The isostatic molding process must be split into two different processes: on the one hand,
isostatic molding applied to pipes, on the other hand, applied to fittings.
The isostatic molding applied to pipes takes place outside the steel pipes themselves and, thanks to the dilatation of specially engineered rubber membranes, PTFE powders are compressed at high pressures in specific metal molds.
This semi-finished product is a three meterslong PTFE pipe: we are the only firm in the world providing pipes this long. The pipe then goes through a sintering process, which ultimately provides the product with the typical properties of PTFE
The isostatic process in relation to fittings is a completely different story: it directly takes place inside the fittings, which act as molds, and in which elastomeric components are inserted. Gaps between the steel body and the rubber form are then created and filled up with PTFE powder.
Once the mold has been sealed, it goes under pressure up to 300 bar, radially expanding the rubber form towards the inside wall of the steel fitting, compressing the PTFE powder: during this process the quality of welds can be monitorized, checking for potential flaws.
Advantages of isostatic molding:
- a completely homogeneous composition of the PTFE lining, providing impeccable mechanical properties throughout the whole piece (preventing potential structural weaknesses or thinning of the lining)
- every fitting is made in a single piece, so there are no leaks whatsoever.
- the isostatic molding process does not accept any qualitative flaw: in case of defects, the whole PTFE lining would shatter.
- a lower deformation and elongation of the lining compared to products obtained through other processes, due to its rock-solid fit into the steel piece.
- a better deformation and bending resistance, taking into account the high tensile strength.
- speaking of fittings, the molded PTFE parts do not suffer stretchings, bendings, deformations or flarings, keeping the initial mechanical properties intact.
- In regards to pipes, the process lets the product keep its resistance constant, both radially and longitudinally, strongly decreasing the material movement, based on its operating temperatures.