Designing Facilities Layout for Small and Medium Enterprises

— Facilities layout is a systematic and functional arrangement of different departments, machines, equipments and services in a manufacturing establishment. It is vitally important to have a well developed plant layout for all the available resources in an optimum manner and get the maximum out of the capacity of the facilities. The problem is of particular importance for Small and Medium Enterprises (SMEs) because of major constraints that include cost and space. Selection of right method is a very important step in layout design. In this paper methods of layout design are discussed taking into consideration the specific issues and limitations of SMEs. Keywords— Facilities Layout; Layout Problems; Computer Aided Layout Planning; Evaluation Methods, Simulation INTRODUCTION The most crucial element that affects efficiency of a production process is the facilities layout. A good layout keeps costs low and reduces unnecessary material handling while maintaining the product flow through the facility. Improving the layout also increases the machine utilization that enhances the machining capacity of the shop floor. Quite often, the management feels the need of redesigning plant layout even when the things are apparently going smoothly for the company. One of the reasons for designing a new layout may be improving the performance of the existing plant. Upgrading the facility by replacing old facility with more advanced machinery is also necessitated many a times [1]. In both the cases the performance measures being targeted for improvement need be identified clearly. An enterprise is considered as an SME based on the annual sales turnover or number of full-time employees of a unit which is a small number, not exceeding 50. The majority of workers are invariably semi-skilled and required to work on more than one machine. Most of SME faces the problem of unsafe movement of operator from one machine to another. It is desired to arrange the machines in such a way that single operator can easily and safely move to number of machines [2]. Improving the layout to get better utilization of machine and operator need lean thinking. Redesigning an existing layout calls for a critical consideration of several key factors including the 13 factors suggested by Apple [3]. The common thing about the all available methods of plant layout development is that they develop number of alternate layouts. The selection of best among these layouts is based on certain evaluation methods. Each plant layout design technique has its own and different evaluation method. Each evaluation method is based on single performance measure. It is therefore very necessary to decide and fix the performance measure has to be improved for designing a new plant layout. The objective of the layout design has to be very clear as it helps in deciding the best method to implement for improved layout design. Further, one must evaluate the proposed layout and compare it with existing layout, based on the chosen performance criterion. In SME’s the nature of plant dynamic i.e. there is frequent change in the demand and scheduling is very complicated. Measuring the performance becomes very difficult by direct mathematical calculations. Use of simulation tools for measuring the performance is suggested by some investigators [4]. It is seen that for designing a new layout it is very important to know the problems faced by the SMEs, the available techniques of layout design, use of simulation in layout design and evaluation methods. These are discussed next. LAYOUT PROBLEMS The facility layout problem is concerned with finding the most efficient arrangement of individual departments with unequal area requirements within a machine or facility. The objective of the facility layout problem in SME, therefore, is to minimize the material handling costs inside a facility subject to two sets of constraints: (1) department and floor area requirements and (2) department location restrictions. These constraints include: 1 Departments should not overlap 2 .All departments must be located within the facility 3 Location of some departments is pre-fixed due to processing sequence 4 Some sections are not allowed to be placed adjoining specific locations 5 Floor loading and 6 Floor-to-ceiling clear-height in multiple-floor facilities. [5] Earlier the facility layout is considered to be static, that is once the layout is planned and executed it is not changed for many years. Now a days that trend is changed, with continues improvement in the technology management had to update the facilities with time. The task of designing a dynamic layout becomes even more difficult when multiple objectives have to be achieved. [6][7] International Journal of Engineering Research and General Science Volume 1, Issue 2, December 2013 ISSN 2091-2730 www.ijergs.org With the increasingly diversified demand in the production, most of the manufacturers are using mixed-product assembly lines (MPAL’s). The design of the assembly line has to take this evolution into account. An MPAL is a production line capable of producing a variety of different product variants simultaneously and continuously. Stations are flexible enough to perform their respective tasks on different variants. The most common problems seen with MPAL’s are: 1. Generic product modelling, 2. Line balancing, 3. Resource planning, and 4. Resources allocation to the workstations in order to balance the workload along the line. Resource planning is concerned with the selection of production means which are adequate for performing the assembly operations specified by the assembly planning. Model launch is based on schedule of the different models to be produced during the course of work shift. [8]. Bottleneck is one of the major problems faced by most SMEs in manufacturing parts that necessitate machining operations. Reason of occurrence of bottleneck is mainly due to improper sequencing of facilities within the work area. Bottlenecks should be eliminated in any operation because it severely affects productivity and throughput improvement of the plant. [9] The facility layout problem is a common industrial problem in which the objective is to configure facilities so as to minimize the cost of transporting materials between machine tools and other processing operations such as welding. Fig. 1 highlights what seems to constitute essential features to characterize layout problems [10]. International Journal of Engineering Research and General Science Volume 1, Issue 2, December 2013 ISSN 2091-2730 www.ijergs.org Fig. 1 Tree representation of the layout problems [10]. LAYOUT DESIGN TECHNIQUES Plant layout design is very old concept and considerable research has already been done in this area. With the time elapsing, various techniques and software tools are now available. The following are some of the well known techniques currently employed for the plant layout design. International Journal of Engineering Research and General Science Volume 1, Issue 2, December 2013 ISSN 2091-2730 www.ijergs.org Manual Method Traditionally, scale templates of various departments are prepared as per dimensions or area requirement and are adjusted by the designer in the available space. The effectiveness of this method is dependent on the designer’s experience and judgment. This method is, therefore, not being preferred these days for designing a layout. 1. Systematic Layout Planning (SLP) Muther [3] has proposed a methodology to design plant layout based on analysis, search and selection procedure as shown in fig. 2. The alternative layouts generated by this method are based on block diagrams. The space relationship diagram is constructed by replacing the unit squares with space templates. For each activity, a space template is constructed to scale, to represent the size and shape of the activity. Since different shapes can have same area, it is possible to construct different space relationship diagram from the same block diagram. This method also relies heavily on the capabilities of the designer. It can, however, prove quite effective if proper care is taken in arranging the templates. Fig 2. Systematic layout planning [3] An important consideration in plant layout design is the human comfort. This should be maximized while minimizing at the same time the distance between the facilities. The human factors which need attention in developing machining facilities include work environment with human body posture, stress and other physiological capacities of the work force. Successfully achieving such human factors enables good working conditions which are conducive for reduction in injuries, effective and highly productive environment and reduced fatigue. It is found that these goals are fairly well achieved by using SLP that takes into consideration the human factors [11]. The SLP has been found to improve spatial distances between facilities (machines, between workstations and between departments) and also improve the flow of material through the plant. Thus cost of material handling is reduced significantly [12]. As a consequence, less material handling time is needed, workers move faster and the overall productivity increases. [9][13][14][15] International Journal of Engineering Research and General Science Volume 1, Issue 2, December 2013 ISSN 2091-2730