Applications of Polymers in Medicine

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Questions and Answers

What is a primary reason for using polymers in medical devices?

Their ability to conduct electricity

Their stable and generally inert nature (correct)

Their high cost-effectiveness

Their ability to absorb large amounts of water

What is an example of a medical device that uses polymers?

Dental fillings

Cochlear implant (correct)

Pacemaker

Contact lenses

What is a potential application of biodegradable polymers?

Delivery of drugs (correct)

Manufacturing surgical robots

Developing artificial organs

Creating artificial skin

What area of research uses polymers as building blocks?

Nanotechnology Signup and view all the answers

What is a potential use of polymers in orthopaedic applications?

Designing orthopaedic joints Signup and view all the answers

What is the primary purpose of forging in metalworking?

To shape metal using forceful blows. Signup and view all the answers

At what temperature range is hot forging typically performed?

400-700 degrees Celsius. Signup and view all the answers

Which forging method primarily utilizes manual processes like hammering and bending?

Blacksmithing. Signup and view all the answers

What does the process of upsetting in forging entail?

Decreasing the length while thickening the cross-section. Signup and view all the answers

Which forging method is especially suitable for producing large or intricate parts using controlled deformation?

Press forging. Signup and view all the answers

In which forging method is a piece of metal forced through a die to achieve a specific shape, usually when cold?

Swaging. Signup and view all the answers

How does forging contribute to the strength of metal components?

By allowing grain flow to conform to the shape of the article. Signup and view all the answers

Which of the following statements is true regarding drop forging?

It produces large quantities of identical parts. Signup and view all the answers

What is a key characteristic of pressure die casting compared to sand casting?

It allows for greater accuracy and precision. Signup and view all the answers

Which statement about brazing is correct?

The filler metal in brazing has a lower melting point than the adjoining metal. Signup and view all the answers

What is the initial step in the investment casting process?

Coating the wax pattern with ceramic material. Signup and view all the answers

Which welding method is specifically suited for non-ferrous metals?

TIG welding Signup and view all the answers

What distinguishes fabrication from casting and forging?

It requires the assembly of individually cut pieces. Signup and view all the answers

In which situation would soldering be preferable over brazing?

When the adjoining metal has a lower melting point. Signup and view all the answers

What is a significant drawback of sand casting?

It has lower accuracy compared to pressure die casting. Signup and view all the answers

What is a common application of electric arc welding?

Joining two or more pieces of metal by melting. Signup and view all the answers

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

Blacksmithing (HOT):
- Involves heating metal until malleable followed by shaping with hammers and anvils.
- Techniques include hammering, bending, cutting, and welding; primarily manual.
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.
Press Forging (HOT):
- Applies slow, continuous pressure for precise deformation control.
- Suitable for creating large or intricate components; usually conducted hot.
Upsetting (HOT or COLD):
- Increases workpiece diameter by compressing its length, versatile for hot or cold methods.
- Common applications include bolt heads and valves.
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

Casting involves pouring molten metal into a cavity, solidifying to form a final article.
Sand Casting:
- Molten metal poured into a sand mold, solidifies and then the mold is broken to retrieve the casting.
Investment Casting:
- Wax pattern coated with ceramic material, wax melted out to create cavity for final product shape.
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

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.
Brazing:
- Joins metals by melting a filler with a lower melting point than the base metals.
Soldering:
- Similar to brazing but uses a lower melting point filler metal specifically for metal parts.
Bolting:
- Involves fastening components together with bolts for secure assembly.