HIFLON 620 powder conforms to type III of the ASTM D-1457/69 specification. They are obtained by coagulation of the emulsion produced by polymerisation under strictly, controlled conditions of extremely pure C2F4 monomer.
It produced by coagulation of PTFE emulsion in controlled conditions. It is having average particle of 400 microns.
The general method of processing application to HIFLON 620 is described in the following.
HIFLON 620 powder has two essential characteristics:
It is not a moulding powder intended for the production of parts by compression moulding. It is designed to be worked by using lubricants which, when mixed with it, convert it to a relatively plastic mass suitable for these methods of transformation.
Two types of working procedures are described: -
- Simple extrusion, designed for the production of rods, tubes and profiles which are sintered after elimination of the lubricant.
- Extrusion followed by calendaring, intended for the production of tapes, which is generally used in the non-sintered form after elimination of the lubricant. This tape is called "unsintered" or "thread seal" tape.
It is very fragile plastic powder; the grains can be crushed or sheared under the action of low mechanical stresses. These deformations cause an irreversible orientation of the crystallites within the grains, which become fibrous in a random manner, leading to defects in the extruded tube.
Great cautions must be taken when handling the powders.
Before processing powder is to be conditioned at > 19 deg C and below 23 deg C. And also sieved the powder with 1.2 mm sieve with gently. Avoid vigorous shaking of the powder while sieving to avoid deformation of powder particles.