The article presents the issues of production analysis of iron
casts manufacturing using automated foundry lines. To streamline
the production fl ow, it was proposed to change the location of
workstations related to grinding, control and machining of casts.
Within the process of constant improvement of manufacturing
processes, the aspect of work ergonomics at a workstation was
taken into account. As a result of the undertaken actions, some
activities without added value were eliminated, effi ciency was
increased and prime costs of manufacturing casts with regard to
fi nishing treatment were lowered

Kukla, Slawomir

English

DSpace at VSB Technical University of Ostrava

BEZPEČNOST A OCHRANA ZDRAVÍ PŘI PRÁCI29SPEKTRUM 1/2014dr inż. Sławomir KuklaUniversity of Bielsko-Biała, Department of Industrial Engineeringul. Willowa 2, 43-309 Bielsko-Biała, Polandskukla@ath.bielsko.plAbstractThe article presents the issues of production analysis of iron casts manufacturing using automated foundry lines. To streamline the production fl ow, it was proposed to change the location of workstations related to grinding, control and machining of casts. Within the process of constant improvement of manufacturing processes, the aspect of work ergonomics at a workstation was taken into account. As a result of the undertaken actions, some activities without added value were eliminated, effi ciency was increased and prime costs of manufacturing casts with regard to fi nishing treatment were lowered. KeywordsSafety in foundry industry, Work ergonomics at workstations.1 IntroductionThe basis of the costs reduction methodology is to identify wastage. It is vital to identify the causes of generating losses. Costs analysis constitutes a kind of map showing the sources generating the biggest losses, but also costs and the places with the highest chances of savings.Searching for more effi cient methods of work, enterprises more and more frequently focus on limiting reserves and processes, and, above all, manufacturing prime costs. Such behaviour also found application of the casting industry by eliminating the operations and activities in manufacturing processes which do not add value to the produced casts.Analysing the activities performed at production workstations, it is possible to divide them into three categories: • activities with added value, which change the shape, dimensions, physical and chemical properties of treatment objects (e.g. melting, forming, pouring, eliminating the gate assembly, etc.), • activities with partially added value, like: fi xing, quality control operations, • activities without added value, like: waiting, unnecessary transportation, storing, repairing faults, etc. The main areas of wastage in foundry enterprises were presented in fi g. 1.Fig. 1 Areas of wastage in a foundryIdentifi cation of the areas of wastage allows an enterprise to create a list of activities, thanks to which it will be possible to eliminate losses suffered by a company. Apart from the activities which do not add value to products, analysis should be carried out also in case of diffi cult and unnatural activities which have a signifi cant infl uence on worker’s tiredness and workload, as well as operations realised only periodically.Identifi cation of the areas of wastage allows an enterprise to create a list of activities, thanks to which it will be possible to eliminate losses suffered by a company. Apart from the activities which do not add value to products, analysis should be carried out also in case of diffi cult and unnatural activities which have a signifi cant infl uence on worker’s tiredness and workload, as well as operations realised only periodically.In relation to technical devices themselves, it is possible to distinguish six kinds of losses: • machine and equipment breakdowns,• changeovers, e.g. pattern plate exchange on a line,• minor stoppages e.g. blocked conveyor, inadequate temperature of liquid alloy,• lower speed, e.g. slowing down on a line due to problems with cooling,• start-up, e.g. starting a line or furnaces after a break,• faults - production of faulty casts and the need to repair them.Also, logistics of materials fl ow in a foundry is of signifi cant importance in elimination of losses. Excessive manipulation of objects (transporting, arrangement, packing) and storing are sources of additional costs [Harris 2010, Nyhuis 2009]. 2 Research object, aim and methodologyThe object of research in the present work is the manufacturing process of iron casts on automated foundry lines (fi g. 2). Cast iron is prepared in electric furnaces and transported in tubs on foundry lines. There casts are prepared, which, after pouring, are transported to the minting workstation in a cooling tunnel. Further, casts on the line are separated from the moulding sand and the gate assembly and are cleaned on through cleaners. After being picked up from the line, casts also undergo control, grinding and, in some cases, initial machining on customer’s request [Kukla 2010]. Fig. 2 Research object - the manufacturing system of iron casts Safety and Ergonomics of Iron Casts ManufacturingMUDAProduction on the storageDefective castingsFailures of machines and devicesAdditional operationsSuperfluous stocksSuperfluous transport in foundryWaiting for cast iron, cores, etcBEZPEČNOST A OCHRANA ZDRAVÍ PŘI PRÁCI30SPEKTRUM 1/2014The main objective of the presented methodology of production systems optimisation in foundries is to eliminate all kinds of organisational losses, machine breakdowns, accidents at work, as well as to improve the quality of the manufactured casts. These aims may be achieved by recording and eliminating losses, improving standards and engaging all workers of a foundry into the process of continuous improvement [Matuszek 2009, Kukla 2012]. The concept of production systems improvement outlined in the paper is based on 10 technical pillars, shown in fi g. 3. The task of cost accounting is to record and allocate costs. For this purpose, a system which aids the decision taking process was created, thanks to which it is possible to simulate and analyse, among others: • manufacturing prime costs,• costs of new casts, introduced to production, • the choice of product range and production batch sizes, • cooperative collaboration,• costs of emergency situations and production losses related to them, • costs of exploitation activities, • costs of improvement activities, • costs of planned investments, etc. Fig. 3 Technical pillars in production systems improvement In order to streamline processes in an enterprise in a situation of limited resources, we should choose the problems which are signifi cant and, at the same time, leave less important ones for later. Improvement of vital processes in a foundry by 50 % is more likely to bring about considerable advantages for the system than improving marginally important processes by 80 %. 3 Description of the obtained resultsIn the fi rst stage (fi g. 2), the model area was defi ned as fi nishing of a chosen group of casts on the basis of the performed Pareto analysis. The optimisation project was carried out according to the scheme presented on fi g. 4.One has proposed a possibility of implementation of manufacturing systems modelling and simulating technique in management of production processes. In course of the study there was implemented ARENA universal software package to modelling and simulation of the manufacturing systems (fi g. 5).To improve this area of the process, a machining cell was designed, where such operation are going to be realised as: USG control, grinding the surface after separating the gate assembly and initial machining (fi g. 6). Previously, the machining workstation was located in a different production hall, signifi cantly distant from the workstations of grinding and control.Fig. 4 Stages of the improvement process realisationFig. 5 Modelling and simulation of workplaces Fig. 6 Design of a machining cell The process of design of a new machining cell took into consideration the minimal equipment needs for workstations (tools, devices, aids). Also, standardisation of methods and order of particular activities was carried out, as well as time of operation duration was estimated.  A labour-consumption analysis was performed both before and after the changes, followed by tests on work ergonomics at particular workstations of the model area. To compare the current state with the planned one, a point-based scale was used for evaluation of particular ergonomic situations (fi g. 6). ?BEZPEČNOST A OCHRANA ZDRAVÍ PŘI PRÁCI31SPEKTRUM 1/2014Fig. 6 Rationalisation of workplace - examplesThanks to the undertaken alterations, it was possible to achieve a number of economical solutions. Transport routes have been shortened by almost 90 %, the level of activities without added value has been decreased by about 17 %, conditions of work ergonomics improved signifi cantly in the machining cell thanks to eliminating uncomfortable activities (improvement by almost 70 %), and labour consumption of manufacturing one piece (cast) has been lowered by almost 11 %.4 ConclusionsThe presented concept aims at ensuring safety and balanced advantages in an enterprise by achieving the goals of no losses, no faults, no breakdowns and no reserves. Analysing diffi cult and unnatural operations allows to identify the activities which are tedious for a worker and may become a stimulus for the introduction of an improvement project at the workstation. Continuous improvement of production systems in a foundry is key to lowering prime costs of manufacturing casts. Thanks to precise costs determination and allocating them to particular activities, it is possible to eliminate actions with no added value. References[1] Harris, R.; Harris, C.; Wilson, E.; Womack, J. (2010).: Making materials fl ow: a lean material-handling guide for operations, production-control and engineering professionals, Cambridge: The Lean Enterprise Institute.[2] Kukla, S. (2012).: Costs analysis of iron casts manufacturing. Archives of Foundry Engineering vol. 12, Issue 2, 45 - 48.[3] Kukla, S. (2010).: Production systems rationalisation on the example of iron foundry. Archives of Foundry Engineering vol. 10, Issue 2, 209 - 212.[4] Matuszek, J.; Kukla, S. (2009).: Analysis of foundry production systems on the basis of modelling and simulation. Acta Mechanica Slovacia, vol. 13, No. 2, 106 - 111.[5] Nyhuis, P.; Wiendahl, H.P. (2009).: Fundamentals of production logistic - theory, tools and applications. Berlin: Springer-Verlag.

Safety and Ergonomics of Iron Casts Manufacturing

http://dspace.vsb.cz/bitstream/10084/131289/1/Spektrum_2014_1_9_Kukla.pdf

Safety and Ergonomics of Iron Casts Manufacturing

Abstract

Similar works

Full text

Available Versions

DSpace at VSB Technical University of Ostrava