Swiss-type lathes are particularly suitable for machining slender shafts mainly due to their unique design structure, machining principles, and technological advantages. The following is a detailed analysis:
- Structural Design Advantages
Spindle and Sub-spindle Working Together: The Swiss-type lathe employs a dual-spindle structure (main spindle and sub-spindle). Slender workpieces can be clamped at both ends during machining, preventing deformation or vibration caused by excessive overhang. The sub-spindle can take over clamping the workpiece during machining, ensuring stability throughout the process.
Short Overhang Design: The cutting tool of the Swiss-type lathe is located near the main spindle, resulting in extremely short workpiece overhang during machining, thus reducing bending deformation caused by centrifugal force or cutting force.
- Machining Principle and Characteristics
Axial Feed Machining: In Swiss-type lathes, the cutting tool moves along the workpiece’s axial direction (Z-axis), while the workpiece itself only rotates (C-axis). This machining method avoids the lateral pressure of transverse cutting forces on slender shafts, reducing the risk of deformation. The radial cutting force of traditional lathes easily causes slender shafts to bend, while the axial cutting force distribution of Swiss-type lathes is more uniform.
Multi-Tool Synchronous Machining: Swiss-type lathes are equipped with multiple sets of tools (such as turning tools, milling cutters, drill cutters, etc.), allowing multiple machining operations to be completed in a single setup, reducing errors and deformation caused by repeated setups.
- Process Optimization
Segmented Machining: Slender shafts can be machined in segments. Through relay clamping by a sub-spindle, cutting, drilling, and tapping operations are completed segment by segment, avoiding uneven stress distribution.
High Speed and Low Cutting Force: Swiss-type lathes typically employ high speed and shallow depth of cut parameters to reduce the single-pass cutting force and further minimize workpiece deformation.
- Comparison with Traditional Lathes
Limitations of Traditional Lathes: When machining slender shafts, traditional lathes typically require a tailstock support. However, adjusting and clamping the tailstock can introduce errors, and simultaneous multi-process machining is not possible.
The Swiss-type lathe’s dual-spindle and short overhang design fundamentally solves the rigidity problem of slender shafts.
- Applicable Scenarios
High Precision Requirements: Slender shafts are commonly used in precision instruments, medical devices, and other fields. Swiss-type lathes can meet their high precision and surface finish requirements.
Complex Shape Machining: Grooves, threads, and irregular contours on slender shafts can all be achieved through the coordinated operation of multiple tools on a Swiss-type lathe.
