Vacuum Casting for Low-Volume Plastic Parts
Vacuum casting is a manufacturing process used to produce low-volume plastic parts with high detail and good surface finish. At 6 CNC, we provide vacuum casting services for projects that require fast turnaround, consistent appearance, and cost-effective small-batch production.
This process is ideal for bridge production between prototyping and injection molding.
- One-stop solution (machining + finishing)
- Fast turnaround & reliable delivery
- Competitive pricing for low-volume production
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When Vacuum Casting Is the Right Choice
Vacuum casting works best when you need:
- Low-volume production (typically 10–100 parts)
- High-quality appearance and surface finish
- Faster lead time than injection molding
- Lower tooling cost compared to mass production
If your project requires high-volume output, injection molding is more efficient.
If your part requires tight tolerances or mechanical strength, CNC machining may be a better choice.
Typical Vacuum Casting Applications
Vacuum casting is widely used for:
- Functional prototypes with improved surface quality
- Small-batch plastic parts for market testing
- Enclosures and housings
- Consumer product samples
- Medical and industrial device components
This process delivers consistent parts with good detail, making it suitable for both validation and early-stage production.
Materials and Capabilities
We use polyurethane resins to simulate a range of plastic materials.
Available options include:
- ABS-like materials for general applications
- Rubber-like materials for flexible components
- Transparent resins for visual or optical parts
These materials allow you to test form, fit, and appearance before moving to full production.
Surface Quality and Detail in Vacuum Casting
Vacuum casting provides smoother surfaces and finer detail compared to many rapid prototyping methods.
This is especially useful for:
- Cosmetic parts
- Transparent or semi-transparent components
- Parts requiring consistent visual quality
You can achieve production-like appearance without investing in injection molds.
From Prototype to Production
Delivery Times and Cost-Effectiveness of Vacuum Casting
Vacuum casting offers shorter lead times compared to injection molding because it uses silicone molds instead of steel tooling.
This reduces upfront cost and allows faster iteration.
It is an efficient solution when you need multiple parts quickly without committing to large-scale production.
A Practical Approach to Small-Batch Production
FAQ About Vacuum Casting
What is vacuum casting used for?
Vacuum casting is used to produce low-volume plastic parts with good surface finish and detail, often for prototyping and small-batch production.
How many parts can be made with vacuum casting?
Vacuum casting is typically used for 10 to 100 parts, depending on mold life and material requirements.
How accurate is 3D printing?
3D printing accuracy depends on the process and material.
It is generally less precise than CNC machining.
What materials are available for 3D printing?
Common materials include resins and engineering plastics.
Material selection depends on your application and testing needs.
Should I choose CNC machining or 3D printing?
3D printing is faster for early-stage prototypes.
CNC machining is better for functional testing, precision parts, and production.
Resources
C110 vs C145: Best Copper Alloy for Conductive CNC Parts
Technical engineering comparison of C110 ETP and C145 Tellurium copper for conductive CNC parts. Analyze IACS, machinability, and solderability.
![Comparison of Operating Principles: This figure illustrates a microscopic comparison of the surface waviness and residual scallop height generated by a face milling cutter and a ball-nose cutter under different stepover and step-down settings. [Figure 4-1]](https://6-cnc.com/wp-content/uploads/2026/06/image-2-300x199.png)
Surface Finish Ranges: Turned Shafts vs Milled Faces
Technical analysis of surface roughness (Ra) in CNC milling and turning. Includes material Ra charts, toolpath stepover effects, and abrasive finishing triggers.
Realistic CNC Tolerances: Milling vs Turning for Prototypes
Technical guide to achievable CNC milling and turning tolerances in prototyping. Includes industry tolerance tables, tool deflection mitigation, and DFM rules.
CNC Milling vs. Turning: The Engineering Guide to Geometric Optimization and Cost Mitigation
Executive Summary: The 30-Second Engineering Check 1. Kinematic Foundations: How Material is Sheared To understand which process suits a given design, one must first isolate
Low-Volume CNC 6061 Prototypes: Tolerances After Anodizing
Master post-anodizing dimensional changes in Aluminum 6061 prototypes. Learn the 50/50 growth rule, bead blasting erosion impacts, and realistic Cp/Cpk tolerance limits.
DFM for CNC: Deburring Reduction Without Manual Work
Manual deburring drives up CNC manufacturing costs. Learn critical DFM rules for tool selection, edge-break drawing callouts, and tolerance tiers to automate finishing.