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Questions and Answers
What is a primary reason for using polymers in medical devices?
What is an example of a medical device that uses polymers?
What is a potential application of biodegradable polymers?
What area of research uses polymers as building blocks?
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What is a potential use of polymers in orthopaedic applications?
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What is the primary purpose of forging in metalworking?
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At what temperature range is hot forging typically performed?
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Which forging method primarily utilizes manual processes like hammering and bending?
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What does the process of upsetting in forging entail?
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Which forging method is especially suitable for producing large or intricate parts using controlled deformation?
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In which forging method is a piece of metal forced through a die to achieve a specific shape, usually when cold?
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How does forging contribute to the strength of metal components?
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Which of the following statements is true regarding drop forging?
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What is a key characteristic of pressure die casting compared to sand casting?
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Which statement about brazing is correct?
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What is the initial step in the investment casting process?
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Which welding method is specifically suited for non-ferrous metals?
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What distinguishes fabrication from casting and forging?
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In which situation would soldering be preferable over brazing?
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What is a significant drawback of sand casting?
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What is a common application of electric arc welding?
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Study Notes
Polymers in Medical Applications
- Polymers are valued for their stable and inert nature, making them suitable for use in physical devices such as prostheses.
- Significant advances have been made in implant technologies utilizing polymers.
- PVC is used to house componentry for synthetic speech processors in cochlear implants.
Biodegradable Polymers
- Biodegradable polymers are used for drug delivery, vascular grafts or stents, wound closures, and orthopaedic joints.
- These polymers are also utilized in tissue engineering.
Polymers in Nanotechnology
- Polymers serve as building blocks in nanotech research, which focuses on microsurgical techniques and virus control.
Forging Process
- Forging shapes metal using forceful blows, applicable to both hot and cold conditions.
- Hot forging occurs above recrystallisation temperatures (400-700°C).
- Forging techniques may alter a metal's dimensions while enhancing its internal structure.
- Grain flow realigns with the forged shape, boosting strength along the axis.
Forging Methods
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Blacksmithing (HOT):
- Involves heating metal until malleable followed by shaping with hammers and anvils.
- Techniques include hammering, bending, cutting, and welding; primarily manual.
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Drop Forging (HOT):
- Metal heated and placed between two dies; upper die is dropped to shape the metal.
- Ideal for mass production of identical parts.
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Press Forging (HOT):
- Applies slow, continuous pressure for precise deformation control.
- Suitable for creating large or intricate components; usually conducted hot.
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Upsetting (HOT or COLD):
- Increases workpiece diameter by compressing its length, versatile for hot or cold methods.
- Common applications include bolt heads and valves.
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Swaging (COLD):
- Cold process forcing workpiece through dies to reduce diameter or achieve specific shapes.
- Often used for tubes, rods, and wires; can utilize rotary machines or hammers.
Casting Process
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Casting involves pouring molten metal into a cavity, solidifying to form a final article.
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Sand Casting:
- Molten metal poured into a sand mold, solidifies and then the mold is broken to retrieve the casting.
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Investment Casting:
- Wax pattern coated with ceramic material, wax melted out to create cavity for final product shape.
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Pressure Die Casting:
- Molten metal forced under pressure into molds for complex shapes with high precision.
- Typically used for large-scale production.
Fabrication Process
- Fabrication differs from forging and casting by assembling multiple cut pieces to create an article.
Joining Methods
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Welding:
- Joins metal pieces by melting and cooling them together for a strong bond.
- Types include electric arc (stick), MIG, TIG, spot, gas, and friction welding.
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Brazing:
- Joins metals by melting a filler with a lower melting point than the base metals.
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Soldering:
- Similar to brazing but uses a lower melting point filler metal specifically for metal parts.
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Bolting:
- Involves fastening components together with bolts for secure assembly.
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Description
This quiz covers the various uses of polymers in medical devices and applications, including prosthetics, implants, and drug delivery systems.
