Machining Hgw 2372

Fabric-based laminates (HGW) belong to the industrial laminates: fabric layers are impregnated with a thermosetting resin and pressed under heat and pressure into sheets, round bars or tubes. For Hgw 2372, the reinforcing fabric is glass fabric and the binding resin is an epoxy resin. Compared with cotton-fabric laminates such as HGW 2282.5, the combination of glass fabric and epoxy resin yields significantly higher strength, lower water absorption and better electrical insulation values; the colour is characteristically light green. Unlike the related, flame-retardant-treated grade HGW 2372.1 (EP GC 202, "FR-4"), Hgw 2372 is not flame-retardant treated.

Hgw 2372 machines well – sawing, milling, drilling and turning produce clean, dimensionally accurate results with sharp, carbide-tipped or diamond-coated tools, and we allow for the increased tool wear caused by the glass fabric. During machining we ensure adequate dust extraction. This allows us to reliably manufacture high-strength, electrically high-performance insulating parts, from single items to series production.

Hgw 2372 is worthwhile whenever high mechanical strength must be combined with good electrical insulation – for example:

• High-strength insulating and partition panels in medium-voltage switchgear technology
• Mechanically highly loaded insulating parts in mechanical engineering
• Jig and fixture components with high electrical stress
• Power-transmission components requiring insulation
• Precision and test engineering requiring low water absorption

Hgw 2372 is an engineering laminate; the price depends on the semi-finished shape (sheet, round bar, tube), dimension, material utilisation (offcut), machining effort and lot size. Hgw 2372 is priced above cotton-fabric laminates such as HGW 2282.5, since glass fabric and epoxy resin require more material effort. We are happy to quote binding prices on request based on your drawing.

Equally important are the limits of the material:

• Direct food contact – Hgw 2372 is not declared for this
• Flame-retardancy requirement (UL 94 V-0) – HGW 2372.1 (EP GC 202, "FR-4") is more suitable here
• Pure cost optimisation without increased mechanical or electrical requirements – a cotton-fabric laminate such as HGW 2282.5 is sufficient here
• Continuous use above approx. 130 °C (thermal class B) – a silicone-resin laminate is more suitable here
• Reshaping or welding – not possible as a thermoset (machining only)

An honest assessment – and how the disadvantages can be mitigated in practice.

Advantages:

• High mechanical strength
• Good electrical insulation properties
• Low water absorption
• High tracking resistance (CTI up to 320)
• Good machinability

Disadvantages:

• Not declared for direct food contact
• Not flame-retardant treated – for UL 94 V-0, choose HGW 2372.1
• Higher tool wear during machining (glass fabric)
• Higher price than cotton-fabric laminates
• Continuous use limited to about 130 °C

Practical tip: Hgw 2372 is the right choice when high strength, low water absorption and good electrical insulation are required but flame-retardant treatment is not needed. If UL 94 V-0 is required, HGW 2372.1 is the right choice; if the strength of a cotton-fabric laminate is sufficient, HGW 2282.5 is the more economical choice.