“Plastics have advantages over metals.” Do you agree with the statement? Give reasons to support your
answer.
Answers
Answer:
Advantages of Plastic over Metal
Plastic materials are low in cost, weight and also have the advantage of low processing cost. Therefore industries are converting their metal parts in plastics. Plastic parts have the following advantages compared to metal parts.
High Strength and Toughness
Plastic has the advantage of higher strength to weight ratio. And they are very tough in nature. Therefore, plastic parts are lighter in weight compared to metal parts.
Superior Design Flexibility
Plastic parts are manufactured by flowing molten plastic in injection mold. This process has an advantage of manufacturing complex features, geometries and integrating multiple metal parts in one plastic part. Therefore it helps in reducing product cost.
Lower Weight and Material Cost
Thermoplastics parts are lighter in weight. Therefore plastic part weight and cost are less compared to metal parts.
Low Manufacturing Process Cost
Plastic parts are manufactured with injection molding process. Which has relatively lower cycle time. Lower cycle time helps in reducing plastic part manufacturing cost compared to metal parts.
No need for Secondary finish Operation
Metal parts require secondary finishing operations to achieve required aesthetics and corrosion resistance. Whereas plastics have inherent corrosion resistance properties and required aesthetic finish can be achieved during injection molding. Therefore plastics offer advantages of eliminating secondary finish operation.
Fasteners can be Eliminated
Plastics manufacturing process has advantages of Integrating assembly features in plastic parts itself. Assembly features such as snap are used to join plastic parts. As a result product assembly time and cost is reduced. Read this article for more details on snap joints.
Corrosion Resistance
Plastics are corrosion resistant and non-conductive in nature.
Reduced Waste / Scrap
Plastic parts are manufactured by flowing molten plastic in the mold. Whereas metal parts are machined from relatively larger blocks. Therefore plastic has the advantage of manufacturing parts with negligible wastage compared to metal parts. If production volumes are high. Plastic wastage during injection molding can be reduced by using hot runner injection mold.
Disadvantages of Plastics over Metal
Along with so many advantages, plastic parts have the following disadvantages as well.
Higher Initial Tooling Cost
Plastics have an disadvantage of higher injection molding tool development cost. Different parts require different injection molds. Whereas machined metal parts do not require special tooling.
Higher Lead Time for Tool Development
Injection molding tool development has longer lead time. But For smaller volumes Plastic Prototyping techniques are used to get samples quicker. Therefore plastic part has disadvantage of higher lead time compared to metal parts
Electrical and Thermal Conductivity
Plastics are not good conductors of heat. Therefore plastic parts can not be used where high heat and thermal conductivity is required. To solve this problem plastic parts are used in conjunction with metal parts.
Lower working Temperature Range
Plastics can not be used for very high and low temperature ranges.
Manufacturing Process
Injection molding process is very difficult to control. If plastic parts design is not as per guidelines or process is not controlled, various Plastic injection molding defects are observed.
Conclusion
To sum up, Designers across various industries are reducing product cost by incorporating plastics parts. You can expect 25 to 30% cost saving with metal-to-plastic conversion.
Explanation:
Answer:
Fabrication refers to any process that cuts, shapes, or otherwise forms a material into an end product, and this article covers the advantages and disadvantages of plastic over metal fabrication, and vice versa. The type of fabrication method used to produce a particular item depends on a wide range of factors, including the products purpose, appearance, and available budget. Before determining whether plastic or metal fabrication is appropriate for a particular job, it is important to first understand the potential advantages and disadvantages of each option.
Types of Fabrication Processes
Both plastic and metal fabrication involve a wide range of distinct manufacturing processes. This range allows for a considerable number of customization and selection options in component design. Some of the more common fabrication processes include:
Cutting: This involves various tools or machines removing excess material from a workpiece to meet size and shape requirements. Band saws and cutting torches are two examples of cutting devices.
Forming: This process uses deforming equipment, such as hydraulic brakes, to bend or press products at a specified angle.
Machining: Machining processes, which include lathing, milling, drilling and honing, use automated or manually controlled equipped to shape material.
Welding: Welding is the process of joining two or more workpieces by applying heat or pressure to form a single product.
Advantages of Plastic Fabrication
Though the results of plastic fabrication greatly depend on the unique characteristics of the type of plastic used (acrylic, Plexiglas, nylon, etc.), the process itself has several advantages, which include:
Ease of forming: Due to its low melting point and high malleability compared to other materials, plastic can be formed into basic and complex geometries with relative ease.
Reduced finishing: Unlike most metals, plastics can be colored prior to fabrication, eliminating the need for certain post-treatment processes, such as painting.
Faster production: Plastic fabrication often involves quick cycle times and fast turnover rates.
Lighter weight: Plastics typically weigh less than metals of comparable dimensions.
Chemical resistance: Plastics are generally less susceptible to damage from chemicals or chemical reactions, such as oxidation or rusting, than metals.
Disadvantages of Plastic Fabrication
Although plastic is useful for fabricating a wide range of parts, it also has its share of limitations as a production material. Some of the disadvantages of plastic fabrication include:
Limited wear resistance: Plastic has a low resistance threshold for elevated temperatures, acidity, and other corrosive elements.
Structural weaknesses: Most plastics are unsuited for applications requiring high structural strength, such as heavy equipment components and most building materials.
Advantages of Metal Fabrication
Like plastic fabrication, metal fabrication depends largely on the family and grade of metal used in production. Some of the more commonly fabricated metals include steel, magnesium, iron, aluminum, copper, and nickel, each with their own various grades. Metals generally provide the following advantages over plastic fabrication: