Machining Hgw 2272

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 or round bars. For Hgw 2272 (MF GC 201), the reinforcing fabric is glass fabric and the binding resin is a melamine resin – the combination delivers the highest tracking resistance (CTI 600) of any glass-fabric laminate in Liedtke's range, combined with flame-retardant behaviour (UL 94 V-0). Compared with the cotton-reinforced melamine-resin laminate MF CC 201 (Hgw 2282.5), the glass fabric significantly increases mechanical strength and dimensional stability, but excludes the food-contact declaration. The colour is characteristically white.

Hgw 2272 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 tracking-resistant, flame-retardant insulating parts, from single items to series production.

Hgw 2272 is worthwhile whenever high tracking resistance must be combined with good mechanical strength and flame retardancy – for example:

• Insulating parts with high requirements for tracking and creepage resistance (terminals, sockets, connectors)
• Switchgear and low-voltage components requiring flame retardancy (UL 94 V-0)
• Components that need both mechanical strength and electrical insulation
• Applications where a light, white surface finish is desired
• Test and measurement technology requiring dimensionally stable, tracking-resistant insulating parts

Hgw 2272 is an engineering laminate; the price depends on the semi-finished shape (sheet, round bar), dimension, material utilisation (offcut), machining effort and lot size. Hgw 2272 is priced between the standard phenolic-resin laminates and the high-performance grades based on epoxy or silicone resin. 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 2272 is not declared for this, unlike the cotton-reinforced MF CC 201 (Hgw 2282.5)
• Applications requiring very high mechanical strength – Hgw 2372.1 is superior here
• Continuous use above approx. 130 °C (thermal class B) – a silicone-resin laminate (Hgw 2572) is the better choice here
• Reshaping or welding – not possible as a thermoset (machining only)
• Skin-sensitive applications without protective measures during machining (glass fibre dust)

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

• Very high tracking resistance (CTI 600)
• Flame-retardant (UL 94 V-0)
• High mechanical strength
• Low water absorption
• Light, white surface

Disadvantages:

• Not declared for direct food contact
• Lower limiting temperature than silicone-resin laminate (Hgw 2572)
• Lower mechanical strength than Hgw 2372.1
• Higher tool wear during machining (glass fabric)
• Higher price than standard phenolic-resin laminate

Practical tip: Hgw 2272 is the right choice when maximum tracking resistance and flame retardancy are required – for example for terminals, sockets or connectors in low-voltage technology. If food contact is additionally required, MF CC 201 (Hgw 2282.5) is the right alternative; for very high mechanical requirements, Hgw 2372.1 is preferable.