3D Printing vs. Injection Molding

Example //A

Example //A

Featured Part Example

(A) Accelerated Lead-Time—While the cost per part is close in this example, the critical requirement was getting parts in days, not weeks. Fathom recommends taking an AM approach as a bridge-to-production solution or avoid tooling and build parts as needed.

Quantity Required //3,500
AM Part Cost / / $3.52 ea (Lead-Time of 5 Days)
IM Part Cost //$3.60 ea (Lead-Time of 35-40 Days, Prototype Tool)
Break-Even Point //3,740 Parts
Material Used & Weight //PA12 (4.6 g)
Part Dimensions //25 mm × 23 mm × 25 mm

Injection Molding with Amortized Tool Price

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(B) Limited Production Run—The tooling cost of this particular part is high because of a complex parting line and challenging features. When a lower volume of parts is required, Fathom recommends taking an AM approach to save on cost and time.

Quantity Required / / 1,500
AM Part Cost / / $8.18 ea (Lead-Time of 6 Days)
IM Part Cost / / $12.46 ea (Lead-Time of 40-56 Days)
Break-Even Point / / 1,829 Parts
Material Used & Weight / / Glass-Filled PA12 (14.2 g)
Part Dimensions / / 111.83 mm × 15 mm × 109.24 mm

Injection Molding with Amortized Tool Price

(C) Beta-Testing—This part is small and easy to nest within an MJF build envelope which makes it inexpensive to additively manufacture—also, less expensive for product testing when design changes are likely to follow. The value in this example is speed and design agility.

Quantity Required / / 1,000
AM Part Cost / / $9.90 ea (Lead-Time of 3 Days)
IM Part Cost / / $8.68 ea (Lead-Time of 35-42 Days)
Break-Even Point / / 815 Parts
Material Used & Weight / / PA12 (14.8 g)
Part Dimensions / / 68.64 mm × 69.88 mm × 50.65 mm

Injection Molding with Amortized Tool Price

Design for Additive Manufacturing

The adoption of a DDM is leading to innovative product designs, shattering long-held manufacturing barriers, and making product development both less risky and more efficient. Check out the examples below that demonstrate how to better leverage the advantages of taking a Design for Additive Manufacturing (DFAM) approach to production parts (thinking beyond direct part replacement). This type of approach is guided by AM’s design freedom, manufacturing possibilities, and technical limitations. Considerations when designing for additive manufacturing extend beyond the minimum print requirements—a DFAM mindset recognizes the variety of new possibilities when designing specifically for AM.

Featured Part Example

(D) Optimized Design—Traditional processes come with strict design rules to ensure cost effective and reliable manufacturability. Even more, many complex designs enabled by AM are unmanufacturable using traditional methods. In this example, the improved design cannot be molded. View blog post to learn more about this part.

Advantage //Performance Improvement & Weight Reduction
Quantity Required //1,000
AM Part Cost of Optimized Design //$15.89 ea (Lead-Time of 4 Days)
IM Part Cost of Original Design //$18.15 ea (Lead-Time of 35-42 Days)
Break-Even Point //1,249 Parts
Material Used & Weight //PA12 (27.4 g)
Part Dimensions //62.8 mm x 53.8 mm x 63.7 mm

Injection Molding with Amortized Tool Price

Additional Part Examples

(E) Function Assembly // Combining parts of an assembly into a single build makes for a very compelling use of AM—reduce part count and cut assembly costs. In this example, two tools and stock components would have been needed, but it’s built as one movable assembly using AM. The value is production speed and no assembly required.

Advantage //No Assembly Required
Quantity Required //1,000
AM Part Cost //$12.83 ea (Lead-Time of 3 Days)
IM Part Cost //$12.58 ea (Lead-Time of 35-42 Days, Prototype Tool)
Break-Even Point //960 Parts
Material Used & Weight //PA12 (32.9 g)
Part Dimensions //64 mm × 19.35 mm × 60 mm

Injection Molding with Amortized Tool Price

(F) Part Consolidation //Taking a part consolidation approach not only reduces costs incurred (e.g. needing multiple tools), but it also reduces other costs, defects, human error, and stacked tolerances associated with assembly. In this example, three tools would be needed but the parts can be made as one using AM process.

Advantage //Consolidation of a 5-Part Assembly
Quantity Needed //2,000
AM Part Cost //$24.69 ea (Lead-Time of 8 Days)
IM Part Cost //$28.72 ea (Lead-Time of 40-56 Days, Prototype Tool)
Break-Even Point //2,150 Parts
Material Used & Weight // PA12 (68.5 g)
Part Dimensions //140 mm × 25 mm × 140 mm

Injection Molding with Amortized Tool Price

As additive technologies continue to mature and associated costs improve, a greater number of geometries become great candidates for AM. Keep in mind that this is an evolving landscape and every application or geometry is different because of its own unique advantages or challenges. An application that was not a good fit three, six, or 12 months ago could very well be a good fit today for AM. If you are interested in exploring this further, contact an additive manufacturing expert at Fathom who can help you identify whether or not your project may benefit from AM—whether that’s technology and material guidance, or other aspects involved throughout product development and production.

What is Injection Molding?

Injection molding (or moulding) is a popular manufacturing process used to make many of the items we use every day. If an object is made of plastic, there is a good chance it was made using injection molding. Commercial, consumer goods, industrial and more all use injection molding to produce products. Injection molding offers businesses the opportunity to create a custom design with details that are unique to their brand. To begin the process, a custom mold is produced according to the project specifications. The material chosen is heated to its melting point and then delivered to the mold cavity. The molten material begins to cool and take shape inside the mold. Once it has fully cooled, the part is ejected from the mold and caught by a bin. The machine resets beginning the process again. Thousands of parts can be produced using this method.

When Should You Use Plastic Injection Molding and When Should You Use 3D Printing?

Injection Molding is Best For //

• Higher Volume Production of 1,000+ Parts
• Longer Turnaround Times
• Final Parts, Not Prototypes
• Different Sizes & Complexities

3D Printing is Best For //

• Low-to-Medium Production Runs
• Faster Turnaround, from Days to Weeks
• Designs That Require Frequent Adjustments
• Smaller Plastic or Metal Parts/Components of Varying Complexities

3D printing and injection molding should be viewed as complementary rather than competing methods of manufacturing. A project may use a 3D printing process to create a rapid prototype and begin their low-volume production, but then switch to injection molding once there is a greater demand for a part. 3D printing has the advantage of producing a part, exactly when it is demanded, in a smaller quantity. Injection molding is perfect for mass manufacturing hundreds and thousands of parts. Therefore, consider how much time is allotted for the project, any potential inventory expenses and whether flexibility of design is required. Whether a project requires one or the other or a combination of both largely depends on the project’s goals.

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