Advanced CNC System Selection: Understanding the Adaptation Boundaries of FANUC, Siemens, and Domestic Systems Through Typical Machining Scenarios

I. Mold Machining Scenario: Competition in Complex Surfaces and Precision Stability

• Siemens systems have obvious advantages in mold machining. Its high-end systems such as 840D sl adopt "NURBS spline interpolation" technology, which can smoothly fit complex surfaces. The surface roughness of machined cavities can be reduced by 10%-15%, eliminating the need for subsequent polishing processes. During continuous machining lasting dozens of hours, Siemens' "thermal error compensation" algorithm can real-time correct precision deviations caused by spindle temperature rise, ensuring dimensional consistency of deep and shallow cavities in molds. Additionally, its "feed axis dynamic following" function can effectively suppress vibration during high-speed cutting, making it particularly suitable for precision machining of hardened steel (HRC 50 and above).
• FANUC systems perform well-balanced in mold machining, especially excelling in efficiency during high-speed rough machining of small and medium-sized molds. The "AI contour control" function of the 31i-B system can automatically adjust feed rates, decelerating at corners and accelerating in straight segments, ensuring both precision and efficiency. Compared with Siemens, FANUC has the advantage of more mature post-processing compatibility with mainstream CAM software (such as UG and Mastercam), shortening the program debugging cycle by approximately 20%, which is suitable for rapid switching production of multi-variety molds.
• Domestic systems have gradually replaced imported systems in low-to-mid-end mold machining in recent years. For example, for molds with low precision requirements (surface roughness of Ra 1.6μm is sufficient), such as home appliance casings, the "surface fitting" function of domestic systems can already meet the needs, and the procurement cost is only half of that of imported systems. However, in scenarios such as large automotive panel molds (machining range exceeding 2 meters) and high-precision optical molds (tolerance ±0.001mm), domestic systems still have gaps in long-term precision retention, making them more suitable as a transitional choice.

II. Automotive Parts Batch Machining: Balance Between Efficiency Stability and Flexibility

• FANUC systems are the mainstream choice for automotive parts production lines. Its 0i-F series optimizes the "rapid tool change" logic for batch production, controlling the tool change time within 1.5 seconds, which is approximately 20% shorter than similar systems. On multi-station machining centers, FANUC's "synchronous control" function can achieve precise coordination between the spindle and the turntable, ensuring the positional accuracy of the cylinder block hole system (usually requiring ±0.02mm). More importantly, its hardware failure rate is extremely low (mean time between failures exceeds 10,000 hours), which can adapt to the high-intensity demand of 24/7 continuous production in automotive factories.
• Siemens systems have more advantages in flexible production lines for automotive parts. For example, when switching the machining of cylinder blocks of different displacements on the same production line, the "program segment pre-reading" function of the Siemens 828D system can quickly load new programs (supporting large programs above 1GB), shortening the production change debugging time by 15% compared with FANUC. Its "process data management" module can store machining parameters of different parts, enabling one-click calling, which is suitable for multi-variety, small-batch automotive parts production (such as new energy vehicle motor housings).
• Domestic systems have outstanding cost-effectiveness in the machining of auxiliary automotive parts (such as brackets and flanges). These parts have low precision requirements (tolerance ±0.1mm) and loose production cycles, and the stability of domestic systems can fully meet the needs. Some domestic manufacturers have also developed exclusive adaptation modules with domestic probes for the "on-line inspection" needs of automotive parts. The inspection data can be directly fed back to the system for compensation, and the cost is only one-third of that of imported solutions.

III. Small and Medium-Batch General Parts Machining: Trade-Off Between Cost-Effectiveness and Usability

• Domestic systems are the first choice for such scenarios. Most domestic systems adopt a full Chinese interface and are equipped with a "graphical programming" function. Workers only need to input part dimensions (such as diameter and length), and the system can automatically generate machining programs without memorizing G-codes, which is particularly suitable for small factories with insufficient technical personnel reserves. In terms of cost, the single-unit investment of domestic systems is 50%-60% lower than that of imported systems, and flexible schemes such as installment payments are supported, reducing the financial pressure on small and medium-sized enterprises. Additionally, for the "turn-mill compound" machining commonly used in general parts, some domestic systems have developed dedicated macro programs to simplify the multi-process programming process.
• FANUC systems still have a market in small and medium-batch machining with certain precision requirements (such as hydraulic valve blocks). The "manual guidance" function of its 0i-MF system can drag the axis to move through the handle and display coordinate values in real-time, facilitating tool setting and trial cutting for workers and reducing operational difficulty. Although the procurement cost is relatively high, the low failure rate and long service life (generally exceeding 10 years) still make it economical in the long run.
• Siemens systems are rarely used in small and medium-batch machining, mainly because their operation interface is relatively complex, the training cost is high, and the cost-effectiveness of basic functions is not as good as that of domestic systems and FANUC's economical series. However, for general parts that occasionally involve simple surfaces (such as special-shaped joints), Siemens' "spline curve programming" function is more convenient than domestic systems, which can reduce programming time.

IV. Supplementary Dimensions for Selection: Operation and Expansion

1. Operation Threshold: Domestic systems ＞ FANUC ＞ Siemens. The Chinese interface and simplified operation of domestic systems are most suitable for beginners; FANUC has a simple interface and clear logic, with a training cycle of approximately 1-2 weeks; Siemens has rich functions but a complex interface, requiring more than 1 month to master proficient operation.
2. Upgrade and Expansion: Siemens ＞ FANUC ＞ Domestic systems. Siemens systems support modular upgrades (such as adding a fourth axis and robot interface later) and have strong compatibility; FANUC upgrades require authorization from the original factory, with slightly less flexibility; some low-end domestic systems have limited hardware performance and small upgrade space.
3. Spare Part Versatility: FANUC ＞ Domestic systems ＞ Siemens. FANUC has a mature global spare part system, and general models (such as servo motors and drives) are easy to purchase; domestic system spare parts have strong versatility but uneven quality; the spare parts of Siemens high-end systems have strong specificity and long procurement cycles.

Conclusion: Focus on Core Needs According to Scenarios

• Mold Machining: Pursue surface precision and stability → prioritize Siemens; balance efficiency for small and medium-sized molds → choose FANUC; low-cost transition → domestic systems.

• Automotive Parts Batch Production: High cycle stability → FANUC; flexible production change → Siemens; auxiliary parts machining → domestic systems.

• Small and Medium-Batch General Parts: Usability and cost-effectiveness → domestic systems; higher precision requirements → FANUC.