Course project. CNC lathe 16A20F3

Contents

INTRODUCTION

1. JUSTIFICATION FOR SELECTION OF MACHINE TECHNICAL CHARACTERISTICS

1.1 Initial data

1.2 Part processability analysis

1.3 Upgrades of the prototype machine

1.4 Definition of structural formula of layout

1.5 Calculation of cutting modes

1.6 Justification of machine technical characteristics

2. DEVELOPMENT OF MACHINE KINEMATIC DIAGRAM

2.1 Selection of electric motor

2.2 Calculation of control ranges

2.3 Plotting of rotation speeds

2.4 Determination of gear numbers

2.5 Calculation of rotation speeds

2.6 Determination of moments on shafts

2.7 Determination of circumferential wheel engagement speeds

2.8 Calculation of transmission parameters

2.8.1 Calculation of belt transmission parameters

2.8.2 Calculation of Gear Parameters

2.9 Calculation of shaft diameters

3. VERIFICATION CALCULATIONS

3.1 Calculation of gears

3.2 Calculation of shafts

3.2.1 Calculation of shaft for static strength

3.2.2 Calculation of shafts for bending and torsion

3.3 Spindle Calculation

3.3.1 Check spindle for stiffness

3.3.2 Check spindle for rotation accuracy

3.4 Selection of rolling bearings

4. FEED DRIVE DEVELOPMENT

5. LUBRICATION SYSTEM SELECTION

6. LIST OF LITERATURE USED

Introduction

The great advantage of the designs of the manufactured machines is the ability to integrate them into automatic lines. The layout of the latter is usually made on the basis of two types of equipment: specially made for work in automatic lines and universal equipment. Practice has shown that in many cases the use of universal equipment is more appropriate. This accelerates the design and manufacture of automatic lines. At the same time as mechanization and automation of machines, the requirements for accuracy and cleanliness of processing increased.

Numerical software control of machines has been particularly developed in recent decades. Microprocessor control devices turn the machine into a machine module, combining flexibility and versatility with a high level of automation. The machine module is capable of providing processing of blanks of a wide range in autonomous mode on the basis of low-density or even deserted technology. Thus, modern machine equipment is the basis for the development of flexible automated production, which dramatically increases labor productivity in medium and small-scale production.

The use of flexible production systems, consisting of a set of machines, manipulators, controls, combined with general control from computers, makes it possible in multi-nomenclature large-scale production to stimulate scientific and technological progress, and the transition to new, more advanced samples of products with minimum costs. The shift from the use of a set of machines and other technological machines to machine systems in the form of flexible production systems of technological equipment, in addition to increasing labor productivity, radically changes the entire nature of engineering production. Conditions are created for gradual transition to labor-saving production with the highest degree of automation.

The improvement of modern machines should ensure an increase in the speeds of working and auxiliary movements with a corresponding increase in the power of the drive of machines, spindle units, traction devices and straight-line guides.

Using Composite Materials for Cutting Tools

allows you to already realize the cutting speed up to 1.5 sound2 km/min, and the feed speed to bring to 20 sound30 m/min. A further increase in speeds will require the search for new structures using different physical principles and ensuring the high operability of responsible machine assemblies.

The use of machine modules is possible only with the complete automation of all auxiliary operations due to the widespread use of manipulators and industrial robots. This applies to the operations related to the change of workpieces, cutting tools, tooling, to the operations of measuring workpiece, tool, to the operations of crushing and removing chips from the working area of the machine.

Equipping flexible automated production machines with various control and measuring devices is a prerequisite for their reliable operation, especially in autonomous and automated mode. Modern machines use a wide range of measuring tools, sometimes very accurate, such as laser interferometers, to collect current information about the state of the machine, tool, auxiliary devices and to obtain reliable data on serviceability.

Increase of stability of dimensions and quality of machined parts, reduction of scrap due to reduction of machine tool errors cycle, optimization of machining modes during programming, improvement of machine tool working conditions and reduction of requirements to its qualification.

The CNC lathe is designed to handle parts having rotation surfaces, threads and screw grooves.

The drives of the main movement with stepless adjustment of the spindle rotation speed allow to accurately withstand the cutting speed, the given processability by the part processing process, and automatically adjust its performance of various technological transitions, compared to drives with stepwise adjustment of the spindle rotation speeds. This improves processing performance and accuracy, and enables automation of the main motion drive control process, so such drives are used in CNC machines. Adjustable DC and AC motors are used as the driving source.

In lathe CNC machines between the motor and the speed gearbox, a belt gear with a gear ratio of i = 0.5... 2 is installed to dampen forced vibrations from the motor.

Justification for selection of machine technical characteristics

According to the technical assignment, it is necessary to design the drive of the main movement of the turning-screw machine, that is, it is required to upgrade it for processing of the Shaft part. To do this, you need to calculate the technical characteristics of the machine.

1.1 Initial data

The initial data for performing the course work are:

machined part drawing;

processing process for one specified operation;

prototype machine passport 16A20F3

The lathe of the model 16A20F3 refers to universal machines. It is used in small-scale and mass production with a frequent change in the object of manufacture. The machine is intended for turning of parts such as bodies of revolution .

1.3 Modernization of the prototype machine

As a modernization of the prototype machine, we modernize the main movement drive and the feed drive of the machine 16A20F3.

We set the requirements for the accuracy and quality of the machined surfaces on the designed machine, for the performance of operations this part is subjected to the following types of processing: face clipping, longitudinal turning, chamfering.

In terms of accuracy, this machine will be designed to perform 12... 6 accuracy quotas, surface roughness Ra = 6.3... 1.25 μm.

1.4 Definition of structural formula of layout

Two structural formulas COXZ and COZX have been proposed for turning group machines.

The differences of the proposed options depend to a greater extent on the geometrical arrangement of the workpieces of the machine. The most suitable embodiment of the structural formula is the COZX base machine .

C - rotation of the workpiece installed in the cartridge machine; O - fixed part of machine - frame; Z - longitudinal movement of machine support along Z X axis - transverse movement along X axis of horizontal turret with tools.