1. What is Acrylic CNC Machining?
CNC machining has become the mainstream high-precision custom processing technology today and is widely used in the manufacturing of various materials. By using CNC machines and pre-programmed instructions, acrylic can be cut, drilled, engraved, and shaped. This is one of the most common and modern processing methods.
Before CNC machining became popular, acrylic processing was mostly performed manually, which inevitably resulted in rough and imprecise outcomes. Today, with the wide adoption of CNC machining, acrylic benefits from high precision, repeatability, efficiency, and the ability to produce complex shapes. It can achieve micron-level accuracy and perfectly meet the high requirements of fields such as signage, optical lenses, display props, precision instrument panels, and medical device components.
2. Acrylic CNC Machining Methods and Processes
A complete CNC machining workflow for acrylic is as follows:
🔹 Flowchart
graph LR
A[Design & Programming (CAD/CAM)] --> B[Material Preparation]
B --> C[Tool Selection & Setup]
C --> D[Tool Zeroing & Parameter Settings]
D --> E[Machining Execution]
E --> F[Post-processing]
3. Acrylic Cutting Parameters: Feed, Speed, and Depth of Cut
This is the key to success or failure. Improper parameter settings may lead to melting, tool sticking, chipping, or surface scratches.
- Spindle Speed: Recommended high speed, typically between 10,000 – 24,000 RPM. High speed generates shearing rather than tearing force, producing smoother cuts.
- Feed Rate: Must match spindle speed. Too slow = excess heat and melting; too fast = excessive cutting force, vibration, or chipping. Recommended chip load (Fz) = 0.05 – 0.15 mm/tooth.
Example: 2-flute 6 mm cutter at 18,000 RPM → Feed = 3,600 mm/min. - Depth of Cut:
- Roughing: ½–⅔ tool diameter (e.g., 3–4 mm for a Ø6 mm tool).
- Finishing: <0.5 mm for best surface quality.
- Cooling: Strongly recommended to use compressed air to remove chips and prevent melting. Avoid water-based coolants, which may cause stress cracking (“crazing”).
4. Which Tools Are Used for Acrylic CNC Machining?
Tool selection directly determines machining quality and efficiency.
🔹 Comparison Table
| Tool Type | Common Applications | Advantages | Disadvantages |
|---|---|---|---|
| Single-Flute Spiral End Mill | Most recommended for finishing and precision cutting | Excellent chip evacuation, smooth & burr-free edges, high transparency | Slightly lower efficiency, higher cost |
| Double-Flute Spiral End Mill | Roughing and semi-finishing | Higher cutting efficiency, faster removal | Smaller chip pockets, lower surface quality than single-flute |
| Compression Spiral End Mill | Cutting multilayer or laminated sheets | Prevents chipping on top/bottom edges, clean finish | Higher cost, limited cutting speed |
| Ball Nose End Mill | 3D surface milling, relief carving | Ideal for complex curves and contours | Lower efficiency, less suited for flat finishing |
| V-Bit Engraving Tool | Text and pattern engraving | Sharp tip allows fine detail | Wears quickly, not efficient for large areas |
Preferred material: solid carbide tools for higher hardness and wear resistance compared to HSS.
5. Special Processes: CNC Grinding and Turning
- Acrylic CNC Grinding: Used for optical lenses or components requiring extreme flatness. With diamond or ultra-fine grinding wheels on CNC grinders, material can be removed at micron levels, achieving nanometer-level surface roughness—essential for high-end optical applications.
- Acrylic CNC Turning: For machining acrylic rods into lenses, domes, or cylindrical precision parts. With sharp diamond or polished carbide tools, CNC lathes can produce mirror-like finishes directly.
6. Types of Acrylic Materials for Machining
Not all “acrylic” is the same—different formulations and manufacturing methods affect machinability.
🔹 Comparison Table
| Acrylic Type | Advantages | Disadvantages |
|---|---|---|
| Extruded Acrylic | Low cost, easy thermoforming | Higher risk of melting and tool sticking, rougher finish |
| Cast Acrylic | Higher molecular weight, tougher, better machinability, smooth edges | More expensive |
| Impact-Modified Acrylic | Much higher impact resistance, shatter-resistant | Reduced edge transparency after machining |
| Colored/Patterned Acrylic | Wide aesthetic options, attractive appearance | Pigments may slightly affect machinability |
7. How to Calculate Acrylic CNC Machining Costs
Quotations are typically based on:
- Material Cost: Sheet cost + wastage.
- Machine/Hourly Rate: Depends on machine type (standard vs. 5-axis) and local labor cost.
- Tool Wear Cost: Especially relevant for large or complex jobs.
- Post-Processing Costs: Polishing, flame finishing, printing, assembly.
- Design/Programming Fees: If production-ready CAD/CAM files are not provided.
- Profit & Taxes.
Customers usually provide 2D DXF/DWG or 3D STEP/IGS drawings for accurate quotes.
8. Leading Manufacturers and Processing Companies
- CNC Equipment Manufacturers for Acrylic:
- International: Haas (US), DMG MORI (Germany/Japan), Mecanumeric (France), MultiCam (US).
- Chinese: Beijing Jingdiao, Jiatie, Han’s Laser, Dingtai—high cost-performance, widely used domestically.
- Acrylic Processing Companies:
- Many are regional specialists. Some global giants like Rogers Corporation and Mitsubishi Chemical also provide acrylic component processing.
- In China, the Pearl River Delta and Yangtze River Delta are hubs, serving clients like Apple, Huawei, and Tesla, as well as optical and medical industries.
Conclusion
Acrylic CNC machining is a precise technology integrating material science, mechanics, and cutting processes. Success depends on understanding PMMA’s properties, carefully selecting tools, optimizing cutting parameters, and designing efficient process paths.
By mastering the principles in this guide, acrylic can be transformed into crystal-clear, high-performance products across signage, optics, displays, and medical applications.
For specific projects, it is recommended to consult professional engineers or processing companies for the most cost-effective solution.
