ONLINE ISSN 2069-7430 ISSN-L 1841-4737 PRO LIGNO Vol. 10 N° 3 2014 www.proligno.ro pp. 55-61 55 THEORETICAL CLARIFICATIONS REGARDING THE CONCEPT OF WORKING CAPACITY OF WOOD-WORKING MACHINE-TOOLS Gavril BUDĂU Prof.dr.eng. – TRANSILVANIA University in Brasov – Faculty of Wood Engineering Address: Str. Universitatii nr. 1, 500068 Brasov, Romania E-mail: g.budau@unitbv.ro Mihai ISPAS Prof.dr.eng. – TRANSILVANIA University in Brasov – Faculty of Wood Engineering Address: Str. Universitatii nr. 1, 500068 Brasov, Romania E-mail: ispas.m@unitbv.ro Abstract: Due to persisting confusions between the concepts “labor productivity” and “working capacity” of a machine-tool, equipment or production line, the authors considered it necessary to define and explain these terms. Starting by defining the notions “working cycle” and “functioning cycle”, the paper details: the theoretical, technological and real working capacity and also the term “working time norm” for wood-working machine-tools. Key words: working cycle; functioning cycle; working capacity; working time norm. INTRODUCTION In the reference literature of the last decades of the last century (years 1980÷1990), during the period of the socialist economy in Romania, the concept of WORKING CAPACITY of a machine-tool (equipment or production line), was assimilated to the notion of the machine tool PRODUCTIVITY (Gherghea 1983, Radu 1977 etc.) and expressed by the formula: T t n Q 1 = = [pcs/min] (1) where: Q = productivity, in pieces/min.; n = the number of identical pieces processed during the assessed period; t = the necessary time for processing 'n' pieces, in min.; T = the period of working cycle, in min. The period of a working cycle T, represents the time needed for processing a single piece: n t T = [min] (2) However, from the economic point of view, the concept of PRODUCTIVITY refers to the way labor is used and is expressed by the production volume reported to labor costs (Barba and Costea 1975). Therefore, we consider that, technically and in accordance with new references (Budău 2008, Budău 2011), in order to define the notion of WORKING CAPACITY of a machine-tool, it is necessary to understand corectly the terms WORKING CYCLE and FUNCTIONING CYCLE, depending on the type of the processing on each machine-tool, namely processing by through-passing or steady processing. Defining the concepts of WORKING CYCLE and FUNCTIONING CYCLE Performing a processing operation on a wood-working machine-tool (WWMT) involves the simultaneous achievement of the cutting motion, usually performed by the cutting tool, and of the feed motion, usually performed by the workpiece. In order to further process other pieces on the same machine- tool (having the same or different size or other parameters of the working regime) a series of auxiliary movements are needed: positioning – fastening or detachment – evacuation (in case of steady processing), idle running (the withdrawal of the working head or the supply with workpieces at a certain distance etc.). Therefore it is possible to define the following notions (Budău 2008, Budău 2011): • the WORKING CYCLE – represents the totality of the generating movements, which are necessary for processing a workpiece (excluding the auxiliary motions), during the time that the cutting tool is in contact with the workpiece, performing the cutting;