Custom Rotational Molding  
  A Free Information Resource for Clients and Molders  
     
     
Home
What is Rotational Molding
The Rotational Molding Process
Planning a Part
Graphics and Labeling
Getting a Mold
Molding the Part
Plastic Selection
Custom Rotational Molding
Find a Molder
Rotational Molder's Forum
Privacy Policy
About Us
Contact Us
.
  What is Rotational Molding?  
  Rotational Molding is one of several ways to mold plastics.  Rotational Molding is one of the oldest methods of making plastic parts.  The concept of Rotational Molding is very simple. Powdered resin is placed in a sealed metal mold.  The mold is attached to a machine that rotates the mold in two directions (two axis).  The mold is moved into an oven where it heats up while continuing to rotate.  After heating long enough for the plastic to melt, the entire inside of the mold will be covered with molten plastic.  The mold is removed from the oven for a cooling cycle which may involve the use of fans or water mist while the mold continues to rotate on 2 axis.  Once the mold and plastic have sufficiently cooled, the mold is opened and the part is removed.  The one-piece molded part will be in the shape of the mold and the wall thickness of the part will be generally consistent.   There will be more thickness in the outside corners of the item giving it more stength and durability.  The plastic will be formed stress free.  
  Rotational Molding is especially appropriate for producing large plastic parts and hollow plastic parts.  Since mold costs for rotational molding are a fraction of the mold costs for many other types of plastic molding, rotational molding is well suited for prototyping projects that may later mvoe to another molding type to achieve high production rates.