问题 问答题 简答题

电火花线切割加工有何特点?最适合加工何种模具?

答案

参考答案:

(1)不需要制造复杂的成形电极;

(2)工件材料被蚀除的量很少,这不仅有助于提高加工速度,而且加工下来的材料还可以再利用;

(3)能够方便地加工各种复杂的精密零件,包括各种微槽和窄缝;

(4)由于采用移动的细长电极丝进行加工,使单位长度电极丝的丝径损耗较小,因而丝径损耗对一般中小模具加工影响不大,有助于电火花线切割加工精度控制在±0.01mm以内;

(5)电火花线切割一般采用精规准一次加工成形,在加工过程中大都不需要转换加工规准。最适合加工冷冲模(以及缝,通孔)

阅读理解

Can you remember the first time you learned to ride a bike or drive a car?Learning these skills changed your life forever and opened up new horizons(视野).Learning about computers can be like learning how to ride a bike or drive a car.Once you have invested the time to master the skills,you will never go back to the old days.The new technology is simply too convenient and too powerful.

Technological developments through the years have enabled us to do more with less effort.We have continuously looked for better ways of doing things.Each invention and new development has allowed us to extend our capabilities.Today we see one of the most dramatic technologies ever developed—the computer.It extends the capabilities of our minds.

Computers have saved organizations millions of dollars. Furthermore,these same computer systems have opened up new opportunities that would have gone undiscovered or neglected.The computer may multiply what we can do,and the return on investment is high.The growth of computer usage is surprising. On the other hand,the computer can do serious damage.Invasion of privacy(侵犯隐私),fraud(欺诈),and computer-related mistakes are just a few shocking examples.The computer is like a double-edged sword.It has the ability to cut us free from some activities,but it can also cut deep into profits,personal privacy,and our society in general.How it is used is not a function of technology.It is strictly a function of how people decide to use or misuse this new technology.The choice is yours,and only through a knowledge of computer systems will you be able to avoid the dangers while enjoying the many,many benefits of the computer age.

小题1:The writer thinks learning about computers is like learning how to ride a bike or drive a car because ______.

A.it is simple and practical

B.it needs a lot of practice

C.it leads people to new life experiences

D.it takes much time to master the skills小题2:According to the passage,computers bring people the following benefits except ______.

A.avoiding mistakes

B.saving money

C.making money

D.opening up opportunities小题3:According to the writer,the bad effects of computers can be avoided if we ______.

A.have some knowledge of computer systems

B.tell people not to misuse computers

C.have strict rules over the use of computers

D.make more investments in the technology小题4:This passage is probably written for ______.

A.computers

B.computer producers

C.computer learners

D.computer programmers

单项选择题