Learning nugget: Molding

SUMMARY:

The objective of molding is to achieve molds with sufficient strength to withstand the ferrostatic pressure of the casting and the subsequent cooling of the metal inside. There are several types of molding, the most important of which are sand molding, either chemical or green sand, shell molding, lost-wax molding, and metal shell molding.

Focusing on green sand molding, the most commonly used method in iron foundries, mold manufacturing can be done manually or using machinery. Foundries used manual molding, but its low productivity, repeatability, and the numerous problems it caused have led to its gradual replacement by mechanical molding, which is currently the most widely used method.

The patterns used to manufacture molds can be constructed from various materials, depending on their application. Manual molding techniques used single patterns, while mechanical molding processes commonly use pattern plates, which can be made of wood, metal, and/or resins.

There are several types of molding machines with varying configurations and production capacities. In general, mechanical molding techniques can be classified into two broad groups: low-pressure and high-pressure molding.

INDEX:

1. BASIC CONCEPTS
2. MOLDING TYPES
3. CHEMICAL MOLDING
4. GREEN SANDS MOLDING

(*) This training session dedicated to molding systems is part of the “Introduction to Iron Casting” series, which consists of 13 short videos lasting between 15 and 40 minutes.