課程名稱︰製造原理
課程性質︰機械系選修
課程教師︰潘永寧 廖運炫 楊申語
開課學院：工學院
開課系所︰機械系
考試日期（年月日）︰96/12/14
考試時限（分鐘）：2hr
是否需發放獎勵金：Y
（如未明確表示，則不予發放）
試題 :
1. State the approach to improve the surface finish in cutting, and explain
why your approach can achieve the desired purpose. (14%)
2. (a) In determining the appropriate cutting conditions, suppose the depth
of cut has been determined based on the machine tool's cutting stability
already. Explain the reason why in determining the rest cutting conditions
(i.e. cutting speed and feed) we would like to fix the appropriate feed
first, and finally the cutting speed. (8%)
(b) Please give a pratical example of the application of the analysis of
economics of cutting operation besides determining appropriate cutting
conditions. (4%)
3. (a) State the reason why we can obtain a very close tolerance and a very
good surface finish of the machined part when the abrasive machining is
applied. (6%)
(b) In cutting and grinding the same material, the specific cutting energy
in grinding is larger, equal to, or smaller than that of the conventional
cutting? Explain as much as you can all the possible reasons why this
happens. (12%)
4. In grinding operation
(a) Taking the abscissa (x-axis) as the grade of the grinding wheel, and
the ordinate (y-axis) as grinding ratio, and explain why they have the
relationship shown in your plot. (6%)
material removal rate
(老師補充 Grinding ratio G = -----------------------)
wheel wear rate
(b) It is found that the wheel wears unexpectedly fast. Without changing the
wheel, how can we improve this condition, and explain the reason why your
proposal will work. (7%)
(c) What will we expected for the dimentional accuracy and surface roughness
of the ground workpiece in applying creep feed grinding. Give the reason(s)
to support your answers. (7%)
5. A two teeth end milling cutter is used in a milling operation. The spindle
speed (rotation speed) is 1200rpm. Suppose that the machine tool-workpiece
system can be represented by a one-degree-of-freedom system:
mx"+cx'+kx=f(t).
(a) What will be the frequency contains in the vibration signal? (4%)
(b) If there is self-excited vibration (i.e. chatter), thenwhat will be the
chatter frequency? (4%)
6. (a) Explain what is regenerative chatter. (4%)
(b) Explain the reason why the machine tool system becomes more stable in
the lower cutting speed range. (5%)
(c) Discuss the effect of feed on cutting stability.(4%)
(d) In cutting materials of the same composition but with different
hardness, What will happen to the b when a harder material is cut as
lim
compared with that when a lower hardness material is cut (i.e. it is
unchanged, becomes larger, or becomes smaller?), Why? (3%)
7. State as complete as possible the approaches to suppress mechine tool
chatter in cutting. (12%)
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.112.5.73