Sand casting has several benefits including:
· Low tooling costs and fast set-up compared to investment or die casting.
· Large casting sizes possible.M-HE is able to cast Aluminium alloys up to 110kg and ferrous alloys up to 3000kg using sand casting methods.
· Complex and intricate castings can be achieved with multiple internal cores.
· Up to 70% of the sand used in the process is reclaimed.
· Very versatile; many different kinds of metal alloy can be cast using this process.
· Sand casting is best suited to low volume or complex non-ferrous castings or large ferrous castings.
1. A wood, resin or metal pattern is made which forms an impression of the component to be cast.
2. The pattern is used to make a mould, usually in greensand or resin bonded sand.
3. If cores are required to form internal structures, these are made in CO2 or resin sand.
4. Molten metal is poured into the mould, which is then allowed to solidify.
5. The casting is then removed from the mould and up to 70% of the sand is reclaimed.
6. The casting then goes through the fettling process to remove the risers and excess material
7. Castings often undergo further surface finishing before dispatch to the customer
Investment casting delivers many benefits including:
· Great versatility; suitable for casting most metals.
· Will allow very intricate castings to be produced.
· Smooth surface finishes are possible with no seam line so machining and finishing are reduced or eliminated.
· Allows un-machinable parts to be cast accurately instead.
· Excellent dimensional accuracy
· High volume production can be achieved with low repeat costs.
· Can be used to prototype and prove designs prior to die casting tooling investment.
· Is ideally suited to smaller, intricate or complex designs although we can cast up to 250kg
1. A metal die is made, the impression being the same as required in the final mould.
2. Molten wax is injected into the metal pattern, allowed to solidify and then removed. Some complex wax patterns are fabricated by joining several separate patterns together using an adhesive.
3. The waxes are then assembled on a wax tree, many parts can be put on the tree depending on size, it is common for components to be in the weight range 0.1kg up to 80kg.
4. The tree is then immersed in several different slurries to coat the wax, the initial slurry is fine as this will be the surface finish of the final casting.
5. After drying, the trees of wax are put into ovens of about 200 degrees to melt out the wax.
6. When all wax is removed the trees are heated up to about 900 degrees to complete preparation for casting.
7. The metal is then poured into the moulds.
Gravity die casting:
Gravity die casting delivers many benefits including:
· Excellent dimensional accuracy
· Smooth cast surfaces
· Thinner walls can be cast allowing intricate shapes
· Inserts, such as threads, heating elements and high-strength surfaces can be cast-in
· Secondary machining is reduced or eliminated
· Production rates can be rapid making longer production runs possible
· Tensile strength is higher than with sand casting
1. A metal die is manufactured, usually in 2 parts, to form a mould.
2. The mould is heated and a lubricant is sprayed into it to assist in controlling temperature and in removal of the casting.
3. Molten metal is poured into the mould.
4. Once solidified, the die is opened and the casting removed either by hand or with the use of pins in automated processes.
5. Excess material including the gate, runners, sprues and flash can be removed using a trim die in a power press or by hand.
6. Scrap metal is then re-used in the production cycle by re-melting.
M-HE can provide precision machinining. Quality assurance and testing is provided. Options include turning, milling, grinding and drilling with final inspection once machining operations are complete and all machining is carried out in ISO9001:2008 accredited machine shops.
Precision turning services deliver axi-symmetric components which typically include features such as holes, grooves, threads, tapers, diameter steps and contoured surfaces.
M-HE can provide high volume milling services for components that are typically not axially symmetric and which require holes, slots, pockets and three dimensional surface contours.
Grinding is generally used to create a precision flat surface, using an abrasive grinding wheel to remove material and produce a smooth surface.
M-HE can provide a variety of drilling operations, depending on the project requirements. As with all machining processes, expertise is needed to avoid adversely affecting the mechanical properties of the component.