations, a web based software tool is recommended. Therefore questions of data security and rights of intellectual property have to be investigated.

Acknowledgements

The research described in this paper results from a project funded by the German Research Foundation (DFG) "Impact Mechanisms of Engineering Changes in Production" (fund number AU 185/15-1).

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