1. Plastics:
Plastics are also called as Polymers. They are made up of carbon, hydrogen and sometimes oxygen, chlorine, nitrogen, fluorine, sulfur, phosphorus or silicon. Majority of the times, polymers are made up of Carbon, Hydrogen, and Oxygen only.
- It is a low-density polymer and thereby it possesses lightweight.
- It is Anti-Corrosive in nature.
- It has low strength.
- These chains are called polymers and that is why many plastics begin with “poly,” such as polypropylene, polyethylene, and polystyrene.
2. Properties of Plastics (11) or Polymers: Properties of plastics or polymers play a vital role in the field of Mechanical Engineering. When you want to apply any type of load on a particular member, you need to know its material properties, density, etc. For that, in this article, I am exploring the necessary properties of polymers in a detailed manner.
Properties of Plastics or Polymers:
The Properties of Polymers or plastics which are essential to know for any mechanical engineer are as follows:
- Bond: It possesses a Covalent bond.
- Strength: The strength of the polymer is low when compared with Metals.
- Binding Energy: The formation of C, H&O atoms forms a polymer. The distance between the atoms is more when compared with metals and thereby the Binding energy is low.
- Ductility: It possesses good ductility also.
- Conductivity: The polymers possess bad electrical conductivity because of the absence of free electrons.
- Thermal Conductivity: The polymers possess bad thermal conductivity.
- Density: The polymers possess low density which means that the weight of the polymer is less and this is one of the advantages of polymers.
- Corrosiveness: The polymers are Anti-Corrosive to the environment.
- Servicing Temperature: The servicing temperature of the polymer is 300̊ C.
- Hazardous: It is hazardous and is not environmental friendly.
- Recyclability: The polymers are recyclable in nature.
These are the 11 properties of polymers or plastics which are discussed in a detailed manner. Hope you had got an idea of what plastic is? Now, let’s discuss the Classification or Types of Plastics.
3. Types of Plastics:
They are two types of Plastics.
- Thermoplastics
- Thermoset Plastics or Thermosetting Plastics
3.1. Thermoplastics:
By heating the polymer, if it turns soft, then it is called as Thermoplastic material. At room temperature, they are available in the form as Solids.
A thermoplastic is a plastic material that becomes moldable above a specific temperature and solidifies upon cooling. In this article, I will be explaining the top 10 properties of thermoplastic materials in a detailed manner.
3.1.1. Top 10 Properties of Thermoplastic Material:
- By heating the polymer, it turns as soft material.
- It is available in the form of solids at Room temperature.
- It is a recyclable process.
- Thermoplastic material in the form of solid is converted into Thermoplastic material in the form of liquid which is done by the action of heating and the Vice-versa also takes place in another direction.
- Loses Strength: By heating the thermoplastic material it loses its strength.
- Gains strength: By the action of cooling, the thermoplastic material gains strength.
- Shape change: During cooling only, the thermoplastic material changes its shape.
- Temperature: The servicing temperature of thermoplastic material is 150°C.
- Structure: The thermoplastic material exhibits Linear structure i.e. -CH2-CH2-CH2-CH2-
- The thermoplastic material is hazardous to the environment which is less when compared to the thermoset and rubber.
3.1.2. Thermoplastic Examples:
- Polyethylene
- Poly Vinyl Chloride(PVC)
- Teflon
3.2. Thermosetting Plastics or Thermoset Plastics:
By heating the polymer, if it turns hard, then it is called as Thermosetting plastic material. At room temperature, they are available in the form as liquids. Thermosetting plastics or Thermoset plastic are synthetic materials that strengthen during being heated but cannot be successfully remolded or reheated after their initial heat-forming called as Thermoset material.
3.2.1 Properties of a Thermosetting Plastic material:
- By heating the polymer, it turns as hard material.
- It is available in the form of liquid at Room temperature.
- It is a Non-Recyclable process.
- Thermoset in the form of liquid is converted into Thermoset material in the form of solid which is done by the action of heating and its Vice-versa is not possible.
- Gains strength: By the action of heating, the thermoset plastic material gains strength.
- No change in the strength of the thermosetting plastic is done by the action of cooling.
- Shape change: During heating only, the thermoset material changes its shape.
- Temperature: The servicing temperature of a thermoset plastic material is 300°C.
- Structure: It exhibits a Cyclic structure.
- It is hazardous to the environment which is more when compared to the thermoplastic and less than the rubber.
3.2.2 Thermosetting Plastic Examples:
- Epoxy Resin
- Phenolic(Bakelite)
- Vinyl Ester Resin
- Cyanate Ester
- Poly Ester
This is the complete explanation with its top 10 properties. Hope this article is helpful to you. I think you had understood about the properties of polymers, thermoplastics, and thermosetting plastics in a detailed way. Now, let’s discuss the Processing of Plastics.
4. Plastic Processing Methods:
In order to get the desired components from various Plastics, we need Plastic Processing Methods. They are as follows.
5.Glass Cutting- Introduction, Mfg, General Properties and Glass Cutting Tools
Introduction to Glass: Glass is a non-crystalline amorphous solid that is often transparent and has widespread practical, technological, and decorative usages in the industry. For example, window panes, optoelectronics, tableware, etc. But, do you know that Glass is made up of liquid sand? In this article, I will be explaining the different aspects of glass i.e.Introduction, Manufacturing, General Properties and Glass cutting tools in a detailed way.
How the Glass is Made?
- The glass is made by heating ordinary sand (which is mostly made up of silicon dioxide) until it melts and turns into a liquid. sand melts at a high temperature of 1700°C (3090°F).
- In a glass plant, sand is mixed with waste glass, limestone (calcium carbonate) and soda ash (sodium carbonate) heated in a furnace.
- The soda reduces the sand’s melting point, which helps to save energy and time during the manufacturing process, but it has a drawback that it produces a kind of glass that would dissolve in water and that(dissolving in water) can be eliminated by adding Limestone to the mixture.
- The end product is called soda-lime-silica glass and it is the ordinary glass that we are using in our domestic applications.
Formation of Glass= { Waste Recycled Glass +Sand + Calcium Carbonate + Sodium Carbonate} —> Heating —>Annealing—>Finishing.
Glass Manufacturing:
Glass Manufacturing is carried out under 4 stages. They are
- Melting a. Pot furnace b.Tank furnace
- Forming and shaping
- Annealing
- Finishing
General Properties of Glass:
- It is amorphous in nature.
- It is very brittle.
- It Softens on heating
- It can absorb, transmit and reflect light.
- It is a good electrical insulator.
- These are affected by alkalis.
- It is not affected by air, water, etc. But, it is soluble in HF which converts into SiF4.
- Possesses high compressive strength and since it doesn’t have any crystalline structure.
- Light in weight because it has a homogeneous internal structure similar to liquids.
Glass Cutting Tools:
The glass cutting tools which are used to cut the glass are as follows.
- Wheel Cutting or Glass Cutter
- CO2 Laser Cutting
1.Wheel Cutting-Glass Cutting Tool:
In the Middle Ages, glass was cut with a heated and sharply pointed rod of iron. The Diamond can also act as cutting material for glass. Nowadays we used different methods to cut the glass. A Glass Cutting Tool consists of 3 Parts
1.Wheel: It is a small wheel attached to the glass cutter whose role is to cut the glass plate w.r.t. the dimensions easily. The glass after cut by cutting wheel has sharp corners. So, care must be taken during operation.
A glass cutter more commonly uses a small cutting wheel made of hardened steel or Tungsten Carbide of 4–6 mm in diameter with a V-shaped profile called a “hone angle” is used.
The greater the hone angle of the wheel, the sharper the angle of the V and the thicker the piece of glass it is designed to cut. The hone angle on most hand-held glass cutters is 120°.
2.Holders or Grips: After marking the glass with the cutting wheel, the glass cutter has to be inserted into the corners of glass and tilt it so that it can break w.r.t the mark made.
3.Ball:
The ball attached at the end of the glass cutter is used for tapping the glass piece if any irregularities are present at the corners of glass after the cut.
This is the explanation of “wheel cutting” tool in a detailed way which is one of the Glass Cutting tools.
2. The Laser Cutting-Glass Cutting Tool:
Cutting the glass with conventional methods(Wheel Cutting) as stated above uses the principle of Scribe and Break. In the sense, you need to scribe on the surface of the glass w.r.t. the dimensions and Break that particular part.
By doing so, relatively low scribing quality results in the formation of micro-cracks and that leads to the damage of glass. In addition to that, various time-consuming processes like grinding, masking and etching are necessary to remove the damage that had been introduced by mechanical processes(Conventional Methods).
Using a laser for the glass cutting process avoids all the limitations stated above.
By this laser cutting, the Straight, angled, curved and chamfered contours are possible.
The laser beam is used to cut different materials like metal, wood, rubber, glass, plastics, etc.
Laser cutting machines are equipped with computer-controlled programming that helps to do the work more efficiently and easily. By this, a high degree of accuracy is maintained.
Advantages of Laser Cutting:
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It can easily cut simple and complex structures.
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Human intervention is for Inspection and repairs and thereby it is a time-consuming process.
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Performs various Operations at a time.
Dis-Advantages of Laser Cutting:
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Metals like copper and aluminum can’t be cut using this technology.
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Laser cutting of plastic components can be of more expensive compared to glass because when the plastic is exposed to heat, it emits the gas. For this reason, the laser cutting service provider should have a well-ventilated room, which is quite expensive.
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No human intervention is required in this process and thereby it affects employability.
This is the explanation of Glass Cutting tools in a detailed manner.