Casting
resins
For casting resins, Lerg® has a cutting-edge installation for the production of furane resins. These materials provide great options for the making of a range of plastic components with extraordinary precision. The use of the right material guarantees the highest accuracy of the target component.
It must by characterized, among others, by:
• optimal viscosity – the lower it is, the better the details of the mould can be reproduced,
• low shrinkage – to ensure the desired size of the target component,
• properties corresponding to the use of a part – depending on the way the finished product is used, appropriate materials should be used (e.g. characterized by high hardness or flexibility).
The casting resins offered by Lerg® are perfect for both full-mould and step casting techniques. You can be sure that with the use of our products you can make both very small precision parts and large-size components.
Our range features products designed for use in the following technologies:
• Self-curing cement technology – for this application, we offer furane materials that are perfect for the production of moulding and core sands,
• Hot-Box technology, which most often employs ready-made components as moulds for iron and aluminium castings,
• Thermoshock – in this case, the best choice will be urea-phenolic-formaldehyde variants,
• CO2-cured cements – an advanced method with core blowing with carbon dioxide,
• Alpha-Set – the best material for this technique is the alkaline, phenolic model.
This technology uses ester-cured, phenolic alkaline resins of the resole type. The core cement is made of quartz, chromite or zircon sand and resin with the curing agent. In the reaction between the resin and the agent, the mould or core become hardened.
The Hot-Box process is used to mould full cores. The bonding reaction is exothermic, which helps further reinforcement process after the removal of heat source. Cores made in this technology are used in iron and aluminium casting (urea-furfural resins) and steel casting (phenolic-formaldehyde resins). The curing of resin is done in the core box preheated to 150-220ºC, depending on the applied resin. The preparation of cement composed of quartz, resin and curing agent is done before injection into the core box. The time that the material stays in the core box depends on the core wall thickness, mass composition and the type of used resin; it usually varies between ten to fifty seconds. This process is particularly recommended for the serial production of cores, as it requires accuracy and repeatability of dimensions and shapes, adequate strength and de-coring.
The Thermoshock method is used to produce thin and flat cores, chiefly for the casting of cast-iron radiators. Our offer consists of urea- phenolic-formaldehyde resins.
Furane resins of the Ekotec® series are intended for the preparation of self-curing moulding sands (cured by means of the “no-bake” method). Ekotec 45 and Ekotec 60 resins are recommended for the preparation of moulding sands and core sands for iron casting in foundries which do not employ sand regeneration. Ekotec 75 R and Ekotec 80 resins are recommended for iron casting in foundries where sand regeneration is used. Ekotec 90, due to the low nitrogen content, is used for the production of sand used in iron and steel casting.
This technology goes with phenolic alkaline resins of the resole type, mainly intended for the production for cores and iron and steel castings. The curing of resin is achieved by blowing the core with CO2.
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Mirosław Ruciński
PRODUCT MANAGER
t: +48 14 680 62 35
k: +48 660 738 127
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