manufacturing - casting methods

Question 1

Name some Casting Methods.

Answer 1

1. Sand Casting
2. Die Casting
3. Centrifugal Casting
4. Vacuum Casting
5. Injection Molding

Question 2

What is the Process of Vacuum Casting?

Answer 2

• Liquid material poured into mold.
• Vacuum used to eliminate bubbles and ensure precise detail.
• Used for prototyping and small production runs.

Question 3

What is the Process of Sand Casting?

Answer 3

Metal casting process using sand moulds.
1. Pattern Creation
2. Gating System - Enclosure
3. Metal Pouring & Cooling
4. Sand Removal.

Question 4

What is the Process of Die Casting?

Answer 4

1. Mould Creation - Dies Machined
2. Metal Preparation - Metal to become hot enough to flow
3. Metal Injection - High Pressure
4. Cooling

Question 5

What is the Process of Injection Moulding?

Answer 5

For plastics.
- Mold is created and clamped shut
- Material is melted to molten - so it can flow
- Material injected into mold
- Left to cool and solidify
- Mold opened and part ejected

Question 6

Pros & Cons of Sand Casting.

Answer 6

Pros:
1. Can be used for any size and shape.
2. Ideal for higher temperatures (steels)
3. Cost effective for small production
Cons:
1. Lower precision and surface finish compare to other methods
2. Longer production time
3. Labor-intensive - may require more post-processing

Question 7

Pros & Cons of Die Casting.

Answer 7

Pros:
1. Suitable for large quantities
2. Small - medium sized castings
3. Precision
4. Speed
Cons:
1. large upfront costs
2. limited to non-ferrous metals
3. can be limited by size of machine

Question 8

Pros & Cons of Vacuum Casting.

Answer 8

Pros:
1. High accuracy
2. repeatable
3. good for prototypes
Cons:
1. only suitable for plastics / rubber
2. slow
3. not suitable for high temps
4. mold can affect quality of cast

Question 9

Pros and cons of Injection Molding.

Answer 9

Pros:
1. efficient for high production
2. low cost per part
3. repeatable
4. low waste
Cons:
1. high initial start up costs
2. limited flexibility (fixed mold)
3. requires high temps and pressure (danger!!)

Question 10

What is discrete casting?
Pros and Cons?

Answer 10

• casting of distinct part.
• often singular
  Pros:
  1. short lead time
  2. complex details
  3.good finishing
  Cons:
  1. high start up costs
  2. can experience defects
  3. not suitable for small-scale

Question 11

What is continuous casting?
Pros and cons?

Answer 11

• process where molten metal is poured into mold to produce ‘semi finished’ part
  Pros:
  1. consistent quality
  2. cost effective
  Cons:
  1. limited flexibility
  2. high start up costs
  3. risks of defects

Question 12

What are common Die Cast materials?

Answer 12

ZINC
ALUMINIUM
MAGNESIUM
COPPER
LEAD AND TIN

Question 13

What are common Sand Cast materials?

Answer 13

ALLY
IRON
STEEL
BRASS
BRONZE
ZINC
MAGNEZ

Question 14

What is Centrifugal Casting?

Answer 14

• rotating mold that distributes molten metal evenly along inner surface of a mold
  -ideal for cylindrical parts

Question 15

What is Investment Casting?

Answer 15

• Wax pattern is created using a die
• Wax part covered in fine dust - to help with intricate details and placed on a tray
• pattern is dipped in slurry multiple times - cermamic can be added whilst wet
• allowed to dry
• heated to remove wax
  -molten metal poured into leftover mold and left to cool
• cermamic shell mould cut away

Question 16

Pros and Cons of Investment Casting?

Answer 16

PROS:
1. complex designs
2. precise
3. good surface finish
4. minimal waste
CONS:
1. high start up
2. time consumig
3. smaller parts mainly
4. complex process

Question 17

Pros and cons of centrifugal casting

Answer 17

PROS:
1. high quality
2. strong
3. efficient
CONS:
1. limited shapes
2. high equipment costs
3. high set up