Computer aided engineering of machine tool drive

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Tgszrnr

n a u k o w e p o l i t e c b h k i ślis k i e j

Seria: MECHANIKA z. 108

_________ 1992 Nr k o l . 1161

Internationa] Conference on

COM PUTER INTEGRATED MANUFACTURING

Internationale Konferenz fiber

RECHNERINTEGRIERTE FERTIGUNGSSYSTEME

Zakopane, M arch 24-27 1992

lan K O S M O L , Andrzej S O K O Ł O W S K I , Tadeusz T Y R L I K

The Institute of Machine Building

Silesian Technical University, Gliwice, Poland

C O M P U T E R A I D E D E N G I N E E R I N G O F M A C H I N E T O O L D R I V E

Summary. The paper presents a description of a computer program to aid engineering

of

machine tool

leed

drives containing d.c. motors together with thyristor feeder, toothed belt transmission and ball screws with bearings. The authors aim was a complex approach to the feed drive engineering problem. Calculation procedures of sets feed drive elements were built by authors, making use the algorithms

proposed by

producers and were joined to the main program.

1. Introduction

One of the main module of the now-constructed machine tools is the feed drive which comprises both ihe operation mechanical part and the control system. In the machine tool syslem the feed

drive has a decisive effect on the machining abilities [1]. Most frequently Ihe feed drive includes d.c.

motors togethei with thyristor feeder, toothed belt transmissions and ball screws with bearings (Fig. 1).

The number of the constituent elements of the feed drive, multiplied by the

multitude

of the firms offering elements of the same type, constitutes the first problem which

must be

solved by an engineer. At Ihe same time, this fact is one of the factors indicating

a possibility of

computer aided engineering.

Tlte next factor decisive about computer application is the fact that many of the calculations made have an iteration character. Multiple repetition of the same partial

calculations, as well as a possibility of algorithmizing of these calculations,

is decisive aboui

the feasibility and advisability of developing computer procedures.

The authors aim was also a complex approach to the problem of feed drive engineering. The procedures of calculating the particular elements of the feed drive have been constructed by

the authors acc. to calculation algorithms suggested by the manufacturers [2|. Such an approach maue possible the construction of a program in which the choice of the given

element constituted at the same time the input data io the successive calculation step without the necessity of independent loading of the data as it is the case of the

calculations realized by means of independent programs.

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Fig.l . S ch em a tic dia gr am of th e en g in ee re d fee d drive s

T H Y R I S T O R FEE D ER

TABLE TABLE

of WACMiMt root T H Y R I S T O R

B EA RIN G ôfîtâc^{mtnt root} B EA RI NG FE E D ER

MOTOR

h i

BALL

B E L T S C REW

T R A N S M I S S I O N

ST RU C T U RA L FLOW C H A R T OF FEED D R IV E ( H o r i z o n t a l B a ll S c r e w , t w o - s i d e s s u p p o r t e d )

•m

MOTOR

f f

B E L T

T R A N S M I S S I O N BAL L SC REW

S T RU C T U RA L FLOW C H A R T OF F EE D D R IV E ( H o r i z o n t a l B a ll S c r e w . O n e - s i d e s u p p o r t e d )

BELT

T R A N S M I S S I O N T H Y R I S T O R I I I 111! 11111 vj-U, I

m m CD

r ■ ■ ■ ■ * -i t r i

F E E D E R

MOTOR

B EA RING

BAL L SCREi

S T RU C T U RA L FLOW C H A R T OF FEED D R IV E ( H o r i z o n t a l B a ll S c r e w . O n e - s i d e s u p p o r t e d )

S T RU C T U RA L FLOW C H A R T OF F EE D D R IV E ( H o r i z o n t a l B a l l S c r e w w i t h r o t a r y N u t )

208

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2. Algorithm of calculations

The algorithm of calculations (Fig.2) is composed of successive steps in which the individual constituent elements of the feed drive are calculated or chosen. There are 2 kinds of steps in the algorithm i.e., choice of the dement, or verification of the choice of element.

During the sete ion of the particular element, the type of an element which is the closest to the ideal solution, and which fulfills the assumed constraints is suggested each time.

Also possible is the choice of the elements different from the proposed ones with a simultaneous signalling of fulfilling or lack of fulfilling of the criteria conditions.

The calculation steps in which occurs a verification of pre-choice of elements are of particular importance for the whole course of calculations. By the way of an example,

verification of the choice of ball screw is reduced to the verification of the criteria referring to the static load capacity and dynamic capacity of the screw, resonance frequency

of the system, insensitivity zone or life of the screw - bearing system. The particular verification criteria are related to various factors e.g., insensitivity zone is related

to the coefficients of friction on the shears of machine tool, and also the rigidity of the pre-chosen screw and the rigidity of the selected bearings. The meeting the particular

criterion results in the necessity of introducing changes in the pre-established values or elements chosen, and in consequence - the necessity of repeated carrying out of the

calculations already done.

The verification step of the choice of motor or feed drive is realized analogically to the verification of the ball screw with a note that in this case the number of the possible combinations is multiplied through the fact of an earlier choice of the elements which may be changed on the level of the

particular step.

X General description of the programm

In its structure, the programs constitutes a specific environment in which the calculations are realized.

Possible in the environment are the operations of recording and reading of

the data and results from a disk and the operations of data transfer and calculation results to the printer.

The menu of the main program has been organized on the basis of the system of developed windows.

In the main menu is shown the current state of calculations, as well as the basic

input quantities for which the calculations are made. In the lower part of the menu "help” is developed in which the assignation of each of the chosen option or sub-options is

briefly described. From the level of the main menu there are available 6 main options containing a number of sub-options.

The main options of the program are (Fig..V):

- "catalog" option: it makes possible a review of the available, from the program level, standard elements

manufactured by various firms;

- option of "elements calculation" described belo- - option of "calculations" described below;

- option of "configuration" which makes possible the loading of input quantities. The option also makes possible the setting of the input output paths of the calculation

results, as well as a review of the visual drawings of the particular elements of the feed drive;

- option "printouts"; the option offers a possibility of loading the printer or disk with technical data of the individual selected elements, input quantities for the

calculations, and the quantities determined in the course of calculations.

- option "description of configurations’; an option making possible current review of the quantities determined during calculations, and the technical data of the elements chosen.

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Fsg.2. General algorithm of feed drive calculations

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F ig 3 . M ain M E N U of th e " S E R V J B M " pr o g ra m

11I-£AIAL0QU£S— - ¹ 1ELEMENTS CALC. GLOBAL CALC. CONFIGUR. PRINTOUT DESCRIP.

i i i i ■ i _ _

KEV FUNCIION

NFORMATION ABOUT PROGRAM ENVIRONMENT J i s k C a t a l o q u e s

CONFIGURATION OF CALCULATED DRIVE GLOBAL CALCULATION OF THE FEED DRIVE

UPPLEMENT CALCULATION OF FEED DRIVE kNPUT OLD CALCULATION FROM THE DISK

N D O F T H E P R O G R A M

DESCRIP. OF STATE Ç

* Pre-choice of BaJ

* D

u i b i i u m

^CALCULAT 1 Screu 1

^ UCdl XIIIJ5 /

* Verificat. of Ball Screo ^'

* Pre-choice of Motor

* Choice of Belt-transmis.

» Verification of Motor

» Choice of the Feeder

q - c loice not matle \ ^- Choice made 0.K. 1 — Second Calcul, necessary

x x x MAIN P M IE R S CO N FIG IM D M E FEED DRIVE x x

**Mass of driven El.=4Mkg] Ratio of B. Trans.= 1.0 Length B* Sc. = 1* 5 tml Max* feed ^ 600 [ rmv/min] Pitch of B. Sc. = 5.01 mm] Life = 2.0E-t4 I hours]**

Comments to choose option (Tor exanpie: Cataioques)

CATALOGUES OF BALL SC IEHS. HOIORS, M I S , THYRISTOR FEEDERS

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The calculations may be realized from level 3 of various sub-options. The first of them the option of the calculation of elements) assumes an interference of the engineer in the

course of the calculations through manual selection of the particular calculation steps.

In the second case (calculation option) the calculations of the whole drive are realized automatically with intervals for decision making about the elements of the feed drive proposed

by the program, or the quantities resulting from intermediate calculations.

In the case then the calculations are not complete, the input data were charged or one of the constituent elements of the drive designed W3S changed, one may make use of the

sub-option realizing the completion of the calculations (calculation option). In this case the program, in an intelligent way, selects these calculation steps which are

required from the point of view of the changes made earlier.

4. Summary

The program presented here in a general way aims at aiding engineering activities in designing offices of the plants manufacturing machine tools. The present program has been used

in the didactic process at the Institute of Machine Construction of the Silesian Technical University in Gliwice, and has been implemented in the factories R A F A M E T in Kuznia

Raciborska, F A T in Wroclaw and D E F U M in Dabrowa Gomicza.

R E F E R E N C E S

11 ] Mierzejewski J.: Servomotors of numerically controlled machine tools. Wydawnictwa Naukowo Techniczne, Warsaw 1977

|2| Catalogs of AVIA-Poland, PORTER-United States, INA-Germany, UNIROYAL-United States, STAR-Germany, SIMENS-Germany

C O M P U T E R U N T E R S T U Z U N G D E R V O R S C H U B A N T R I E B P R O J E K T I E R U N G

Zusammenfassung

In dem Bericht ist eine Beschreibung ein Computerprogramm zu der Unterstützung der Vorschubantriebprojektierung vorgestelt. Der Antrieb ist von Gleichstrommotor mit Thyristorfeeder, Riemen-Zahnradgetriebe, Kugelgewindetriebe mit Kugellager zusammengesetzt. Die Autoren wolten die Vorschubantrieb- Projektierung komplexive erfassen. Die Autoren haben die Abrechnungprozedure den Vorschubantriebelementen gebaut. Sie haben die Abrechnungalgorithmuse vorgeschlagten vom Hersteller ausgenutzt und zu dem Hauptprogramm angeschlossen.

K O M P U T E R O W E W S P O M A G A N I E P R O J E K T O W A N I A N A P Ę D Ó W P O S U W O W Y C H O B R A B I A R E K

Streszczenie

W artykule przedstawiono program komputerowy dla wspomagania projektowania napędów posuwowych obrabiarek. Napęd posuwowy składa się z: silnika prądu stałego, zasilacza tyrystorowego, przekładni paskowo zębatej i przekładni iruhowo-tocznej. Celem pracy było kompleksowe ujęcie problemu projektowania napędów posuwowych. Opracowany został algorytm obliczeniowy dla wszystkich elementów napędu. Poszczególne procedury obliczeniowe opracowano na podstawie zaleceń producentów elementów napędu.