英文翻译 Introduction of Machining

山

东

轻

工

业

学

院

中英文翻译

院系名称

机械工程学院

学生姓名

席福洋

专业班级

机械设计制造及其自动化

05-3

班

指导教师

宫涛

二○○九

年

五

月

十

日

Introduction of Machining

Have a shape as a processing method, all machining process for the production

of

the

most

commonly

used

and

most

important

method.

Machining

process

is

a

process generated shape, in this process, Drivers device on the workpiece material to

be in the form of chip removal. Although in some occasions, the workpiece under no

circumstances, the use of mobile equipment to the processing, however, the majority

of

the

machining

is

not

only

supporting

the

workpiece

also

supporting

tools

and

equipment to complete.

Machining

know

the

process

has

two

aspects.

Small

group

of

low-cost

production.

For

casting,

forging

and

machining

pressure,

every

production

of

a

specific shape of the workpiece, even a spare part, almost have to spend the high cost

of processing. Welding to rely on the shape of the structure, to a large extent, depend

on

effective

in

the

form

of

raw

materials.

In

general,

through

the

use

of

expensive

equipment and without special processing conditions, can be almost any type of raw

materials,

mechanical

processing

to

convert

the

raw

materials

processed

into

the

arbitrary shape of the structure, as long as the external dimensions large enough, it is

possible. Because of a production of spare parts, even when the parts and structure of

the

production

batch

sizes

are

suitable

for

the

original

casting,

Forging

or

pressure

processing to produce, but usually prefer machining.

Strict

precision

and

good

surface

finish,

machining

the

second

purpose

is

the

establishment of the high precision and surface finish possible on the basis of. Many

parts, if any other means of production belonging to the large-scale production, Well

Machining

is

a

low-tolerance

and

can

meet

the

requirements

of

small

batch

production. Besides, many parts on the production and processing of coarse process to

improve its general shape of the surface.

It is only necessary precision and chooses

only the surface machining. For instance, thread, in addition to mechanical processing,

almost no other processing method for processing. Another example is the blacksmith

pieces keyhole processing, as well as training to be conducted immediately after the

mechanical completion of the processing.

Primary Cutting Parameters

Cutting

the

work

piece

and

tool

based

on

the

basic

relationship

between

the

following four elements to fully describe: the tool geometry, cutting speed, feed rate,

depth and penetration of a cutting tool.

Cutting Tools must be of a suitable material to manufacture, it must be strong,

tough,

hard

and

wear-resistant.

Tool

geometry

--

to

the

tip

plane

and

cutter

angle

characteristics -- for each cutting process must be correct.

Cutting

speed

is

the

cutting

edge

of

work

piece

surface

rate;

it

is

inches

per

minute to show. In order to effectively processing, and cutting speed must adapt to the

level of specific parts -- with knives. Generally, the more hard work piece material,

the lower the rate.

Progressive Tool to speed is cut into the work piece speed. If the work piece or

tool

for

rotating

movement,

feed

rate

per

round

over

the

number

of

inches

to

the

measurement. When the work piece or tool for reciprocating movement and feed rate

on each trip through the measurement of inches. Generally, in other conditions, feed

rate and cutting speed is inversely proportional to

。

Depth of penetration of a cutting tool -- to inches dollars -- is the tool to the work

piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting

chip thickness. Rough than finishing, deeper penetration of a cutting tool depth.

Wears of Cutting Tool

We already have been processed and the rattle of the countless cracks edge tool,

we learn that tool wear are basically three forms: flank wear, the former flank wear

and V-Notch wear. Flank wear occurred in both the main blade occurred vice blade.

On

the

main

blade,

shoulder

removed

because

most

metal

chip

mandate,

which

resulted in an increase cutting force and cutting temperature increase, If not allowed

to

check,

That

could

lead

to

the

work

piece

and

the

tool

vibration

and

provide

for

efficient cutting conditions may no longer exist. Vice-bladed on, it is determined work

piece

dimensions

and

surface

finish.

Flank

wear

size

of

the

possible

failure

of

the

product and surface finish are also inferior. In most actual cutting conditions, as the

principal in the former first deputy flank before flank wear, wear arrival enough, Tool

will be effective; the results are made unqualified parts.

As Tool stress on the surface uneven, chip and flank before sliding contact zone

between stresses, in sliding contact the start of the largest and in contact with the tail

of zero, so abrasive wear in the region occurred. This is because the card cutting edge

than

the

nearby

settlements

near

the

more

serious

wear

and

bladed

chip

due

to

the

vicinity of the former flank and lost contact wears lighter. This results from a certain

distance from

the cutting edge of the surface formed before the knife point Ma pit,

which

is

usually

considered

before

wear.

Under

normal

circumstances,

this

is

wear

cross-sectional shape of an arc. In many instances and for the actual cutting conditions,

the

former

flank

wear

compared

to

flank

wear

light,

Therefore

flank

wear

more

generally as a tool failure of scale signs. But because many authors have said in the

cutting

speed

of

the

increase,

Mateo

surface

temperature

than

the

knife

surface

temperatures

have

risen

faster.

But

because

any

form

of

wear

rate

is

essentially

temperature changes by the significant impact. Therefore, the former usually wear in

high-speed cutting happen.

The main tool flank wear the tail is not processed with the work piece surface in

contact, Therefore flank wear than wear along with the ends more visible, which is the

most common. This is because the local effect, which is as rough on the surface has

hardened layer, this effect is by cutting in front of the hardening of the work piece.

Not

just

cutting,

and

as

oxidation

skin,

the

blade

local

high

temperature

will

also

cause

this

effect.

This

partial

wear

normally

referred

to

as

pit

sexual

wear,

but

occasionally it is very serious. Despite the emergence of the pits on the Cutting Tool

nature

is

not

meaningful

impact,

but

often

pits

gradually

become

darker

If

cutting

continued the case, then there cutter fracture crisis.

If any form of sexual allowed to wear, eventually wear rate increase obviously

will be a tool to destroy failure destruction, that will no longer tool for cutting, cause

the work piece scrapped, it is good, can cause serious damage machine. For various

carbide cutting tools and for the various types of wear, in the event of a serious lapse,

on the tool that has reached the end of the life cycle. But for various high-speed steel

cutting

tools

and

wear

belonging

to

the

non-uniformity

of

wear,

has

been

found

:

When the wear and even to allow for a serious lapse, the most meaningful is that the

tool can re-mill use, of course, In practice, cutting the time to use than the short time

lapse. Several phenomena are one tool serious lapse began features: the most common

is the sudden increase cutting force, appeared on the work piece burning ring patterns

and an increase in noise.

The Effect of Changes in Cutting Parameters on Cutting Temperatures

In metal cutting operations heat is generated in the primary and secondary

deformation zones and this result in a complex temperature distribution throughout

the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can

be seen that, as could be expected, there is a very large temperature gradient

throughout the width of the chip as the workpiece material is sheared in primary

deformation and there is a further large temperature in the chip adjacent to the face as

the chip is sheared in secondary deformation. This leads to a maximum cutting

temperature a short distance up the face from the cutting edge and a small distance

into the chip.

Since virtually all the work done in metal cutting is converted into heat, it could

be expected that factors which increase the power consumed per unit volume of metal

removed will increase the cutting temperature. Thus an increase in the rake angle, all

other parameters remaining constant, will reduce the power per unit volume of metal

removed and cutting temperatures will reduce. When considering increase in

unreformed chip thickness and cutting speed the situation is more complies. An

increase in unreformed chip thickness and cutting speed the situation is more complex.

An increase in undeformed chip thickness tends to be a scale effect where the

amounts of heat which pass to the workpiece, the tool and chip remain in fixed

proportions and the changes in cutting temperature tend to be small. Increase in

cutting speed; however, reduce the amount of heat which passes into the workpiece

and this increase the temperature rise of the chip in primary deformation. Further, the

secondary deformation zone tends to be smaller and this has the effect of increasing

the temperatures in this zone. Other changes in cutting parameters have virtually no

effect on the power consumed per unit volume of metal removed and consequently

have virtually no effect on the power consumed per unit volume of metal removed

and consequently have virtually no effect on the cutting temperatures. Since it has

been shown that even small changes in cutting temperature have a significant effect

on tool wear rate, it is appropriate to indicate how cutting temperatures can be

assessed from cutting data.

The most direct and accurate method for measuring temperatures in

high-speed- steel cutting tools is that of Wright&Trent which also yields detailed

information on temperature distributions in high-speed-steel tools which relates

microstructural changes to thermal history.

Trent has described measurements of cutting temperatures and temperature

distributions for high- speed-steel tools when machining a wide range of workpiece

materials. This technique has been further developed by using scanning electron

microscopy to study fine-scale microstructural changes srising from over tempering of

the tempered martens tic matrix of various high-speed-steels. This technique has also

been used to study temperature distributions in both high-speed-steel single point

turning tools and twist drills.

Automatic Fixture Design

Assembly equipment used in the traditional synchronous fixture put parts of the

fixture mobile center, to ensure that components from transmission from the plane or

equipment

plate

placed

after

removal

has

been

scheduled

for

position.

However,

in

certain applications, mobile mandatory parts of the center line, it may cause parts or

equipment

damage.

When

parts

vulnerability

and

may

lead

to

a

small

vibration

abandoned, or when their location is by machine spindle or specific to die, Tolerance

again or when the request is a sophisticated, it would rather let the fixture to adapt to

the location of parts, and not the contrary. For these tasks, Elyria, Ohio, the company

has developed

Zaytran a general

non- functional

data synchronization West

category