Tool Management in Manufacturing Systems Equipped with CNC Machines
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PRODUCAO Tool Management in Manufacturing Systems Equipped With CNC Machines Giovanni Tani Dipartimento di Meccanica e Tecnologie Industriali - Facolta di Ingegneria Universita di Firenze - Via S. Marta 3 - FIRENZE - ITALIA Key words: Tool file, Tool Card, Automatic Tool Selection ABSTRACT This wolk has been carned out for the purpose ofrealizing an automated system for the integrated management of tools within a company. By integrating planning, inspection and tool-room functions, automated tool management can ensure optimum utilization of tools on the selected machines, guaranteeing their effective availability. The first stage of the wolk consisted of defining and developing a Tool Management System whose central nucleus is a unified Data Base for all of the tools, forming part of the company's Technological Files (files on machines, materials, equipment, methods, etc.), interfaceable with all of the company departments that require information on tools. The system assigns code numbers to the individual components ofthe tools and file them on the basis of their morphological and functional characteristics. The system is also designed to effect assemblies of tools, from which are obtained the "Tool Cards" required for compiling wotking cycles (CAPP), for CAM progranuning and for the Tool-room where the tools are physically prepared Methods for interfacing with suitable systems for the aforesaid functions have also been devised. Belo Horizonte, Vol 7, N" 2, p.177-187 Nov. 1997 177 PRODUCAo 1. Introduction tools are taken from the warehouse, prepared for machining, preset, reground or regenerated. While tool management is a particularly urgent need in FMS Within the sphere of Production installations, it is also becoming Systems, the development of the concept increasingly important in shops that of integration has subsequently led to produce small lots. Efficient planning and considering the integrated management control of production necessarily calls for of tools. Data on tools do not concern shop real-time knowledge of the situation of the procedures alone, but are absolutely production system, within which tools essential for establishing the working have an important role. cycle of a product and for programming machine tools to carry out the various In response to market demand, companies now produce highly operations. Some information, moreover, differentiated products. As a result, must also be made available to the manufacturing has become enormously company's management system.(Fig.l) more complicated and increasingly greater resources are needed to stay The objectives that may be attained competitive. One of these resources through the implementation of an consists expressly of tools, which have integrated TMS system include: now taken on significant weight also as - improvement in performance of the regards financial aspects. The complexity Production System of the tools, the performance level - high levels of machine utilization required and the great number of services - reduction in downtime demanded make their overall cost a major - optimum tool selection item in a company's accounts. - reduction in variety and number of tools used Frequently, moreover, the lack of - optimized industrial purchasing effective standardization of tools leads to - supplying tools to machines just in their excessive proliferation as well as time continuous modifications in the solutions involving the engineering adopted by the programmers of CNC department in the concerns of the shop. Machine Tools. When an integrated tool management For these reasons, specialized software system is adopted, changes must be made systems for the implementation of tool in many company procedures while at the management procedures (Tool same time each department involved must Management System - TMS) have been be encouraged to utilize the potential of introduced, starting in the 1980s. The first the system to best advantage. Correct applications were chiefly concerned with application of the system, however, can tool management on the shop level; here yield significant financial results very in fact TMS is utilized for "physical" quickly (in some companies the management of tools, both in the Store application of TMS has resulted, in less Room where tools for current use are than a year, in 30% and more reduction usually kept and in the Tool Room, where in the number of tools in circulation). 178 I iT~BI S ele ctionIC onfigunt. Simulating tool flow p E-B-{f. _. -1- L ~ \l / ~~O A C ~ N Cutting parameters Tool Schedules, capacity, .... N C Vo = +--+ Data Base 0 I (~) ap= f I j ::: N "- ..- -- N T G Checking tools Monitoring tool flow / ~ R .,!:) 0 ~- ~~o L '--' I I Store room I 1Toolroom 1 I I L r MANUFACTURING ) Fig! - TMS functions 2. The project File, utilizing a Data Base of the relational type designed to serve as single source of The objective of the work carried out information on tools and thus to be was that of designing a Tool Management utilized by all of the different users within System able to provide management of tools, perfectly integrated with the the company. Consequently, it must company departments involved in this contain a great variety of data needed by activity, more specifically with the the different departments. This file will Schedules and Methods Department and form part of the Company Technological the Shop Engineering Department, the Files, consisting of Processes File, Tool Store Room and the Tool Room, the Machine Tools File, Materials File, Industrial Purchasing and Accounting Equipment File, Manufacturing Sheets Departments. File, Cutting Data File, and will The project, carried out in several necessarily be interfaceable with them and stages, first calls for the creation of a Tools perfectly integrated with them. (Fig. 2) 179 PRODUCAo Processes IMaterials IMachines ITools IMethods IFixture ICutting Data Teclmological Data - Bases ~~ IManufill:turing I Warehouse Tool- Room Enpeerin8 I I I Pro:ms I I I - Pro cess Planning - Pw:chasing - Defining working - Prep ering c orre ction cycle, data - Scheduling - Storing - Def. assemblies - Setting up tools - Machine, utili:J:won -Coding - Def. cutting data - Tools regeneration - Sp are parts - Prep. theoretical - Prep. physical tool card tool card Fig 2 - Utilizers of TMS The Tool Management System environment can be used to create Data developed, based on this file, can be used Bases of Relational type. to obtain the assemblies of tools and the Tool Card utilized in compiling work This Data Base was then implemented cycles, CAM programming and in the mechanical production "physical" preparation of tools in the Tool environment, and procedures for its rooms, ensuring correct rationalization utilization in C language were developed, and standardization of tool use. (Fig. 3) using within them SQL (Structured Query Language) commands for interface with 3. The Tool File and the TMS the Data Base. developed The functions provided by the system include: The structure ofthe data base utilized a) Organization and creation offiles is the standard DEC RDB (Relational for the representation of elements, Data Base), which in the VMSIUNIX association trails, fields of application. 180 b) Automatic generation of coding of f) Graphical representation of the elements to be linked to the analog individual elements and elements of a functions of the company management completed assembly. software. c) Manual or guided creation of the g) Generation of tool cards and assembly compositions and automatic monitoring of the elements utilized. generation of the assembly code number and of the geometric parameters of the h) Interface with the CAM system assembly. allowing transfer of assembly geometries and connection between the two d) Creation of trails with spare parts environments. and inserts. e) Identification of utilizations through i) Interface with the Tool Room technological research keys. Software. Managing Elements - tree structure -levels - variables CAM Inteface Managing Assemblies - dimensions - Tool-code - graphic. repro - UID codes - tool code - Composition - technology Managing Tool Card Coding - Tool-code - Management - Correctors Program - Offset values Interface - Elements code - elements - dimensions - assemblies - tool card Tool Room Interface Fig 3 - Functional diagram of TMS 181 4. File structure of object which is utilized in warehouse management of the Tool-Room software. Data regarding elements (tools, 3) FAMILIES: From this level on, the mandrels, accessories, etc.) are stored in work of grouping is carried out to meet the DB for subsequent processing by the the specific requirements of the company. program for the purpose of executing the In general, in passing from one level to various operations of association, search another, one or more characteristics of the and linkage necessary to enable the elements which are to be entered are required functions. specified. Accordingly, the organizer of the library is responsible for deciding The objective to be attained was that which properties of the object should be of classifying the elements according to evidenced starting from the "highest" criteria of grouping and subdivision into levels. levels, reflecting either the common or the specific nature of certain characteristics For example, after the group (type) of of the objects. Groups or sub-groups are milling cutters has been specified, a more thus established with the precise aim of detailed description is given which serves making the object immediately to identify