Design of An Automated Vegetable Cutter and Slicer: Guide S Ganyani
Design of An Automated Vegetable Cutter and Slicer: Guide S Ganyani
Guide S Ganyani
University of Zimbabwe
Department of Mechanical Engineering
Post Office Box MP167
Mount Pleasant Harare
Zimbabwe
gsganyani@gmail.com
Tawanda Mushiri
University of Zimbabwe
Department of Mechanical Engineering
P.O Box MP167,
Mt Pleasant, Harare
Zimbabwe
tawanda.mushiri@gmail.com
Abstract
Manual cutting and slicing of vegetables has proved to be very time consuming and is prone to the risk of
contamination of the food leading to high rates of foodborne diseases. Various methods have been implemented
in the process of size reduction of vegetables ranging from manual, electric and automated. The desire to make a
design that simplifies, that saves time, that is relatively cheaper and efficienct during the process of size reduction
of vegetables was the main scope of the whole project. The contaminant free products will be produced through
the use of U.V light and this machine will incorporate U.V light as its integral component. The principle of
operation of the machine is attached to the theory of rotating hollow discs. Experiments were conducted at the
Department Laboratory and a force of 19.5N was obtained for the hardest vegetable. The machines available in
Zimbabwe have posed to be very expensive while they are only availed abroad. The machine must always be used
with caution since it has rotating elements. In conclusion, the objectives were met and the most importantly the
cost was in the desired range hence acceptable to the market. From the cost analysis, the total price required for
the vegetable cutter and slicer is $890.73.
Keywords
Vegetable cutter and slicer, UV-light, Zimbabwe, Low cost
1 Introduction
Vegetables are defined as an herbaceous plant or a part of a plant that is eaten whole or in part (Welbaum, 2015).
Over the years, world vegetable production has increased. For example, there was over four times increase in
world vegetable production from 1970 until 2009 (FAO, 2011). The increase has largely been as a result of a
prolonged technological advancement. On a large scale, vegetables are produced to suit the supermarkets and
some food industries for example those which do canning. The major problem arises on reducing the size of the
vegetable for it to be easily consumed by the customer. Cutting and slicing have prevailed for over a long period
of time and several methods have been used to carry out the special tasks. Traditional methods made use of knives
and other machines devised for those purposes. These methods have posed to be tiresome and great time-
consuming tasks especially in our busy lives.
46
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
Throughout the industrial era revolution, automated machines have gradually become a vital component of human
life daily. Compared to their manual counterparts, automated machines have continuously saved most of the
people’s time to carry out a certain task and this enhancement has greatly led to a more and more competitive and
faster way of doing things. In the late 90’s, automation was the main focal point of design (Tony, et al., 2014), the
engineering field tremendously worked night and day to bring about significant improvements to modern
automated products (Talapatra, 2013). Kitchen equipment is being a necessity to commercial kitchen areas these
days. Modern kitchen equipment is in a great need in the worldwide market because of their absolute efficiency,
durability and they are very reliable (Naveen, 2016).
1.1 Background
The existing vegetable cutters and slicers have been designed based on different criterion. The technology of
slicing and cutting of vegetables has dated since long back at around the 1970s (Jiang, 2013) . Traditional methods
of cutting and slicing vegetables have been used since long back, people cut and or slice their vegetables using
knives. This method is regarded the cheapest one as it does not require sophisticated mechanisms to carry out.
Complications arises when evaluating the accidents associated with this method, people tend to accidentally cut
themselves whilst trying to make suitable cuts and slices. The structure of the slicer can be split into either
horizontal or vertical depending on the shaft and the bearing orientation (Zhou, 2003). Typical cuts such as the
brunoise, macedoine etc. require highly skilled personnel to carry and if not, one is most likely to injure himself.
Due to these complications this has led to reduction in productivity e.g. within a food industry and more money
will be required to train the required labour. The major disadvantage of the method comes due to great time
consumption.
2 Preliminary review
Vegetables include, carrots, rape vegetables, tomatoes, cabbage, potatoes, cauliflower and others, they take part
in the contribution of water amount in the body as well as several vitamins and some minerals which assist to
maintain body weight and a healthy skin. (FAO, 2013). They can also be referred to as fresh components of plants
which, either if raw, cooked, canned or processed in some other way, give adequate human nutrition.
2.1 Cutting
As referred to the context of the project, cutting refers to the removal of something from something larger by
using a sharp object such as a knife and blade. The final product is the exact required shape of the vegetable even
with the dimensions attained to almost perfection, for example a brunoise cut measures exactly 1/8’ x1/8’ x1/8’.
This clearly implies that a cut is derived from a slice, the thickness of the slice will determine also the thickness
of the cut. One of the most relevant factors during the cutting operation is the type of cutting tool used (Jiang, et
al., 2011). Implying that the sharpness of the blades or the knife can affect the storage life of the vegetables. Blunt
knives tend to harm the tissue layers of the vegetable (Allende & Gill, 2012).
47
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
2.2 Slicing
Slicing is the cutting of food into thin, relatively broad slices, reducing the size of the vegetable into smaller and
thin pieces of the original vegetable, the process is usually carried out by the use of knives or blades and the shape
of the slice is simple as compared to that of a cut. The main difference between a cut and a slice as referred to the
context of this project is that a cut is the required shape of the vegetable while a slice is simply a thin dividend of
the original vegetable
Table 1. showing some standard cuts and slices.
TYPE DESCRIPTION
Julienne: • An average Julienne is (4 x 4) mm x 5cm
Chiffondale: • is a cut that is mostly used on green and leafy vegetables and herbs, however the
definition is not formal because there seem to be no definite size of the cut
48
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
The fundamental equations for determining the hoop and radial stresses within the disc are 1 and 2.
ρω 2 R 2R 2
σ r =(3 + υ ) [( R12 + R2 2 − 1 2 2 ) − r 2 ].............................. (1)
8 r
ρω 2
R 2R 2
σ H = (3 + υ ) [( R12 + R2 2 + 1 2 2 ) − (1 + 3υ )r 2 ]................. (2)
8 r
The principle of operation for the machine lies within the concept of rotating discs, the disc will be attached a
blade which will be carrying out the slicing operations, the rotation of the disc will provide the slicing and
action and the dicer below the slicer will be producing the required cuts. The feeding system comprises of the
conveyor feed, hopper. The conveyor has a variable speed to match the required demand at different times. The
feed vegetables are placed on the conveyor belt which leads them to the hopper arrangement, the hopper leads
the vegetables to the disc housing were the disc is fixed and the dicer underneath it. If only slicing is required
the dicer will be removed and if required both of them are coupled together. The hopper contains some rails
sideways which allows it to be easily opened for changing of the dicers and discs. An ejector plate is also part of
the disc housing which then forces the cut vegetables out and them not to accumulate inside the housing. The
ejector plate leads the products through to the delivery conveyor belt which carries the products out of the
system. From the top of the frame is a very important platform for UV light which projects a beam of light
directed towards the conveyor containing the cut or sliced vegetables. The final products are obtained at the
delivery platform and the products are assumed to be partly clean and safe from pathogens.
49
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
2009) U.V light projection on food stuff is entirely a non-thermal, does not constitute of chemicals and is cost
effective. Moreover, after its operation it does not produce any by-products therefore it’s a clean and smart way
of securing your products (Tatiana, et al., 2010).
In the electromagnetic spectrum there are three regions of ultraviolet light which are present which are UV-C with
a wave length of (200–280) nm, UV-A with a wave length of (315–400) nm and UV-B of wavelength (280–315)
nm and. Of the three regions the UV-C contains the properties needed for killing pathogens (Tatiana, et al., 2010).
According to study, the disinfection of the substance occurs when the UV-C penetrates the outer membranes of
the pathogen’s cells thereby causing damage of its DNA. The dimers formed by the later operation therefore
prevents the continuously production of more pathogens leading to death of their cells. Generally, the use of UV
technology has proved not to cause any alterations on its products using (Krishnamuthy, 2006)
3.1 Automation
Using Siemens, the automation process will be used to control and select the suitable speed range for cutting the
different types of vegetables, control the movement of all moving parts such as the conveyor belts and to connect
the sequence linking the components that make up the machine.
50
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
The values obtained for the maximum hoop and radial stresses were precisely as:
Graphs below indicate the scattered experimental data for the experiments
Using the values obtained for the maximum hoop and radial stresses, the motor which drives the cutting and
slicing assembly was rated at 1.9kW.
slicer
dicer
Figure 3. a) the whole machine assembly b) machine assembly without the frame c) UV light arrangement, disc
and dicer.
51
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
etc.). Moreover, the Implemented U.V platform ensures safe products for immediate consumption without any
harm both to the user and the food. Use was made of locally available materials to construct the design to success
thus a great margin was achieved in terms of costs. However, the actual performance of the machine is only visible
when it is brought to operation after manufacture and allowed to perform its tasks as according to the design.
Force meter reading = 14.5N. Perpendicular distance = 20cm, the results obtained showed that a force of 14.5N
was needed to just slice a carrot into two pieces
=Data : v 0.55
= m / s, mass flowrate 3000kg / hr
l = 1, 9m
Type of conveyor used : belt conveyor
massflowrate × lenth of belt (l )
The mass m =
linear velocity of belt
3000
but mass flowrate
= = 0.83kg / s
3600
0.83 × 1.9
=m = 5.26kg , adding the mass of the rollers and conveyor belt
0.3
mass of rollers and belt = ≤ 10kg
assu min g that µT = 1
mass (m)= 5.26 + 10= 15.26kg
Fµ = µT × g × m
=1× 9.81× 15.26 = 150 N
Fµ × v
Power ( P ) =
η
Assu min g that η = 0.8
150 × 0.55
Power
= ( P ) = 103.25W
0.8
The power to drive the conveyor belt is thus 104W
This is the power that must be sup plied by the motor
52
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
r2 − r1
sin α
= = x 0.67
x
r2 − r1 0.7 − 0.04 0.7 − 0.04
=sin α = = , α sin −1
0.67 0.67 0.67
N1 D1 = 2.57°
D2 =
N2 θ 180° − 2α =, 180° − 2(2.53°) = 175°
=
13(188)= 175 π
= = 90mm = 3.05rads
28 , 180°
L = π ( r1 + r2 ) + 2 x +
( r1 − r2 )
x
53
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
= (T1 − T2 )(v)
Pshaft
13π (0.55)
105
= (T1 − T2 )
60
105
= (T1 − T2 )(0.37)
105
(T1 =
− T2 ) , (T1 =
− T2 ) 280 N
0.37
4.2 Finite Element Analysis: von Misses Stress analysis for the components.
Analysis using the von Mises is a method that is utilised by design engineers to confirm if their design will
withstand a prescribed load condition without failure. For desirable results, the von Mises stress for the material
component should be less or equal to the design stress of the that component. For desirable results the bellow
relation must be met.
1.3×108
Assuming a factor of safety 1.68, 𝜎𝜎𝑑𝑑 = = 3.69 × 108
1.68
54
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
2.088×108
Assuming a factor of safety 1.68, 𝜎𝜎𝑑𝑑 = = 1.24 × 108 = 1.263 × 107 ≤ 1.24 × 108 therefore, the design
1.68
2.088×108
is safe (13MPa≤124MPa). In this case assuming a factor of safety of 1.68, 𝜎𝜎𝑑𝑑 = = 1.24 × 108
1.68
2.088×108
In this case assuming a factor of safety of 10 𝜎𝜎𝑑𝑑 = = 2.088 × 107 6.531 × 106 ≤ 2.088 × 107
10
55
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
4.4 Shear Force Diagram (SFD) AND Bending Moment Diagram (BMD)
4.4.1 Shear Force Diagram (SFD) AND Bending Moment Diagram (BMD) for the roller
Figure 7. Shear Force Diagram (SFD) AND Bending Moment Diagram (BMD) for the roller
56
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
• Never open the disc housing if the disc and ejector plate have not come to a complete halt
• Do not touch the sharp edges of the slicing blade and dicing grid
57
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
• Scheduled services must be carried out using standard task procedures in order to avoid any injuries and
fatalities.
• the disc replacements must be done only when every part is stationery (lock out system),
• the U.V radiation lamps should be carefully handled and before any process is carried out it must be
ensured that they are off.
• The vegetables must be fed only when they have been reduced of their cross-sectional area
• The speed of the disc should match only with the required type of vegetable to be sliced.
• The disc and the dicer should be kept at an enclosed space free from people
• For effective output by the U.V light the machine must operate while the door is closed.
5.6 Conclusion
Designing of the automated vegetable cutter and slicer was successfully implemented within the required budget
of USD1000, the machine can do several cuts and slice sizes depending on the consumer requirement (macedoine,
julienne, etc). Moreover, the Implemented U.V platform ensures safe products for immediate consumption
without any harm both to the user and the food. Use was made of locally available materials to construct the
design to success thus a great margin was achieved in terms of costs. However, the actual reveals of the machine
are only visible when it is brought to operation after manufacture and allowed to perform its tasks as according to
the design.
6 References
Allende, A. & Gill, M., 2012. Minimal processing.Decontamination of fresh and minimally processed produce,.
58
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
Jiang, A., Tian, M. & Qi, H. P., 2011. Effect of mechanical demage on the potatoes's nutrients,.
Jiang, X., 2013. Design and Research on Household Food Slicer. Advance Journal of Food Science and
Technology, Volume 2, p. 1296.
Krishnamuthy, K., 2006. Decontamination of milk and water by pulsed UV light and infrared heating. PhD Thesis.
Pennylvania State University.
Naveen, J., 2016. DESIGN AND FABRICATION OF LOW COST MULTIPURPOSE KITCHEN EQUIPMENT.
Pereira, N., Vicente, A. & Montenegro, J., 2009. Environmental Impact of novel thermal and non-thermal
technologies in food processing. Journal of Food Research, 1(8), p. 15.
Ruan, R., Chen, P. & Montentenegro, J., 2002. Inactivation of E-coli0157:H7 using a pulsed non-thermal plasma
system. Journal of food science.
Srinivasarao, Bandla, Choughary & Ruplal, 2012. Ultraviolet Pasteuriisation for Food Industry. International
Journal of Food and Nutrition Engineering, 2(5), p. 13.
Talapatra, S., 2013. Implementation of Product Design Tools for the Development of an Automated Vegetable
Chopper. Journal of scientic research, p. 1.
Tatiana, et al., 2010. UV Light For Fruits and Fruit Products, Guelf Food Research Centre: Guelph ON NIG 5C9.
Tony, T., Bravo, M. & Sibling, G., 2014. DESIGN AND DEVELOPMENT OF AUTOMATED VEGETABLE
CUTTING. Journal of Food Science, Volume 2, pp. 8-10.
Warriner, K., Movehedi, S. & Waites, W. M., 2004. Laser Based Packaging Sterilisation in Aseptic Processing
In Improving the Thermal Proessing. Cambridge: Woodhead Publishing Limited.
Welbaum, G., 2015. Vegetable History, Nomenclature, and Classification. In: Vegetable Production and
Practices, pp. 1-2.
Zhou, Y., 2003. The Design of Vertical Pineapple Slicer machine and design.
Biographies
Mr Guide Simbarashe Ganyani is a male born in Chivhu at Nharira Hospital, conducted his primary education
at Daramombe Mission, Lwendulu primary school, Chikomba primary school and completed at Trojan primary
school in 2008. He carried out his secondary education at Chipadze High School and completed it at Chipindura
High School in 2014. Currently he is enrolled at the University of Zimbabwe studying for a bachelor of science
honors degree in Mechanical engineering and was once attached to Bindura Nickel Corporation were, he gained
most of the industrial tactics in terms of engineering research and design. His interest lies in Solid Mechanics and
machine design were with the help of Dr T Mushiri he has managed to gain more knowledge from the competent
Solid Mechanics lecturer. Guide looks forward to be part of a design environment and part of a team which aspire
to bring a change to the world through Solid Mechanics.
Dr Tawanda Mushiri received his Bachelor of Science Honors Degree in Mechanical Engineering (2004-2008)
and a Masters in Manufacturing Systems and Operations Management (MSc. MSOM) (2011-2012) from the
University of Zimbabwe, Harare, and a Ph.D. from the University of Johannesburg, South Africa (2013-2017).
He also obtained a Certificate with Siemens in Programmable Logic Controllers in the year 2013 where he worked
with SCADA and PLC Programming. His doctorate involved fuzzy logic and automated machinery monitoring
and control. Currently, he is a Senior Lecturer and Senior Research Associate at the University of Zimbabwe and
University of Johannesburg, respectively. In the past (2012-2013), he has also lectured at the Chinhoyi University
59
Proceedings of the International Conference on Industrial Engineering and Operations Management
Pilsen, Czech Republic, July 23-26, 2019
of Technology, Zimbabwe, lecturing mechatronics courses. He has also been an assistant lecturer for
undergraduate
60