Investment Casting, also known as Lost Wax Casting is a metal-forming technique. What makes this technique unique is its use of wax moulds to create complex metal structures.
Investment casting is a technique that has been in use for thousands of years. Its earliest recorded use dates back to 2500 BC, to create idols, ornaments and jewellery. In its earliest uses, natural beeswax made the patterns and clay created the moulds. Today, we use master die wax to create an infinite range of designs.
That wax is then coated in a thick layer of ceramic shell castings and left to dry and solidify to create the mould. It is then placed in a furnace to melt and remove the wax leaving only the mould. We then pour the liquid metal into the cast, where it is then cooled down and the cast removed. The cast must still be hot so that the metal can flow into the small grooves and corners.
Examples of Sylatech Lost Wax Castings
Our Unique Lost-Wax Casting
We use a unique block moulding version of the Lost-Wax Casting method. This affords customers a process capable of producing thin walls and lightweight components. For this process, we work only in the casting of non-ferrous metals. This specialist process delivers small castings with a ceramic shell wall as fine as 0.2mm. Ourrapid prototyping capability allows us to test metal prototypes within days.
Our in-house tooling capability is integral for the production of tools. We use these tools in the creation of wax patterns. We incorporate the gating system within the tool’s design to ease the casting process.
The plaster-based refractory materials we use are unable to sustain a high temperature. This limits the process to the casting of non-ferrous metals only. This is unlike ceramic mould materials when creating stainless steel castings.
We are able to ensure all casting has exacting dimensional accuracy. This is all due to our in-house CNC Machining capabilities. Our unique manufacturing method affords greater benefits compared with other techniques. They cannot compete with the surface finishes, lightweight and fine tolerances achieved.
The Lost Wax Casting Process is a fast and cost-effective metal casting method. It is perfect for both small batches and large quantities of up to 150,000 per year. It is able to produce parts with complex details, superior finishes and thin wall capabilities, without the need for machining.
We are able to produce non-ferrous foundry castings with a wall thickness as fine as 0.2 mm, more likely 1-3 mm. Our rapid prototyping capability affords engineers a fast route to test their prototype designs in metal within a few days.
Our unique casting process allows for rapid production in a cost-effective manner. By combining our non-ferrous investment casting technology with best practice CNC machining, Sylatech can overcome many of the constraints placed on engineering design whilst delivering the highest quality.
+/- 0.1 per 20mm
+/- 0.1 per 20mm
Metal Casting Company
Sylatech is one of the largest Metal Casting Companies in the UK, manufacturing a wide range of bespoke metal components for a broad range of companies across the globe. We are supported by a heritage of 57 years of delivering precision custom metal castings.
We are trusted by our partners to produce high-quality systems and components matching their exact designs.
In response to customer demands to supply alternative alloys, Sylatech has developed relationships with a number of other suppliers globally.
Where projects require components from other suppliers, we are able to manage this process for you and aim to be a single source for all of our customer’s precision components.
We take full responsibility for ensuring the product is to the correct specification and the correct quality. We also actively manage all customs and shipping on behalf of our customers.
Examples of global sourcing projects that we have undertaken for our customers include:
Lock industry components are sourced overseas and machined at Sylatech.
Steel cast links for the rail sector.
Brass components are used in the food industry.
Electronics connecting couplings are used in mining.
Door and retail furniture components.
Sizes and Tolerances
Sizing and Tolerances depend on the geometry of each part, but the following tolerances are suggested as a guide to designers.
Lengths including hole diameters held to:
0 - 15
0.0 - 0.6
15 - 25
0.6 - 1.0
25 - 50
1.0 - 2.0
50 - 75
2.0 - 3.0
75 - 100
3.0 - 4.0
100 - 125
4.0 - 5.0
125 - 250
5.0 - 10.0
Generally held to ±0.13mm (0.005") per 25mm (1.00") square.
Generally held to ±0.1mm (0.004") max per linear 25mm (1.00").
Squareness and Angularity
±0.5 degree Note: Angular tolerances are affected by irregular geometries.
When tolerancing, use of a central feature as a datum may allow detail to be cast that would otherwise carry too large a tolerance. Where a mechanical
interface feature is required on a surface, it helps to use the centre of the feature as a datum.
Constant section thin walls are preferred but large changes in the section can be accommodated through critical analysis of the component design and special tooling design features.
Suggested Wall Thickness
up to 10mm (0.4")
0.2mm - 1.0mm (0.008" - 0.04")
0.5mm - 1.5mm (0.02" - 0.06")
1.0mm - 3.0mm (0.04" - 0.12")
1.5mm - 3.0mm (0.06" - 0.12")
above 100mm (4.0")
2.0mm (0.08") upwards
Wall thickness and flatness over large surfaces are better controlled if through-holes and ribs are incorporated in the design.
Wall Section Tolerances
up to 0.5
up to 0.020
0.5 - 1.0
0.020 - 0.040
1.0 - 2.0
0.040 - 0.080
2.0 - 4.0
0.080 - 0.160
4.0 - 8.0
0.160 - 0.320
Complex internal features such as swept bends can be formed by the use of soluble cores (orange wax). Tolerances however may require relaxing.
Tooling for a complex component can sometimes be simplified by joining two or more patterns together at the wax stage. This enables the requirement for brazing after casting to be eliminated.
Cast Gears and Teeth
Components requiring teeth for gripping or gear applications may be impossible to produce by machining. The definition achieved by the Sylatech process is ideal for these applications.
Integrally cast rivets can be peened over to give an economic, strong and permanent joint.
It is possible to include many types of permanent product identification which can eliminate the further need for labelling. Logos and text may be produced with the minimum cost if the design ensures that detail is in the line of the draw of the wax from its die.
Ideally, cast labels should use raised lettering on the casting face (engraved into the wax tool). Where such information must be below a functional surface, it can be sited on a pad sunk into the cast face.
Preferred depth of engraving: 0.25mm - 0.5mm (0.010" - 0.020")
Types of Labels
ID for version traceability
Raised pad for engraved serial no.
“As cast” – parts removed directly from the mould have a surface finish equal to or better than 0.8 micrometres (32 micro inches); this finish may show variable colour.
Removes any sharp edges left after finishing, leaving a surface suitable for most subsequent “finishing” processes.
Using stainless steel shot is generally suitable for brass components and gives a slightly polished surface.
Glass Bead Blasting
Produces a more highly polished surface finish and is most suitable for aluminium parts.
Special Surface Effects
Such as textures and knurling can be incorporated within the Sylatech casting process.
Automatic Grit Blasting
Gives a uniform matt finish, suitable for most subsequent finishing operations.
Applied Surface Treatments
We can apply the following treatments:
Alocrom1200/1000 / Chromate Conversion
Surtec 650 Roche complaint processes provide corrosion resistance to aluminium parts whilst providing an electrically conductive surface.
Protective purposes can be carried out on aluminium alloy castings but cast alloys do not readily accept decorative anodised finishes due to the silicon content.
Can be applied to most alloys.
Hipping (Hot Isostatic Pressing)
Is used to improve the mechanical properties of aluminium castings by sealing internal voids.
Can be carried out on “as cast” or machined parts where pressure tightness is essential.
For protection or visual purposes.
Various heat treatments can be applied to harden components. This is carried out generally to aid subsequent machining and enhance component stability. Suffixes to the material grade are used to denote the heat treatment carried out: UK and equivalent USA and EN suffixes are shown below:
Solution heat treated and artificially age hardened
Artificially age hardened
Solution heat treated and artificially age hardened