PTFE, PEEK Processing & Manufacturing Capability
Compression Moulding
Compression Moulding is performed using metal tube moulds for solid rod and cylinders and steel block moulds for sheet, PTFE powder is loaded into the mould and compressed under vertical pressure in a hydraulic press for a specified time delivering the desired shape (known as preform). It is then stripped from the mould, cooked (sintered) in a hot air oven and then cooled gradually to deliver the finished product. Rod, sheet and cylinders are manufactured using this process.
Isostatic Moulding
Isostatic moulding is accomplished by compressing PTFE powder in a pressure vessel consisting of a metal tube with a silicone rubber internal bladder that is inflated with very high hydraulic pressure, causing the PTFE powder to be compressed radially (equally from all directions rather than from the ends as per compression moulding.). The desired shape is extracted and then cooked in a hot air oven. Rod and tubes are manufactured using this unique process and is far superior to ram extruded products as Isostatic moulding guarantees consistent physical properties across each length of product. This is imperative for small part production runs particularly where application performance and dimensional stability is critical.
Skiving
Skived sheet, rolls and tapes are produced by peeling a PTFE cylinder using a similar process to manufacturing wood veneers. A PTFE cylinder is pressed onto a mandrel and mounted onto a lathe. A special cutting tool is mounted onto the cross slide which at a constant speed advances towards the PTFE cylinder skiving off a continuous film at a constant thickness.
Etching
Due to the low surface tension of PTFE, nothing sticks to it, giving PTFE the lowest coefficient of friction of any known solid material. It is possible to adhere PTFE through a process which alters the molecular structure known as etching. The only element to react with PTFE is sodium metal which in a controlled environment strips away the fluorine atoms from the PTFE resulting in a surface that is bondable. At Fluoro Pacific we have an etching plant that is environmentally safe and capable of etching sheet, skived tape and machined parts.
Ram Extrusion
PTFE cannot be extruded like traditional polymers due to its very low coefficient of friction and high melt viscosity. Commonly known as a non-melt processable polymer, PTFE can be extruded at slow rates using ram extrusion. PTFE powder is compacted by a ram, forced into a die, heated to its processing temperature and then moulded under high load into the desired shape.
All products manufactured by Fluoro Pacific are accompanied with Batch Test Reports containing the following key data:
- Tensile Strength to ASTM Standard D638-03
- Elongation % and Elongation at Break to ASTM Standard D638-03
- Hardness of Moulded Billet (Shore D) to ASTM Standard D2240
- Shrinkage of Moulded Billet (% change from moulded size of 57mm) to ASTM Standard D4894-04
- Bulk Density to ASTM Standard D4894-04
Retained batch samples are kept for a minimum of 24 months, should further testing be required and formulation logs are kept for several years.