Design and Fabrication of Ragi Ball Machine

Design and Fabrication of Ragi Ball Machine
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
Design and Fabrication of Ragi Ball Machine
Vinay V Kumar J 1, Shashidhar 2 , Suraindir Malhothra 3, Veeranagouda 4, T.Madhusudhan5
U.G. Student, Department of Mechanical Engineering, SJB Institute of Technology, Uttarahalli, Bangalore, India1,2,3,4
Professor and HOD, Department of Mechanical Engineering, SJB Institute of Technology, Uttarahalli,
Bangalore, India5
ABSTRACT: Finger millet, popularly known as ragi flour is an annual herbaceous plant widely grown as a cereal crop
in the arid and semiarid areas in Africa and Asia. Ragi Mudde or Ragi Sangati is a wholesome meal in the state of
Karnataka and the Rayalaseema region in Andhra Pradesh. In this project, a Ragi Mudde Machine is proposed, where
the finger millet and the water are boiled inside a stainless steel vessel using a burner and then the dough is made by
continuous stirring of the mixture by using stirrers and pusher plates. Thus obtained mixture is forced out automatically
through a pipe via pusher plates and then formed into round shape using a bowl powered manually.
KEYWORDS: Stainless steel vessel, Stirrers and Pusher Plates, Extrusion pipe, Rotating bowl, Sol-gel coating.
India is the leading producer of small millets namely, finger millet (ragi), kodo millet (kodo), foxtail millet (kangni)
and little millet (kutki). Annual planting area under them is around 2.5 million hectares and nearly 1.5 million hectares
is under finger millet comprising 40-50% of crops global area. Its annual production is maintained around 2.4 million
tonnes. The protein content in ragi is more or less equal to that of wheat, rice and maize. Finger millet contains the
lowest fat. It is relatively rich in iron and phosphorus. It has the highest calcium content among all the food grains.
The most common primary processing of finger millet is to convert the grain in the form of flour which is achieved by
pulverizing or milling. Some of machines for milling are conventional stone mills, burr mills, hammer mills, ball mills
etc. on demand of the recipe the coarser flour is separated by sieving the whole meal. Finer flour is preferred for
making chapathi (rotti), whereas coarser flour is suitable for mudde. Mudde is a typical preparation of Karnataka and
very often prepared using social functions. Coarser flour helps in making lumps during mudde preparation and that of
finer flour absorbs more water due to higher surface area and facilities flattering for chapathi making.
In recent years the consumption of finger millet along with other millets has been increased particularly in the urban
sector due to awareness about the inherent nutritional and medicinal properties of millets. Millet is gluten free and safe
to eat for those who experience gluten sensitivity.
Various materials are analyzed and the most suitable ones are selected. Several properties including corrosion
resistance, chemical inertness, hardness, ductility are considered.
Stainless steel is an alloy of iron containing at least 12 per cent chromium. Chromium combines with oxygen in the
surroundings to form an adherent chromium oxide film on the surface. This oxide film, also referred to as the passive
layer, offers resistance to corrosion and will spontaneously self-repair when damaged in air or water. So the corrosion
Copyright to IJIRSET
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
resistance is in the metal surface, and the stability of the passive layer is therefore decisive to the corrosion resistance of
the stainless steel.
Grade 316 is the standard molybdenum bearing grade, second in importance to 304 amongst the austenitic stainless
steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304[4], particularly higher
resistance to pitting and crevice corrosion in chloride environments. It has excellent forming and welding
characteristics. It is readily brake or roll formed into a variety of parts for applications in the industrial, architectural,
and transportation fields. Grade 316 also has outstanding welding characteristics. Post weld annealing is not required
when welding thin sections.
In this project, we have used this material as it is of corrosion resistance which makes safe for contact with the food
Sol-gel technology is a hybrid of organic and inorganic chemistry. Coatings produced using sol-gel technology are
more accurately described as ceramic-like; they feature many of the same characteristics as ceramic but to a lesser
extent. Compared to PTFE, sol-gel coatings are harder (9H pencil hardness), and can function at higher temperatures
(up to 450°C/840°F).
With sol-gel coatings, there is a specific time by which the activated and filtered coating should be applied to achieve
maximum effectiveness. The coatings are applied via conventional spray equipment. They are available in one- and
two-coat systems. Sol-gels must be applied only to preheated parts that maintain about 50-70°C/120-160°F throughout
the spraying process. If parts are not heated and kept at this temperature, the coating could sag, cause wetting defects or
dry spray. An IR thermometer can help check the pans to ensure proper temperature.
In this project, we have covered the stainless steel vessel, stirrers and the pusher plates with this coating to ensure that
dough is non-sticky to the surface of the vessel which reduces the resistance for mixing action.
 The supporting frame structure for the machine is fabricated using stainless steel 202.The SS bars are welded
according to the design plan.
 The metal parts that do not come in direct contact with the food particles are fabricated using MS, machined and
formed to the required shape. These parts include washers, plate to house the gearbox, coupling to connect the
gearbox to motor.
 The parts that come in contact with the food particles are fabricated using Stainless steel 316. These parts include
vessel, shaft, stirrers, pushers, and cap.
 The parts that cannot be welded are fastened using suitable fasteners.
 The parts which are required to be removed are fastened using bolts and nuts.
 The parts that come in direct contact with the food are coated with non-stick Sol-Gel coating.
 The parts are not painted to avoid food contamination. Also the outer visible parts that don't come in contact with the
food are buffed for aesthetic appeal.
 The gearbox and motor are mounted in such a way as to avoid leakage of oil.
 All the components are mounted in such a way as to distribute the weight evenly.
 Sufficient gap has been provided under the structure to house the gas burner.
Copyright to IJIRSET
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
 The cap has been provided on the side of the structure to easily access the dough.
 The design and fabrication is done keeping in mind the servicing and ergonomics aspect of the machine.
 The various parts, materials, and their details are included in the Bill of Materials.
Ragi consumption is increasing because of its high nutritional contents in the form of mudde, rotti and ambli. Ragi
mudde is the highest consumed ragi food in Karnataka and some parts of Andhra Pradesh. But preparation of mudde
involves lot of efforts since the ragi dough is very thick to stir. It is prepared manually by adding the finger millet to the
boiling water and again cooked for few minutes. Once the mixture of water and ragi flour is boiled, it is stirred well by
using a wooden stick continuously until all the lumps formed are totally broken and a thick uniform consistent dough is
obtained and is allowed to expand under low flame. Thus obtained dough is picked in smaller quantities and made into
round shapes by hand and served. Addition of salt and butter also reduces the formation of lumps and will result in
much softer and tasty ragi mudde. However, preparation of mudde in larger quantity manually is a tedious task as
large force is required for mixing by more number of people.
In this project, we have tried to reduce the effort in making mudde by designing and fabricating a machine that could
mix the water and flour to required consistency and force it out through a pipe and finally ball shape is made by
rotating the dough in a round vessel.
Stainless Steel Vessel
The vessel used here is made of stainless steel 316 of around 2mm thick. It is made by welding a sheet in
cylindrical form with a round sheet welded to it at the bottom. It helps to store the mixture of ragi flour and water
during the preparation. It also houses the stirrer blades and the pusher plates used for stirring the mixture inside it
connected by shaft at the centre of the vessel.
Support Structure
The support structure is made of stainless steel square bars of 202 type. It helps the vessel rest on it to accompany
the overall procedure. It also provides for accommodating motor, gear box along with batteries to run the machine.
Shaft with stirrers and pusher plates
The shaft and stirrer assembly is made of stainless steel 316 which rests on the vessel above a ball bearing. The
four stirrers are provided at an angle of 45 degrees to the centre and the 2 pusher plates are provided at an angle of
180 degrees to each other. The stirrers and the pusher plates helps in stirring the mixture inside the vessel to
required consistency and also helps in forcing out the dough out of the vessel.
Extrusion pipe
A Stainless steel pipe is being welded tangentially to the bottom surface of the vessel which is used to force the
mixture of it once it is ready. The pipe will be closed with stainless steel cap with a rubber flap to avoid leakage of
water and flour during the process using nut and bolt assembly.
Non-stick sol gel coating
Coating is provided on the inner surface of the vessel, stirrers, pusher plates and extrusion pipe to avoid the
mixture getting sticked to it and also for smooth rotation during mixing process. Its composition is PTFE and its
thickness is around 60 – 70 microns.
Copyright to IJIRSET
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
Motor with gear box
To run the shaft assembly for mixing, it is powered using a 0.5HP DC motor coupled with a gear box of 30:1 ratio
to obtain a speed of 100 rpm which is run by a 24 volts battery.
Fasteners are used to mount the vessel on the outer structure and also for resting the motor on the support structure
an assembly of steel rod is fastened to it.
Rotating bowl
A stainless steel bowl with an handle is being used to rotate the dough coming out from the extrusion pipe and form
it into round shape.
A detachable burner is provided at the bottom of the vessel to heat the mixture to the required temperature powered
by a gas cylinder.
Figure 1: 2D model of assembled parts of ragi ball machine
Copyright to IJIRSET
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
Water is added to the stainless steel vessel and boiled using a burner. Then 2-3 spoons of ragi flour is added to it in
order to obtain malt like mixture along with 2 cubes of salted butter and is allowed to boil again until it reaches the
brim of the vessel. Then ragi flour is added onto it and again allowed to boil for around 6 minutes. Then the stirrers are
powered which stirs and blends the mixture continuously until all the lumps break and the flame is lowered and the
mixture is allowed to expand. Once the consistent dough is obtained, the cap on the extrusion pipe is opened where the
dough starts coming out and is cut by a cutter provided at the end of the pipe. The dough is collected on a steel bowl
where it obtains round shape by continuous hand rotation of the bowl and finally ragi mudde will be ready to be served.
Figure 1: Isometric view of ragi ball machine
The above figure shows the isometric model of the machine designed using Catia. All the components were designed
individually and then assembled.
This equipment will help in reducing the effort to make mudde in large quantities. Mass producers of mudde like in
temples, hostels, restaurants can make good use of the machine. It also saves the time required to clean after cooking in
it due to the non-stick coating. Thus, it helps to produce healthy ragi mudde which is very soft, tasty and completely
free from lumps.
[1] Rafique A. Memon, Mahera E. Baloch, Anwer Solangi, Ahsanullah Baloch ,”Numerical Analysis of Rotating Mixing of Fluids in Container
Induced by Contra Rotating Stirrers”, International Journal of Modern Engineering Research (IJMER), pp-2754-2757 ISSN: 2249-6645, Vol. 3, Issue.
5, Sep - Oct. 2013
[2] Basil E. Okafor, “Design of Power Driven Dough Mixing Machine”, International Journal of Engineering and Technology, Volume 5 No. 2,
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[3] D. Rajavathsavai, A. Khapre and B. Munshi, “Study of mixing behavior of CSTR using CFD”, Brazilian Journal of Chemical Engineering, pp.
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[4] Saranya Ashokkumar, Jens Adler-Nissen Accoat A/S, Munkegardsvej, “Evaluating non-stick properties of different surface materials for contact
frying”, Journal of Food Engineering , pp. 537–544, 2011.
Copyright to IJIRSET
ISSN(Online) : 2319-8753
ISSN (Print) : 2347-6710
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 6, Issue 6, June 2017
[5] Rachel A. Caruso and Markus Antonietti, “Sol−Gel Nanocoating: An Approach to the Preparation of Structured Materials”, Max Planck
Institute of Colloids and Interfaces, D-14424 Potsdam, Germany, Chem. Mater., 2001, 13 (10), pp 3272–3282, DOI: 10.1021/cm001257z
[6] Shreekant, Dr. M. S. Aspalli, “Chopper based Speed Control of DC Motor using ATMEGA16 Microcontroller”, International Journal for
Scientific Research & Development,| Vol. 4, Issue 12, 2017
[7] Paul Kramer, Balagizi Karhagomba,” The form of the cooking vessel and the energetic efficiency of cooking”, Journal of Engineering Science
and Technology ,Vol. 4, No. 3, 2009.
[8] Jagruti R. Surange, Navneet K. Patil, Akhilesh V. Rajput, “Performance Analysis of Burners used in LPG Cooking Stove”, IJIRSET, Volume 3,
Special Issue 4, April 2014.
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