Transcript The Development of a New Course in Nontraditional Machining Kuen-Ming Shu* and Shan-ying Pan** *National Formosa University, Huwei, Yunlin, Taiwan, R.O.C ** National Tsing Hua.

The Development of a New Course
in Nontraditional Machining
Kuen-Ming Shu* and Shan-ying Pan**
*National Formosa University, Huwei, Yunlin, Taiwan, R.O.C
**
National Tsing Hua University, Hsinchu, Taiwan, R.O.C
Introduction
• Nontraditional machining course was initiated in
the MMED at NFU in Taiwan in 1998.
• 2 credits with a 2hrs lecture per week.
• It is developed to offer students with a
knowledge-oriented nontraditional machining
technology.
• To increase the student’s learning experience,
it is necessary that learning process should
involve more than the usual learning by doing
approach.
• In order to bridge the gap between theory
and practice, we establish this new course
called “Nontraditional machining technology
and practice”.
Nontraditional machining
• Nontraditional machining is a group of processes
involving mechanical, thermal, electrical or
chemical energy (or combinations of these
energies).
• They do not use a sharp cutting tool in the
conventional sense.
LECTURE COURSE
• There are literally dozens of nontraditional
machining processes, most of which are
unique in their range of applications.
• The nontraditional processes are often
classified according to principal form of
energy used to effect material removal.
Four types of nontraditional machining
Type
Process
Symbol
Mechanical
Water-jet machining
Abrasive-jet machining
Ultrasonic machining
WJM
AJM
USM
Electrical
Electrical chemical machining
Electron beam machining
ECM
EBM
Thermal
Electrical discharge machining
Laser beam machining
Plasma arc machining
Ion beam machining
EDM
LBM
PAM
I BM
Chemical
Chemical machining
CHM
Problems with traditional instruction
• Students didn't learn skills
• Students are not given the opportunity to
•
pursue new knowledge in the service of
achieving intrinsically motivating goals.
The knowledge or skills is divorced from real
life
New course description
• We developed a practice-based course for
teaching and learning.
• It has 1 hr lecture and two hrs of
workshop experiments per week for 18
weeks.
The chose practice courses
LBM
EDM
CHM
Practice
course
USM
ECM
AJM
EDM processes
1.
2.
3.
4.
Electrode fabrication
Set EDM parameters
EDM
Surface polishing
Guide rod and Engraving cutting tool grinding
3D engraving
The products of 3D engraving
Electrical discharge machining
（EDM）
• Remove metal by a series
of discrete electrical
discharges (sparks) that
cause localized
temperatures high
enough to melt or
vaporize the metal in the
immediate vicinity of the
discharge.
The products of EDM
Electrochemical machining
（ECM）
• Remove or plate metal
from an electrically
conductive workpiece by
anodic dissolution or
cathode reduction, in
which the shape of the
workpiece is obtained.
The products of ECM
Ultrasonic machining
• A tool vibrating at low
amplitude and high
frequency to weld
material, or abrasives
contained in a slurry are
driven by tool at high
velocity against the
work.
The products of USM
Abrasive jet machining
•
A material removal process
that results from the action
of a high-velocity stream of
gas containing small
abrasive particles.
The products of AJM
Laser beam machining
• The source of energy is a
laser, which focuses optical
energy on the surface of the
workpiece. The highly
focused, high-density
energy melts and evaporates
portions of the workpiece in
a controlled manner.
The products of LBM
Work sheet
N0.
Term
Processes
2D AJM
1 .Prepare a plate mirror.
2. Paste a layer of tape as maskant.
3. Engrave a pattern on tape.
4. Tear off the unnecessary tape.AJM the mirror that isn’t protected by tape.
3D AJM
1. Prepare a glass or ceramic bottle.
2. Paste a layer of tape as maskant.
3. Engrave a pattern on tape.
4. Tear off the unnecessary tape.
5. AJM the mirror that isn’t protected by tape.
3
3D pattern
1. Prepare a piece of wood plate or acrylics plate.
2. Get a half pattern with draft.
3. Stick the plate and the pattern.
4
Guide rod grinding
5
Engraving cutting tool
grinding
1
2
6
3D engraving
1. Get a Φ6mm high speed steel rod
2. Grind this rod by grinding machine into ball end.
1. Get a Φ6mm high speed steel rod.
2. Grind this rod by grinding machine into cutting edge.
1. Get a soap and fix on engraving machining.
2. Set guide rod, engraving cutting tool, and 3D pattern.
3. Engrave a replica on soap.
Worksheet
N0.
7
8
9
10
11
12
(Cont.)
Term
Processes
EDM graphite electrode
1. Get a used AAA battery and draw graphite central rod out.
2. Engrave the end of graphite central rod.
EDM
1. Get a piece of steel plate and fix it on EDM machine.
2. Set the graphite electrode and progress EDM.
LBM
1. Get a piece of wood or acrylic and fix on laser machine.
2. Use CoreDraw 9 software to create a design on personal computer.
3. Control the laser machine to engrave this design on wood or acrylic surface.
ECM
1. Prepare a Cu tube as cathode, a steel block as anode, and NaCl solution as electrolyte bath.
2. The electrolyte bath flows rapidly between the two poles to carry off the dissolution material and form
a concave hole.
USM
1. Get two pieces of plastic plate.
2. Set the parameters of USM.
3. Progress ultrasonic welding.
CHM
1. Get a photo resist coated circuit board.
2. Draw a design on transparency as mask
3. Expose on exposure unit.
4. Develop resist.
5. Etch in etching tank.
Instruction methods
• For the first week, all the equipments to
perform the experiments were introduced.
• The following weeks, the students were
asked to prepare materials, design projects,
implement projects, and evaluate and
demonstrate their products in teams.
Evaluate and demonstrate products
in teams
Evaluation sheet
Evaluate results
•
84 students (i.e. 70%) were
very satisfied after took this
course, while 34students (i.e.
28%) were satisfying.
90
84
80
70
• Only 1 student choice the
“Average” or “unsatisfying”
item respectively.
60
50
Persons
40
34
30
•
It seems that almost all
students enjoy this new
developed course.
20
10
0
1
Very
satisfying
Satisfying
Average
1
Unsatisfying
0
Very
unsatisfying
The intention of students to take similar course
• It is shown that 111
students (i.e. 93%)
are very interested in
this new developed
course and claimed
that they would take
the similar course if
they were provided
120
111
100
80
Persons
60
40
20
0
Take
6
3
It depends
No more take
Conclusions
• In order to promote traditional instructing methods, we
•
•
•
have developed of a new course on nontraditional
machining.
Both contents of lecture and practice are demonstrated
in this new course.
The worksheet for practice experiments and evaluate
questionnaire sheet were also developed.
The new course was developed successfully.
END
Thanks for your attention