Unit FourUnit Four

Passage Two

Machining Centers

Learning Targets

• To understand the whole passage

• To know how to express types of machining centers and parts of the CNC Machining Center in English

• Step A: Lead in • Step B: Passage Understanding• Step C: Structural Analyzing • Step D: Assignment

Teaching Procedures

Do you know?

1.What are the types of machining centers?

2. What are the parts of CNC Machining Center ?

You can find the answer after fast reading.

Passage Understanding

Passage Understanding

Types of machining centers

卧式加工中心

horizontal spindle type

Passage Understanding

立式加工中心

Types of machining centers

vertical spindle type

Passage Understanding

Parts of the CNC Machining Center

bed

saddle

column

table

床身

溜板

立柱

工作台

Passage Understanding

servo system

spindle

tool changers

MCU

Parts of the CNC Machining Center

伺服系统

主轴

刀具交换装置

机床控制单元

Passage Understanding托盘

梭子

滑鞍

导轨

参数

pallet

shuttle

saddle

bedway

specification

Sentences StructureThe vertical spindle machining center is a saddle-type construction with sliding bedways which utilizes a sliding vertical head instead of a spindle movement.主句的表语后面有较长的后置定语，在翻译时把 with sliding bedways 转换成前置定语，而把定语从句作为一个单句来处理。

立式加工中心是一种带有滑动床身导轨的溜板型结构，它是利用垂直方向的床头的滑动来代替主轴的移动。

Sentences StructureThe bed is usually made of high-quality cast iron which provides a rigid machine capability of performing heavy-duty machining and maintaining high precision.

这一句比较长，在翻译时应转化为两个短句。定语从句中 ,provides 的宾语是 capability 。床身通常由优质铸铁制成 ,铸铁为刚性机床提供了执行重载加工任务和保持高精度加工的能力。

Sentences StructureThe servo system, which consists of servo drive motors, ball screws, and position feedback encoders, provides fast, accurate movement and positioning of the XYZ axis slides.主语： the servo system 谓语： provides

定语从句： which consists of servo drive motors, ball screws, and position feedback encoders伺服系统包括伺服电机、滚珠丝杠和位置反馈编码器，它提供快速而准确的 XYZ 轴的移动和定位。

Sentences StructureTool changers are usually bidirectional, which allows for the shortest travel distance to randomly access a tool.

which 指代的是前面整个句子。做这种用法时， which 可以替换成 as.

刀具交换装置通常是双向的，这样就允许以最短的路径任意地存取刀具。

Structural Analyzing

Part one: para1- 4

Part two: para 5- 13

Part three: para 14

Types of machining centers

Parts of the CNC machining center

Machine axes

ExercisesPut the following into Chinese and Put the following into Chinese and recite them.recite them.NC: numerical control

NC machine tools

计算机数控CNC: computerized numerical control

数字控制

MCU: machine control unit

机床控制单元

数控机床

ExercisesPut the following into Chinese and Put the following into Chinese and recite them.recite them.

a DC motor

incremental positioning

步进电机a stepper motor

直流电机

absolute positioning 绝对定位

相对定位

ExercisesTry to identify the subject, predicate, object Try to identify the subject, predicate, object and attribute of the following sentences and to and attribute of the following sentences and to underline them separately.underline them separately.

1. The bed is usually made of high-quality cast iron which provides a rigid machine capability of performing heavy-duty machining and machining high precision.

The bed is usually made of high-quality cast iron which provides a rigid machine capability of performing heavy-duty machining and machining high precision.

ExercisesTry to identify the subject, predicate, object Try to identify the subject, predicate, object and attribute of the following sentences and to and attribute of the following sentences and to underline them separately.underline them separately.

2. New MCUs are becoming more sophisticated, making machine tools more reliable and the entire machining operations less dependent on human skills.

New MCUs are becoming more sophisticated, making machine tools more reliable and the entire machining operations less dependent on human skills.

AssignmentAnswer the following questions Answer the following questions according to the text.according to the text.

1. What are the types of machining centers?

2. What are the parts of CNC Machining Center?

3. What is the five-axis machining center?