Injection moulding has long been regarded as a cost-efficient method for producing plastic components, particularly at large production scales. However, the initial investment in mould tooling can be substantial, involving complex design and costly CNC machining. This often restricts its economic viability to production runs numbering in the tens of thousands or more. But what if there was a game-changing technology that could make injection moulding feasible for smaller quantities, even down to a single part? Welcome to the world of additive manufacturing and its potential to disrupt the injection moulding industry.
Traditional CNC-Made Mould Tooling
For decades, metals like steel and aluminium have been the materials of choice for injection moulding tooling. These materials are prized for their durability, essential to withstand the high temperatures and pressures involved in the plastic injection moulding process. Metal moulds can endure tens of thousands or even millions of cycles without needing replacement.
Moreover, metal moulds, crafted with precision through CNC machining, offer exceptional accuracy and smooth surface features. This precision is crucial when producing parts with strict tolerances consistently.
Metals also excel in thermal conductivity, allowing for rapid dissipation of heat from the injected plastic, leading to faster cooling and shorter cycle times. This advantage translates to increased production within a given timeframe, making injection moulding suitable for a wide range of industries, from automotive to consumer goods, medical, and aerospace.
However, these benefits come at a significant cost. The upfront expenses for designing and manufacturing metal moulds, especially for smaller components, can run into thousands of dollars, with larger moulds reaching into the millions.
3D Printed Metal Mould Tooling
While metal 3D printing processes like LPBF (laser powder bed fusion) and EBM (electron beam melting) have been capable of creating components for injection moulding tooling, they have traditionally required extensive post-processing to achieve suitable surface finishes. This post-processing often involves heat treatment (annealing), wire EDM cutting, and CNC milling, substantially adding to production costs.
Recently, a US-based company named "Mantle Inc." has developed a ground breaking solution that allows both 3D printing and machining within the same system. Their proprietary True Shape Process streamlines the production of metal moulds.
This process involves extruding a flowable metallic paste containing metal powder and a binder, adding layers, heating, and then milling until the final shape is achieved. After completion, the part is sintered in an oven to densify the metal powders and remove the binder.
The TrueShape process ensures an accuracy of +/- 0.001" per inch and offers production-grade tools with high hardness, strength, and corrosion resistance. Additionally, the Mantle process significantly reduces lead times, enabling CAD to mould in a matter of days, and reducing traditional wait times.
3D Printed Plastic Mould Tooling
For lower production runs, 3D printing can offer a cost-effective solution. However, most 3D printed plastic parts do not match the mechanical properties of injection moulded parts, as they often exhibit varying degrees of anisotropy. Injection moulded parts, in contrast, are isotropic and equally strong in all orientations.
In recent years, specific plastic 3D printing processes have emerged for injection moulding plastics. One innovative method is soluble moulding, pioneered by companies like "Addifab." This process utilizes a DLP resin printer and soluble, sacrificial moulds for complex moulded parts that would be challenging to produce with traditional CNC moulds.
Additive manufacturing, particularly 3D printing, has the potential to revolutionize the injection moulding industry. Technologies like the Mantle process and soluble moulding are offering new possibilities for rapid prototyping, reducing lead times, and enabling the production of complex parts economically. While CNC-produced metal moulds still hold their value for large production runs, additive manufacturing is changing the game for those seeking efficiency and speed.
At MOLDEX India 2024, you can witness leading innovations and technologies in additive manufacturing that are reshaping the future of the injection mouldingindustry. Join us and be a part of this transformative journey!