Views: 0 Author: Site Editor Publish Time: 2026-09-15 Origin: Site
Polycarbonate (PC) is one of the most popular engineering plastics for industrial equipment, electronics, medical devices, and transparent protective components. It features high transparency, extreme impact resistance, and excellent dimensional stability.
When manufacturing PC parts, manufacturers mainly adopt three processes: Laser Cutting, CNC Machining, and Injection Molding. However, many buyers and engineers choose the wrong process, resulting in cracking issues, poor appearance, high defect rates, or extremely high production costs.
To help customers clearly understand which process suits their product structure and order quantity, we fully compare the three manufacturing methods and add four real industrial case studies for practical reference.
Laser cutting uses ready-made flat PC sheets with fixed thickness. A high-energy laser beam melts and vaporizes plastic along the 2D CAD outline to cut shapes and holes.
Key limitation: It only cuts flat planes. It cannot create steps, flanges, slopes, or draft angles. Any 3D structure requires secondary bending or gluing, which weakens the part greatly.
CNC machining cuts excess material from solid PC blocks or thick sheets. It uses rotating cutters to mill full 3D structures, including steps, flanges, tapered surfaces, and custom angles.
Key advantage: No mold needed, one-piece forming, no assembly gaps, perfect for complex prototype and small-batch structural parts.
Injection molding melts PC plastic pellets into liquid and injects the material into a precision steel mold. After cooling, the part obtains the exact 3D shape of the mold cavity.
Key advantage: Mass production stability, customizable surface texture, lowest unit price for large orders, and consistent mechanical performance.
Laser Cutting: Only flat 2D shapes. Cannot make steps, flanges, or draft angles.
CNC Machining: Supports all 3D structures, including stepped edges and 2° draft angles.
Injection Molding: Perfect for complex structured parts with ribs, snaps, bosses, and tapered surfaces.
Laser parts: Thermal cracks, edge yellowing, carbonization, easy to crack under vibration or solvent contact.
CNC parts: Stable structure, no splicing gaps, minor tool marks, reliable for small batch assembly.
Injection parts: Uniform internal stress, smooth surface, best toughness and durability for long-term use.
Laser: Cheap for prototypes, expensive for large quantity.
CNC: No mold cost, suitable for 10–500 pcs, high unit price for mass orders.
Injection: High mold investment, lowest cost above 1000 pcs.
Project Background
A European automation customer ordered PC equipment panels with perimeter stepped flanges and assembly slopes. The customer initially chose laser cutting to save mold cost.
Processing Method
The manufacturer laser-cut flat PC sheets and bent the edges manually, then glued the corners to form steps.
Problem & Failure
1. Bending positions generated huge residual stress. 2. Glue joints cracked after vibration testing. 3. Laser edge micro-cracks caused breaking after alcohol cleaning. 4. 60% of the batch was rejected.
Conclusion
Structured PC parts with steps or flanges cannot use laser cutting. Laser cutting is only valid for pure flat plates.
Project Background
A medical device client needed 200 pcs of customized stepped PC covers with 2° draft angles for new product testing, no mold budget allowed.
Solution
We adopted CNC one-piece milling. All steps, tapered slopes, and mounting holes were milled from solid PC material without bending or gluing.
Result
Perfect tolerance, no stress cracks, stable assembly, fully passed vibration and disinfection tests. The customer successfully launched the trial production.
Conclusion
CNC is the best intermediate solution for structured PC parts in low-to-medium volume orders (10–500 pcs).
Project Background
A consumer electronics brand needed 50,000 pcs/year transparent PC housings with stepped edges, uniform gloss, and strict batch consistency.
Problem of CNC & Laser
If using CNC, the cost would be 3 times higher, and surface uniformity cannot be guaranteed. Laser cutting cannot form the required 3D structure.
Injection Molding Solution
We built S136 hardened steel mold with customized surface polish. All structural features were formed in one shot.
Result
Ultra-low unit cost, zero assembly gaps, perfect transparent appearance, 100% qualified rate for mass shipment.
Conclusion
For orders over 1000 pcs with structural requirements, injection molding is the only economical and reliable solution.
Project Background
A factory required 80 pcs of simple flat PC safety guards, no steps, no slopes, only outline and hole cutting.
Solution & Result
Laser cutting completed all parts within 1 day, zero tooling cost, fully meeting temporary machine protection needs.
Conclusion
Laser cutting remains the fastest and cheapest option for simple flat PC prototype parts.
Pure flat 2D plate without any steps or flanges
Only small prototype quantity below 100 pcs
Urgent delivery within 24 hours
Parts have steps, flanges, or draft angles
Quantity between 10–500 pcs
No budget for mold opening
High precision assembly required
Structured PC parts needing stable appearance and strength
Order quantity over 1000 pcs
Need uniform surface texture (VDI finish / mirror polish)
Long-term mass production project
Laser cutting, CNC machining, and injection molding are not interchangeable for PC parts.
Laser is only for flat prototypes. CNC fills the gap for small-batch structured parts. Injection dominates high-quality, low-cost mass production.
Most failed PC part projects are caused by using laser cutting for 3D structural products. Correct process selection ensures better quality, lower defect rate, and reasonable cost.
This selection logic applies to most thermoplastics, not only PC. Laser cutting works best for flat acrylic and PC sheets, but PP, PE and POM get sticky burrs or charred edges. CNC machining is versatile for nearly all plastics to make 3D structures like steps and slopes. Injection molding supports all thermoplastics for mass production, though mold design must account for each resin’s shrinkage and flow properties. The core rule remains unchanged: flat low-volume parts can use laser; 3D small-batch parts use CNC; high-volume structured parts choose injection molding.
We provide professional PC laser cutting, CNC precision machining, and custom injection mold manufacturing services. Send your 3D drawings to us, and our engineer will evaluate the most suitable process and offer the best solution for your project!
