chipbreaker geometry comparison. Get instant Helical Path Radius (mm), Program Feed (mm/min) for your machining parameters.
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Request a Proposal →Even with high-end tooling from Dormer Pramet and Tungaloy, things go wrong. Here are the most common Helical Interp-related issues our technical team sees, and how to fix them.
Diagnosis: Your surface speed is likely too high. Even Dormer Pramet AlTiN-coated carbide can't outrun excessive heat generation. Check that your Helical Interp matches the actual material hardness — a shift from HRC 28 to HRC 32 4140 changes everything.
Fix: Reduce SFM by 15-20%. Verify coolant concentration with a Hexagon refractometer (target 8-10% for steel).
Diagnosis: Your Helical Interp might be fine for straight cuts, but corner engagement increases dramatically. Tungaloy application engineers call this the "corner trap" — the tool sees 180° of engagement in a 90° internal corner.
Fix: Add a finish pass at 0.1mm radial depth with a separate finishing tool. Program the DMG Mori to reduce feed rate to 50% in corners.
Diagnosis: You're applying Dormer Pramet Helical Interp values to Tungaloy tools — or vice versa. Each manufacturer's carbide substrate and coating system has a different sweet spot.
Fix: Download the specific Helical Interp chart for your exact tool from the manufacturer's website. Dormer Pramet CoroPlus and Tungaloy NOVO both offer free digital tools.
Helical interpolation (helical boring) combines circular interpolation with a simultaneous Z-axis feed to create or enlarge bores with a single tool. The tool follows a helical path — a circle with a vertical pitch per revolution.
Helical interpolation is faster for roughing bores and works with standard end mills. Use it for bores that don't require boring-head precision, or to rough out a bore before finishing. For tolerances under IT7, finish with a boring head or reamer.
The bore must be at least 1.05× the tool diameter to allow the tool to enter. For practical cutting, bore should be at least 1.2× tool diameter. Below that, the tool rubs on the bore wall and chip evacuation is poor.
G02/G03 with X, Y, Z, I, J (or R) on the same line. Example: G03 X0 Y0 Z-2.0 I10 J0 F500 — makes one full helix of 2 mm depth with 10 mm radius. Use multiple lines to stack helices for deeper bores.
Enter the bore diameter, tool diameter, depth per revolution, and ramp angle. The calculator shows the helical path radius and the compensated feed rate to maintain the correct chip load at the tool centre.
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Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
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