Spiral router bits

VHM Spiral Router Bits for CNC – Industrial Precision and High Cutting Performance

Solid carbide (VHM - Vollhartmetall) router bits are manufactured from micrograin tungsten carbide bonded with cobalt. This construction provides exceptional rigidity, high wear resistance, and the ability to operate at high feed rates and spindle speeds on CNC machines. The helical cutting edge ensures continuous tool engagement, reduces vibrations in the machine-tool system, and efficiently evacuates chips from the cutting zone.

Classification and Helix Geometries in VHM Bits

• Positive Helix (Up-cut): Pulls chips upwards toward the spindle, preventing chip re-cutting in deep groove milling. Ensures a clean, chip-free bottom edge on laminated boards.
• Negative Helix (Down-cut): Pushes chips downward, eliminating top-edge laminate chipping and preventing small workpieces from lifting off the vacuum table.
• Roughing Geometry (Chipbreaker): The serrated cutting edge breaks chips into smaller fragments, reducing cutting forces, lowering spindle load, and enabling deeper passes.
• Finishing Geometry (Smooth Edge): Provides a smooth surface finish, eliminating the need for sanding before painting or lamination.

Key Parameters for Selecting a VHM Solid Carbide Bit

• Number of Flutes (Z): Proper flute volume determines chip evacuation capacity and maximum feed rate.
• Protective Coatings (e.g., TiAlN, DLC): Hard PVD coatings reduce friction, prevent resin build-up on the cutting edge, and increase thermal resistance.
• Rigidity and Tolerances: The high Young's modulus of solid carbide minimizes radial deflection, ensuring tight dimensional tolerances under heavy cutting loads.

Applications and Compatible Materials

Designed for nesting, contouring, grooving, and finishing operations in materials such as: hard and soft solid wood, raw and laminated chipboard, MDF, HDF, plywood, composites, and engineering plastics.

Frequently Asked Questions (FAQ)

1. How does the number of flutes (Z1, Z2, Z3) affect VHM bit performance?

The number of flutes dictates chip gullet volume and optimal feed rate. Single-flute (Z1) bits offer the largest chip clearance, preventing plastic melting (PMMA, PVC) and chip clogging in aluminum. Z2 and Z3 bits are the industry standard for wood and panel processing, allowing higher feed rates while maintaining smooth edge quality.

2. When should you choose a roughing (chipbreaker) bit versus a finishing bit?

Roughing bits (with chipbreakers) are used for rapid material removal with reduced cutting forces and lower spindle load, leaving micro-marks on the edge. Finishing bits (smooth edge) are chosen for final contouring passes where a clean, defect-free surface finish is the main priority.

3. When should you use Up-cut versus Down-cut geometry?

The main difference is chip ejection direction and edge protection. Up-cut geometry pulls chips upward, guaranteeing a clean bottom edge while potentially fraying the top laminate (ideal for deep grooves). Down-cut geometry pushes chips downward, protecting the top laminate/veneer and pressing small parts down onto the vacuum table.

4. When is it worth investing in a PVD protective coating?

Coated bits (TiAlN, DLC, PVD) are recommended for highly abrasive materials (MDF, HDF, plywood, filled plastics) and high-speed dry machining. The coating significantly lowers friction, prevents resin adhesion, and extends tool life by 200% to 300%.