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3D Printing vs. Injection Molding

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3D Printing vs. Injection Molding

As additive technologies, materials and processes mature, so does the argument for using Additive Manufacturing (AM) to make production parts. Let go of traditional manufacturing constraints and embrace a new mindset that explores additive manufacturing as a serious means of production.

Additive Manufacturing vs. Injection Molding Comparison

The additive technologies most commonly used for production of plastic parts include Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS) and Multi Jet Fusion (MJF). The break-even point of AM compared to Injection Molding (IM) was once a few hundred parts, but is now pushing into the thousands with trends showing the cut-off point even higher in the coming years. Although, if you are projecting production volumes in the tens, hundreds of thousands, or even millions, AM can still prove to be a strong option for manufacturing throughout the early stages of production.


Additive Manufacturing Benefits

AM has many benefits that are not explicit to part price comparisons.

#1 // Choose from a Wide Range of Production-Grade Materials

Material development has been, and continues to be, a priority within the additive manufacturing community (see the chart for an example material comparison).

#2 // Reduce Total Cost of Ownership & Time-to-Market

Soft launching or beta-testing can easily inform the design process with little impact on per-part cost. With additive manufacturing you can avoid scrapping an expensive mold when a tool can’t be reworked.

Lead times for AM can be measured in hours/days instead of weeks/months. Avoid tooling altogether or for an initial release while tooling kicks off and production ramps up.

#3 // Enable Greater Design Flexibility & Break Free from Traditional Manufacturing Constraints

Get parts on demand using the latest file revisions. Modifications, improvements and customization can be implemented at any time. Introducing a design revision while in production is as easy as updating the CAD file.

An exciting use of AM is to solve the unsolvable with the freedom of design. Traditional methods have undercut limitations and can’t accommodate complex structures. Complexity and severe undercuts are possible with AM.

Arkema Rilsamid® PA12 for Injection Molding
PA12 for HPs Multi Jet Fusion (MJF)
Tensile Strength
43 MPa / 6240 psi
48 MPa / 6960 psi
Tensile Modulus
1440 MPa / 208 ksi
1800 MPa / 261 ksi
Elongation at Break
Charpy Impact, Notched
0.7 J/cm^2
0.95 J/cm^2
HDT @ 0.45 MPa
HDT @ 1.82 MPa
135 ºC
55 ºC
175 ºC
95 ºC

Direct Part Replacement with Additive Manufacturing

As designers and engineers become more accustomed to using AM, and more materials become readily available at lower prices, additive technologies will only continue to grow as a significant force in the manufacturing process. AM has steadily matured into a means of enhancing multiple stages of the product development process, including the production of end-use parts. This process, termed Direct Digital Manufacturing (DDM), is when AM is used to fabricate the final product and/or parts used during production and assembly of finished goods.

The easiest way to use AM is what is referred to as direct part replacement—this is when a part is designed for a traditional manufacturing method, but instead is made using AM. Advantages to taking this approach can be accelerated lead-times and lower costs. It is common to opt for direct part replacement when only a few thousand parts are required or as a bridge-to-production solution while injection molding tooling ramps up.

Featured Part Example


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 25-30 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

Additional Part Examples

(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 30 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 30 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. The examples below 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. The experts at Fathom can help guide you and your team on DFAM best practices.

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 30 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 Days for Prototype Tool + 5 days for Production)
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 35 Days for Prototype Tool + 5 days for Production)
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 any other aspect in the product development process.

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. The machine resets beginning the process again. Millions of parts can be produced through injection molding technology.

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
  • Cost Reduction at Higher Volumes
  • Strict Material Requirements
  • Tight Tolerancing
  • Consistency
  • 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 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 smaller quantities. Injection molding is perfect for mass manufacturing thousands to millions of parts. Fathom’s capabilities are further enhanced by ICOMold by Fathom’s international production capacity which allows for quick turnaround times on small to large orders. However, it’s important to consider how much time is allotted for the project to account for potential inventory issues and international shipping.

A high-quality option to consider for smoothing your 3D printed parts is the AMT PostPro3D technology. The AMT PostPro3D achieves a high quality surface finish that matches injection molding techniques using 3D printing processes. This processing is a smart and automated solution for smoothing 3D printed parts. This enabling technology reduces lead-time, cost of manufacture, operational and maintenance costs providing the ‘missing piece’ in the digital manufacturing chain. The PostPro3D machine makes 3D part surface finishing speed and cost competitive for high volume production.

Talk to an expert at Fathom today to take your parts to the next level using AMT PostPro3D for post processing.

Get an Instant 3D printing quote and a traditional manufacturing quote in as soon as one hour.

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