- Operating Principle: Step-over Turning Method
- Geometry Definition and Automated Calculations
- Tool Definition and Preparation
- Cutting Strategy and Technological Parameters
- Multi-start Worms and the “Q” Parameter (Mazak Specifics)
- Handling Workpieces Without Undercuts (Entry/Exit Motion)
- Finishing Strategy and Corrections
- Coordinate Systems and Safety (EIA/ISO vs. Mazatrol)
- Project Management and NC Code Generation
Tool Definition and Preparation
Estimated reading: 2 minutes
Choosing the right tool is half the battle. EvoSpline allows you to use standard turning inserts, but you must understand how the software interprets their shape to ensure the final part is correct.
Why do we choose a tool type in the software?
The program needs to know if the cutting edge is „pointed” (like a triangular insert) or has a specific width (like a grooving tool). This determines how the algorithm calculates the Z-axis offsets.
1. VBMT / VCMT Type (Rhombic/Triangular Inserts)
This is the most common choice for worm step-over turning.
- Principle: The program assumes the tool is wedge-shaped with a rounded tip.
- Alternative: Instead of an original VBMT insert, you can use any other tool with a similar shape (e.g., a profiling tool), provided that its tip has a full, known radius (Tool nose R).
- Important: The tool’s included angle must be smaller than the worm’s flank angle to prevent the sides of the insert from rubbing against the material.
2. Grooving Type
Select this option if you are using a tool with a flat front and a specific width (Tool width).
- Pro Tip (Trapezoidal Inserts): You can successfully use a trapezoidal thread insert as a „grooving” tool. Why? Because the flank angle of a trapezoidal thread (14.5∘ or 15∘) is smaller than the standard worm flank angle (20∘). This allows the trapezoidal insert to fit freely within the worm groove, and the software will guide it to machine the correct profile.
The Key to Success: Tool Tilting (Lead Angle)
This is the most common setup error. A worm is essentially a very „fast” thread. If you set the tool perpendicular to the workpiece, its side flank will rub against the worm’s spiral, ruining the surface or breaking the insert.
- Check the Result: Look at the Angle of the worm thread field in the program. This is the angle at which the worm’s helix travels.
- Tilt the Holder: You must physically tilt the tool holder by this same value.
- Adjustable tool holders or angled shims are used.
- Simple Rule: The tool must „flow” with the thread, not stand across it.
