This topic contains a solution. Click here to go to the answer

Author Question: Describe the principle similarities and differences between RIM and low-pressure foam molding. ... (Read 109 times)

DelorasTo

  • Hero Member
  • *****
  • Posts: 548
Describe the principle similarities and differences between RIM and low-pressure foam molding.
 
  What will be an ideal response?

Question 2

What is meant by blowing the cells open, and how can this event be controlled?
 
  What will be an ideal response?

Question 3

Explain why open-cell structures are created when the mold expansion in high-pressure foam molding is quite rapid and why closed-cell structures occur when the molding is slower.
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

cascooper22

  • Sr. Member
  • ****
  • Posts: 312
Answer to Question 1

In low-pressure foam molding the mold is only partially filled and then allowed to expand to complete the filling of the mold. In RIM the mold is completely filled but the foaming occurs simultaneously with the filling of the mold. RIM also has the capability of adding a reinforcement inside and of foaming around metal inserts which would be very difficult with low pressure foam molding.

Answer to Question 2

Blowing the cells open is the conversion of closed cells to open cells by the rupturing of the cell walls. This can be controlled by controlling the amount and rate of expansion of the gas inside the cells. This control can be achieved by limiting the expansion of the mold in high-pressure foam molding. It can also be

controlled by reducing the temperature at which the foaming occurs. Other methods that limit the expansion of a gas, such as increasing the pressure under that expansion occurs, can also prevent blowing the cells open.

Answer to Question 3

Rapid expansion of the mold tends to allow the gas inside the cells to expand very rapidly and to expand to a much larger size. This large expansion can rupture the walls of the foam and change closed cells into open cells.




DelorasTo

  • Member
  • Posts: 548
Reply 2 on: Aug 19, 2018
Wow, this really help


smrtceo

  • Member
  • Posts: 344
Reply 3 on: Yesterday
Gracias!

 

Did you know?

Malaria mortality rates are falling. Increased malaria prevention and control measures have greatly improved these rates. Since 2000, malaria mortality rates have fallen globally by 60% among all age groups, and by 65% among children under age 5.

Did you know?

Alzheimer's disease affects only about 10% of people older than 65 years of age. Most forms of decreased mental function and dementia are caused by disuse (letting the mind get lazy).

Did you know?

Signs and symptoms of a drug overdose include losing consciousness, fever or sweating, breathing problems, abnormal pulse, and changes in skin color.

Did you know?

In 1844, Charles Goodyear obtained the first patent for a rubber condom.

Did you know?

Your heart beats over 36 million times a year.

For a complete list of videos, visit our video library