Lost mould casting

Green sand preparation starts with the mixing of the sand, clay binder and necessary additives. This may be done in atmospheric- (the most common situation) or vacuum mixers (see Section 4.3.2.1). Both methods are considered to be BAT. For vacuiun mixing, an additional condition is that the sand capacity needs to be higher than 60 t/h. 

Chemically-bonded sand mould and core-making 

Various binder types are in use, all with their own specific properties and applicability. All binders are determined as BAT if they are applied according to the discussed good practice measures, which mainly involve process control and exhaust capture measures to minimise emissions (Section 4.3.3.3, 4.3.3.4). BAT associated emission levels are given below (Table 5.6). 

Additionallly, for amine-hardened urethane-bonded (cold-box) core preparation, BAT is all of 

BAT is to minimise the amount of sand going to disposal, by adopting a strategy of regeneration and/or le-use (see section 4.8.13) of chemically-bonded sand (as mixed or monosand). In the case of regeneration, the following conditions apply  

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Dust and particles releases are a general issue in all stages of the foundry process, and for all processes used. Dust is generated in the production and processing of sand moulds and cores, as well as in the finishing of the castings (both from lost moulds and permanent moulds). 

On the moulding side, a basic distinction is made between permanent and lost moulds. Foundries casting in permanent moulds, buy these metal moulds (dies) externally, but typically operate an in-house mould repair and maintenance shop. Foundries casting in lost moulds, often buy wooden, metal or plastic patterns (for their mould design) and operate an in-house pattern maintenance and repair shop. Moulds, cores and lost models are generally produced as part of the foundry process. 

Expendable pattern casting (Lost Foam/full mould casting) 3.9.6.1 Unbonded sand - Lost Foam... 

Casting, cooling and shake-out, using lost moulds... 

Alternative moulding/core-making methods Lost Foam casting... 

Iron casting (moulding) Use of lost moulds made of bentonite-bonded sand. 

Lost mould or single use moulds, a mould that is specially made for each casting and is destroyed after pouring. The moulds are generally made of sand, chemically-bonded or clay-bonded, or even unbonded. Investment casting can also be included in this family... 

INVESTMENT CASTING, LOST FOAM CASTING AND SHELL MOULDING... 

After compaction, molten metal is poured into the mould causing the foam to burn up and vaporise as the molten metal replaces the foam pattern, exactly duplicating all the features of the original pattern. Like other investment casting methods, for each new casting produced, a new pattern must be made hence the name lost foam casting. 

Where required, chapters have heen updated in line with current developments, e.g. lost foam casting and metal injection moulding. 

Investment casting, lost foam casting and shell moulding... 

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