5 Forms of Diamond Core Drill Bits Wear and Solutions

Diamond core drill bits are essential tools in construction and geological exploration, renowned for their ability to precisely cut hard materials. However, like any tool, they are subject to wear, which can affect their performance and lifespan. Understanding the various forms of wear, and taking effective countermeasures are essential to maintaining the efficiency of diamond drill bits.

Exposing Diamonds Too Early

One of the most common forms of wear on diamond drill bits is premature diamond exposure. This occurs when the matrix (the bonding material that holds the diamond in place) wears away faster than the diamond itself. As a result, the diamond is exposed prematurely, leading to several issues:

1. Shortened life: When diamonds are exposed prematurely, they may chip or break, greatly shortening the life of the drill bit.

2. Reduced efficiency: Exposed diamonds may not cut effectively, resulting in slower drilling speeds and increased wear on the drill bit.

3. Increased costs: Frequent drill bit replacement due to premature wear leads to higher operating costs.

Reasons for premature exposure to diamonds

1. Too high drilling pressure: If the drilling pressure is set too high and does not match the rotation speed, it will cause excessive wear on the matrix, resulting in premature exposure of the diamond.

2. Inadequate water flow: Water is essential for cooling the drill bit and flushing away debris. Inadequate water flow can lead to overheating and accelerated matrix wear.

3. Insufficient matrix hardness: If the matrix material is not hard enough for the type of material being drilled, it will wear too quickly, resulting in premature exposure of the diamond.

Countermeasures

1. Adjust drilling parameters:

• Increase rotation speed: By increasing the rotation speed of the drill bit and reducing drilling pressure, you can help balance the wear of the carcass and diamond. This adjustment allows for more efficient cutting without overloading the carcass.

• Optimize drilling pressure: Make sure the drilling pressure is appropriate for the material being drilled. A balanced pressure setting helps extend the life of the drill bit.

2. Enhance water flow:

• Increase water flow: Ensure adequate water flow during drilling. This will help cool the drill bit, reduce friction, and flush away debris, preventing overheating and excessive wear on the substrate.

3. Upgrade matrix material:

• Change to a harder matrix: If prematurely exposed diamonds are a recurring problem, consider using drill bits with a harder matrix material. A harder matrix will wear more slowly, allowing the diamond to maintain its cutting ability longer.

4. Regular maintenance and monitoring:

• Check your drill bits regularly: Check your drill bits regularly for signs of wear or damage. Catching problems early can help prevent more serious problems later.

• Adapt technique to material: Adapt drilling technique and parameters to the specific material being drilled. Different materials may require different approaches to optimize performance and minimize wear.

Drill Burning

Drill bit burn occurs when the matrix material of a diamond drill bit overheats during operation, causing it to melt. This overheating can cause water channels within the drill bit to close, which in turn affects the cooling and lubrication required for efficient drilling. When the water channels are damaged, it can lead to further overheating, reduced drilling efficiency, and ultimately premature failure of the drill bit.

Causes of drill bit burns

1. Water channel leak: If there is a leak in the water channel, the cooling effect of the water will be weakened. This will cause local overheating and eventually burn the drill bit.

2. Poor water circulation: Inadequate water flow or poor circulation will prevent effective cooling of the drill bit. If the water supply is insufficient, the friction generated during the drilling process will cause the substrate to overheat.

Countermeasures to prevent drill bit burns

1. Increase water supply:

Make sure that adequate water is supplied to the drill during operation. Increasing the water flow will help maintain lower temperatures and prevent overheating. Check the water supply system regularly to ensure that it is functioning properly.

2. Check the working status of the mud pump:

The mud pump is responsible for circulating water and drilling fluid to the drill bit. Check the pump regularly to ensure it is operating efficiently. Any problems with the pump may result in insufficient water flow, increasing the risk of drill bit burns.

3. Check the sealing of the drill pipe joint:

Check that the drill pipe joints are properly sealed. Leaks at the joints can cause loss of water pressure and flow, which can lead to overheating. Make sure all connections are secure and free of damage.

4. Adjust the inner tube length as needed:

The length of the inner tube affects water circulation. If the inner tube is too long, it may block water flow to the drill bit. Adjusting the inner tube length to optimize water circulation can help prevent drill bit burnout.

The Drill Bit Is Polished

When a diamond drill bit is polished, the surface of the diamond particles becomes smooth and shiny, which hinders the drill bit's ability to cut effectively. This condition often results in the drill bit being unable to penetrate the material being drilled, leading to inefficiencies and increased operating costs.

Possible reasons for polishing drill bits

1. Low drilling pressure:

If the drilling pressure is set too low relative to the rotational speed, the drill bit may not effectively engage the material. This results in insufficient cutting action, causing the diamond particles to be polished rather than worn away.

2. Too much water:

Water control that is too high will have a cooling effect, causing the drill bit to not generate enough heat to cut effectively. While water is essential for cooling and flushing debris, too much water will result in a lack of friction required for effective drilling.

3. High matrix hardness:

If the drill bit matrix (the material that holds the diamonds) is too hard for the material being drilled, poor cutting results will result. The hard matrix may not wear away enough, resulting in a polished diamond surface.

Corresponding treatment measures

1. Sharpening drill bits:

If the drill bit has been worn out, sharpening it can help restore its cutting ability. Special sharpening tools can be used, or the drill bit can be replaced if repair is not possible.

2. Adjust drilling parameters:

• Reduce rotational speed: Reducing the rotational speed helps increase the effective drilling pressure of the drill bit, allowing it to engage the material more effectively.

• Increase drilling pressure: Adjusting the drilling pressure to a higher level can enhance the cutting action of the drill bit, helping to prevent polishing and improving progress.

3. Control water supply:

Reducing the water supply helps maintain the friction required for effective cutting. A balance must be found between sufficient cooling without too much water that impedes the drilling process.

4. Consider changing to a softer matrix drill bit:

If the matrix of your current drill bit is too hard for the material you are drilling, consider switching to a drill bit with a softer matrix. Softer matrix drill bits are designed to wear more easily, allowing for better diamond exposure and more efficient cutting.

Inner Diameter Wear

Inner diameter wear occurs when the inner surface of a diamond drill bit wears away, which can lead to a variety of operational issues. This wear affects the drill bit's ability to maintain its geometry, leading to inefficient drilling, increased friction, and possible drill bit failure.

Possible causes of inner diameter wear

1. High drilling pressure:

Setting the drilling pressure too high can cause excessive wear on the drill bit's inner diameter. High pressure causes the drill bit to come into too intense contact with the material, which accelerates wear.

2. Extremely broken stratum structure:

Drilling in severely fractured or damaged formations increases stress on the drill bit, causing uneven wear on the inside diameter. Irregularities in the formation cause additional impacts on the drill bit, which increases wear.

3. The core left in the hole:

If the core remains stuck in the hole during drilling, it creates additional friction and drag, causing increased wear on the drill bit's inner diameter. This condition also impedes the drill bit's ability to advance effectively.

4. Insufficient matrix hardness:

If the drill bit matrix is not hard enough for the material being drilled, the drill will wear too quickly, causing wear on the inside diameter. A softer matrix may not be able to withstand the rigors of drilling through hard materials.

Solutions to inner diameter wear

1. Increase the rotation speed:

Increasing the drill bit's RPM helps reduce the effects of drilling pressure. Higher RPMs allow for more efficient cutting and help distribute force more evenly across the drill bit, reducing wear on the inside diameter.

2. Reduce drilling pressure:

Reducing drilling pressure can significantly reduce ID wear. By finding the optimal balance between pressure and rotational speed, operators can improve the performance of the drill bit and extend its life.

3. Consider using a harder matrix drill:

If inner diameter wear is a recurring problem, consider using a drill with a harder matrix. A harder matrix wears slower, helping to maintain the integrity of the ID and improving overall drilling efficiency.

4. Increase water supply:

Increasing the water supply during drilling can improve the cooling effect of the drill bit. Adequate cooling helps reduce friction and wear, extend the life of the drill bit, and maintain the performance of the drill bit.

5. Check and adjust the inner tube length:

Check the inner tube length regularly to ensure it is appropriate for the drilling operation. Incorrect inner tube length can affect the drill bit geometry and cause wear. Adjusting the inner tube length as needed will help maintain accurate drill bit geometry.

Outer Diameter Wear

Outer diameter wear occurs when the outer surface of a diamond drill bit wears away. This wear can lead to a variety of operational issues, including reduced cutting efficiency, increased friction, and possible drill bit failure. When the OD is damaged, it also affects the drill bit’s ability to maintain its geometry, further complicating drilling operations.

Possible causes of outer diameter wear

1. Drill bit vibration:

Vibration during drilling can cause uneven wear on the drill bit's outer diameter. Excessive vibration can cause localized stress points that accelerate wear and can damage the drill bit.

2. High speed setting:

If the drill speed is set too high, it will cause increased wear on the outer diameter. High speeds create excessive heat and friction, causing wear and shortening the life of the drill.

3. Insufficient water supply:

Water is essential for cooling the drill bit and flushing away debris. Inadequate water supply can lead to overheating and increased OD wear as the drill bit may not be able to dissipate heat effectively.

4. Cave wall collapse:

If the borehole wall collapses or the borehole expands abnormally, additional friction and resistance will be generated against the drill bit's outer diameter. This condition can lead to accelerated drill bit wear and potential failure.

Solutions to external diameter wear

1. Increase water supply:

Ensuring adequate water supply during drilling is critical to cooling the drill bit and reducing wear. Increasing water flow helps maintain lower temperatures and minimizes friction, thereby extending the life of the drill bit.

2. Appropriate deceleration:

Turning the drill bit's RPM down helps reduce wear on the OD. Finding the best balance between speed and drilling pressure is critical to efficient cutting and minimal wear.

3. Check the outer diameter of the reamer:

Check the OD of the reamer regularly to ensure it meets the required specifications. If the reamer is worn or damaged, it may need to be replaced to maintain effective drilling performance.

4. Add drilling fluid treatment agent:

Adding drilling fluid treatment agents helps reduce the effects of vibration during drilling. These agents can improve the stability of the drilling fluid, minimizing vibration and its wear on the drill bit.

5. Adopt a new drill bit structure:

Consider using drill bits with improved design, such as increasing the side water groove depth or enhancing the water inlet design. These improvements can improve water circulation and cooling and reduce OD wear.