What Is Trochoidal Milling — And Why Are Malaysian Manufacturers Switching to It?
If you have been reading about high-efficiency machining or heard terms like HEM (High Efficiency Milling), dynamic milling, or adaptive clearing — trochoidal milling is the core strategy behind all of them. It is one of the most significant shifts in CNC machining strategy over the past decade, and it is rapidly being adopted by manufacturers across Malaysia's Automotive, Mold & Die, and General Engineering sectors.
But what exactly is it, why does it work, and is it right for your operation? This guide answers those questions in plain terms.
What is trochoidal milling?
In conventional milling, the tool takes a wide radial cut — often 50–100% of the tool diameter — and moves in a straight line through the material. This creates a large contact arc between the tool and workpiece, generating high cutting forces, significant heat, and rapid tool wear.
In trochoidal milling, the tool takes a very small radial cut — typically 5–15% of the tool diameter — but moves in a continuous looping (trochoidal) path through the pocket or slot. The result is:
Very short contact arc between tool and workpiece — the tool engages the material for a small portion of each revolution, then disengages.
Much lower cutting temperature — the tool has time to cool during the disengagement phase.
Lower cutting forces — the small radial depth generates a fraction of the force of conventional milling.
High axial depth of cut — because radial forces are low, you can use the full flute length of the tool (ap = 1.5–3x tool diameter) in a single pass.
Faster overall material removal rate — despite the seemingly indirect path, the combination of high axial depth and constant tool motion removes material faster than conventional approaches in many applications.
Why does it extend tool life so dramatically?
Heat is the primary killer of cutting tools. In conventional milling with a wide radial engagement, the cutting edge stays in contact with the workpiece for a long arc — generating heat that accumulates in the tool. Over time, this thermal cycling fatigues the carbide and accelerates wear.
In trochoidal milling, the short contact arc means the cutting edge spends most of its time out of the cut — cooling down. The thermal load per revolution is a fraction of conventional milling. In hardened steel and difficult alloys, this can extend tool life by 300–500% compared to conventional approaches.
Which materials benefit most?
Hardened steel (Mold & Die — P20, H13, S136) — trochoidal milling allows aggressive material removal in hardened steel that would destroy a tool in conventional milling. Standard in modern mold shops globally.
Stainless steel — the low cutting force prevents the work hardening that destroys tools in conventional stainless milling.
Titanium and high-temperature alloys — trochoidal milling is one of the few strategies that makes titanium machining cost-effective. The disengagement cooling phase prevents the catastrophic heat buildup that destroys tools in conventional titanium milling.
Aluminium alloy (Automotive structural) — extremely high material removal rates achievable. Trochoidal at Vc 800–1200 m/min in aluminium is standard practice in modern automotive machining centres.
Inconel and Inconel-family alloys — trochoidal milling reduces cutting forces dramatically, making Inconel machining significantly more predictable and tool-life more consistent.
Which materials see less benefit?
Cast iron — conventional milling with indexable insert cutters is often more economical for grey and ductile cast iron at high volume.
Very soft materials (copper, brass, plastics) — conventional milling with high cutting speeds is typically more efficient.
Shallow features and very short runs — the programming time and setup for trochoidal toolpaths may not be justified for simple shallow features.
What do you need to implement trochoidal milling?
CAM software with trochoidal or dynamic milling capability — most modern CAM systems (Mastercam, Hypermill, Fusion 360, Siemens NX) have this built in. Your CAM programmer needs to know how to activate and configure it.
A CNC controller that can execute high-density curved toolpaths smoothly — older controllers with slow look-ahead may struggle. Modern Fanuc, Siemens, and Mitsubishi controllers handle trochoidal paths well.
The right end mills — trochoidal milling uses the full flute length, so end mills need long flutes and high core rigidity. MOLDINO and Mitsubishi Materials both have tooling optimised for high-efficiency milling strategies.
Recommended tooling for trochoidal milling
MOLDINO Impact Miracle series (VFMHV) — designed for high-efficiency milling in hardened steel. AlTiN nano-composite coating, variable helix to suppress chatter. Ideal for Mold & Die trochoidal milling in H13 and S136.
MOLDINO MRBSH series — excellent for trochoidal roughing in pre-hardened mold steels (P20, NAK80).
Mitsubishi Materials iMX exchangeable head system — cost-effective for trochoidal milling where solid carbide cost is a concern. Carbide head on steel shank.
Mitsubishi Materials VFMHV (High Helix End Mill) — variable helix for chatter suppression in trochoidal steel and stainless milling.
OSG AE-VML series — multi-flute variable helix end mills for trochoidal milling in steel and stainless.
A simple cycle time comparison
To illustrate the benefit — consider a 30mm deep pocket in P20 mold steel (33 HRC) with a 12mm carbide end mill:
Conventional milling: radial depth 6mm (50% tool diameter), axial depth 6mm (0.5D), Vc 100 m/min. Multiple axial passes required. Cycle time: 28 minutes. Tool life: 3 pockets.
Trochoidal milling: radial depth 1.2mm (10% tool diameter), axial depth 30mm (2.5D, full depth in one pass), Vc 130 m/min. Single axial pass. Cycle time: 18 minutes. Tool life: 12 pockets.
Result: 36% cycle time reduction, 4x tool life improvement. Cost per pocket drops from RM 12 to RM 4 in tooling alone — before the machine time saving.
Ready to switch to trochoidal milling?
KS Precision Tools can advise on the right end mills for your trochoidal milling application, recommend starting cutting parameters, and connect you with our CAM partner contacts if you need programming support. As authorised distributor for MOLDINO, Mitsubishi Materials, and OSG in Malaysia, we stock the tooling that delivers the results described above.
Call 03-8941 7168 or email kokyong@ks-precision.com. Based in Seri Kembangan, Selangor.
Comments