Overview
| Variant | Principle | Typical use |
|---|---|---|
| Conventional ceramic shell, air melt | Induction melting and gravity pouring in air | Carbon, low-alloy and stainless steels, corrosion-resistant nickel alloys, copper alloys |
| Vacuum investment casting | Melting and pouring in a vacuum chamber | Superalloys with reactive elements, high-integrity parts |
| Counter-gravity, vacuum-assisted filling | Metal drawn upwards into the shell by reduced pressure | Very thin-walled parts, high cluster yield |
| Centrifugal investment casting | Rotation increases filling pressure | Small parts, jewellery, dental, some titanium castings |
| Solid mould (block mould) | Cluster embedded in a flask of refractory | Aluminium, jewellery, dental, prototypes |
| Directional and single-crystal solidification | Shell withdrawn from a hot zone to control grain structure | Turbine blades |
| Printed or machined patterns | Patterns made without a die | Prototypes, spare parts, very small batches |
| Titanium casting | Inert shell systems, vacuum or inert-gas melting | Aerospace, chemical and medical parts |
Air melt and vacuum
Air melting is the economical standard and is technically appropriate for the great majority of industrial alloys. Vacuum is required when the alloy contains elements that oxidise readily or when specifications limit oxygen and nitrogen. It adds equipment cost and cycle time and is therefore reserved for parts that need it. A drawing or material specification that requires vacuum-melted or vacuum-cast material must be identified at the enquiry stage.
Filling variants
In counter-gravity processes the shell is placed above the melt and filled from below under reduced pressure. Filling is calm and controllable, thin walls fill well, and metal remaining in the central sprue can flow back into the furnace, improving yield. Centrifugal casting presses metal into the cavity by rotation; it is long established for very small castings and for reactive alloys poured in cold-crucible systems.
Solid mould casting
The original industrial form of the process survives where its advantages apply: a block mould supports delicate patterns uniformly and suits vacuum-assisted pouring of aluminium. The mould is heavier, slower to burn out and cool, and limited in size, which is why ceramic shell dominates for steel.
Rapid prototyping and additive-manufactured patterns
Patterns can be produced directly from CAD data by printing in wax-like materials, photopolymer resins, polymer powders or polystyrene-type materials, or by machining wax. This allows castings in the production alloy within a short time and without tooling investment. Points to consider:
- surface quality and accuracy follow the printing process and are usually below those of injected wax;
- non-melting patterns need adapted burnout to avoid shell cracking and residues;
- cost per pattern is high, so the route is economic only for small quantities;
- properties of the casting are those of the production process, which makes the method suitable for functional prototypes.
Ceramic shells and cores can also be printed directly, an approach used for particular complex parts.
What LOSTWAX offers
The standard LOSTWAX scope is conventional ceramic shell investment casting of steels, stainless steels and related alloys for general industrial applications, combined with machining, heat treatment and inspection as described under capabilities. The other variants on this page are described as part of the technical reference. Their availability for a specific project, including vacuum casting, titanium, hot isostatic pressing and printed patterns, depends on the part and on qualified partner capacity, and is confirmed individually on enquiry rather than assumed.