Development
is the dynamic process and it never stops. Country like Nepal, is in the transformation phase and the
construction works is bound to increase aggressively. And this requires a leap
in the performance of the construction materials in our country. Bricks are one
of the most used materials in construction today and they are going to be vital
during the restructuring and construction processes. And the production of
quality bricks will most certainly be the future demand.
The
way most of the Nepalese brick industries have been following to mold brick is
still traditional and they are still not able to mass produce the bricks as per
the requirements. Percentage of first class brick is always low due to
different problems in production. The
most of the brick industries Nepal use traditional methods of brick production
and there are only few mechanized brick producing facilities. The brick molding
process can be made more efficient by using brick molding model.
The
idea of fabricating the manually operated brick molding model which helps to
modernize the brick molding process, thus reducing the cost efficiency, time
consumption along with increase in the production of quality bricks in short
period of time. This idea can be much helpful to the workers as it reduces
their effort.
The
idea is to develop the model of low cost brick molding model for producing
quality bricks of standard size. It is an attempt to improve the production of
bricks for housing and general construction purpose.
Significance
The scopes are;
·
Uniform
product size and better finish of the bricks.
·
Resources
savings – Energy and Human Resources.
·
Reduction
in human effort and manual work
Limitations
There are few limitations. And
they are;
·
If
the conveyer belt and wooden frame is not cleaned frequently, clay might stick
stick in the conveyer belt and frame and cause jam in the pathway.
METHODOLOGY
Theoretical/ Conceptual Framework
The
model that is designed and fabricated is low cost brick molding model for
producing bricks. The model works on the principle of compound lever to
compress and mold the clay that is fed through a feeder.
Multiple
links form a mechanism that allows to do different works at the same time
harnessing the forces applied and movement. The engineering characteristics of
bricks depend upon the physical and chemical properties of the raw material and
the molding pressure that we provide. So it is focused to maintain the
calculated compressive force in order to produce standard bricks.
The
design of the model was optimized by making it simple and less labor intensive.
The design of each component of the model was optimized to reduce the weight of
the model. It is priority for the locally available resources and materials
while developing the model.
Study Design and Component Description
The
prototype that is being developed, works by compressing the raw material of
bricks with the help of compound lever and transport it by the help of
conveyor. It consists of different parts and components that include material
supplying box, molds, lever mechanisms and frames, sprockets, chains and
driving motor. The individual parts are briefly explained below with
figures.
Feeder
It is a box made of the sheet
metal and the main purpose of this box is to supply
or feed the mold with the clay required to make the brick. The box is in a
truncated pyramid shape and the main purpose of this is to supply the required materials.
Mold
The mold is designed to press and
produce three brick at a time. The dimension
of the mold is same as standard brick size (240 mm*115 mm*54 mm). The height of
the mold is accommodated to take account of the volume of loose un-compacted raw material and take into
account, the shrinkage so that the
product will meet the dimensional standards.
Compound lever
The compound lever is used to
alter the force as necessary so that the clay
can be pressed with adequate amount of force. When the lever is pushed down the conveyer belt transfers
clay toward mould. While we push the
lever upward the press moves downward and compress the clay to form brick.
Wooden Frames
The two wooden planks of height
slightly more than that of bricks and length
around one third of the conveyer belt
are used to make frames on the conveyer belt from the sides and acts as the
path for the material that are passed to conveyer belt and guide up to the
press. The width of the frame is 115
mm and the height also is more than the height of brick considering the compressibility of brick. The length is
accommodated considering the length of conveyer belt.
Unidirectional sprocket
A sprocket
or sprocket-wheel is a profiled wheel with teeth, cogs, or even sprockets that
mesh with a chain, track or other perforated or indented material. The name
'sprocket' applies generally to any wheel upon which radial projections engage
a chain passing over it. The sprockets used in our project are of unidirectional type, meaning that the motion is
constrained to one direction
only while the motion on another direction is not transmitted. This effectively
turns the vertical input force into a driving force for conveyor in forward
direction only.
Conveyer Belt
Conveyer belt is used to carry
the materials fed through the feeder up to the press.
Through the feeder the raw materials is passed and the conveyer belt carries this raw material up to the press
which presses the material to give the brick size. The conveyer belt as shown
in figure is designed to consist two idlers and rubber belt supported with a
mild steel plate. The width of conveyer
belt is same as the width of brick i.e. 110 mm with certain tolerance. The length of belt is approximately
2100 mm.
Calculations
The input force is primarily
required for two purposes, one is to compress the clay and next is to drive the
conveyor.
Here, x and y represent the
effort distances and load distances of the primary and secondary level
respectively.
The arrangement of lever is such that it
consists of 2 lever links, one of 1.3 meters and another of 0.8 meters the
fulcrum of which is adjusted such that the ratio of effort distance to load
distance is 1/4 in each and ideally the input force gets reduced 16 times.
Young's modulus for brick
moulding clay according to reference is 45kN/m2.
Taking cross section area of
brick and change in dimension per unit length into account,
i.e. A=230mm*110mm and change in
length=20mm,
we get force of 144 N. since the
input is reduced 16 times we get ideal input of about 9 N used for compression
of brick. And the remaining force is used for driving of the conveyer belt.
Amount of compression for a
standard brick is given in following table:
Table:
linear shrinkage of treated and untreated soil
Type of soil
|
Shrinkage
|
Total Length
|
Percentage
|
Soil
|
48
|
600
|
8.0
|
Soil + 4 %CLS
|
46
|
600
|
7.6
|
Soil + 8 %CLS
|
43
|
600
|
7.1
|
Soil + 12 %CLS
|
41
|
600
|
6.8
|
Soil + 16 %CLS
|
40
|
600
|
6.6
|
It is important to note that the
F drive should be lesser than the static friction force for the mass to be
driven on the surface of conveyor. The maximum and minimum friction considering
coefficient for friction for rubber to surface.
The hopper will be a truncated
pyramid, as shown in illustration, the volume of the hopper and the mass of
clay it can hold at ideal condition.
Working Mechanism
The
model that is fabricated is of manual type. There is use of the lever mechanism
and unidirectional sprocket so that the force applied at a single point is
utilized to rotate the conveyer belt and at the same time. The press compresses
the materials to from the brick. The
lever mechanism along with the conveyer belt is driven by push pull force
applied by human. We used chains and sprockets to drive the conveyer belt in
forward direction. When lever is pushed down the die press the brick but the
conveyer belt does not move forward as the unidirectional sprocket does not
come into act during this process. However when the lever is pushed up, the die
comes up and at the same time sprocket makes the chain to drive conveyer belt
in forward direction. The sprocket and lever is connected with a long rod so it
helps to transmit the motion. Suitable
adjustments were made for the smooth operation of the model.
DESIGN
DESIGN
The
conceptual design or outlook of brick
moulding model is shown in figure below. Different designs were made and those
initial designs were modified as per the requirements to come up with this
final design. The design was done using SolidWorks.
Reference:
https://www.researchgate.net/project/Design-and-fabrication-of-manual-brick-moulding-machine
YV Nitesh
10th jan 2019
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