Rotational Moulding

• Why is blow moulding not suitable for objects in need to high wall thickness and so rotational moulding used instead

  It stretched the walls too thin in the moulding process
• What is rotational moulding used for

  To produce heavy duty seamless hollow objects in need of large wall thickness
• What are some products made by rotational moulding

  Traffic cones

  Children's play equipment

  Water tanks

  Kayaks
• What are 2 typical polymer used in the rotational moulding process 

  HDPE and PP
• Why is rotational moulding usually used for large-scale batch or mass production

  Altthough moulds can be changed quickly, set up costs are high  
• How is the rotational moulding process carried out

  1.Polymer powder/granules loaded into mould, clamped and sealed

  2.Mould transferred to oven, 260-370°C(depending on polymer), rotated slowly around 2 axes(less than 20 per min),coats the inside of the mould

  3.Once achieved correct thickness, mould is cooled. By fan and/or water

  4.Polymer solidified and will shrink slightly, so it can be removed