Design for Manufacture and Assembly in the Construction Industry - Coursework Example

Introduction Since its inception in the 1990’s Design For Manufacture and Assembly (DFMA) has been seen as being the direction that all future engineering and construction industries were to take. In current construction scenario DFMA is taken as being a process that is simultaneously integrated in the design stage of a project. DFMA fundamentally is a method that aims at reducing the total number of parts needed during design thus facilitating the process of assembly through simplifying the design that is to be put together (Stamatis, 2002). Clarke and Charles (2002) note that for most engineers, designing for manufacture has been seen to be an implicit part of the entire design process. 2.0 Background of DFMA in construction industry With most companies in the construction industry being faced by the challenge to be extremely cost effective and retain high quality the need for a tool to help in achieving this will be highly welcome. Fueled by this need the year 1977 saw the conception of Design For Assembly (DFA) software and methodology (O’Brien et al. 2000). In the early work concentration was on design fulfillment for both manual and automatic assembly (Knight,1998). Before DFMA came into existence, design and manufacture was considered as being an ‘over the wall’ thing with the two being considered to be discrete with not connection (Xie 2002). The traditional way of doing things involved using programs such as CAD, then the design would be handed to the manufacturer for creating of a sample that would be looked at the be sequentially redesigned. In this way there was a lot of time wasting in the entire engineering process which meant high financial input into the process. The DFA was used for accurate prediction of costs at the design stage. With the costs being predicted accurately it makes it possible for companies to see how alterations in the design can impact the subsequent costs. Having a design that is easily assembled, there is reduction in the cycle time and subsequently the costs. 2.2 Advancement in Methodology The inability of measuring the cost of manufacturing and assembly operations for different designs during the design stage was seen as a major huddle. This resulted to DFMA being established by Dr Geoffrey Boothroyd and Dr Peter Dewhurst. Through improvement of DFA model, the two put focus on finding the optimum design solution that was capable of delivering cost effective production and assembly. Thus the ultimate role of DFMA was to be able to give quantifiable comparison for different designs. 2.3 Modern approach As pointed out by Stamatis (2002) the current approach aims at reducing costs through Having a simple design Economics in materials, parts and components Ease in assembly Integrity in product features Additional to making assembly and manufacturing easy there is reduction in the overall time cycle since with DFMA put into use product design, development and manufacturing are undertaken simultaneously. Determination of whether apart is to be included in the design the questions that need answers are Is there a motion of the part relative to other parts Is there need for the part to be isolated from other parts Is access to other parts possible only if the part is separate If none of the three questions are in affirmative, then a part may be considered as being unnecessary. The fact that this criterion may result in elimination of some important parts in seen to be the major setback and thus this criterion by Knight (1998) is to be taken as a guide and not a rule of doing away with parts. In the construction industry, DFMA goes hand in hand with modular construction, with sections of the project being designed offsite followed by transportation to the assembly site (Omigdodun, 2001). This engineering was put into use in the construction of Eureka towers where walls, columns and floors were precast. Using this method quality of parts was ensured. Also in conformation to DFMA the construction work involved team work with each member of the team being given distinct role. 2.4 Benefits of DFMA DFMA has many benefits in engineering process. Just to give an example, through increased ease of manufacture, companies are in a position of directly saving on labour costs, material costs as well as equipment and supplier costs. In a study conducted by Clarke and Charles (2002) it was revealed that through software and methodology there was reduction in product lifecycle by a margin of 50%, part count reduction was in the range of 30-70% while in assembly time was reduced by 50%. The benefits of companies by use of DFMA is made clearer from what was compiled by Boothroyd and Dewhurst using published case studies as can be seen in fig 1. Figure 1 According to Dewhurst (2010), just having a basic DFMA analysis would lead to substantial reduction in costs. Without use of DFMA there have been attempts of many companies to bring down cost through exhausting all avenues from design to launch, including reduction in costs of materials and manufacturing processes. The end result of this is often compromising the quality and integrity of the part with minor difference in cost being achieved. An attempt to reduce costs of production through refining the whole manufacturing process have been found to achieve low reduction in cost in the range of 3-4% while alterations made at the design stage by use of the software has been found to result to reduction in costs in the range of up to 35%. This is attributable to the fact that 85% of project is completed before manufacturing is commenced (Stamatis, 2002). This translates to having greater outcome through refining of the design other than refinement in manufacturing process. Being able to project the time requirement for manufacture and assembling of the design is seen as a key asset in using of the software. The software on average has had a prediction of total completion time to be within 6% if not the exact time (Knight, 1998). The Software has also been recognized as being able to estimate costs in the margin of 1% of the actual cost (Clarke and Charles, 2002). 2.5 Shortcomings of DFMA Even though DFMA has been seen to be very cost effective, it does not lack some weakness. One of the shortcomings is that choosing to have parts for construction manufactured offsite is that transportation cost of parts to assembly site may be prohibitive. In projects such as construction of bridges, large obsolete objects may be involved. Transportation of this parts is found to be expensive and time consuming. This calls for having parts that are smaller in size for ease of transportation even though this means increased cost in assembling the smaller parts. This makes DFMA not to be necessarily the optimal solution in its attempt to reduce number of parts. The software is not in a position of providing an alternative design option so as to modify the shape of parts when a suggested design is found to be unsuitable. This is because the software always attempts to get an optimal design solution by focusing on ease of manufacturing and assembly through alteration in materials and reduction in number of parts. 2.6 Conclusion DFMA has been associated with being highly cost effective and as a tool of great benefit in both manufacturing and construction industry. Even though there is no wide use of the ‘definitive’ DFMA when it comes to construction industry, the methodology has shown as having positive outcomes since its inception. By improving on the early DFA technology, DFMA has its focus design aspects which directly impact on the ease in manufacturing and assembly. With proper implementation put in place, the DFMA methodology has clearly demonstrated its capability in reduction of labour costs, number of parts, time for assembly and overall cost. It has also been seen to exhibit high accuracy in prediction of the total cost in the margin of 1% of actual amount while amount of time required to complete a project has prediction accuracy to within 6%. Even will all this benefits DFMA does not lack its shortcomings, including the difficulty paused in transportation of large section from manufacturing point to point of assembly and also DFMA does not give the option of altering the design output. Even though a number of studies have been undertaken, there is still low level of understanding and data relation with regard to its application in the construction industry. It is therefore believed that through further implementation, the inadequacies in DFMA methodology will be highlighted and subsequently then can then be solved. References Boothroyd G. (2005). Product design for high-speed automatic assembly and robot assembly. Assembly Automation and Product Design. Clarke C. (2001). Design for manufacture. Manufacturing computer solutions. Dewhurst N. (2010). Design for manufacture can cut costs while improving overall manufacturing process. Manufacturing Engineering. Knight W. A. (1998). Group technology, concurrent engineering and design for manufacture and assembly. Group Technolo0gy and cellular Manufacturing. O’Brien M. et al. (2002). Design for assembly. Industrializing the residential construction site. Omigbodun A. (2001). Value engineering and optimal building projects. Journal of Architectural Engineering. Stamatis D. H. (2001). Design for manufacturability/assembly (DFM/DFA ORDFMA). Six Sigma and Beyond. CRC Press. Xie X. (2002). Design for manufacture and assembly. Dept. of Mechanical Engineering Universiy of Utah. Read More