With the rapid development of high-frequency, high-power full-hydraulic rock drilling equipment, the market’s requirements for the matching and manufacturing technology of supporting rock drilling tools have increased. Under such a background, shank adapters with various structures that are fully machined and formed with high precision are produced.
The shank adapter is the transmission connection part between the rock drill and the drill rod, and its main function is to directly bear the impact and the torque of the rock drill. During the drilling process, the shank adapter end is subjected to high frequency and high energy axial and torsional high amplitude stress cyclic impact of the rock drill piston. Among them, 75%-87% of the energy transfer must be transferred for drilling, and 13%-25% of the remaining energy is in its internal consumption such as contact, wear, and heat generation. Therefore, the work of the shank adapter is in a stress state where high-amplitude stress cycles, severe external friction, and internal friction exist simultaneously, and its service life will be severely tested.
Nowadays, as one of the supporting drilling tools for rock drilling, the shank adapter has developed into an indispensable and important accessory in modern rock drilling tools. Because of the particularity of the working environment, it is also one of the large quantities of scrapped consumables in the rock drilling site. Although the failure of the shank adapter is inevitable, we can adjust to prevent the failure of the shank adapter, to improve the service life of the shank adapter.
13 Ways to Solve Shank Adapter Failures
1. The solution to the impact marks, chipped corners, and mushroomed end caused by misalignment due to worn bushings: Replace worn components.
2. The solution to the failure of approx. 25mm from strike face caused by worn chuck driver: Replace worn components.
3. The solution to the failure at the top of the spline due to lack of lubrication: Grease rock drill regularly.
4. The solution to the failure at the top of the spline due to excessive feed force: Monitor coupling temperatures and adjust feed pressure according to recommendations.
5. The solution to the failure at the top of the spline due to worn chuck driver or front bushing: Replace worn components.
6. The solution to the failure across splines due to heavy rotational torque: Adjust drilling pressures.
7. The solution to the wear on the bottom of the spline’s shoulder caused by excessive rotation when the drilling tool is retracting string: Adjust drilling pressures.
8. The solution to the failure at the front head caused by misalignment from worn front bushing: Replace worn components.
9. The solution to the failure of above threads caused by hole deviation: Employ straight hold drilling devices or systems.
10. The solution to the failure in the main body of threads caused by improperly joined in coupling sleeves too much times: Replace worn components. Do not put a worn coupling sleeve on a new drill rod. Change out-coupling sleeves with a new shank adapter.
11. The solution to the chipped thread end due to the shank adapter not being properly coupled to the drill rod: Replace the damaged or worn coupling sleeves.
12. The solution to the chipped thread end due to the drill rod end not being square: Forward for analysis.
13. The solution to pitting and galling on splines caused by excessive rotation in the soft or broken ground: Adjust the drilling pressure.
The failure of the shank adapter is the same as the failure of other rock drilling tools, and there are many forms. However, a large part of the failure of the shank adapter comes from the wear or damage of other components, so in order to improve the efficiency of the shank adapter, there are some preventive measures we can take.
Measures to prevent shank adapter failure
Select a high-quality shank adapter
When purchasing a shank adapter, choose brands and products with good quality and high reputation. At the same time, we should adopt the appropriate specifications and models according to actual needs to avoid using inappropriate shank.
Regular inspection of the shank adapter
Check the shank adapter regularly, including appearance inspection, dimension measurement, structural strength assessment, etc. Timely discover and deal with problems with the shank adapter to avoid failure during use.
Strengthen site management
Strengthen site management to ensure the shank adapter is used and maintained correctly during use. For example, set up a specific storage area for the shank adapter to prevent it from being contaminated and damaged; formulate shank adapter use regulations to regulate the behavior of operators.
Improve safety awareness
Improve the safety awareness of operators and let them fully realize the hazards of shank adapter failure. At the same time, strengthen safety education and training to improve the safety quality and operating skills of operators.
Conclusion
Shank adapter failure is a common problem. By taking appropriate solutions and preventive measures, we can effectively reduce the risk of shank adapter failure and improve project quality and operation efficiency.
