Aerospace & Automotive Titanium Alloy: Slot (Trochoidal) Milling

Titanium Alloy Slot (Trochoidal) Milling: Machining Pain Points

The hardness of Titanium Alloy (taking the common Ti-6Al-4V as an example) is approximately 41 HRC. Although the hardness of Titanium Alloy is not particularly high among hardened steel materials compared to traditional metals (for instance, certain tool steels or tungsten carbide will have higher hardness).

The reason why it is classified as an extremely difficult-to-machine "hard-to-cut material" is mainly because it simultaneously possesses the following physical characteristics:
 

• Low Thermal Conductivity

  The cutting heat generated during machining is extremely difficult to dissipate through chips. The high heat accumulates entirely on the cutting edge, which easily causes the tool to soften and wear under high temperatures.

• High Ductility & Work Hardening

  The material exhibits good plasticity and high-temperature deformation performance under high temperatures. During cutting, it is prone to adhesive wear, causing chips to repeatedly stick to the tool.

• High Strength & High Toughness

  This makes the chips difficult to break. If a long overhang tool is used to machine deep slots, it can easily trigger severe tool chatter and chip-tangling problems.

When performing deep slot machining on titanium alloys, the primary challenge faced is that the tool overhang is as high as 60mm, which easily generates tool chatter issues during the machining process. Small vibrations in the long overhang state will directly affect the surface quality of the final workpiece.

In addition, for slot (trochoidal) milling in deep slotting, traditional methods (without ultrasonic assistance) make it difficult for cutting fluid to flow smoothly into the machining zone for cooling. The cutting heat that cannot be effectively eliminated easily leads to abnormal wear of the tool coating, such as oxidation discoloration (with a width up to 0.2mm), thereby severely shortening tool life.
 

【HIT Ultrasonic】Titanium Alloy Slot (Trochoidal) Milling: Machining Results

Titanium Alloy Slot (Trochoidal) Milling: Workpiece Quality Up↑

After introducing the assistance of the HIT Ultrasonic Module, the high-frequency micro-vibration helps reduce cutting resistance and effectively suppresses the tool chatter phenomenon caused by the long overhang. The machined surface texture is uniform and perfectly conforms to the true trochoidal machining path. Actual observation data shows that the surface roughness (Sa) without ultrasonic is 0.328 μm, while with the assistance of HIT Ultrasonic, the surface roughness (Sa) drops to 0.121 μm, representing a massive +67% leap in surface fineness.

Fig 1. Comparison of Surface Roughness With and Without Ultrasonic

Titanium Alloy Slot (Trochoidal) Milling: Tool Life Up↑

In addition to reducing resistance, the high-frequency micro-vibration of the ultrasonic wave allows the cutting fluid to flow more easily into the deep slot machining zone at the instant of "intermittent tool lifting" produced by the micro-vibration, significantly enhancing the cooling effect. This successfully prevents the tool coating oxidation discoloration caused by cutting heat in traditional non-ultrasonic machining, effectively reducing tool wear and extending service life.

Fig 2. Comparison of Tool Surface Condition With and Without Ultrasonic

Titanium Alloy Slot (Trochoidal) Milling: Machining Efficiency Up↑

Combining the aforementioned advantages of vibration suppression and cooling enhancement, using HIT ultrasonic technology allows for the direct achievement of "finishing" surface quality under "roughing" machining parameter conditions. This means that process integration can be achieved, eliminating extra finishing time and bringing a significant boost to overall process efficiency.

Fig 3. Comparison of Slot (Trochoidal) Milling Machining With and Without Ultrasonic

🕜 Machining Efficiency - Achieves finishing surface quality under roughing parameter conditions, realizing process integration.
📈 Workpiece Quality - Reduces cutting resistance and effectively suppresses tool chatter, improving surface fineness by 2.7 times!
⚙️ Tool Life - Intermittent tool lifting allows cutting fluid to flow in easily, effectively reducing cutting heat and tool wear.

Industry Application of Titanium Alloy(Ti-6Al-4V)

Titanium alloy slot (trochoidal) milling features are frequently applied in the aerospace and defense industry, biomedical devices and implants industry, and premium 3C consumer electronics industry. Especially for aircraft fuselage frames, landing gear components, engine blisks and casings in the aerospace industry; titanium bone plates, bone screws, joint replacements, and hip prostheses in the biomedical devices and implants industry; and smartphone frames and premium smartwatch cases in the premium 3C consumer electronics industry.

Compared to other metal alloys, the hardness of titanium alloy is not high. Titanium alloy features stable structure, lightweight material, low density, and high strength, along with excellent toughness, plasticity, and machining distortion at high temperature performance. These characteristics make it widely adopted across many industries.
 

Among them, in addition to its non-toxic property, titanium alloy is one of the best metals known for biocompatibility, and is therefore regarded as the best metal biomedical material today, with application products such as bone plates, bone screws, and joint replacements. Titanium alloy also has anti-fingerprint and anti-fouling characteristics, making it highly suitable for smartphone chassis and smartwatch frames. Furthermore, the high strength and heat resistance properties of titanium alloy also make it the material of choice for the chassis structure of the electric vehicle Tesla Model S, preventing the battery from being damaged by road bumps.
 

Hantop Intelligence Tech's Ultrasonic Machining Module brings a brand-new solution to the machining of advanced materials!

HIT's Ultrasonic-assisted Machining Technology can effectively enhance machining efficiency, save overall machining time, and simultaneously drastically reduce the edge chipping size.

It not only meets the standard of the client's requirements but also creates multiple values for customers around the globe!

💡 Learn More About HIT Ultrasonic Machining Cases for Metals, Alloys, Steel, and Hardened Steel Materials
 

• Grinding & Threading of Tungsten Carbide
• M2 Internal Threading of Tungsten Carbide
• Deep Hole Drilling of AISI-1045 Carbon Steel with Gun Drill
• Side Milling of AISI-4140 Alloy Steel
• Bottom Milling of AISI-D2 Tool Steel
• Side Milling of Titanium Alloy (Ti-6Al-4V)