1, the concept of lathe:

Lathe refers to a machine tool that is used as a turning tool for feeding motion to cut the workpiece that is the main rotating motion.

2, lathe job description:

When turning, the workpiece is clamped on the chuck or the center connected with the spindle, and the spindle rotates with the chuck or the center. The turning tool is installed on the tool rest, and the tool rest moves longitudinally or transversely (longitudinally parallel to the bed guide rail and transversely perpendicular to the bed guide rail), so that the turning tool can feed, thus turning the workpiece.

3, the types of lathe:

(1) There are many kinds of lathes, which can be divided into floor-standing and horizontal lathes, vertical lathes, instrument lathes, single-axis automatic lathes, multi-axis automatic and semi-automatic lathes and hexagonal lathes according to different purposes and structures.

(2) Ordinary lathes can be divided into floor lathes, horizontal lathes, saddle lathes, lead-free lathes, chuck lathes and spherical lathes.

4, lathe processing characteristics:

(1) the machining accuRacy of ordinary lathe can reach IT 10 ~ IT7, and the surface roughness ra value can reach1.6 μ m. ..

(2) The lathe has a wide machining range. The turning surface is mainly processed on the lathe, including: turning the excircle, turning the end face, slotting, drilling, boring, turning the conical surface, turning the thread, turning the molding surface, drilling the center hole and knurling.

Figure 4-7 Example of Parts Processed by Lathe

Figure 4-6 Schematic Diagram of Turning Processing

A, ordinary lathe

1. Overview:

Ordinary lathe is one of the most widely used lathes, accounting for about 65% of the total number of lathes. Because its spindle is placed horizontally, it is a horizontal lathe. CA6 140 is a typical ordinary lathe.

2. Features:

Because CA6 140 lathe has a wide processing range, complex structure and low degree of automation, it is suitable for single piece and small batch production.

3. Transmission path:

(A) the main structure of ordinary lathe

The main components of CA6 140 lathe are spindle box, feed box, carriage box, tool rest, tailstock, polished rod, lead screw and lathe bed.

1. headstock.

(1) The headstock, also known as the headstock, is equipped with a spindle and a spindle speed change mechanism. Its main task is to make the spindle achieve the required forward and reverse speed through a series of speed change mechanisms.

(2) The workpiece is clamped by the chuck or installed in the center to do the main motion rotating with the spindle, so as to realize cutting processing, and at the same time, the spindle box divides a part of power to transmit the motion to the feed box.

(3) The spindle in the headstock is the key part of the lathe. It is supported on rolling bearings and bears cutting force when cutting. The spindle and its bearings are required to have high accuracy and stiffness. Once the rotation accuracy of the lathe spindle decreases for various reasons, the use value of the machine tool will decrease.

2. Feed box.

(1) Feed box is also called feed box. It is fixed on the left front side of the lathe bed, and is set to adapt to different processing conditions, reasonably select the feed or specify the pitch.

(2) The feed box is equipped with a speed change mechanism for feed movement. By adjusting the speed change mechanism, the required feed or pitch can be obtained, and the movement can be transmitted to the carriage box through the polished rod or lead screw.

3. Screw and polished rod.

(1) The lead screw and polished rod are installed at the front side of the lathe bed, connecting the feed box and the slide box, and transmitting the motion and power of the feed box to the slide box, so that the slide box can move vertically and linearly.

(2) The screw is specially used for turning various threads. When turning other surfaces of the workpiece, only polished rods are used instead of screws.

4. That box. In fact, the carriage box is the control box of lathe feed movement, which is equipped with a mechanism to convert the rotary motion of lead screw and polished rod into the linear motion of tool rest. The vertical feed motion, horizontal feed motion and rapid motion of the tool rest are realized by polished rod transmission, and the turning tool on the tool rest is driven by the lead screw to make vertical linear motion to turn threads.

5. Knife rest.

(1) The tool rest is used to clamp the turning tool and make it move longitudinally, transversely or obliquely.

(2) The tool rest is divided into three layers.

The bottom layer is called a longitudinal skateboard, which can move longitudinally on the guide rail of the bed.

The second layer is a transverse skateboard, which can move horizontally along the guide rail of the longitudinal skateboard perpendicular to the guide rail of the bed.

The third floor is equipped with a turntable which can rotate at any angle in the horizontal plane. A small skateboard is installed on the turntable, which can move a short distance along the guide rail on the turntable. There is a square tool rest on the small slide seat, and the turning tool is clamped on the square tool rest with screws, and at most four turning tools can be installed at the same time. When changing tools, loosen the handle and turn the square tool rest to turn the required turning tool to the working position. When working, the handle must be tightened to fix the square tool rest.

6. Tailstock (tailstock). When machining a slender workpiece, a center is installed in the tailstock to support one end of the workpiece. If the tool tip is removed and tools such as drill bit are installed, drilling, reaming and tapping can be realized on the lathe.

7. Sleep.

(1) The lathe bed is installed on the left and right legs to support three boxes (spindle box, feed box and slide box), two bars (polished rod and lead screw) and two racks (tool rest and tailstock) on the lathe.

(2) The left leg of the machine tool is equipped with a lubricating oil tank and a driving motor. The right leg of the bed has a coolant tank and a coolant pump.

(2) CA6 140 Lathe Technical Specification

Technical specifications of machine tools are technical data reflecting the working performance of different varieties and types of machine tools, and are an important reference for selecting machine tools. The technical specification of general machine tools consists of five parts:

1. Technical parameters. Parameters that mainly reflect the machining capability of machine tools, including main parameters and second main parameters.

2. Machine tool working speed series and adjustment range.

3. Machine tool main motor power.

4. Overall dimensions of the machine tool.

5. The weight of the machine tool.

Table 4-5 ca 6 140 Main technical performance of common lathe

Serial number item

The turning diameter of the workpiece on the lathe is 400 mm.

The center is 205 mm high.

Workpiece length: 750mm, 1 0,000mm, 1 0,500mm, 2,000mm.

The diameter of the spindle hole is 48 mm.

Taper of spindle front end

2. The spindle speed is 24. .......................................................................................................................................................................

Reverse 2nd gear ... L4 ~1580 rpm.

The longitudinal feed speed is 0.028 mm ~ 6.33 mm/revolution (64 stages).

Level (level 64) level 64

The longitudinal fast moving speed of the carriage and the tool rest is 4m/min.

3. The main motor power is 7.5kW. ..

Car fast moving motor

4 overall dimensions of the machine tool (length× width× height, when the length of the workpiece is 1000 mm)

.................. 2 668x1000x1267mm.

5 Machine tool weight (when the workpiece length is 1 000 mm)

Second, the vertical lathe

(1) Overview:

The main feature of vertical lathe is that the spindle is vertical, the worktable is on the horizontal plane, and the workpiece is clamped on a large worktable, which is driven by the spindle belt to rotate.

(2) Classification:

Vertical lathes are divided into single column and double column, and the machining diameter of single column vertical lathes is smaller (less than1600 mm). ); The machining diameter of double-column vertical lathe is large (the machining diameter of vertical lathe is more than 2500mm), and it can clamp 80t heavy workpieces.

(3) Motion description: The workpiece is mounted on the workbench and driven by the spindle as the main motion. The feeding movement is realized by the vertical tool rest 3 and the side tool rest 4.

Because the workpiece is installed on the horizontal workbench, it is more convenient to clamp the workpiece. The quality and cutting force of the workpiece are borne by the rotating guide rail between the workbench and the base, which reduces the load of the spindle and its bearings, has good working stability, is easy to ensure the machining accuracy, and can ensure the working accuracy of the lathe for a long time.

(4) The main features of vertical lathe are:

1. The workbench is in a horizontal plane, and the installation and adjustment of the workpiece are convenient and safe.

2. The workbench is supported by the guide rail, with good rigidity, smooth cutting and good stress condition of the spindle.

3. There are several tool holders, which can be cut with a variety of tools and can be quickly replaced. The machining accuracy of vertical lathe can reach IT8~IT7, and the surface roughness Ra can reach 1.6 μ m ~ 0.8 μ m. ..

Triangular and hexagonal lathes

(1) Features: There is no lead screw and tailstock, but a hexagonal tool rest (turret tool rest).

(2) Description of movement:

On the hexagonal lathe, all the tools used can be pre-installed on the lathe and their position and size can be adjusted; The travel end position of each group of tools can be controlled by the stop on the machine tool body. After the machine tool is adjusted, it is not necessary to disassemble and adjust the tool repeatedly when machining each workpiece. Therefore, the operation is convenient and quick, the auxiliary time can be saved, and the productivity is high.

(3) Classification:

Hexagon lathes are divided into vertical turret lathes (Figure 4- 12) and rotary lathes (Figure 4- 13).

The rotation of the hexagonal tool rest around the horizontal axis is called a lathe.

(4) Features:

When machining an excircle with a hexagonal lathe, the accuracy can reach IT1~ it8, and the surface roughness Ra value can reach 3.2 ~1.6 μ m. When machining holes, the accuracy can reach IT7 and the surface roughness Ra value can reach 0.8 μ m. ..

Example 6? The multiple-choice questions in the following procedures can be completed on an ordinary lathe ()

A. boring

B. Drilling holes

C. milling keyway

D. grinding the excircle

E. embossing

Answer: Abe

Example 7? Multiple choice questions (2008) Among the following statements about the use of lathes, the wrong one is ().

A. No matter what workpiece is processed, the spindle should be used.

B. If snails and mosquitoes are not treated, they don't need screws.

No matter what workpiece is processed, the tool must be installed on the tool rest.

D. When turning the excircle of a disc-shaped part, the tailstock is not needed.

Answer: c

Example 8? The following statement about lathe is incorrect ().

A. When cutting, the spindle always bears cutting force.

Lead screw is specially designed for turning various threads.

C. The carriage is the control box for the lathe feeding movement.

D. A mechanism for converting the rotary motion of the lead screw and the polished rod into the linear motion of the tool rest is installed in the feed box.

Answer: d

[Synthesis 1]

(6 points out of 10) A company is using a lathe, model CA6 140× 1500, which has been used for two years. The original price of this lathe is 60000 yuan. At present, the performance of the new lathe of the same model has not changed, but the market price has dropped to 45,000 yuan. The appraiser believes that the visible wear degree of the lathe is 20% through the on-site appraisal of the wear degree and accuracy of the main parts of the lathe.

Question:

(1) What are the first and second main parameters of this lathe? What is the difference?

(2) What are the main parts of the lathe? What are the main sports?

(3) What kind of invisible wear does the lathe have? What is the degree of invisible wear? What is the comprehensive wear degree?

Answer:

(1) The first main parameter is 40, indicating that the rotating diameter of the workpiece is 400 mm.

The second main parameter is 1500, indicating that the length of the workpiece is1500mm;

(2) Lathe is mainly composed of spindle box, feed box, slide box, tool rest, tailstock, polished rod, lead screw and lathe bed.

The headstock, also known as the headstock, is equipped with a spindle and a spindle speed change mechanism. Its main task is to make the spindle achieve the required forward and reverse speed through a series of speed change mechanisms. The feed box, also known as the feed box, is fixed on the left front side of the lathe bed, and is set to adapt to different processing situations, reasonably select the feed amount or specify the pitch. The lead screw and polished rod are installed at the front side of the lathe bed and connected with the feed box and the carriage box, and the motion and power of the feed box are transmitted to the carriage box, so that the carriage box can obtain longitudinal linear motion. In fact, the carriage box is the control box of lathe feed movement, which is equipped with a mechanism to convert the rotary motion of lead screw and polished rod into the linear motion of tool rest. The vertical feed motion, horizontal feed motion and rapid motion of the tool rest are realized by polished rod transmission, and the turning tool on the tool rest is driven by the lead screw to make vertical linear motion to turn threads. The tool rest is used to clamp the turning tool and make it feed longitudinally, transversely or obliquely. When machining a slender workpiece, a center is installed in the tailstock to support one end of the workpiece. If the tool tip is removed and tools such as drill bit are installed, drilling, reaming and tapping can be realized on the lathe. The lathe bed is installed on the left and right legs of the lathe to support three boxes (spindle box, feed box and slide box), two bars (polished rod and lead screw) and two racks (tool rest and tailstock) on the lathe.

Main motion: the rotating motion of the workpiece with the spindle.

Section 3 Drilling Machine and Boring Machine

Common hole processing methods include drill drilling, reamer reaming, reamer reaming and boring with boring tool.

First, the drilling machine

1, definition:

Drilling machine is mainly a machine tool for machining holes in workpieces with drill bits. Usually, the rotary motion of the drill bit is the main motion, and the axial motion of the drill bit is the feed motion. Drilling, reaming, reaming, tapping, countersinking and countersinking can be carried out on the drilling machine.

Figure 4- 14 Main Work of Drilling Rig

There are many kinds of drilling machines. According to different structures and uses, there are commonly used table drilling machines, vertical drilling machines and radial drilling machines.

They * * * are characterized by the fixed workpiece, the rotary feed of the cutter along the spindle direction, and the operation can be manual or electric.

The drilling accuRacy can reach IT 12, and the surface roughness ra can reach12.5μ m. ..

The main parameter of drilling machine is drilling diameter.

(1) table drilling machine

Small drilling machine with drilling diameter ≤ 13mm.

The change of spindle speed is realized by changing the position of V-belt on the tower pulley.

(2) Vertical drilling machine

1, component:

It consists of a spindle, a gearbox, an upright post, a workbench and a base. The transmission of the spindle gearbox and the feed box is driven by a motor through a pulley, and the spindle rotates through the spindle gearbox.

2, sports characteristics:

The spindle rotates in the spindle sleeve, and at the same time, the spindle sleeve is driven to do linear motion through the feed box, so that the spindle rotates and automatically feeds with the spindle sleeve in the axial direction according to the selected feed amount. The feed box and workbench can be adjusted up and down along the guide rail on the column to adapt to the processing of workpieces with different heights. The spindle of vertical drilling machine cannot move in the plane perpendicular to its axis. When drilling, the workpiece must be moved so that the drill bit coincides with the center of the workpiece hole. Therefore, the vertical drilling machine is only suitable for machining small and medium-sized workpieces.

(3) radial drilling machine

1, sports characteristics: the rocker arm drill has a rocker arm that can rotate 360 around the upright post, and the headstock is installed on the upright post, and the headstock can also move along the horizontal guide rail of the rocker arm. Therefore, the spindle can be adjusted to any position within the machining range of the machine tool. Workpieces are usually installed on a workbench for processing. If the workpiece is large, it can also be directly placed on the base for processing. According to the height of the workpiece, the rocker arm can move up and down along the column to adjust the machining position.

2. Scope of application: suitable for processing large porous workpieces.

Second, boring machine

Motion description:

The boring cutter is installed on the spindle or flat turntable; The workpiece is fixed on the workbench and can move longitudinally or transversely with the workbench.

The rotation of boring tool is the main movement, and the movement of boring tool or workpiece is the feeding movement. Mainly used for machining large holes, parallel holes and concentric holes.

Scope of work:.

The boring machine can not only bore holes, but also mill planes, grooves, drills, reams, turning ends, excircles, internal and external annular grooves and turning threads.

Figure 4- 18 Main work that can be completed by horizontal boring machine

Classification:

Boring machine is the main equipment for processing large box parts. According to different structures and uses, boring machines can be divided into six types: deep hole boring machines, coordinate boring machines, vertical boring machines, horizontal boring machines, diamond boring machines and boring machines for repairing automobiles and tractors.

(1) horizontal boring machine

1, component:

Ordinary horizontal boring machine consists of spindle, turntable, workbench, spindle box, front column, lathe bed, rear column and tailstock.

2. Motion description:

When machining, the tool is installed on the spindle or rotary table, and various speeds and feeds are obtained by the spindle box. The headstock can move up and down along the guide rail on the column.

The workpiece is installed on the workbench, and can move longitudinally or transversely with the workbench along with the lower slide seat or the upper slide seat, and can rotate to a required angle around the circular guide rail below the workbench together with the workbench to process holes or planes with a certain angle. Because there are many moving parts in the boring machine, in order to ensure working reliability and machining accuracy, each moving part is equipped with a clamping mechanism.

3. Scope of work:

Mainly processing holes, especially many large holes, concentric holes and parallel holes on box parts.

4. Features:

The boring method can ensure the dimensional accuracy and position accuracy of these holes, the boring accuracy can reach IT7, and the surface roughness Ra value is 1.6 micron ~ 0.8 micron. ..

5. Main parameters:

The main parameter of horizontal boring machine is spindle diameter.

(2) Coordinate boring machine

Coordinate boring machine is a high-precision machine tool.

1, structural features:

1) Precision measuring devices with coordinate positions, such as precision reticle, grating ruler, laser interferometer positioning measuring device, etc.

2) The machine tool itself has high manufacturing precision;

3) It shall be assembled and used at constant temperature.

2. Scope of work:

Coordinate boring machine is mainly used for boring precision holes. In addition, it can also be used for drilling, reaming, reaming, scraping end face, slotting, fine milling plane, precision marking of scale and template, etc. It can also be used as measuring equipment to check the coordinate dimensions of workpieces processed by other machine tools.

3. Classification:

Coordinate boring machines are divided into single-column coordinate boring machines, double-column coordinate boring machines and horizontal coordinate boring machines according to the overall layout.

The spindle of single-column coordinate boring machine and double-column coordinate boring machine is placed vertically, and the spindle of horizontal coordinate boring machine is placed horizontally.

1) Single-column coordinate boring machine consists of lathe bed, column, headstock, workbench and slide seat.

2) The double-column coordinate boring machine consists of a lathe bed, a workbench, a cross beam, a spindle box, left and right columns and a top beam.

3) The horizontal coordinate boring machine consists of a lathe bed, a workbench, an upright post and a headstock.

4. Features

(1) has good structural rigidity and can drill and bore precise holes on solid workpieces;

(2) high spindle speed and small feed;

(3) There are vertical and horizontal moving tables, whose fine adjustment can reach 1 micron ... and there is an accurate coordinate measuring system, which is suitable for processing holes with small hole spacing error.

(3) Diamond drilling machine

1, function:

It processes with small feed and high cutting speed. The dimensional accuracy is IT6, and the surface roughness Ra can reach 0.2 micron. ..

2. Main parameters:

The main parameter of horizontal diamond boring machine is workbench width, and the main parameter of vertical diamond boring machine is boring diameter.