design of a small-scale palm fruit processing plant_group 12_2b
TRANSCRIPT
ENGINEERING DESIGN DESIGN OF A SMALL-SCALE PALM FRUIT PROCESSING PLANT (MAJOR PROJECT 2B) -GROUP 12
YIJIE CHEN, JIACHENG FENG, ABDULRASHID WAKIL, AYMAN SIDDIQUE
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Contents List of Tables ......................................................................................................................................................... 3
List of Figures ........................................................................................................................................................ 3
1. INTRODUCTION/PROBLEM DEFINITION ...................................................................................................... 4
1.1 Data Collection/Survey ....................................................................................................................... 4
1.2 Plant Operation Procedure ........................................................................................................................ 5
2. NEEDS METRICS ............................................................................................................................................ 6
2.1 Needs Table ......................................................................................................................................... 6
2.2 Metrics Table ....................................................................................................................................... 7
3. HOUSE OF QUALITY ...................................................................................................................................... 8
4. CONCEPT DESIGN ......................................................................................................................................... 9
4.1 Concept Presentation .......................................................................................................................... 9
4.1.1 Concept 1 ............................................................................................................................................. 9
4.1.2 Concept 2 ........................................................................................................................................... 11
4.1.3 Concept 3 ........................................................................................................................................... 12
4.1.4 Concept 4 ........................................................................................................................................... 13
4.2 Concept Scoring ................................................................................................................................. 14
4.3 Concept Selection .............................................................................................................................. 15
5. EMBODIMENT DESIGN ............................................................................................................................... 16
5.1 Embodiment Design .......................................................................................................................... 16
5.2 Embodiment Design Calculations ..................................................................................................... 18
5.2.1 Calculations for Thresher .............................................................................................................. 18
5.2.2 Calculations for Digester/Steriliser ................................................................................................... 18
5.2.4 Calculation for Oil Presser................................................................................................................. 20
6. FINAL DESIGN ............................................................................................................................................. 23
6.1 Final Design Description .................................................................................................................... 23
6.2 Components ............................................................................................................................................. 24
6.2.1. Thresher/Stripper ............................................................................................................................ 24
6.2.2 B Digester/Steriliser .......................................................................................................................... 25
6.2.3 Presser ............................................................................................................................................... 26
7. CONCLUSION .............................................................................................................................................. 26
8. REFERENCES ................................................................................................................................................ 27
9. APPENDIX ................................................................................................................................................... 28
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List of Tables Table 1: Palm oil features survey .............................................................................................................. 4
Table 2: Palm oil purchases survey ............................................................................................................ 4
Table 3: Table of Needs ............................................................................................................................ 6
Table 4: Table of Metrics .......................................................................................................................... 7
Table 5: Parameters required for oil pressing machine ............................................................................ 20
List of Figures Figure 1: Needs-Metrics Matrix ................................................................................................................. 7
Figure 2: House of Quality diagram for small-scale palm oil processing ...................................................... 8
Figure 3: Concept Scoring Matrix ............................................................................................................ 14
Figure 4: Concept Selection Matrix.......................................................................................................... 15
Figure 5: Embodiment design for small-scale palm fruit processing plant ................................................. 16
Figure 6: Front view of plant ................................................................................................................... 17
Figure 7: Side view of plant ..................................................................................................................... 17
Figure 8: Final detailed design of plant .................................................................................................... 23
Figure 9: Thresher assembly features ...................................................................................................... 24
Figure 10: Digester/Steriliser assembly features ...................................................................................... 25
Figure 11: Screw Presser assembly features ............................................................................................ 26
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1. INTRODUCTION/PROBLEM DEFINITION The objective is to design a small-scale palm fruit processor suitable for small-hold farming communities
in rural areas. With the current rise in global demand for palm oil, it is necessary to create avenues in
which the production of palm oil can be done at a smaller scale in order to provide access to the desired
product where demand is most high.
1.1 Data Collection/Survey
The survey above (Table 1) was done to gauge customer satisfaction with competing oil producers in
African, Caribbean, and Pacific (ACP) countries supported by the Technical Centre for Agricultural and
Rural Cooperation ACPEU (CTA). 60 customers were questioned regarding the colour, taste, clarity, and
their satisfaction with the overall quality of the palm oil they purchase from competing producers in the
region. This survey shows that 50% of the customers believe the quality does not justify the price they
pay. This means there is room for a producer of either better quality, or similar quality at a lower price.
The production of which would be done in lower income areas as justified by Table 2.
Table 2: Palm oil purchases survey
Table 1: Palm oil features survey
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It is clear that the regular demand for the product is vastly higher in lower income areas. This is
apparent because the production of palm oil in such areas provides sustenance and jobs for farmers and
their respective communities.
1.2 Plant Operation Procedure
The procedure of the palm operating plant is shown below in Figure 1 [2]:
Figure 1: Palm oil processing stages
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2. NEEDS METRICS
2.1 Needs Table
Table 3 provides a list of assumed customer needs based on the literature review. There are 14 relevant
needs listed with their comparative importance ranging from 1-5, 1 being the most important. It can be
seen that the needs listed s most important are as such because of the relation to the problem
definition as well as design constraints, with the addition of safety.
No. Needs Importance
1 Easy to use 4
2 Accommodate maximum palm fruit input 2
3 Separates nut/fiber from mesocarp 1
4 Extracts oil from mesocarp quickly 3
5 Uses by product for fueling 5
6 Separates kernel and red palm oil 1
7 Easy to maintain 4
8 Affordable operation techniques low power/manual 2
9 Crude palm oil, palm kernels & husk output 1
10 Safety 1
11 Affordability 2
12 Reduced flow time 4
13 Fits in dimensional constraint 1
14 Reliable (for at least multiple seasons) 3
Table 3: Table of Needs
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2.2 Metrics Table
No. Needs Metrics Importance Units
1 2,5,9,10 mass of bunch (20kg) 1 kg
2 1,2,7,13 frame size (max 1.5*1*1m) 2 m
3 3,5,7 heat of sterilizer 3 J
4 3,5,12 stripping/threshing speed 1 kg/hr
5 4,12 rate of extraction 3 kg/hr
6 9 density of palm fruit mesocarp & endocarp 4 kg/m^3
7 5,6,13 storage tanks(kernel/oil) capacity 1 mm
8 4 diameter of threaded shaft in screw press 3 mm
9 12 speed of conveyor belt 4 m/s
10 2,9,12 number of input palm fruits 1 /hr
11 8,11,14 cost 2 gbp
12 14 Life time 2 year
Table 4: Table of Metrics
After compiling the needs of the customers Table 4 was developed to relate the metrics with relevant needs
of the customers. The same scale is used for importance, and the units are provided. It can be observed that
the measured factors with the most relevant needs are directly related to the assumptions and design
constraints of the processing plant. Figure 1 shows the developed Needs-Metrics Matrix.
Figure 2: Needs-Metrics Matrix
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3. HOUSE OF QUALITY The following house of quality diagram has been compiled using the needs and metrics discussed in the
previous sections, and shown in Figure 2:
Figure 3: House of Quality diagram for small-scale palm oil processing
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4. CONCEPT DESIGN
4.1 Concept Presentation
4.1.1 Concept 1 Concept 1 Processing Principles:
Sterilization: Igniting previously discarded empty fruit bunches to weaken pulp structure by
essentially cooking the fruit bunch in heated water. The steam generated will have an outlet to
prevent increase in oil oxidation.
Threshing: This is done by a rotating drum to serve also as a digester using the water absorbed
from sterilization to aid in destroying the exocarp and breaking down the mesocarp structure.
Extraction: By use of a manually powered horizontal screw press. This separates the crude palm
oil from the cake.
Clarification: Passing crude palm oil through a screen into the tank and allowed to settle for a
couple of hours, where by the droplets float to the surface as the density is less than that of
water, while remaining solid particles fall to the bottom of the tank under water.
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Concept 1 Embodiment:
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4.1.2 Concept 2 Concept 2:
Concept 2 Embodiment with principles:
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4.1.3 Concept 3 Concept 3 Processing Principles:
Sterilization: Fruit bunch is heated by steam
Threshing: Rotates fruit bunches like a centrifugal machine.
Digestion: separate heat process and kernel removing process
Oil pressing: By use of screw oil expeller
Oil clarification: Involves precipitation
Concept 3 Embodiment:
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4.1.4 Concept 4 Concept 4 Processing Principles:
Threshing + Sterilization
Rotating drum made of steel pillars.
Spikelet’s are removed and thrown out through the gaps by centrifugal force.
Using steam to sterilize the palms.
Palms exit the system at the bottom of the drum.
Digestion + Separation
Use steam to digest the palms.
Top plate pressuring on the palms by manual operation.
Size of screw holes is much lower than the size of the kernel.
Remaining kernels are removed and collected through the side exit by pushing the side plate.
Concept 4 Embodiment:
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4.2 Concept Scoring In this section, the 4 individual concepts are compared to the overall combination of functioning components
listed in the UN report compiled by Kwasi Poku (FAO consultant).
Selection Criteria Concept
1
Concept
2
Concept
3
Concept
4
Reference
Ease of use + + + + 0
Maintainability - - - - 0
Cost - - - + 0
Safety + + + + 0
Power Consumption 0 0 - - 0
Must provide adequate temperatures for sterilization + + + + 0
Entire palm fruit bunch must be threshed - + + + 0
Minimal friction when manually rotating screw press handle + + + 0 0
Adequate separation of palm kernel and red palm oil + + - + 0
Sufficient clearance for palm kernel and fibres + + + + 0
Should meet the allocated dimensional constraints + + + + 0
Sustainability + - - + 0
Combination of required processing functions + + + + 0
Should have a manual option 0 0 0 0 0
Easy to assemble - - - - 0
Prevention of leaks + + + + 0
Sum '+'s 10 10 9 11 0
Sum '-'s 4 3 6 3 0
Sum '0's 2 2 1 2 0
Net Score 6 7 3 8 0
Rank 3 2 4 1 0
Continue? No Yes No Yes
Figure 4: Concept Scoring Matrix
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4.3 Concept Selection
In order to proceed with a detailed embodiment design, the two concepts ranked highest are again
compared in a concept scoring matrix to decide on which concept would be the best to move forward
with.
Selection Criteria Weight (%)
Concepts
No.2 Reference No.4
Rating Score Rating Score Rating Score
Manual Option 10% 2 0.5 3 0.6 4 0.65
Minimal friction when rotating screw press
10% 4 0.35 3 0.25 2 0.2
Does not exceed dimensional constraint 20% 5 0.6 3 0.2 5 0.6
Maximum fruit bunch input 15% 3 0.6 3 0.6 3 0.6
Combination of processing functions 20% 5 0.2 3 0.15 5 0.2
Easy to assemble 15% 1 0.15 3 0.4 1 0.15
Prevention of leaks 10% 5 0.6 3 0.15 4 0.55
Total Score 3 2.35 2.95
Rank 1 3 2 Figure 5: Concept Selection Matrix
It can be observed that the even though Concept 2 is barely ranked highest, it was decided that a
combination of the two concepts would be beneficial in developing the most efficient processing plant.
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5. EMBODIMENT DESIGN
5.1 Embodiment Design
Following the concept evaluation in the section, 4.3 Concept Selection, the following embodiment
design is presented in Fig 5.1, where key design components, or processes are highlighted:
Figure 6: Embodiment design for small-scale palm fruit processing plant
Thresher/
Stripper Boiler
Screw
Press
(not
visible)
Digester
Oil Filter
Bunch Entry
Trap Door
Motor with
Pulley
Rotary
motor
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Figure 7: Front view of plant
Figure 8: Side view of plant
Figures 6 and 7 show that all the sections of the plant fall within the specified design constraints.
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5.2 Embodiment Design Calculations
5.2.1 Calculations for Thresher
Based on research of previous strippers, the beater shaft can keep stripping efficiency at 60% and
average stripping time at 35s with 250 RPM(N).
𝑡ℎ𝑟𝑜𝑢𝑔ℎ𝑜𝑢𝑡 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 =𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑞𝑢𝑎𝑟𝑡𝑒𝑟𝑒𝑑 𝑏𝑢𝑛𝑐ℎ
𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑠𝑡𝑟𝑖𝑝𝑝𝑖𝑛𝑔 𝑡𝑖𝑚𝑒= 0.15𝑘𝑔/𝑠
𝑡𝑜𝑡𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑟𝑖𝑝𝑝𝑒𝑑 𝑓𝑟𝑢𝑖𝑡𝑠 = 𝑠𝑡𝑟𝑖𝑝𝑝𝑖𝑛𝑔 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 × 𝑡𝑜𝑡𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑓𝑟𝑢𝑖𝑡𝑠 = 2.7𝑘𝑔/𝑚𝑖𝑛
The fruit outlet is equal to oil expeller processing speed, so it is acceptable.
Torque requirement to drive beater shaft with 100mm beater length :
𝑇 = 𝐹 × 𝐿 = 20𝑁𝑀
Power requirement of the machine:
𝑃 =2𝜋𝑁𝑇
60= 0.6𝑊
5.2.2 Calculations for Digester/Steriliser
Palm parameters:
Palm fruit size: 3x3x5 cm, number of palms=1000
Digester parameters:
Diameter of the chamber=455mm, height of the chamber=350mm,
Diameter of the shaft=24mm, pulley on the shaft=50mm,
Witch of the hammer (angle iron) =19x 19mm, thickness of the hammer (angle iron) =3mm,
Length of the hammer (angle iron) =210mm, number of hammers mounted on shaft=7
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Volume for 1000 palms,𝑉𝑝 = 30 × 30 × 50 × 1000 = 4.5 × 107𝑚𝑚3
Volume of the chamber,𝑉𝑐 = (𝐷
2)
2𝜋ℎ
𝑉𝑐 = (455
2)2𝜋 × 350 = 5.688 × 107𝑚𝑚3
Total volume of 7 hammers,𝑉ℎ = 2(𝑊 + 𝑡)𝐿
𝑉ℎ = 2 × (19 × 3) × 210 × 7 = 0.0168 × 107𝑚𝑚3
Since,𝑉𝑐 > 𝑉𝑝 + 𝑉ℎ
The size of the digester can meet the requirement of 1000 input palms.
Centrifugal force developed in the system, 𝐹𝐶 = 𝑀𝜔2𝑟1
Where, 𝑀 is the inertia mass of the hammer before attaching to the shaft (kg), 𝜔 is the angular velocity
of the shaft (rad/s), 𝑟1 is the radius of the shaft (m).
𝜔 =2𝜋𝑁2
60
Where, 𝑁2 is the rotating speed of the shaft (rpm), by doing the research, the optimal rotating speed for
a digester is approximately 620rpm.
And, 𝑀 = 𝜌𝑉ℎ = 7.3 × 103 × 0.000168 = 1.223𝑘𝑔
Therefore, 𝐹𝑐 = 1.223 × (620×2𝜋
60)2 × 0.012 = 61.87𝑁
Torque on the pulley on the shaft, 𝜏 = 𝐹𝑐 × 𝑟2
Where, 𝑟2 is the radius of the pulley on the shaft (m).
𝜏 = 61.87 × 0.05 = 3.0935𝑁𝑚
Power requirement of the machine, 𝑃 = 𝜏𝜔
𝑃 = 3.0935 ×620 × 2𝜋
60= 200.85𝑊
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5.2.4 Calculation for Oil Presser
Parameters Value
Shear strength (0.58 tensile yield strength) 119MPa
Motor torque (RPM 1420; POWER 3KW) 20.2Nm
Pulley ratio 2
Designed RPM 30
Density of palm (𝛒) 659kg/m3
Require pressure for pressing(P) 17mpa
Coefficient of friction(f) 0.56
Shaft diameter(d) 45-55mm
Outer radius of thread(ro) 40mm
Thread depth 12-18mm
Thread pitch 38-50mm
Thread angle at bearing angle(θ) 0.262rad
Mean pitch(L) 44mm
Mean depth(h) 15mm
Table 5: Parameters required for oil pressing machine
Torque requirement
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Angle of thread at mean radius:
𝛼 = atan (𝐿
2𝜋𝑟𝑚) = 0.176
Angle between tangent to tooth profile and a radial line
𝜃𝑛 = 𝑡𝑎𝑛𝜃 × 𝑐𝑜𝑠𝛼 = 0.26
Thread constant
𝑅𝑐 =𝑡𝑎𝑛𝛼 +
𝑓𝑐𝑜𝑠𝜃𝑛
1 − 𝑓𝑡𝑎𝑛𝛼𝑐𝑜𝑠𝜃𝑛
𝑟𝑚 = 28.74
Axial force on all thread is P * mean pitch * mean thread depth * thread turns[1]:
𝐹𝑋 = 𝑃 × 𝐿 × ℎ × 9 = 101KN
Torque required to drive skew shaft is[2]:
𝑇𝑆 = 𝐹𝑋 × 𝑅𝐶 = 2900𝑁𝑀
Gear ratio between screw shaft and drive is 5, so torque on drive shaft is 580NM.
Since the required torque on drive shaft is 31 times of motor torque, a gearbox would be required
between them.
Calculation for justification of torsion in shaft
Critical length of skew shaft is 168 mm
Critical length of drive shaft is 618 mm
Shear stress caused by torsion:
𝜏 =𝑇𝑟
𝐿
Where torque as above results, in skew shaft is 2900NM, and in drive shaft is 580NM.
Meanwhile, since the yield strength in stainless steel 304 or 316 is 205MPa[3], so shear strength is
119MPa.
Therefore, required diameter for skew shaft and drive shaft would be 38mm and 22m respectively.
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Justification of barrier thickness
Thin wall condition
Hoop stress is:
𝜎ℎ =𝑃𝑟
𝑡
The hoop stress should lower than yield strength 205MPa, and pressure is 17MPa [4], so minimum
thickness would be 1.8mm
Processing speed:
�̇� = 𝑣𝑜𝑙𝑢𝑚𝑒 × 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 × 𝑠𝑝𝑒𝑒𝑑 = 2.7𝑘𝑔/𝑚𝑖𝑛
𝑤ℎ𝑒𝑟𝑒, 𝑣𝑜𝑙𝑢𝑚𝑒 = 0.25𝜋(𝑑𝑜2 − 𝑑2)𝐿
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6. FINAL DESIGN
6.1 Final Design Description
Following the embodiment design adjustments, the final design is presented in Fig 6.1.
As observed in Figure 8, the final detailed design is essentially the same as the embodiment design,
except for the fact that an additional pulley and motor combination is used for the digester. This is done
to reduce the speed of the digester beating arms.
Figure 9: Final detailed design of plant
Pulley system added
in conjunction with
motor
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6.2 Components
6.2.1. Thresher/Stripper
Figure 10: Thresher assembly features
The threshing system has a slotted sliding door panel to allow the entire bunch to be threshed at once. The
spiked shaft enhances the speed and accuracy at which the palm fruit spikelets are detached, hence leaving
only palm fruits to fall through the spacing of the cage bars. The spiked shaft is attached to a motor-driven
pulley. The detached fruits fall onto the conveyor belt, and are subsequently transported to the
digester/steriliser system.
Sliding
door panel
Spiked
Shaft
Rotating
Thresher
Cage
Detached fruit
outlet
Bunch inlet
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6.2.2 B Digester/Steriliser
The layout for the digester/steriliser combination is shown below:
The threshed fruit enters the digester/steriliser system via the slot opening shown in Fig. The fruit is
sterilised by the steam provided by the boiler, and met by beating arms, attached to a motor-driven
shaft. The resulting fruit pulp is the then transported to the next pressing stage of the plant operation.
Rotary
beater arms
Outlet
feeding
fruit pulp
into oil
presser
Slot opening
for conveyor
belt entry
Rotary shaft
attached to
motor-driven
pulley
Threshed
fruit inlet
Steam from
boiler
Figure 11: Digester/Steriliser assembly features
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6.2.3 Presser
The fruit pulp seeps down through the opening of the presser case, where it is met with the screw press
head. The screw press is essentially a shaft which increases in diameter with length, and threaded using
various pitches. It is connected to a gear system, that enables the system to be driven automatically using a
motor, or manually using a handle. The layout for the presser is given in Figure 10, below.
It must be noted that the force generated by the presser head is not sufficient to break the palm kernel,
and hence the possible contamination of the red palm oil by kernel oil is avoided. The palm kernels are
later separated from the oil cake.
7. CONCLUSION
The designed small-scale plant therefore is able to take the input of palm fruit bunches and produces an
output of the palm husk, palm kernel and palm oil.
The final design could be further improved by introducing mesh screens at various points during the
plant process. However, such adjustments would not bode well with the design constraints, and would
be quite expensive. As the majority of the material used in the plant is steel, fabrication of the plant
would be relatively straight forward. Due to the increased toughness and heat resistivity of the steel, the
plant would be able to undergo operation cycles for several seasons.
Palm
kernel
pushed
out with
oil cake
oi
Figure 12: Screw Presser assembly features
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8. REFERENCES
i) Axtell B, Fellows P. Setting up and running a small-scale cooking oil business. CTA; 2012.
ii) Fao.org. 3. PALM OIL PROCESSING [Internet]. 2015 [cited 2nd December 2015]. Available
from: http://www.fao.org/docrep/005/Y4355E/y4355e04.htm#TopOfPage
iii) Camus G, Guillaumat L, Baste S. Development of damage in a 2D woven C/SiC composite
under mechanical loading: I. Mechanical characterization. Compos Sci Technol
1996;56:1363–72.
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9. APPENDIX
Gantt Chart
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Minutes and Agendas
Meeting Chair Secretary Minutes Agenda
1 rashid feng 45 Meet the group members and discuss about the basic of the
design topic
2 feng chen 30 Decide the jobs for each group members
3 chen feng 90 Discussion on the individual Needs and Metrics from each
members
4 feng ayman 60 Develop the Group Needs and Metrics
5 ayman rashid 120 Discussion on the individual Embodiment design from each
members
6 feng rashid 120 Develop the Group Embodiment design
7 chen ayman 60 Discussion on the Calculations
8 feng chen 150 Discuss the adjustment made on the CAD
9 ayman chen 180 Preparation of the presentation
10 rashid ayman 180 Finishing the Final report
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CAD Drawings
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