Manufacturing Process of FRP Pipes

Clean and polish the mandrel to ensure a smooth surface without any potholes, dust, debris or other fixtures affecting the quality of FRP pipes. Then wrap a thin mylar parting film around the mandrel to make the pipe extraction much easier.

Check up on the equipment and make sure it is operating properly, especially resin and curing agent are in correct composition and the dual pump performs well without any clogging. All of this is to ensure high precision and stable operation of your equipment.

• Compound the resin for liner layer according to the requirements of local regulations, working environments and temperature conditions.
• Prepare the reinforce materials of liner layers. Cut reinforce materials into certain width and mounted them to specific position for easy winding.
• Manufacture the liner layers based on the design requirements. Impose reasonable tension during the winding process for excellent lapping. Meanwhile, use compression rollers to press bubbles out and ensure the reinforce materials are fully steeped with resin.
• Check the liner layer to ensure required thickness is achieved without white patch, bubbles, poor adhesive and adhesive hanging phenomena.

The liner layers are cured through far infrared depth curing process to enhance solidification degree and improve anti-corrosion properties.

Check the pipe again to ensure liner layers in manufactured without bubbles, impurity, white patch, part curing phenomena. Most all, ensure the liner layer is qualified with reasonable resin ratio.

The filament is automatically impregnated in the resin tank, and then reciprocating winded around the rotating mandrel at a specific angle. Normally, different helical angles impart different strength in the hoop or axial direction as required.

After the filament winding process, FRP pipes are far infrared cured about 1 hour to 2 hours based on weather condition. Meanwhile, the mandrel rotates at an even speed to ensure the pipe is cured evenly.

When the Barcol hardness of the FRP pipe is more than 30, then trim the pipe and separate it from the mandrel.

Test the pipe through following aspects:

• Visual inspect: Ensure the surface of FRP pipes is smooth without cracking, delamination, holes, debris, burrs, bubbles and obvious defects that affect pipe performance. In addition, the pipe end should be flush.
• Dimensional inspection: check the length, thickness, Barcol hardness and socket size of FRP pipes.
• Hydraulic pressure leakage test: Fill the pipe with water until the pressure reach about 1.5 times of pipeline design pressure and then retain the water no less than 2 minutes. Check the surface of FRP pipe and piezometer carefully. The pipes without leakage are qualified.
• Mechanical property testing.