Overview
Glass-mat hard laminates ("hartmatten", GM) belong to the family of laminated sheet materials: glass-fibre mats are impregnated with a thermoset resin and pressed under heat and pressure into sheets or round bars. In EP-GM-203, the reinforcing material is a glass-fibre mat, and the binding resin is an epoxy resin. Unlike thermoplastics, the cured thermoset does not melt but remains dimensionally stable, hard and mechanically resilient. Its colour is characteristically yellow-brown.
Within the glass-mat hard laminate family, EP-GM-203 differs from UP GM 203 (Hm 2471) in its binding resin: while UP GM 203 is based on unsaturated polyester resin and operates at a limiting temperature of 130 °C, EP-GM-203 uses an epoxy resin – enabling a significantly higher limiting temperature of 180 °C and higher mechanical values (flexural strength, compressive strength, modulus of elasticity), albeit at a higher price. For general electrical insulation and structural applications up to 130 °C, UP GM 203 (Hm 2471) remains the more economical choice; where high continuous temperature and high mechanical load coincide, EP-GM-203 is superior.
EP-GM-203 achieves typical values of around 360 N/mm² flexural strength at room temperature (still around 100 N/mm² at 180 °C), a tensile strength around 250 N/mm² and a compressive strength (⊥ to laminations) around 600 N/mm². Typical applications are electrical engineering and switchgear construction in high-temperature applications, power supply and transformer engineering, as well as aerospace and rail technology. EP-GM-203 is not declared suitable for direct food contact.
Technical Data
| Property | Value | Test Standard |
|---|---|---|
| Mechanical Properties | ||
| Flexural Strength 23 °C | ≥ 360 N/mm² | ISO 178 |
| Flexural Strength 150 °C | ≥ 200 N/mm² | ISO 178 |
| Flexural Strength 180 °C | ≥ 100 N/mm² | ISO 178 |
| Tensile Strength | ≥ 250 N/mm² | ISO 527 |
| Compressive Strength ⊥ to Laminations | ≥ 600 N/mm² | ISO 604 |
| Modulus of Elasticity (Flexural) ⊥ | ≥ 20000 N/mm² | ISO 178 |
| Notched Impact Strength | ≥ 50 kJ/m² | ISO 179 |
| Electrical Properties | ||
| Comparative Tracking Index CTI | 180 | IEC 60112 |
| Electric Strength ∥ (90 °C, oil) | ≥ 60 kV | IEC 60243-1 |
| Electric Strength ⊥ (90 °C, 3 mm) | ≥ 13 kV/mm | IEC 60243-1 |
| Insulation Resistance after Water Immersion | ≥ 5 · 10⁹ Ω | IEC 60167 |
| Thermal Properties | ||
| Limiting Temperature | 180 °C | EN 60893 |
| Thermal Conductivity | 0.35 W/(m·K) | ISO 8302 |
| General Properties | ||
| Density | 2.0 g/cm³ | ISO 1183 |
| Water Absorption | ≤ 40 mg | ISO 62-1 |
| Colour | yellow-brown | – |
Frequently Asked Questions about EP-GM-203
1What is EP-GM-203?+
EP-GM-203 (to EN 60893) is a glass-mat reinforced epoxy resin hard laminate ("hartmatte"). It consists of epoxy resin reinforced with glass-fibre mats and combines high mechanical strength with good electrical insulation performance, at a limiting temperature of 180 °C that is unusually high for glass-mat hard laminates. Its colour is characteristically yellow-brown.
2How is EP-GM-203 machined at Liedtke?+
We machine precision parts from EP-GM-203 sheets or round bars. Sawing, milling, drilling and turning produce clean, dimensionally accurate results with sharp, carbide-tipped or diamond-coated tools. Because of the abrasive glass-fibre content, we use wear-resistant tools and ensure adequate dust extraction.
3What determines the price of an EP-GM-203 part?+
The component price is determined mainly by sheet thickness or rod diameter, dimensions, material utilisation (offcuts), machining effort and batch size. EP-GM-203 is priced at the upper end of the glass-mat hard laminates, as epoxy resin is more expensive than polyester resin. We are happy to provide binding prices on request based on your drawing.
4When is EP-GM-203 not the right choice?+
EP-GM-203 is not declared suitable for direct food contact. If no particular temperature requirement above 130 °C is needed, UP GM 203 (Hm 2471) is more economical. Where very high tracking resistance is required, epoxy resin (CTI 180) falls short of melamine resin grades (CTI 600). As a thermoset, EP-GM-203 also cannot be reshaped or welded.
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