3D Printing provides an Advantage over Traditional Dies and Tooling
For decades, the manufacture of plastic parts has been dominated by a single process – injection moulding. However, the rise of industrial additive manufacturing has rewritten the rulebook. A shift in market demands – favouring customisation and speed over sheer volume – has tilted the scales in favour of 3D Printing. To understand this realignment, one must first understand the technologies themselves.
3D Printing, or additive manufacturing, is the process of creating a three-dimensional object from a digital Computer-Aided Design (CAD) model by depositing material layer upon layer. Unlike traditional methods that cut away material (subtractive) or force it into a cavity (formative), 3D Printing builds objects from the ground up. The printer’s software slices the digital model into thin, two-dimensional cross-sections and translates these into machine instructions. The printer then follows these instructions, adding material – typically plastic resin, powder, or filament – only where needed. This fundamental mechanism eliminates the need for tooling, enabling the fabrication of complex internal geometries and organically shaped structures that are impossible to achieve via any other method.
Injection moulding, by contrast, is a formative manufacturing process used to produce high volumes of identical parts. It involves melting plastic granules in a heated barrel and injecting the molten material under high pressure into a closed metal mould. Once the material cools and solidifies, the mould opens, and the part is ejected. The per-part cost is low, and the initial investment is recovered with usage and saving on process time, and material used. Moulds are precision-machined from steel or aluminium, can cost hundreds of thousands of rupees, and typically take three to four months to fabricate. Injection moulding is an engineering feat of repeatability, but it is a process that demands certainty before production begins.
3D Printing – Going Tooling Free
The most significant advantage 3D Printing holds over injection moulding is the complete elimination of tooling. Injection moulding requires a physical, custom-made mould for every unique part design. If a design change is required, the mould must be physically re-cut or entirely replaced – a process that is both prohibitively expensive and time-consuming. This locks manufacturers into designs months before a product hits the market.
3D Printing bypasses this entirely. It is tool-free manufacturing. There are no moulds to machine and no lead times for tooling. If a design needs to be tweaked, the engineer simply modifies the CAD model, hits ‘slice’, and prints. This iteration cycle takes minutes or hours, not months. In an era where product life cycles are shrinking and consumer preferences are volatile, this agility is not just convenient – it is a competitive necessity. Injection moulding simply cannot match this agility.
The Economics
Injection moulding’s economic model is built on economies of scale. The astronomical initial investment in the mould is amortised over hundreds of thousands or millions of parts, driving the unit cost down. However, this creates a massive financial penalty for low-volume production or customisation. If you need only fifty units, or even five thousand, the mould cost renders the project economically unviable.
3D Printing inverts this equation. Because there is no upfront tooling investment, the cost per unit remains stable regardless of quantity. Whether you print one part or one hundred, the price is roughly the same per part. This makes 3D Printing the undisputed king of low-to-medium volume production. It allows for mass customisation without impacting manufacturing costs. While injection moulding requires the market to conform to the mould, 3D Printing allows the product to conform to the customer.
Unlocking Geometric Complexity
Injection moulding is a process of compromise. To eject a part from a hard metal tool, designers must incorporate draft angles, avoid undercuts, and design with uniform wall thicknesses. Complex features often require complex “side-actions” and slides in the mould, which exponentially increase tooling costs and introduce potential points of mechanical failure.
3D Printing thrives on complexity. The additive process has no such geometric restrictions. Designers can create parts with conformal cooling channels, lattice structures for weight reduction, and intricate internal passageways that would be impossible to mill into a steel mould. This design freedom allows engineers to optimise for performance rather than manufacturability. The result is parts that are lighter, stronger, and functionally superior. In injection moulding, complexity is a cost burden; in 3D Printing, complexity is free.
Speed to Market and Supply Chain Resilience
The lead time is often the invisible currency of manufacturing. For injection moulding, the clock starts ticking slowly. While the mould is being cut over several months, the product cannot generate revenue. 3D Printing compresses this timeline from months to days. This speed extends beyond the prototyping phase. In today’s volatile supply chain environment, holding vast inventory of injection-moulded parts is a liability. 3D Printing enables on-demand, digital warehousing. Instead of storing physical finished goods in a warehouse, companies store digital files in the cloud and print them only when an order is received. This eliminates inventory carrying costs.
Addressing the Perceived Gap in Quality
Historically, critics have argued that injection moulding maintains a monopoly on high-quality surface finish and tight tolerances. However, this gap is rapidly closing. Until recently, manufacturers had to choose between the accuracy of moulding and the flexibility of printing. This is no longer the case. For example, Stratasys has unveiled game-changing solutions that directly challenge injection moulding on its home turf. The Stratasys Origin Two is a DLP (Digital Light Processing) 3D Printer designed specifically for manufacturers seeking an alternative to traditional tooling for short production runs. This system achieves a dimensional accuracy of ± 50 µm and an excellent surface finish smoothness. For industries like aerospace, automotive, and connector manufacturing, this erases the final excuse to stick with legacy tooling for low-volume, high-precision needs.
Furthermore, for production environments not yet ready to abandon moulding entirely, Stratasys’ industrial FDM (Fused Deposition Modeling) Printers allow manufacturers to 3D print the moulds themselves. This bridge tooling approach allows companies to use printed moulds to produce small quantities of functional parts using actual production-grade materials, validating the design before committing to a multi-thousand-rupees steel tool. This hybrid capability, spearheaded by companies like Stratasys, gives 3D Printing a strategic edge – it can play both the long game and the short game simultaneously.
Conclusion
Injection moulding is not obsolete. For runs of a million identical parts, its efficiency is undisputed. But the demand today is for agility, customisation, and speed. In current scenarios, 3D Printing offers an edge that injection moulding cannot replicate: the freedom to change your mind without financial penalty. The future belongs not to the process that can make the most of one thing, but to the process that can make anything viz 3D Printing.
