Question

Can you explain how the following constraints affect the construction of a factory used in the  manufacture plastic bricks . Time constraint, scope constraint, cost constraint ,resources constraint. 500 words

Answer 1

Stones are a widely applied construction and building substance around the globe. Regular bricks usually are produced coming from clay-based with high temp kiln firing or received from common Portland cement (OPC) tangible, and so contain huge embodied energy and have got got large carbon impact. Inside many areas regarding typically the world, right now there exists already a fresh deficit of natural supply substance for production in connection with regular bricks. Regarding environmental security and environmentally friendly growth, substantial research provides recently been conducted on creation regarding bricks from spend supplies. This paper gives a state of the art review regarding research about using spend materials to be able to produce stones. Numerous spend materials have got recently been studied to generate rocks with different methods. Typically the investigation can be split directly into three basic categories centered on typically the methods regarding creating stones from spend materials: shooting, cementing in addition to be able to geopolymerization. Although much research have been conducted, typically typically the commercial production of rocks from waste material remains extremely limited. The achievable causes are related to manage to the methods for generating bricks from waste substance, typically the potential toxins from typically the spend material used, the scarcity of relevant standards, inside addition to the slower acceptance regarding waste materials-based bricks by just industry in addition to public. Regarding wide creation and program of stones from waste materials, further analysis and development is necessary, not merely on the technological, monetary and environmental factors but also on standardization, government policy and open public education related to spend recycling and sustainable growth.

Design Aspects

The design concept consists the following:

a) Maximum volume of the melt needed to fill the mold. This entails length of the screw conveyor (l), diameter of the barrel (d), melt density (ρ_m) and melt mass (m);

b) Design of barrel which entails diameter of the barrel.

c) Design for screw conveyor.

While the design analysis entails the following units:

a) The Extruder unit comprises of the hopper, barrel, band heater, nozzle, screw conveyor, bearing housing and gear box

b) The clamping unit consists of the mold and clamping for locking device.

c) The electrical panel comprises of temperature control box, and thermocouple.

3. Machine Construction

The major techniques employed in construction of the designed machine include machining operation on lathe machine, drilling operations on drilling machine, boring operation on lathe machine, keyway cutting on slotting machine, flame cutting using oxyacetylene gas welding machines, grinding for good finishing, electric welding using arc welding machine. Basically, these constructional techniques were broken down into four sub-heading namely; cutting operation, machining operation, welding operation and assembly; and finishing operation.

Materials Selection

Materials are selected based on designed and metallurgical properties of the materials such as machinability, formability, weldability that greatly influence the construction methods and other joining methods. Other factors considered are cost of the materials; and mechanical properties of the materials.

Equipment

The parts used are as follows: 3 phase, 2HP, Induction motor, 1:10 Worm gear reduction box, tapered and ball bearing, ceramic band heaters, thermocouples, Temperature control box other such as mainframe is cut into sizes using oxyacetylene gas welding, grinding and welding operation on mold box, barrel and Screw conveyor were faced using the lathe machine, drilling, milling, using drilling machine, milling machine and respectively. Drilling operation on the lathe machine was performed on the components such as the mold, barrel, flanges, and the supporting frame. Milling operation was carried out on the barrel.

All the general finishing operation was carried out on the machine such as grinding of all rough edges using a hand grinding machine. Cutting saw or frame cutting were used for cutting the various metals into sizes and required shapes.

Working

The operational principle of this machine is as follows:

(a) Switch on the heater and set the required temperature slightly above the melting point of different waste plastics.

(b) Mixing waste plastics, rubber composites and calcium carbonate in required quantity and is poured into the hopper when the required temperature in the control box has reached.

(c) Switch on the motor and the screw conveyor starts rotating at 80 rpm.

(d) The waste plastics from the hopper gets melted and conveyed towards the nozzle.

(e) A brick mold is kept at the end of the nozzle tip and the molten plastic/rubber composite material starts filling the mold box. After the mold is filled completely the mold box is removed from the nozzle tip dipped in the water bath and kept inside the bath for an hour for proper cooling.

(f) The final product is removed from the mould box and is sent for compression testing using Hydraulic Brick testing machine.

5. Testing of the Product

5.1. Different Types of Brick Materials Tested

Various waste plastic sample bricks are produced from the machine and its details are given in Table 1.

Experiment Setup and Procedure

The equipment used for testing various samples is Hydraulic Brick Testing Machine (shown in Figure 3) which can apply a maximum compressive load of 2000kN.

The waste plastic/rubber composite brick is placed in between the top and bottom compression pads as shown in Figure 4 and load is applied hydraulically till the failure of the brick.

6. Results and Discussion

Compression tests were conducted for all the 4 samples and the average values of 3 trials are noted and presented in Table 2.

From the Figure 6, the maximum compressive load sustained by the Polypropylene/Rubber composite brick (Sample 2) is 17.06 tons which is much higher than the clay brick which sustained only 9.03 tons. Therefore we can come to a conclusion that bricks made of waste plastics will sustain a much higher load and compressive strength compared to the normal clay bricks. Also by mixing rubber powder and calcium carbonate into the waste plastic mix, we come to know that the composite brick yields very high compressive strength compared to other commercially available bricks. From the results it is evident that the bricks produced by waste plastic and rubber powder can be used for commercial applications.

Compression strength of the Plastic/Composite bricks varies based on the material composition used to manufacture and the degree of cooling of bricks in water. The compression strength of individual Plastic/Composite bricks shown in Figure 6 is only relative in value that affords a basis of comparison between different kinds of Plastic/Composite bricks developed for testing.

Bricks are usually tested flat as they are more often used in that manner during construction of walls etc. Plastic/composite bricks incorporate polymer material typically post-consumer recycled plastics as a primary component, with reinforcing rubber powder and CaCO₃ to contribute enhanced properties. The Plastic/Composite bricks shall resist decay and insect attack and water absorption shall not cause loss of strength in the plastic/composite bricks.

7. Conclusions

This work effectively converts waste plastic into useful building materials like building bricks and floor interlocks which can effectively reduce the environmental pollution and further decreases the problem of waste plastics in the society. Rather than the waste plastics going into the landfill or incinerators it can be used as construction materials at a much lower cost after undergoing certain specific processing. It also reduces the construction cost by eliminating the use of mortar during construction by using recyclable plastic/composite bricks and floor interlocks. From the compression testing results we come to know that waste plastics material when effectively mixed with Rubber powder and Calcium Carbonate gives the highest compressive strength and sustains high compressive load.