COMPUTER METHOD FOR THE DETERMINATION OF MATERIALS HANDLING RELATIONS
Péter Telek PhD., assoc. prof.
University of Miskolc, Institute of Logistics
INTRODUCTION
Design procedure of materials handling contains numerous, different and exactly defined steps which enable effective solving methods for the handling tasks [1].
First step of the design of a materials handling process is - in most of the cases - the analysis of the required material flow to determine the basic parameters, which depend on the materials handling relations of the system objects.
This research is focusing on the determination possibilities of materials handling relations, which is not a simple task in most of the cases. Our aim is to develop computer software which is suitable to determine the handling relations based on the technology parameters.
In this paper we present the MHRelCalc software, developed by our institute, which is suitable to determine and demonstrate the handling relations and matrices of an existing materials handling system, based on technology data.
1. MATERIALS HANDLING RELATIONS
The most important task of handling processes is the moving and its related activities (loading, storing, etc.) of goods among the objects. All individual moving activities have to be linked to two given system objects, which is named as material handling relation and these relations are the basis for all of the design steps (equipment selection, location planning, etc.) of the materials handling processes [3].
Materials handling relation means a special connection between two objects (production or service objects), which contains any kind of handling activity.
Handling relations can be defined by the two linked objects and one handling parameter existing among them [3].
In the aspect of handling requirements, handling relations can be always described between one source and one destination object, however at the realisation of the handling tasks we can also determine relations between two source or two destination objects (e.g. collection systems) [4].
Handling relations in generally involve one handling parameter (e. g. materials and their quantities, distances and routes among the objects, etc.) and its value describes the characterisation of the object relation during the design and operation of the handling process [3]. Materials handling relations can be defined and demonstrated by different methods, e. g. handling process charts, materials handling graphs or matrices, etc. [2].
MultiScience - XXXI. microCAD International Multidisciplinary Scientific Conference University of Miskolc, Hungary, 20-21 April 2017
ISBN 978-963-358-132-2
DOI: 10.26649/musci.2017.046
Figure 1
Example for the handing relations [2]
The most important application field of handling relations is the design of materials handling devices and processes. If all of the handling relations are described in every detail, then the design steps can be realised. The main problem of this concept is the determination of the handling relations, because the input data do not contain the required parameters directly. In generally, there are different methods for determining the handling relations with suitable knowledge and designer experiences, but the process depends on the given objects and their characterisations.
The most often used device to define the relations among the objects of a handling system is the application of materials handling matrices. The most frequently applied materials handling matrix is the material flow-intensity matrix [2], which contains the quantity of the material flow between the objects of the given relation during an exact time interval.
2. COMPUTER METHOD FOR THE DETERMINATION OF HANDLING RELATIONS
General procedure of the determination of the handling relations can be described by the next steps [2]:
1. Uncovering the technology abilities 2. Analysis of the product parameters 3. Definition of the served objects
4. Description of the relations among the objects
5. Determination of the values of the materials handling matrices
As the determination of the materials handling relations and their parameter values is in generally very complex and long procedure (see [2]), mainly at large handling systems with many objects and tasks, so it is expedient to use computer method for the realisation of it.
Computer software has already played important role in the field of materials handling from decades, mainly in the simulation of handling processes and systems.
There are several materials handling and logistics software in the market, which
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were developed for especially handling processes to increase their effectiveness (e.
g. ExtendSim [5], FlexSim [6], etc.). In the international literature many papers deal with computer solutions and optimisations of logistic and handling tasks [7, 8, 9].
Many of the papers use also the handling relations as input parameters for the solution of given design tasks [10], but there is not any computer algorithm for the determination of the relations.
The main advantages of computer software used for the determination of the handling relations are the linking possibility of the technology and logistic processes and the using in education processes of logistic experts, where the main aims are the transformation of the technology and handling parameters, and the demonstration of the existing relations.
2.1. General algorithm of the process
Task of computer software is to realize a given process based on an algorithm, using different input parameters, which results certain output parameters.
In the aspect of materials handling, the algorithm is a chain of related steps (calculations, logical decisions, etc.), based on certain input parameters of the handling system, which results handling parameters or activities as output values [11].
Input parameters of the determination process of the handling relations are the data of the production system (parameters of the raw materials, the elements, the interoperation semi-finished units, the technology objects and the finished products).
Based on the input parameters, a general algorithm can be built, which is suitable for the determination of materials handling parameters, as described in [11].
In this research, the relations, as handling matrices are taken into consideration, so the input and output parameters have to be also used in matrix form.
Main task of the algorithm is the determination of the matrix values, which cannot be solved by a general method, because of the different parameters and calculation procedures of the individual matrices.
The output parameters of the process are the handling characterisations of the system (e. g. materials handling intensity).
3. REALIZATION OF THE COMPUTER METHOD
Realisation process of the algorithm described in [11] will be different on different program languages or computer software. In this paper, an application of this algorithm in Microsoft Excel running environment is developed, using Visual Basic Applications (VBA) program language.
Using of VBA programs in Microsoft Excel running environment combines the advantages of the Excel worksheets (simple input data handling), the programming in Visual Basic (complex calculation processes) and the visualization of the output parameters on Excel diagrams or on VBA forms.
For our purposes we developed a VBA software (MHRelCalc), which uses an Excel document (xlsx) as the source and embedding environment. All of the data
we use in the program have to be filled into Excel sheets and the results can also presented in it.
3.1. Input data structure of the software
One of the most important advantages of the using of Microsoft Excel is the easy and simple input of the data. On Figure 2-5 the input tables of the program can be seen, where we use different ranges of the excel cells as the source of the basic data of the production system. In our program, we use different worksheets for all of the data-types defined in [2]:
• object parameters (Figure 2),
• parameters of the elements and raw materials (Figure 3),
• parameters of the half-finished units (Figure 4),
• product parameters (Figure 5).
There are many object parameters but only some of them have influence on the handling relations at this research phase. The most important information on the objects is the produced units (Figure 2). In this paper we do not analyse the effects of the storing objects.
Figure 2
Input cells for the objects
Figure 3 contains the data of the elements (a1, a2, …) used for the production process. At this moment, our software calculates only the theoretical relations and do not deal with the physical parameters of the transport, so we do not need the geometry and load unit characterisations of the elements. The software can take more than one element store into consideration, but because of the visualisation of the process we have only one input store.
The method we described in [2] uses the units produced by the individual objects (F1, F2, …) as the linking elements of the handling process. With the determination of the relation of the units, elements and the objects we can define and calculate the handling relations of the production system (Figure 4).
Figure 3
Input cells for the elements
Figure 4
Input cells for the units
In the software we define the products as one of the units produced by the objects (except the stores), which makes the software highly flexible, because we can use any of the units as products. Of course, in most of the cases, the last unit will be the product of the production process. As a result of this approach we need only the type of the unit and the produced quantity to define the products (Figure 5), of course in the knowledge of the unit parameters.
Figure 5
Input cells for the products
3.2. MHRelCalc software
As Microsoft Excel is not applicable for complex calculations (containing many iteration process), we made the calculation processes in Visual Basic for Applications environment. Because VBA is embedded into the Excel environment, the data transfer between the Excel and VBA is obvious. Our software (MHRelCalc) uses the data from the Excel sheet and based on Visual Basic language.
MHRelCalc is usable for the calculation of the materials handling relations of a production process defined by the input sheets (Figure 2-5), and for the visualisation of the handling process.
The software contains three different steps (Figure 6):
1. determination of the parameters required by the calculation procedure based on the production process (Initializing),
2. calculation of the handling relations (Calculation), 3. visualisation of the handling relations (Visualisation).
The process steps have to be realised in direct order (1 → 2 → 3).
For the calculation of the handling relations the product types have to be selected, so we cannot take more than one products into consideration at the same time at this program version.
Figure 6
Window of MHRelCalc
Visualisation of the software contains possibilities to present the different relations visually:
• relations of the elements (between the stores and the objects),
• relations of the units (between the production objects),
• relations of the products (between the final objects and the product store).
In all of the cases it is possible to show the relations of the individual elements or all of the elements together, for the elements and also the units. At this version the software can present the handling relations for one product, but it can be recalculated with different product types.
The visualisation shows (Figure 6) the relations as a matrix, where the vertical column contains the objects as sources, and the horizontal row contains the objects as destinations of the material-flow.
3.3. Output data and results of the software
At this version, MHRelCalc software is suitable to calculate and demonstrate the materials handling relations of a production system, so the output data is the matrix of the handling relations. The program calculates two different matrices, one for the elements and one for the units.
The main aim of the research was to calculate and demonstrate the relations among the objects, so the software can demonstrate the relations in two different ways:
• filling the elements of the relation matrices into an Excel sheet or
• visualize them in the window of the software.
There are different possibilities to fill the relation matrix into Excel cell ranges, e.
g. we can use one sheet with dynamical sizing for all of the relations, or we can use individual sheets for the different relations (e. g. for different element types). In this version, we present the matrix elements on one sheet, and uses different ranges for 8 objects (Figure 7).
Figure 7
Presentation of the unit relations on an Excel sheet
The second possibility to present and demonstrate the results of the software is the drawing the relations onto a VBA form (Figure 8).
This solution has two main advantages:
• enable to check the relations visually, together or elements by elements,
• present the direct relations between the objects for explaining the handling process for students.
In the software we use three different colours for the different material types:
• red arrows for the element relations,
• blue arrows for the unit relations and
• green arrows for the product relations.
The visualisation method we used in the software is usable for maximum 10 objects and one element and one product stores, for more than 10 objects another method has to be applied.
Figure 8
Drawing of the results on a form 5. SUMMARY
Relations are very important parts of the design process of materials handling systems, but there is a big problem related to them, which is the determination procedure, because there are no direct transformation possibility between the technology and handling parameters.
In this paper we presented MHRelCalc computer software, which is suitable to determine and demonstrate the handling relations and matrices of an existing materials handling system, based on technology data.
In the paper we described the structure and the details of the software, form the input data to the handling window. This software is applicable for the calculation of complex production systems, but the demonstration possibilities are limited.
The most important result of this research is to realize a possibility, which enables to link the technology and logistic processes and transform the technology parameters into handling parameters.
The next steps of the development can be the application for larger systems, demonstration of more than 10 objects and linking the results to other design applications (e. g. location planning).
Acknowledgements
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 691942.
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