Machining Challenges of Cemented Carbide and Titanium Alloy – How Does a Precision CNC Die-sinker EDM Machine Handle These “Hard Bones”?

When facing difficult-to-machine materials such as cemented carbide and titanium alloy, what fatal bottlenecks do traditional machining methods encounter?

In modern precision manufacturing, cemented carbide (such as tungsten steel, generally with hardness above HRC60) and titanium alloy are widely used in aerospace, medical devices, and high-end molds due to their extremely high strength, wear resistance, and corrosion resistance. However, these excellent material properties have become a “nightmare“ in the field of mechanical machining.

First, tool wear is extremely high. When traditional milling or grinding faces ultra-hard materials, it is like “hard against hard“ – tools wear out very quickly, and frequent tool changes directly drive up manufacturing costs. Second, cutting forces cause deformation and micro-cracks. Titanium alloy has a low elastic modulus, and cutting forces easily cause thin-walled parts to deform, while cemented carbide is prone to micro-chipping under mechanical stress. Finally, when machining complex blind cavities or deep narrow slots, traditional tools with high length-to-diameter ratios are extremely prone to interference, deflection, and even breakage, and chip evacuation is extremely difficult, easily causing workpiece scrap.

Why is EDM the preferred solution for difficult-to-machine materials?

Facing the above bottlenecks, EDM provides a technical path of “overcoming hardness with softness.“ EDM is a non-contact discharge erosion process, and there is no macroscopic mechanical cutting force between the tool electrode and the workpiece.

This principle brings two fundamental advantages: first, it is completely unrestricted by material hardness – as long as the material is conductive, it can be machined no matter how hard it is; second, there is no cutting stress, making it particularly suitable for machining thin-walled, easily deformed precision components. As a company with deep cultivation in the field of special processing equipment in China, NOVICK has carried out in-depth software and hardware optimization for difficult-to-machine materials on its AF Series precision CNC Die-sinker EDM Machines. Its built-in complete process parameter database covers extremely complex material combinations, such as: copper machining cemented carbide, graphite machining titanium alloy, copper-tungsten alloy machining cemented carbide, etc. Operators only need to call up a standard code in the system to retrieve a complete set of matching discharge parameters, completely eliminating the tedious blind trial process.

In special material machining, how can extremely high machining efficiency and extremely low electrode wear be balanced?

Efficiency and electrode wear have always been the core contradiction in EDM of difficult-to-machine materials. To improve efficiency, the machine must be able to withstand continuous discharge at high current, but this also easily leads to excessive electrode wear and surface burning.

The NOVICK AF Series effectively balances this contradiction through the synergy of an underlying all-digital pulse power supply and fuzzy logic algorithms. In terms of hardware configuration, the AF Series comes standard with 50A current. If the optional 100A current module is selected, the maximum machining speed when machining 45# steel can reach 550mm³/min. More critically, thanks to the system‘s precise detection and control of every discharge pulse, its relative volumetric electrode wear can be stably controlled at ≤1%. In addition, to address the difficulty of chip evacuation during deep slot and narrow gap machining, the AF Series is equipped with a high-speed electrode lift function. Faster electrode lifting can quickly extract erosion products from the machining area, avoiding arcing burns while greatly improving the material removal rate in deep cavity machining.

Beyond high efficiency, how does a precision EDM machine guarantee the ultimate surface quality in cemented carbide/titanium alloy machining?

Aerospace and medical devices not only require dimensional accuracy but also have strict standards for surface integrity (such as no micro-cracks and low roughness). If EDM parameters are not properly controlled, the surface is extremely prone to a thick recast layer (white layer).

To ensure ultimate surface quality, the AF Series adopts a high-rigidity C-type cast iron integrated bed in its mechanical structure, combined with a fixed worktable design, isolating vibration interference with discharge stability from the source. At the same time, the X/Y/Z three axes use precision linear rolling guides and ball screw pairs, combined with a 2500line optical encoder, ensuring micron-level servo feed accuracy. In the finishing stage, by finely adjusting pulse width and gap voltage, the AF Series achieves optimal surface roughness of Ra ≤ 0.1μm under the condition of copper electrode machining S136 mirror steel. This mirror-level machining effect greatly reduces subsequent manual polishing man-hours and effectively avoids dimensional out-of-tolerance and precision loss that may be caused by manual grinding.