Course project - Modernization of machine 16k20

Introduction

A metal-cutting machine-tool designed to make parts of other machines by removing chips mainly with a blade or abrasive tool. The cutting process on the machine is carried out by means of coordinated relative movements of the cutting tool and the workpiece, which form the shape of the surface of the future part. [1, page 4]

Metal cutting machines are more diverse than any other process machine. They are distinguished by their technological purpose and cutting tools, by size and typical varieties, by control systems and the degree of automation, and, in addition, by layout. The variety of arrangements is a consequence not only of the many technological tasks, sizes and shapes of the workpieces to be machined, but also of the development of machine structures and machining methods, and in the very relative nature of the shaping movement there is a variety of possible variants of workpiece and tool movements, and therefore of machine arrangements. [2 pages 3]

This work considers the modernization of the machine 16K20F3, namely, the modernization of the main movement drive.

Justification for Selection of NC Machine Technical Characteristics

According to the specification, the spindle head of the CNC lathe machine is required, that is, it is required to upgrade it for processing of the part "Crankshaft pulley." To do this, you need to calculate the technical characteristics of the machine.

The drives of the main movement with stepless adjustment of the spindle speed allow you to accurately withstand the cutting speed set by the processing process of the part and automatically adjust it during various technological transitions, compared to drives with stepwise adjustment of the spindle speed. And this increases the accuracy and performance of processing and makes it possible to automate the process of controlling the main motion drive, so such drives are used in CNC machines. Adjustable DC and AC motors are used as the driving source.

In CNC machines of the turning group between the electric motor and the speed gearbox, a belt gear with a gear ratio of i = 0.5... 2 is installed to suppress forced vibrations from the electric motor. The belt gear is also placed between the box and the spindle, if the frequency of the latter is more. As a rule, at such high speeds of the spindle, finishing and finishing operations are carried out when smooth vibration-free rotation of the spindle is required. [1 page 119]

Source Data

The initial data for performing the course work are:

- machined part drawing;

- processing process per operation

- passport of 16K20F3 prototype machine tool.

Part to be processed - "Crankshaft pulley." On as preparation the casting of normal accuracy, material - VCh50 is used.

The lathe of the model 16K20F3 refers to universal machines of the normal accuracy class (H). It is used in small-scale and mass production with a frequent change in the object of manufacture. The machine is designed to process parts of the type of bodies of revolution.

Upgrade of prototype machine

As a modernization of the prototype machine, we upgrade the speed box for the machine box with CNC 16K20F3.

We will establish 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: trimming of the ends, longitudinal turning, chamfering, cutting of the grooves, thinning of the holes. In terms of accuracy, this machine will be designed to perform 14... 7 accuracy quotas, surface roughness Ra = 12.5... 1.6 μm

Specification definition and requirements

Machine Layout

Due to the limited variety of layout options for lathe machines, 4 structural formulas ChOXZ, ChOZX, ChZOX, ChOZXC are proposed. The differences of the proposed options depend to a greater extent on the geometrical arrangement of the workpieces of the machine.

The most suitable variant of the structural formulas relating to the base machine ChOZXC.

With - rotation of the preparation established in the boss of the machine;

About - a motionless part of the machine - the bed;

Z- longitudinal movement of machine support along Z axis along machine guides;

Note that in cross section the guide machines have a certain angle of inclination. This configuration ensures that the guides are automatically cleaned from chip ingress during part processing.

X - cross movement along axis X of horizontally located revolving support.

Rotation about the Z axis of the turret.