Integrated design: Electric lawn mower Essay

INTRODUCTION Quality must be part of the design of a product not something that has to be based from an inspection done after the design. Quality means satisfying the requirements and needs of the customer. The focus of quality is to identify the customer requirements and to translate this into design constraints. QFD also takes into account what are the limits of hardware design based on existing or available resource or technology. All these requirements must be satisfied in order to produce a quality design. STATEMENT OF THE PROBLEM The purpose of this document is to apply the Quality Function Deployment (QFD) into the planning stage of a lawn mower design. This document seeks to answer the extension lead requirements of a lawn mower. The end result is the design concept of how to implement the lawn mower extension lead based on customer requirements and hardware constraints. DESIGN Identification of Requirements Using the data provided, the following customer and hardware requirements are generated. The design will then focus on satisfying these requirements. The customer requirements are the following: †¢ Electric Lawn Mower – Powered electrical energy instead of combustible fuel such as gasoline. †¢ Variable Length Flexible Lead – Since the size of the household that will use the electric lawn mower is variable, there is no definite fixed length of the flexible lead. The hardware constraints: †¢ The use of extension lead would render the to overcome the lack of length fixed mower lead the suppressor and earth breaker will not work efficiently, causing the disruption of power to the mower. Design Analysis The initial main requirement of the design is to make an electric lawn mower. One of the main obstacles of the design is the variable length flexible lead. The hardware requirement of inefficiency in the suppressor and earth breaker when using extension lead makes the extension lead not an option anymore. This leads into two possible solutions. 1. Use of the longest possible customer length requirement, to satisfy all needs. 2. Use of re-chargeable battery to remove the constraints of the need for variable length flexible lead to power the electric lawn mower. The length can be fixed just enough for charging the batteries. Analyzing the first requirement, to satisfy all the length requirements of flexible lead using the longest possible lead requirement seems to be the most cost effective solution. The problem is, this would also mean that the lawn mower will have to carry the weight added by the lengthy flexible lead. And to satisfy all requirements, this means that the flexible lead had to be considerable long. Considering the current requirements of a lawn mower, the flexible lead had to be relatively larger than average home extension wires. Just imagine how much weight this would produce. Therefore as a designer, this is not a good option. Analyzing the second requirement, which is now the remaining solution, we should be able to contrast the negative effects with the negative effects of the first solution. This therefore boils down to the weight issue. The lawn mower requires a considerable amount of power to run, therefore the battery has to be able to sustain sufficient operating time. The most viable battery would still be the lead-acid, otherwise it would be very effective, one standard automotive battery would surely not be enough. Looking at the power requirements, this should be calculated in detail based on the power requirements of the lawn mower. Since the power requirement of the lawn mower is not yet available at this level of conceptual design, we can make some estimate. Assuming the lawn mower consumes 3000 Watts of power, more than double for the average vacuum cleaner. Two hours of lawn mower operation is probably sufficient for as long as it can be recharge. At 12 V Lead-Acid battery, and 2 two-hours of operation would required the following ampere-hour requirements. Japanese standard car batteries could deliver up to 150*Ah, thus we can calculate the number of batteries So we need roughly four batteries. The weight of four batteries is still acceptable therefore this is a better solution compared to having the longest possible flexible lead. CONCLUSION The final solution presented based on QFD analysis of customer requirements yielded with a battery packed electric lawn mower. The battery is able to solve the flex lead requirement by just fixing the length to a relatively short distance enough for re-charging.