A Step-by-Step Guide to Moulding a Flexible Prosthetic Socket

Pull the perfect prosthetic sockets

The soft and supple Orfitrans thermoplastic sheets are ideal for the fabrication of flexible prosthetic sockets and can be used as a comfortable lining material.

In this guide, we explain how to expertly mould our flexible thermoplastic sheets for smooth and soft sockets. We show how to prepare the sheet, optimize your positive mould and share some general moulding tips.

Follow the steps and pull the perfect sockets time and time again. 


1. Pre-heat your oven to the correct temperature.

All Orfitrans products require different heating temperatures and heating times. Check the heating instructions for each Orfitrans sheet. 


2. Prepare the positive mould:
  • Scratch four air extraction ducts in the base of the positive mould with a cutter. These help the air to escape later when activating the vacuum.
  • Spray the positive mould with acrylic varnish and let it dry.
  • Read our five tips for the perfect positive mould for more information.


3. Prepare the Orfitrans sheet:
  • Remove the protective film on both sides of the sheet.
  • As an optional step, you can cut the sheet to the shape of the supporting frame. The excessive material could otherwise get in the way during the moulding process.
  • Wedge your thermoplastic sheet firmly into the supporting frame.


4. Position the positive mould:
  • Pull a piece of stockinette over the base of the positive mould to aid in the removal of the socket later. Just make sure it does not cover the actual socket area, this will result in a rough inner surface.
  • Position the positive mould on the vacuum pump. You can lightly spray the mould with a silicone de-moulding spray to aid in the socket removal afterwards. Note: silicone de-moulding spray can be used for all Orfitrans sheets, except Orfitrans Excel.
  • Look at the long and short edges of your positive mould and picture how you will be placing the bubble. Make sure you have enough material to cover the long side of the mould.


5. Make sure the sheet is heated sufficiently:

  • Place the sheet in the oven and set the timer to the recommended activation time.
  • Do not leave the sheet unattended in the oven. If flexible socket materials stay in the oven for too long, they could drop excessively and melt onto the bottom of your oven.
  • Once the bubble has dropped sufficiently, take it out of the oven.


6. Mould the thermoplastic sheet:
  • Position the bubble slightly off-centre over the positive mould and let the material form against the mould. Support the frame and offer some resistance to avoid that the sheet drops too quickly.
  • Activate the vacuum slowly in order to let the material conform to the positive mould.
  • Check whether the material is conforming evenly. If necessary, press the material lightly against the plaster to smooth out any gaps.
  • Allow the material to set on the positive mould until completely cool.


Written by Marc Blij

Marc studied in Brussels and London and is a certified Orthotist and Prosthetist.

After working in an O&P lab at the Universities of Louvain and Brussels, he decided to set up his own O&P lab in Antwerp. For over 30 years, he ran his own practice, together with his wife.

Since 2006, Marc works at the Orfit Industries headquarters in Wijnegem (Belgium) as a Product and Educational Specialist in Orthotics & Prosthetics and Physical Rehabilitation.

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