Plastic products are in our lives everywhere. During the plastic products development process, Plastic prototype verification before mass production is very common. But do you know how to make the plastic prototypes? Today we will explore different rapid prototyping methods for creating plastics Prototype.
What is Plastic Prototyping？
Plastic prototyping is the process of creating a preliminary version of a plastic part or product. It’s a way to assess or present a physical product before going to mass production. Depending on your design’s maturity, a plastic prototype can be created with different prototyping methods and materials.
Four Rapid Plastic Prototyping Methods
CNC machining
CNC machining is an effective method for creating plastic prototypes with high precision and accuracy. With computer-controlled cutting tools, a CNC machine can cut a solid block into a functional prototype. CNC machining offers lots of advantages for plastic prototyping, including fast turnaround times, high precision, and high-quality surfaces especially for the optic clear prototypes.
3D Printing
3D printing is an additive manufacturing process. it creates the plastic prototype by depositing melted plastic material layer-by-layer based on a digital design file. in this way, 3D printing can manufacture prototypes with remarkable complexity and short lead time at low cost. there are different 3D printing technology include FDM 3D printing, SLA 3D printing, SLS 3D printing and DLP 3D printing.
Urethane Casting
Urethane casting, also known as silicone molding or vacuum casting, is a cost-effective method for producing plastic prototypes with low-volume manufacturing of less than 100 pieces. This process has something similar to traditional injection molding, it uses a silicone mold to cast Liquid urethane resin to create urethane casting prototypes.
Rapid injection molding
Injection molding can be used for creating plastic prototypes even this process is mainly used for mass production. injection molding prototyping uses soft steel for tooling material and a more simple tooling constructor to inject low-volume plastic prototypes. this process is usually required to make the plastic prototype with the same material with mass production.
Steps for Creating Plastic Prototype
Steps for CNC machining
CNC plastic prototyping requires several steps as below:
Step 1: Plastic Prototypes CAD design.
due to the limitations of the CNC machining process, the Prototype designer will design the product that could fit the machines, a Complex structure of plastic products will be split piece by piece.
Step 2: Machining on CNC machines.
Once the designer finishes the design, the CAM software with Generate the CNC program by translating the CAD design into machine-readable code, also called G-code and M-code. This involves specifying the tool paths, cutting depths, feed rates, and any other machining instructions necessary to produce the desired prototype.
Step 3: Bonding.
After all the pieces are prepared, use adhesive bonding techniques to securely join them together. this is to get the complete prototype with good strength.
Step 4: Grinding and polishing.
Sanding the surface of the prototype to remove any rough edges, burrs, or imperfections, ensuring a smooth surface, and then Apply polishing methods to further enhance the surface finish of the prototype. use specialized tools, compounds, and buffing techniques to achieve the desired level of smoothness and glossy of the prototype surface.
Step 5: Surface finishing.
this depends on the end user’s requirement to apply different aesthetic effects on the surface of plastic prototypes. the main surface finishing methods include dyeing, Painting colors, Vacuum Metallization, Matte Finish, Laser Engraving, Screen printing, and Brushing.
Steps for 3D Printing
Step 1: Prepare The 3D Printer.
Set up the 3D printer, ensuring it is properly calibrated and the printing bed is clean and level. Install the correct printing material and ensure the printer settings match the desired specifications.
Step 2: Slice The 3D Model and Start The Printing.
Use slicing software to convert the 3D model into instructions which is called G-code. Adjust settings such as layer height, infill density, and speed, Load the G-code file onto the 3D printer initiate the printing process, and then wait for the printer to run.
Step 3: Grinding and polishing.
once the printing process is finished. make the same grinding and polishing process with CNC machining above.
Step 4: Surface finishing.
this is the same process as CNC machining above.
Steps for Urethane Casting
Step 1: Create The Master Pattern.
Master Pattern is used for making silicone mold. it can be created by CNC machining and 3D Printing.
Step 2: Making The Silicone Mold.
Use the master pattern to Make a silicon mold for casting. Pouring Liquid silicone to be around the master and remove all air to form the silicone mold.
Step 3: Casting prototype.
Pour the mixed urethane resin into the silicone mold, Cure the liquid urethane resin in the mold and After the resin has fully cured, open the mold and take out the plastic part.
Step 4: Grinding and polishing.
Step 5: Surface finishing.
Steps of injection molding
Step 1: Mold design.
Design the rapid mold with simple construction to lower the cost.
Step 2: CNC machining the soft steel mold.
Use CNC machines to mill the steel to make the mold according to the mold design.
Step 3: injection molding.
Inject the plastic material into the mold to form the plastic parts.
Step 4: surface finishing.
this could be the same process with other plastic prototyping methods.
Comparison of Plastic Prototyping Methods
Different plastic prototyping methods use different plastic materials and with different timing and cost. we introduce a comparison for you when you need to choose for making a plastic prototype.
| Processing Methods | Materials | Application | lead time | cost |
|---|---|---|---|---|
| CNC machining | Engineering plastic sheets such as Acrylic sheets, Polycarbonate sheets, POM sheets, ABS sheets, Nylon sheets, etc. | For those plastic prototypes with high precision and strength for function prototypes. | 3 to 7 days | Moderate |
| 3D printing | Photopolymers for SLA, and Plastic Filaments for FDM and SLS. | Use for just looks-like plastic prototypes. | 1 to 3 days | low |
| Urethane Casting | Clear Urethane Resins and Non-clear Urethane Resins are used for casting, a similar performance to engineering plastics. | Use for looks-like plastic prototypes with small quantities from 5 to 100 pieces. | 3 to 7 days | low for each piece |
| Injection molding | Engineering plastic particle materials same as CNC machining. include Acrylic, ABS, Polycarbonate, etc. | Use for function prototypes that have exactly the same performance as mass production | 15 to 20 days | High |
Find more about these four rapid prototyping technique comparisons.
- CNC Machining vs 3D Printing
- Urethane casting vs injection molding
- CNC Machining vs Injection Molding
- CNC Machining vs Urethane Casting
Plastic Prototypes Finishing
To obtain a more realistic appearance, texture, durability, or other performance, it is necessary to make surface finishes on the Plastic Prototypes. this is a very critical step for plastic prototyping. we introduce some common plastic surface finishing methods below table:
| Finishing Method | Characteristics |
|---|---|
| Dyeing | Dyeing is used for acrylic material to create clear colorful plastic prototypes. |
| Spray Painting | Applying one or multiple layers of paint on a plastic surface for color or protection. |
| Electroplating | Depositing a layer of metal on a plastic surface through an electrolytic process, often to improve conductivity or appearance. |
| Screen Printing | Printing ink directly onto a plastic surface through a mesh screen, is commonly used for text and simple graphics. |
| UV Coating | Applying a UV-cured coating to enhance durability, scratch resistance, and gloss. |
| Matte Finish | Achieving a non-glossy, dull surface through physical or chemical means. |
| Laser Engraving | Etching patterns or text onto a plastic surface using a laser. |
| Mechanical Buffing | Buffing a plastic surface using mechanical methods to remove scratches or unevenness. |
You may also want to know How To Add Color To Plastic Prototype, Click the link to find out more.
How can I get a plastic prototype made?
There are many factors you need to consider before creating the perfect plastic prototype such as materials, budget, and timing. KUSLA’s rapid prototyping service can help you make plastic prototype parts faster, easier, and more efficient. We support all of the above plastic prototyping methods with very high-quality standards.
FAQ
How Much Does a Prototype Cost?
the cost of a prototype depends on the prototyping process and the complexity of the parts. generally, A plastic prototype part can cost from $50 to $200, and for a complex prototype assemble can cost from $1000 to $10000 and even more. Check Rapid Prototyping Cost Overview for more details.
How to make a prototype at home?
With a desktop 3D printer, you can make a prototype at home. just finish your design in the CAD software and load it into the 3D printer, then you can print the prototype with the materials prepared.
