Development of CAD software for the main drive sys

Development of CAD software for machine tool main drive system

1 Introduction

computer aided design is abbreviated as CAD, which is the abbreviation of English computer aided design. It refers to the whole process of engineering and technical personnel designing with computer as a tool, including data retrieval, scheme conception, calculation and analysis, engineering drawing and preparation of technical documents. It is a comprehensive high-tech technology formed with the development of computer, peripheral equipment and software. Modern cutting is developing towards high speed, high efficiency and high precision, which puts forward higher and higher requirements for the structure and performance of machine tools, such as high speed, high power, wide speed range, low noise, good dynamic performance, high reliability. The main transmission system of machine tool is the key in the design of machine tool. Therefore, how to adapt to the market demand and design and manufacture cutting and processing equipment required by the market in a complex and volatile market economy is the embodiment of the strength and scientific and technological level of the manufacturing industry. Therefore, the application of computer aided design (CAD) technology to machine tool design has always been the goal of many manufacturers. In the past, the design of machine tools in China used drawing boards for manual drawing, which often led to a large workload, resulting in a long development cycle, and it was easy to make mistakes in the design process. Therefore, how to apply computers to machine tool design and how to develop a set of general and effective design software for machine tool main drive system are our motivation to write this paper

2. Object-oriented programming method

as a concept, object-oriented is a new method of software system design and implementation at first. Because of the great advantages of this thinking method, it has also had a more and more extensive impact in other fields

object-oriented method is a new method to represent real objects and solve problems by building object models around the concept of the real world. Its expansibility and reusability greatly improve the development speed of the system. It controls the complexity and maintainability of the software by encapsulating and hiding the design parameters and separating the design and implementation

object-oriented methodology believes that the objective world is composed of various "objects", everything is an object, and each object has its own operating law and internal state. By analogy, objects with the same characteristics and functions form classes (induction). Each object belongs to a "object class" and is an instance of that object class. The combination and interaction of different objects constitute an objective system that we should study, analyze and construct. Object classes can form the hierarchy of classes through inheritance relationships, and "subclasses" can directly inherit the properties and functions (deduction) of "parent classes". The objects interact with each other through messages, which is to inform the object to complete an operation that is allowed to act on the object. The details of how the object will complete this operation are encapsulated in the definition of the class, which is hidden from the outside world

object-oriented analysis is to study problems with object-oriented ideas, and construct a model reflecting the essence of the problem according to the real world. The model explains what the system must do, not how to do it, that is, the details of doing it. Object-oriented design is to construct a problem-solving model. Because the analysis model is established by object-oriented method, which is similar to the structure of software solution, object-oriented design is the refinement of the analysis model (describing the object and its relationship), as well as the process of constructing the objects involved in the implementation

object-oriented method provides more natural and reasonable concepts and technologies than structured method. Moreover, its abstraction, encapsulation, inheritance, polymorphism and so on are better than structured method, making it a more powerful tool and method

3. According to the basic principle of object-oriented method, the conceptual model of NC lathe main drive system is established, and VC is used as the development tool of program design. Because the design of the main drive system of CNC lathe is mainly a parametric design process, the program mainly completes this work in the way of human-computer interaction. In view of this characteristic, I divide the whole system into many interfaces, and abstract these interfaces as entities into certain object classes

the object classes of the whole system are roughly as follows:

object class 1: motor model dialog box

object class 2: gearbox speed change series dialog box

object class 3: transmission ratio dialog box

object class 4: transmission pair tooth number dialog box

object class 5: gear material dialog box at the beginning of China Zhongwang's establishment of product and process design team

object class 6: gear module (by contact) Dialog box

object class 7: gear module (by bending) dialog box

object class 8: gear module (standard) Dialog box

object class 9: synchronous toothed belt calculation power property page

object class 10: synchronous toothed belt modulus property page

object class 11: large and small pulley diameter property page

object class 12: synchronous toothed belt tooth number property page

object class 13: shaft diameter estimation dialog box

according to the above basic object classes, Further, the design part of the main drive system of CNC machine tool is divided into four subsystems:

according to the above system model and structure based on object-oriented analysis, the module decomposition of the program can be directly obtained. With the above four subsystems, it is easy to design the overall module structure of the programming part of the system

(1) motion design module

in this module, it mainly completes the work of determining the model of machine tool motor, the limit speed of machine tool, speed change stages, transmission ratio of transmission pair and the number of gear teeth

(2) gear design module

in this module, it mainly completes the selection of transmission gear materials and heat treatment methods, the calculation of transmission gear module according to contact fatigue strength, the calculation of transmission gear module and module rounding according to bending fatigue strength

(3) synchronous toothed belt module

in this module, it mainly completes the work of determining the calculated power, module of toothed belt, speed ratio of toothed belt, number and diameter of teeth of large and small belts, width of toothed belt, center distance of pulley and number of teeth of toothed belt

(4) shaft diameter estimation module

in this module, it mainly completes the work of determining the maximum machining diameter of the lathe, the diameter estimation of the general transmission shaft, the diameter estimation of the front Journal of the main shaft, the diameter estimation of the rear Journal of the main shaft and the average inner diameter estimation of the main shaft

according to the relationship between the above object classes and the modular division of the system, at the same time, in order to ensure the effectiveness of data transmission of each object class in the design process. When designing object classes, we first encapsulate a part of the data members (attributes) related to each object class. Then declare the structure corresponding to each object class in the program. The structure contains the data members encapsulated in the object class one by one. 3. After installing the computer universal material testing machine, you should also learn how to find the corresponding variables. The variables in these structures play a very important role in initializing object classes, transferring data between object classes, and saving important design parameters. Finally, just define an object for each structure in the "document" class, and use some important methods of the "document" class and the "view" class in visual c++ to complete these tasks. The following figure shows the organizational relationship between data. These works can also be done directly through the objects of classes rather than using the objects of structures, but for the convenience of organizational coordination and management, we rely on the idea of intermediate bridges to organize and transmit data

the following is a specific example to illustrate the working principle:

1. data encapsulation

l object class 1: motor model dialog box class name: acmotorselectdlg

class acmotorselectdlg: public cdialog

{

//construction

public:

cnclathedesignview* pview;//visual object (pointer type)

cnclathedesigndoc* pdoc//document class object (pointer type)

int index;// AC motor power list box selection index

float power[7]//AC motor rated power array

long basespeed[7]//AC motor rated speed array

long maxspeed[7]//AC motor maximum speed array

acmotorselectdlg (cwnd* pparent = null)//standard constructor

//Dialog Data

//{{AFX_DATA(ACMotorSelectDlg)

enum { IDD = IDD_ACMOTOR_SELECT };

CListBox m_ powerlist;

CString m_ information;

long m_ ebspeed;

long m_ emaxspeed;

float m_ epower;

//}}AFX_ DATA

};

l object class 2: variable speed series dialog box class name: gearshiftselectdlg

class gearshiftselectdlg: public cdialog

{

//construction

public:

cnclathedesignview* pview;//visual pointer object

cnclathedesigndoc* PDOC;//document pointer object

double NJ;//spindle calculation speed

double RN;//spindle speed regulation range

double RNP;//spindle constant power speed regulation range

double RP;//motor constant power speed regulation range

gearshiftselectdlg (cwnd* pparent = null) ;// standard constructor

//Dialog Data

//{{AFX_DATA(GearShiftSelectDlg)

enum { IDD = IDD_GEARSHIFT_SELECT };

CButton m_ calculate;

float m_ inputmaxspeed;

float m_ inputminspeed;

int m_ twoshift;

CString m_ spispeedrange;

CString m_ motspeedrange;

//}}AFX_ DATA

};

these two pieces of program code encapsulate the member variables required by object class 1 and object class 2 respectively. Among these member variables, there are two member variables cnclathedesignview* pview and cnclathedesigndoc* PDOC, which are media. Through this medium, it is associated with the structure object defined in the "document" class cnclathedesigndoc (a class derived from the cdocument class), so that the object class can reference its own structure or variables in the structure associated with other object classes. In these two pieces of program code, they are defined in//dialog data and//}} AFX_ The member variables between data are associated with the controls in the dialog box to describe the state and value of each control. At the same time, they also rely on these member variables to communicate with the variables in the structure through the media

4. The application of database technology in the design of machine tool main drive system

the traditional design of machine tool main drive system needs to find a lot of data, which will make the design workload very large. How to organize the basic data required in the design together and build a compact and efficient database to shorten the search time and improve efficiency is an important link to be solved in the process of software design and development

vc includes two independent database access systems: ODBC (open database interconnection) and Dao (data access