Rotational Moldings and Linings

In addition to liners and coatings, Edlon is also a provider rotationally molded and lined parts. Rotomolding and rotolining are excellent solutions to handling complex shapes. Edlon uses 6 different fluoropolymers for this fabrication method:

• PE and PP – high purity applications.
• PVDF – PVDF offers resistance to many chemicals, including bromine, at a low cost. PVDF is often used in ultra-pure water systems.
• ECTFE – ECTFE offers chemical resistance and results in a very smooth surface when rotomolded or rotolined. ECTFE is often used in ultra-pure water systems and high purity applications.
• ETFE – ETFE is used only for rotolining. ETFE is useful for high purity applications.
• PFA – PFA offers universal chemical resistance.

Typical aplications for rotomolding and rotolining include:

• Filter housings
• Columns
• Vessels and vessel covers and heads
• Spool sections
• Complex shapes
• OEM free standing parts

Rotomolding

Rotomolding is a method of creating seamless, free-standing, plastic parts. Plastic resin is placed inside a metal mold which is heated to the fluoropolymer’s melting point and rotated on multiple axes. When the plastic is melted, it flows around the inside of the mold coating the entire interior surface evenly. The mold is cooled while still rotating to create a uniform thickness throughout the interior of the mold. There are many advantages to rotomolding:

• Low cost tooling. There is no core required to the mold, which greatly reduces cost for this tooling.
• Stress-free parts. Since there is no core to these molds, the plastic flows freely into all cavities, rather than being forced into the mold cavity under pressure.
• Design flexibility. Again, because there is no inner core, it is much easier to modify molds after prototyping.

Rotolining

Rotolining is very similar to rotomolding, except that the metal mold becomes the exterior of the finished part. This solution is ideal for complex shapes, or for when a fluoropolymer lining needs to be thicker than a coating.

For applications involving elevated temperatures or vacuum, Edlon offers a variation on rotolining called Fluorolock (TM). Fluorolock is offered in both ETFE and PFA. A wire screen or mesh is welded to the interior of the metal before being rotolined. When the plastic cools, it will have cooled under, around, and over the wire screen, creating a stronger mechanical bond with a liner capable of withstanding more severe conditions.