Alternative spray arm design for dishwasher

Nowadays, studies on household appliances that simplify people's lives is increasing every day. Producing machines with low energy consumption and more performance is the main goal of the companies. For this purpose, research and development activities are carried out in R&D centers of companies. The companies in the white goods sector are separated from each other by the technologies they develop while competing with each other and develops products that address customer perception. Producing high ergonomics, functional and accessible products that address the customer's last address increases the competition between firms. Dishwashers take part almost every home nowadays and they have been being designed so as to ease style of human living. In this extent of study, history of dishwasher has been examined. Dishwashers are defined as machines which perform kitchen equipments cleaning and rinsing. The first cleaning system has been discovered at second half of 19th century and they are not automatic as today's machines and they have more likely mechanic structure. Then, automatic dishwashers have been coming into human life at 20th century. By development and optimization, these machines has been transformed into current figure. A dishwasher is a mechanical device for cleaning dishware and cutlery automatically. Unlike manual dishwashing, which relies largely on physical scrubbing to remove soiling, the mechanical dishwasher cleans by spraying hot water, typically between 45 and 75 °C at the dishes, with lower temperatures used for delicate items. A mix of water and dishwasher detergent is pumped to one or more rotating spray arms, which blast the dishes with the cleaning mixture. Once the wash is finished, the water is drained, more hot water enters the tub by means of an electro-mechanical solenoid valve, and the rinse cycle begins. After the rinse cycle finishes and the water is drained, the dishes are dried using one of several drying methods. In this study, the spray arm mechanism designed to improve the washing performance of the dishwasher, which is one of the washer household appliances, was investigated. The detail designs of the spray arm were developed and introduced to the market by mass production. Firstly, dishwasher working principle and dishwasher components were examined. Afterwards, the parameters affecting the washing performance were determined within the scope of the literature research. These parameters can be listed as mechanical effect, chemical effect, time and temperature. The state of the art was determined by patent research and a multifaceted research was conducted by examining the washing systems of companies. The criteria for the determination of dishwasher cleaning performance evaluation criteria and washing performance classes according to the standards specified in the literature were investigated. System requirements have been determined in order to create solutions to improve dish washing performance. The structure of the Arcelik dishwasher, which is considered to be implemented the proposed solution has been examined. System limits have been drawn by determining system dimensions, construction constraints and operation. Following these studies, a list of requirements was created according to the construction system. Customer wishes and company requests were taken into account when creating requests list. In order to increase washing performance, it was decided to change the design of the spray arm. After determining the list of requests, alternative function structures were created. After the creation of alternative functional structures, draft drawings of alternatives were prepared. Concept designs have been created by modeling draft drawings in CAD environment. The basic function of each alternative created is to increase the scanning area of the spray arm, but the way it performs the function is different. The advantages and disadvantages of each of the sub-functions of alternative functional structures created for spray arm design have been determined. The alternative with the best score was determined from the alternatives in the weighted targets matrix. In the detail design phase, the gear mechanism used in the system was firstly dimensioned. It was decided to produce all the parts to be used in the mechanism by plastic injection method. For this reason, the parts are designed according to the design criteria of plastic parts. The detail design work was completed and the prototype of the system was made. During the operation of the mechanism and problems that may occur during the manufacturing and assembly stages were identified. In the prototyping stage, gear wheel components and drive spray arm parts are manufactured from POM material by machining; three-spoke propeller and filter support parts manufactured in 3D printer with rapid prototyping method. After the parts were determined to be in accordance with the dimensions given in the design, the gear mechanism was assembled and the test phase was started. In the test phase, the system was assembled into the dishwasher and the preliminary washing performance tests were performed. After the washing tests, technical problems have been identified and solutions to the problems have been established. Raw materials to be used in mass production were selected. Structural analysis and tolerance analysis studies were conducted to determine the source of the problems occurring during the washing tests. The proposed solutions were transferred to the design. Due to the high diversity in the market, the increase in competition among the firms and the economic conditions, the solutions developed by the brands must be customer-oriented. Offered solutions is gaining shape by the problems, shortcomings and desires of the user in daily life. Therefore the presented solution results in user experience. With the determination of the problem, the address of the new spray arm design to be applied in the dishwasher is the end user. In the user experience test, as well as an improvement for the dishwasher washing system, the user is also intended to use the spray arm and components around the spray arm easily. For this purpose, the new spray arm design has been put to usability test. The test was carried out by participants to perform tasks that simulate daily use at home. Perceptual quality questions were also asked during the test. User's spray arm experience has been analyzed and aspects of development tried to be detected. While finalizing the design, these criteria were taken into consideration and revision was made in the design and the open aspects of the system were tried to be closed. The tests were carried out in Arçelik Dishwasher Plant based on the standard titled EN 50242 "Measuring the performance of domestic dishwashers". In these tests, it is aimed to determine the designed spray arm's washing efficiency and to measure the washing performance difference between it and the conventional spray arms. It was observed that the efficiency of washing increased with the use of new design spray arm and the improvement in washing performance was determined quantitatively/ numerically. The washing performance score of the spray arm was calculated and the washing performance class was determined by proportioning the score according to the reference machine.