Investment casting is one of the oldest manufacturing methods available, developed over 5500 years ago in Egypt and China and is still commonly used to create metal pieces today. 3D printing has complemented it well, proving that even reliable, time-tested techniques can benefit from new technology. Common parts manufactured by this process include dental fixtures, gears, cams, ratchets, jewellery, turbine blades, machinery components and other parts of complex geometry.
Investment casting is precise, but it is also time-consuming and expensive. The traditional method of using a wax injection tool to create an axial turbine blisk mould requires at least five weeks and can cost upwards of US$20,000 from start to finish. Using 3D printing to create patterns for investment casting can significantly cut production costs, overall time and manual effort compared to traditional processes.
Benefits of 3D Printed Investment Casting
1) Timely and cost-efficient production of casted parts
In comparison to traditional methods, the time and cost investments for 3D printed investment casting patterns are much lower, and 3D printing can also produce patterns of greater complexity. One can create a 3D printed investment pattern overnight; in the morning it is ready for the foundry, all for a cost below US$2,000.
2) Produce patterns with greater design complexity
Removed from the limitations and restrictions of traditional wax pattern production processes, 3D printed casting patterns can deliver higher design complexity.
3) Produce patterns significantly faster
Customers have cut weeks and months from the time taken to produce casting patterns and reduced time to casting by 90% or more.
4) Save significant costs of production
Customers have saved hundreds of thousands of dollars with 3D printed casting patterns in direct comparisons. Rapid production of casting patterns also helps quickly identify design flaws to reduce the need for costly design changes and rework that can lead to massive time and cost overruns.
5) Increase product quality and finish
The perfect surface resolution of stereolithography (SLA) casting patterns delivers an unprecedented level of quality to the final casted parts, reducing lengthy machining and post-processing requirements.
Actual Uses of 3D Printing in Investment Casting
Here, we can see that 3D printing is increasingly playing a bigger role in investment casting, with casting companies experimenting with 3D printed parts in conjunction with this traditional method. There are several ways 3D printing works hand in hand with investment casting.
Rapid tooling tools can be 3D printed to mitigate time expenses during injection mould tool production, thus saving costs.
Quickcast patterns are hollow 3D printed SLA patterns developed by 3D Systems for large, complex wax patterns used in investment casting. Large wax patterns can become distorted when exposed to pressure or heat, hence loss wax casting is not feasible for use. Quickcast mitigates distortion and yields consistent results, making it more attractive.
Wax Printed Patterns
Depending on the size and shape of the object and the equipment, wax patterns can be directly 3D printed. This method is easier to adopt in foundries compared to SLA.
3D Printing Ceramics for Investment Casting
Dutch designer Olivier van Herpt directly 3D prints the final ceramic moulds that are then cast in metal. The moulds can be up to 80 by 50 cm in size and are 3D printed in under three hours. The mould then dries and is fired before being cast and then broken away. This method is faster and more cost-effective as the material used is regular clay or ceramics.
For such an age-old process, investment casting has made some of the most technologically advanced products, especially in the aerospace industry. By combining 3D printing with this traditional technology, it is now possible to make high-quality parts more effectively and at a reduced cost.
Whether prototype, individual part or small series, 3D printing technology makes it possible to produce highly complex design and investment casting models quickly, easily and cost-effectively. It is an enormous advantage for customers who are looking to save costs.
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