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cnc plastic prototyping process

The Comprehensive Guide to Plastic Prototyping: Methods, Costs, and Considerations

Plastic parts hardly get the deserved credit for the role played in product manufacturing despite being everywhere and having multiple applications in various industries.

Manufacturers and product developers often utilize plastic parts for different purposes, ranging from lids for coffee cups to computer keyboards, cable insulation, surgical gloves, and window frames. However, it would help to note that all plastic products started as prototypes.

This guide discusses the comprehensive guide to plastic prototyping. You’ll learn everything about the significance of plastic prototypes, plastic prototype development, methods for plastic prototyping, costs, and essential tips. Let’s get to it!

The Significance of Plastic Prototypes

plastic prototype industrial components
Plastic Prototype Industrial Components

Prototyping is a resourceful design process for many entrepreneurs and manufacturing businesses. As such, plastic prototypes are used for various applications across industries. Product designers rely on plastic prototypes to physically assess plastic parts before initiating mass production. These plastic prototypes help you study your plastic parts’ physical representation without delay.

Besides, plastic prototype manufacturing allows manufacturers to engage potential investors and customers. They can test these prototypes themselves. As such, these plastic parts prototypes help you gauge your potential customer’s interest in the product before launching.

Additionally, plastic prototyping allows product designers to optimize or modify designs with prototyping companies before plastic machining. As a result, it mitigates risks of design errors and failed prototyping, ensuring the production of functional plastic prototypes.

Preparing for Plastic Prototype Development

preparing for plastic prototype development
Preparing for Plastic Prototype Development

The CAD model creation is a fundamental requirement in plastic prototype development. The Computer-Aided Design (CAD) model digitally represents your proposed plastic part. It portrays how the plastic parts should appear.

A CAD model illustrates how the plastic components assemble and function. Preparing a CAD model for your plastic prototypes helps you to make a physical prototype model that is either visual or functional.

  • Visual Prototype: Visual prototypes offer the final representation of the plastic part. However, you don’t need the visual prototype to function as the final product. Consequently, 3D printing provides the cheapest and fastest means of developing them.
  • Functional Prototypes: A functional prototype portrays the desired final product from material to mechanics. These prototypes are help test the product designs before mass production.

Popular Methods for Plastic Prototyping

Plastic prototyping is among the versatile methods of rapid prototyping. You can choose the ideal procedure to produce prototypes from the range of available manufacturing processes. Here are four of the effective plastic prototyping methods:

Vacuum Casting: Process and Benefits

vacuum casting plastic pprototype
Vacuum Casting Plastic Prototype

This plastic prototyping process allows you to imitate as many plastic prototypes as possible. It uses a master model to form parts that are perfect for testing. When you use the vacuum casting technique for your plastic prototypes, you must inject molten plastic (raw material) into a silicone mold to form the prototype. However, it would be best to make a master model before creating your silicone molds.

You can develop your master models for vacuum casting operations using CNC machining or 3D printing. Then, you have to create silicone-based cutting molds after completing the master model. You’ll have to inject the molten plastic/raw material into the mold cavity using a vacuum bell jar. The mold parts usually take 30-40 minutes to solidify to create a prototype replica.

The vacuum casting method works well with an extensive range of materials, ranging from opaque to transparent. Moreover, you can reuse the silicone-based casting molds to make about 25 plastic prototypes. This technique facilitates faster design actualization and ensures the close proximity of your product development and mass production.

Benefits of Using Vacuum Casting for Your Plastic Parts Prototyping

Below are some of the advantages of using Vacuum casting to make your prototypes:

  • The silicone molds make detailed replicas of the master model within a short period.
  • Vacuum casting helps manufacturers to create plastic prototypes with higher precision and fine details.
  • This process is perfect for making plastic parts with complex shapes.
  • The vacuum casting technique is compatible with several plastic materials with varying texture rigidity and flexibility.
  • A standard mold material will offer a prototype with exact qualities as the intended final part.

3D Printing: Techniques and Advantages

plastic prototyping 3d print
Plastic Prototyping 3D Print

3D printing or additive manufacturing comprises various manufacturing technologies. It is one of the cutting-edge prototyping techniques following the advent of Industry 4.0 that revolutionized the manufacturing arena. 3D printing is an umbrella term, as stated earlier. Below are three of the most common techniques for 3D prototype plastic parts fabrication:

Fused Deposition Modeling (FDM)

FDM 3D printing is the most common 3D printing technique used in plastic prototyping. It usually includes extrusion for a layer-by-layer plastic material deposition until it creates the final product.

Depending on the chosen materials, you can make plastic prototypes with greater strength and resolution with industrial-grade FDM printers. Additionally, FDM 3D is a flexible procedure well suited to various materials such as polycarbonate, PLA, Nylon, ABS, PETG, etc.

Stereolithography (SLA)

SLA 3D printing uses plastic resin materials to make 3D plastic prototypes. It employs a high-powered laser to solidify the model. This technique can be used for prototyping medical, dental, and general consumer electronics applications.

Selective Laser Sintering (SLS)

SLS technique utilizes a high-powered laser like SLA 3D printing. However, it forges powdered materials together to create a 3D model. It offers a superior print quality compared to the FDM 3D technique. You’ll discover that plastic prototypes made using SLS 3D have higher resolutions and are more functional. As such, they are usually more durable and flexible compared to FDM prints.

Benefits of Using 3D Printing for Your Plastic Prototype

Below are some of the reasons why 3D printing is the ideal technique for your plastic prototypes:

  • 3D printing lets you upload your CAD files directly into the 3D printer software while the machine reads it effectively, permitting a seamless workflow.
  • 3D printing processes can produce plastic prototypes faster while lowering the overall costs of the production process.
  • The 3D printing techniques offer flexible material choices that allow you to test various materials when creating prototype plastic parts.
  • This additive manufacturing process helps to create a perfect plastic prototype from product designs in about 24 hours or less.
  • You can easily make changes to the CAD file of your products before uploading it to the printer in 3D printing. Therefore, you can create multiple design iterations within a shorter time.

CNC Machining: Process and Benefits

CNC machining is an effective and fast-paced plastic prototyping method. It utilizes multiple tools to create 3D models of your design from solid blocks of materials. It uses a subtractive process to create prototypes. That is, this technique operates conversely to 3D printing. It removes material from the solid block, unlike the additive 3D printing process. Nonetheless, it doesn’t mean you cannot create plastic prototypes with varied materials.

Digital milling machines ensure the effectiveness of the CNC machining process. Hence, you must provide the proper process automation with a computer available to control the CNC milling machine using uploaded 3D files. Moreover, you do not need molds to create prototype CNC plastic parts. As a result, it is more cost-effective and requires CAD rendering to begin CNC plastic prototyping.

Benefits of Using CNC Machining for Your Plastic Prototype

CNC machining is another effective and viable rapid prototyping technique with the following benefits:

  • CNC machining allows the use of various materials, which makes it easier for you to choose a preferred material for your prototypes.
  • It facilitates faster turnaround times considering the plastic prototype model complexity.
  • This plastic prototyping technique allows you to test the plastic prototype parts’ fit, form, and function without necessarily making injection mold tooling.
  • CNC machining aids the creation of various surface finishes on the prototype, including polishing, painting, powder coating, anodizing, and more.
  • CNC machining offers greater potential for tight tolerances, threads and undercuts, and size limitations.
  • The resulting plastic prototypes possess close mechanical properties to the injected part with varying outcomes depending on the desired functionality and appearance.

Injection Molding: Process and Benefits

molds and plastic products
Plastic Injection Molding

Injection molding is the ideal fabrication method whenever you need limited plastic parts prototype production runs. It offers valuable ways of manufacturing prototypes despite being a popular method for full-scale production. The injection molding technique includes the creation of a metal die. You must mix the plastic resin into a heated barrel and forcefully inject it into the metal die.

Rapid cooling of the plastic injection molds into a solid component is the last step of the injection molding process. It offers a prototype with outstanding mechanical properties and a high-quality surface finish. Injection molding is compatible with common thermoplastic materials like Nylon, ABS, Polycarbonate, Polyethylene, etc.

Prototype plastic injection molding forms the base for subsequent molds needed to complete your production runs. Industries such as medical, consumer goods, automobiles, electronics, and packaging utilize injection molded parts.

Benefits of Using Injection Molding for Your Plastic Prototypes

Here are reasons why injection molding is perfect for your plastic parts prototypes:

  • Injection molding aids fast and cost-effective product concept testing without sacrificing quality.
  • It aids the fabrication of functional prototypes and complex parts with varying shapes and weights.
  • This technique helps to achieve quick insights into the plastic prototypes’ operational capabilities by making real-life, near-perfect replicas of final products.
  • Prototype injection molding is the most effective process for minimal production runs.
  • Injection molded parts and prototypes are perfect for industries like the medical sector that require product considerable testing and certification.

AT-Machining is the ideal partner for your prototype manufacturing and fabrication needs. Submit your file and get an instant quotation now!

Key Considerations for Effective Plastic Prototyping

pei ultem plastic cnc machined prototype
PEI (Ultem) Plastic CNC Machined Prototype

Since prototypes have varied quality requirements, choosing the ideal plastic prototyping method for your applications is essential. Although your prototypes and production parts can have an approximate resemblance in the early stages, both must match closely when development approaches launching. As such, here are critical considerations for effective plastic prototype production:

Purpose and Application of the Prototype

Your plastic prototype’s application should be your initial consideration when producing plastic prototypes. Product developers usually use plastic parts in various industries and for varying purposes. Your plastic parts prototype might be for functional testing with prospective consumers. Conversely, you might need the prototype for non-functional testing for marketing or sales.

Therefore, ensure you choose a method that offers prototype parts with the final product’s exact colors, geometry, and surface finishing.

Design Form and Complexity

The design form and complexity may include intricate internal features and tight tolerances. As such, these factors help to decide the ideal prototyping technique for your prototypes. It would be best to note that the geometry of designs often limits some manufacturing options. They may require high-level Design for Manufacturing (DFM) optimization to be cost-effective or economical at best. The ideal choice is to choose technologies that can effectively match the intended geometry of your plastic prototype.

Volume, Cost, and Lead Time Considerations

The plastic parts’ size and volume significantly influence the product’s final cost and lead time of the prototyping process. The intended prototype’s total volume significantly influences the choice of the ideal prototyping technique.

Certain processes may have higher initial setup and tooling costs while they make inexpensive parts. Conversely, other techniques may require lower startup costs but higher part costs due to lesser automation, slower cycle times, and labor costs. The costs of such processes only reduce marginally, even with increased volumes.

However, how soon you need your plastic prototype may determine your choice of a rapid prototyping technique. Some methods use cutting-edge tooling with automation to achieve plastic prototypes within 24 hours or less. Unfortunately, the tooling and setups for some methods could result in weeks as lead time. Therefore, choosing the process that creates parts quickly is advisable if you need to test your plastic prototype quickly.

Material Selection for Prototyping

The specific stresses or stains that a part will be exposed to determine the perfect plastic prototype material. You must balance cost with your prototype’s functional requirements and aesthetics before picking the ideal material. Therefore, before concluding, you must compare the available plastic prototyping techniques with the ideal application characteristics.

Understanding the Costs of Plastic Prototyping

custom plastic prototype components
Custom Plastic Prototype Components

Several factors can influence plastic parts’ prototyping costs. These factors include the preferred material, the part’s complexity, and the chosen fabrication technique. Although 3D printing is often less costly than CNC machining, injection molding is relatively more expensive than the 3D printing processes and CNC machining due to mold milling costs.

3D printing techniques have low fixed costs, ensuring zero economies of scale. Moreover, the first imitation has the exact cost as the last copy. Likewise, CNC machining has low fixed costs, with total costs increasing steadily. So, the cost of each part will be a little higher than the similar parts created with 3D printing. The cost of the first few parts is relatively high, as in the case of prototype plastic injection molding. However, the cost reduces gradually as the volume increases.

Therefore, it is evident that these plastic prototyping techniques have comparable costs, which depend majorly on the method used and the required volume.


Plastic prototyping is essential to developing high-quality plastic components that meet the intended purposes. Also, choosing the appropriate prototyping method helps to ensure the cost-effective and flexible manufacturing of high-quality plastic prototypes and parts. Hence, it is essential to understand everything about prototyping technologies. However, AT-Machining is your best bet if you need professional help with your plastic prototyping and rapid tooling!

plastic cnc machining services
AT-Machining Plastic CNC Machining Services

AT-Machining is the right manufacturing service provider capable of offering the solution for your plastic machining needs. We have good years of experience and a team of expert designers and engineers that allow us to handle your project best and deliver superior-quality plastic prototypes.

We leverage our broad network of partners in several industries to bring your design ideas to reality in the best possible ways. As you submit your design file today, experience our professional feedback and recommendations for effective plastic part prototyping. Contact us now, and let professionals handle your plastic prototyping projects!


What Are the Common Plastic Materials Used for Plastic Prototyping?

Due to their strength, durability, and functionality, plastic product designers often make prototypes using nylon, ABS, acrylic, polycarbonate, and polyphenylsulfone.

Which Plastic Is Best for 3D Printing of Plastic Prototypes?

ABS (Acrylonitrile Butadiene Styrene) is an easy-to-use thermoplastic commonly used in filament form. It exists in powder form for SLS (Selective Laser Sintering) processes. More importantly, it is one of the most cost-effective and accessible materials for 3D printing.

Is Plastic Prototype Important to Product Development?

Plastic prototyping is beneficial to plastic product development because it facilitates the stimulation of the final product features. Therefore, it is easier to test the product’s functionality and the design’s correctness before mass producing the product.

What Is Rapid Prototyping for Plastic Parts?

Plastic parts rapid prototyping is helpful in the quick development of plastic parts for initial design verification and validation. It reduces the overall product development time and costs. Unlike injection molded parts, rapid prototyping for plastic parts offer lower tool modification cost.

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