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The cutterhead of the tunneling machine has turned into a “wheel of fire”—is it because the cutting picks are hard enough, or are there operational hazards at play?

2026-01-23

The cutterhead of the tunneling machine has turned into a “wheel of fire”—is it because the cutting picks are hard enough, or are there operational hazards at play?

On the front lines of mining operations, we often receive videos from our customers showing the cutting head of a roadheader spinning at high speed in pitch-dark tunnels. When it strikes the rock walls, sparks fly everywhere, creating a spectacle that looks just like “the Wheel of Fire.”

Regarding this phenomenon, industry opinions are mixed. Some people believe that this is... Proof of “good teeth”—it shows the cutting teeth are hard enough to gnaw through tough bones. ; Some people are also concerned that this is “Bad things” mean increased wear and tear and heightened safety risks. 。

What is the truth, exactly? As a specialist in wear-resistant materials with two decades of experience, Xinda Machinery offers you an objective technical breakdown.

Positive interpretation

Sparks truly embody “hard power.”

INTERPRETATION

First, we need to acknowledge one thing: Under specific operating conditions, the ability to produce sparks indeed confirms that the cutting picks’ “hardness” and “strength” meet the required standards.

When the rock hardness reaches Level 10 and above and contains a large amount of highly abrasive components such as quartz, The laws of physics dictate that any metal-cutting tool will produce sparks when it strikes at high speed. 。

1. Performance of generic teeth

When you encounter such a tough nut to crack, often before you even have a chance to spark any friction, the alloy tip already... Lacks resilience and cracks directly. Or, due to insufficient hardness, they may soften and become blunt in an instant.

2. Performance of high-quality teeth

Only adopt High-hardness alloy and high-strength brazing Only high-quality cutting picks can maintain structural integrity under extreme impact and continue to engage in high-intensity, “hard-to-hard” friction with rock.

From this perspective, The sparks are indeed proof that the cutting teeth can deliver a powerful strike. 。

Risk Warning

The Hidden Danger of “Thermal Damage” Behind Sparks

RISK

However, when we see sparks flying everywhere, we mustn't simply stop at the level of “being happy.” The physical essence of these sparks is... Friction generates heat. ”。

A bright spark suggests that the instantaneous temperature at the cutting point may have already... Over 600℃-800℃ This high temperature poses a significant threat to the service life of cutting picks:

1. Alloy annealing

Although cemented carbides are heat-resistant, if they are exposed to extreme high temperatures for prolonged periods without adequate cooling, their hardness will significantly decrease, severely compromising their wear resistance.

2. Hot cracks

The cutting picks, repeatedly alternating between high-temperature rock and cooling water, are highly susceptible to thermal fatigue cracks, which can lead to the fracture of the alloy tip.

3. Safety Red Line

Especially in high-gas coal mines, continuous high-temperature sparks are an absolute safety taboo and can easily ignite methane gas.

Response Strategy

Good teeth also require “good water” to go with them.

TACTICS

Since sparks are difficult to completely avoid during hard-rock tunneling, how can we control their negative impacts? The key lies in “thermal management.”

Forced cooling:
As soon as sparks are observed, the internal and external spray systems of the tunneling machine must be checked immediately. Ensure sufficient water pressure, high flow rate, and that the nozzle is directly aimed at the cutting point of the cutter bit. The atomization of water can effectively remove heat, suppress sparks, and protect the alloy tip from annealing.

Special Selection:

For high-gas mines or rock formations with extremely high hardness, it is recommended to choose Xinda’s specially customized products. “Low-spark cutting picks” or “cold-cutting cutting picks” By optimizing the alloy composition and tooth structure, we can reduce the coefficient of friction during cutting, thereby minimizing heat generation at the source.

Conclusion

CONCLUSION

To summarize:
Under hard-rock conditions, the ability to produce sparks demonstrates that your cutting picks are a sharp “quick blade”; but can you effectively manage the high-temperature risks posed by these sparks? It depends on your “water-use skills” and “safety awareness.” 。

Good cutting teeth It’s for cutting stone, not for melting alloys. Only through scientific use can a great product realize its full potential.