Filament Wound Epoxy Fiberglass Tube

Thin-wall, close-tolerance filament-wound epoxy glass tube for switchgear, breaker, medical, aerospace and cryogenic insulation.

Filament winding lays continuous glass rovings in epoxy resin around a mandrel, so the fibers run the full length of the tube with no joins. That gives the highest hoop strength for a given wall and the best concentricity of any round tube process, which is why it is the choice when the wall is thin, the tolerance is tight and the part has to be both strong and insulating. The trade is cost and lead time versus a rolled or pultruded tube.

The buyers are the ones who cannot accept a seam or a wall variation: breaker and interrupter makers, medical-equipment OEMs, aerospace and cryogenic suppliers, and fuse OEMs where the tube is a structural insulator, not a cover. They send a drawing with a thin wall and a close ID/OD, and we wind to it and machine the ends without cracking the laminate.

Technical specifications

Applications by industry

• Switchgear and breaker OEM insulation
• Interrupter and fuse structural tubes
• Medical equipment insulation components
• Aerospace and precision tubing
• Cryogenic and low-temperature equipment
• Industrial machinery insulating sleeves

Filament winding vs rolled or pultruded tube

A rolled tube is built from sheet wound on a bias and has a seam; a pultruded tube pulls profile through a die and is cheaper but lower in hoop performance. Filament winding has neither seam nor compromise on hoop strength because the fibers are continuous and oriented for the load. For a thin wall that must stay round and insulated under pressure, that is the process that holds the tolerance. The cost is higher and the run longer, which is why it is specified where performance, not price, leads.

Machining thin walls without delamination

Thin-wall composites delaminate if the tool rubs instead of cutting, so we machine with sharp tooling, proper support and controlled feed, and we deburr the edges so no lifted glass starts a track. The inspection point is the bore and the end-squareness: a skewed or burred end seats badly in a breaker or interrupter and concentrates stress. Small, odd-shaped cross-sections are normal, not a problem.

Inspection and traceability

We check ID/OD/wall and concentricity, verify end-squareness and edge quality, and run burst and dielectric checks on request with lot traceability.

• ID / OD / wall and concentricity measurement
• End-squareness and edge-quality check
• Burst-strength check on request
• Dielectric test on request
• Lot traceability for qualified programs

Related components

Common questions