Most traditional manufacturing processes, such as injection molding, thermoforming, or casting, require specialized tooling to create parts for specific applications. However, these toolings come with high initial costs and long lead times from suppliers, lasting weeks or months, which delay product development and prolong time to market.
Integrating in-house rapid tooling processes, such as molds, prototypes, and 3D-printed dies, into the product development process allows businesses to verify and confirm design and material selection before transitioning to mass production. It also provides a cost-effective way to produce custom or limited-edition parts for specific applications.
This comprehensive guide will cover:
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What distinguishes rapid toolmaking from traditional toolmaking?
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The diverse applications of rapid tooling.
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Real-world case studies involving rapid toolmaking.
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Manufacturing processes that can benefit from rapid tooling.
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How to quickly start building your own in-house tools.
What is Rapid Tooling?
Rapid tooling is a group of techniques used to produce tools quickly, at low cost, and efficiently, replacing traditional manufacturing processes to create parts within tight deadlines or in smaller quantities.
Traditional tools are often manufactured from durable metals using technologies such as machining, milling, and casting. However, these processes are costly and best suited for large-scale production cycles. When used for multiple tool rework cycles or to produce tools for small batches of parts, costs increase significantly and lead times are greatly extended.
Integrating rapid tooling into the product development process allows manufacturers to verify and validate designs and material selection before transitioning to mass production, accelerating product development, making rapid design improvements, and bringing better products to market. Rapid tooling enables engineers to use the same grade of materials as in actual production to evaluate how parts will perform under real-world conditions and allows for the production of limited quantities for beta testing and validation. Rapid tooling can also help resolve manufacturing process issues before investing in expensive production tooling.
On the other hand, rapid tooling is also a method for producing custom-made or limited-batch parts for practical applications using traditional manufacturing processes that would be too costly to employ. This method allows manufacturers to test the market for new products, offer a wider range of products, or customize parts to meet customer needs.
| section | Rapid Tooling | Conventional Tooling |
|---|---|---|
| Speed | 24-hour in-house production using additive manufacturing techniques. | 4–8 weeks of outsourced production. |
| Tooling cost | Low cost, similar to rapid prototyping, low hidden costs. | It's very expensive and has many hidden costs. |
| Optimal production volume | 1 to 10,000 pieces, depending on the process and materials of the tool. | Approximately 5,000 pieces or more, varying depending on the manufacturing process. |
| Applications | Prototyping, testing, and validation of bridge tooling products; short-run production; custom-made or bespoke designs. | Mass production |
Rapid Tooling vs. Rapid Prototyping
Those familiar with rapid prototyping may question the difference between rapid prototyping and rapid tooling.
Rapid prototyping is a group of techniques used to quickly produce scaled-down models of physical parts or assemblies based on three-dimensional computer-aided design (CAD) data. Because these parts or assemblies are often created using additive manufacturing techniques rather than traditional machining methods, the term has become synonymous with additive manufacturing and 3D printing.
Rapid tooling uses additive manufacturing or machining processes to create “tools” rather than directly making parts. Instead, it creates molds, dies, or castings, which are then used in traditional manufacturing processes to produce the final parts. This approach bridges the gap between (rapid) prototyping and actual production, enabling the production of parts for real-world applications.
Soft Tooling vs. Hard Tooling
The terms soft tooling and hard tooling are often used in the context of rapid tooling. Soft tooling generally refers to the use of silicone molds and urethane casting processes. Similar to rapid tooling, it is often used for prototyping, bridge tooling, and small-scale production. Prototypes for urethane casting are often produced using 3D printing.
Hard tooling is a term used to describe tools made of metal, primarily in the context of injection molding. Hard tooling can be produced using rapid tooling methods and is mostly made from aluminum. Hard tooling is durable and capable of high-volume production, but it is significantly more expensive than soft tooling or most rapid tooling methods, making it more suitable for large-scale production.
Applications of Rapid Tooling
Rapid tooling can be used to support a variety of traditional manufacturing processes to produce parts made from plastics, silicone, or rubber, composite materials, and even metal parts.
Plastic parts fabrication:
- Injection molding
- Thermoforming
- Casting
- Overmolding and Insert Molding
- Compression molding
Silicone or rubber parts fabrication:
- Injection molding
- Casting
- Compression molding
- Overmolding and Insert Molding
Composite parts fabrication:
- Thermoforming
- Compression molding
- Forming
Metal parts fabrication:
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Casting
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Sheet Metal Forming
Different rapid tooling methods can be categorized into two main categories: direct tooling and indirect tooling.
Indirect tooling involves using master patterns to produce molds or tools, which are then used to manufacture the final parts.
In direct rapid tooling, industrial-scale 3D machines or printers directly create molds, dies, or tools, which are then used immediately in the production of final parts.
Injection molding
Injection molding is one of the most popular manufacturing processes for thermoplastic, silicone, or rubber parts. Due to the very high cost of traditional metal tooling, this process is one that can best benefit from rapid tooling.
With affordable desktop resin 3D printers and high-temperature resistant 3D printing materials, it's possible to create in-house 3D-printed injection molds to produce functional prototypes and small, functional parts using production-grade plastics.
For low-volume production (approximately 10–1000 pieces), 3D-printed injection molds offer significant time and cost savings compared to expensive metal molds. They also facilitate a more agile approach to product manufacturing and development, allowing engineers and designers to create functional prototypes or parts in small quantities to test and validate material selections and continuously refine designs with short lead times and low costs before investing in hard tooling.
Stereolithography (SLA) 3D printing is a cost-effective alternative to machining aluminum or steel molds. SLA-printed parts have a solid, isotropic material composition and can withstand a heat deflection temperature of up to 238°C at 0.45 MPa, meaning they can withstand the heat and pressure of injection molding processes.
The Shenzhen-based contract manufacturer Multiplus used 3D-printed injection molds with a high-fiberglass-reinforced, heat-resistant Rigid 10K Resin on a Formlabs 3D resin printer, reducing the lead time for a small batch of approximately 100 injection-molded parts from four weeks to just three days.
Additional examples include emergency mask straps by the petrochemical company Braskem, and prototype and pre-production parts for customers of the manual injection molding machine manufacturer Holimaker.
As an alternative for medium-volume production of approximately 500 to 10,000 pieces, machining aluminum molds can also help reduce the fixed costs associated with mold manufacturing. Aluminum machining is about five to ten times faster than steel and results in less tool wear, meaning shorter lead times and lower costs.
Furthermore, aluminum conducts heat faster than steel, reducing the need for heat dissipation channels and allowing manufacturers to design simpler molds while maintaining shorter cycle times.
thermoforming
Thermoforming is a comprehensive manufacturing process that encompasses various methods manufacturers can choose to shape heated plastic sheets, such as vacuum forming and pressure forming. Thermoforming allows manufacturers to produce parts from a wide variety of thermoplastic materials, including composites.
Many businesses choose SLA 3D printing to create molds for thermoforming processes because it offers rapid production times at low cost, especially for short runs, custom parts, and prototyping. 3D printing also provides superior design freedom, allowing for the creation of molds with complex and delicate shapes. A desktop SLA printer like the Form 4 is used to produce small molds, while a larger Form 4L 3D printer is used for molds up to 35.3 x 19.6 x 35 centimeters (13.9 x 7.7 x 13.8 inches).
Glassboard, a product development company, leverages the high printing speed of its Fast Model Resin material to rapidly produce molds and prototype polycarbonate items such as helmet shells or packaging. They are able to create complex mold shapes that are difficult to manufacture using traditional methods, including intricate details and holes to help distribute vacuum pressure more evenly across the surface.
Glassboard, a product development company, uses 3D-printed molds to thermoform polycarbonate prototypes such as helmet shells or packaging.
Cosmetics manufacturer Lush used to create master molds for their popular products by hand, but more recently they have turned to 3D printing to create detailed and intricate vacuum forming molds. This allows them to transform concepts into actual products in less than 24 hours and test over a thousand design concepts each year. 
Lush's team printed the master prototype using an in-house 3D printer for use in the vacuum forming process.
3D-printed rapid tooling is also ideally suited for cost-effectively producing custom or bespoke parts for practical applications. For example, vacuum forming on 3D-printed models is a primary method used to manufacture clear aligners for orthodontics. 
Vacuum forming and pressure forming on 3D-printed models are the primary methods used to manufacture clear aligners for orthodontics.
High-performance composite materials, such as carbon fiber, can be hand-laminated onto 3D-printed molds. SLA 3D printing provides a smooth surface finish, a key characteristic for layup molds.
The TU Berlin Formula Student Team hand-layered carbon fiber onto a 3D-printed mold for a race car. The mold, printed with Tough 1500 Resin, demonstrated strength and structural support during the layering process, while also being flexible enough to easily separate the finished piece from the mold after curing, opening up a wider range of design possibilities.
3D-printed molds and carbon fiber parts removed from the molds for the front steering wheel cover.
Overmolding and insert molding.
Rapid tooling, which uses molds printed with a 3D printer, can also be used to mold plastic, silicone, or rubber parts, as well as overmolding internal inserts or hardware.
The Google ATAP team uses 3D-printed stand-ins, or surrogate parts, instead of overmolded sub-electronic assemblies for initial tool tuning in-house.
Designers at the Google Advanced Technology and Projects Lab (ATAP) were able to reduce costs by more than $100,000 and shorten test cycle time from three weeks to just three days by using a combination of 3D printing and insert molding. The Google ATAP team found that by 3D printing test parts, they could save both time and money compared to using expensive electronic components that had to be ordered and shipped from suppliers.
Dame Products, a Brooklyn-based startup, designs products for the healthcare and wellness industry using silicone insert molding to encapsulate internal hardware for customer beta prototypes. Dame Products' product line includes complex ergonomic shapes completely encased in a skin-safe, brightly colored silicone layer.
Dame Products uses a silicone insert molding process to encapsulate the internal hardware for beta prototypes for customers.
Engineers can create dozens of insert and overmolding prototypes in a single day, rotating three or four sets of SLA 3D-printed molds. While the silicone rubber of one prototype is curing, the next can be demolded and prepared for the next pour. Detailing and cleaning of the demolded prototypes are performed simultaneously.
When the prototype hardware is returned to the company, the beta devices are cleaned and sanitized, a thin layer of silicone is removed, and the internal hardware is reused in new beta prototypes.
Compression molding
3D-printed rapid tooling for compression molding processes can be used to produce thermoplastic, silicone, rubber, and composite parts. For prototyping small to medium-sized parts, 3D printing may be the lowest-cost and fastest way to create molds. Designs can be quickly modified multiple times using CAD software, then reprinted and tested. 3D printing is most commonly used with compression molds designed primarily for non-heating applications.
Product developers at kitchen appliance manufacturer OXO used 3D printing to prototype flexible, rubber-like parts, such as gaskets, using a two-part silicone compression molding process through 3D-printed molds.
3D printing is a fast and low-cost method for creating molds for the compression molding process.
Casting
Engineers, designers, jewelry makers, and hobbyists can leverage the speed and flexibility of 3D printing by integrating traditional casting processes such as indirect investment casting, direct investment casting, pewter casting, and sand casting into 3D-printed molds, or casting directly into 3D-printed molds. Metal parts cast using 3D-printed rapid tooling can be produced in a fraction of the time and at significantly lower costs than traditional casting methods.
Stereolithography (SLA) 3D printers offer high precision and a wide range of materials, making them ideal for casting processes. They can produce metal parts at lower costs, with greater design freedom and in less time than traditional methods.
Typically, molds for direct investment casting are hand-carved or machined if the piece is a one-of-a-kind item or only a few pieces are expected to be produced. However, with 3D printing, jewelry makers can print molds directly, eliminating the design and time limitations often encountered in other processes.
3D-printed jewelry designs and rings cast from precious metals.
Similar to investment casting, 3D printing can be used to create models for sand casting. Compared to traditional materials like wood, 3D printing allows manufacturers to create complex shapes and enables a direct transition from digital design to the casting process.
With 3D printing, manufacturers can also directly print molds for their castings using materials such as High Temp Resin or Rigid 10K Resin, which is a high-temperature resistant resin. The same method can be used to create molds for direct pewter casting.
A mold printed with clear cast resin and a finished cast metal piece.
Besides metal, casting is also a popular method for producing silicone and plastic parts for medical devices, audiology equipment, food-safe applications, and more.
The medical device company Cosm produces custom-made pessaries for patients with pelvic floor muscle disorders. They print molds using an SLA 3D printer and inject biocompatible, medical-grade silicone into the mold to create the device. The use of rapid tooling combined with 3D printing allows for the production of bespoke parts without the high cost of traditional tooling.
A custom-made pessary for each patient, produced using the silicone molding process.
3D-printed custom ear mold manufacturing has also revolutionized the field of audiology. For applications such as hearing aids, hearing protection, and personalized earmuffs, digital manufacturing offers greater control and precision than traditional mold-making methods, significantly reducing errors and rework.
A step-by-step process for making custom earplugs using silicone ear molds.
Sheet metal forming
3D-printed rapid tooling also exhibits attractive properties for sheet metal forming processes. Characterized by high precision and smooth surfaces, SLA 3D printers can produce tools with excellent registration features, resulting in improved repeatability.
With a diverse range of materials possessing varying mechanical properties, selecting the right resin for specific applications can significantly improve molding results. SLA resins exhibit isotropic properties and relatively good stability under stress compared to other 3D printing materials.
In addition, tools made of plastic can help reduce the sanding step, as plastic dies do not leave marks on the metal sheet like metal dies do.
Upper and lower die sets in various versions, manufactured using 3D printing, for use in forming replacement blade guards.
