Troubleshooting of radial drilling machines

Troubleshooting of Radial Drilling Machine: From Phenomenon Location to Quick Resolution

In mechanical processing workshops, sudden malfunctions of radial drilling machines often disrupt the entire production plan and delay the processing schedule. Many maintenance personnel often don't know where to start when facing faults, or blindly disassemble and expand the scope of the fault. In fact, the faults of the radial drilling machine all have corresponding characteristic manifestations. As long as the reasonable troubleshooting logic is followed, and the troubleshooting is carried out step by step from the outside to the inside and from the easy to the difficult, the fault point can be quickly located and the repair can be completed efficiently. This article, in combination with common types of faults, sorts out a set of practical troubleshooting ideas and methods to help maintenance personnel solve problems quickly.

Ⅰ. Basic Principles to Follow for Troubleshooting

Before starting to disassemble and repair, it is necessary to first clarify the basic principles of investigation to avoid blind operation

1. Observe from the outside to the inside, observe first and then disassemble

First, check the visible external status of the equipment, such as whether the power switch is turned on, whether the oil level meets the requirements, and whether the clamping handle is in place. Do not disassemble the internal components of the box at the very beginning. Many malfunctions are actually minor external issues, such as power tripping or insufficient fuel. They can be quickly resolved by observation without the need for extensive disassembly.

2. Electrical first, then mechanical; easy first, then difficult

The faults of the radial drilling machine can be roughly divided into two categories: electrical faults and mechanical faults. Electrical faults are often easier to troubleshoot. First, check the power supply, fuses, button contacts and other parts that are prone to problems. After eliminating the electrical problems, check the mechanical transmission, clamping structure and other parts to reduce unnecessary disassembly work.

3. Record the fault phenomena and investigate the causes

Before troubleshooting, carefully observe the specific manifestations of the fault, such as whether the main shaft does not rotate or cannot be clamped tightly, what type of abnormal noise it is, whether the rotational speed is completely stationary or fluctuates between fast and slow. Based on the characteristics of the fault, narrow down the scope of troubleshooting and do not blindly try and make mistakes.

Ⅱ. Troubleshooting Ideas for Common Electrical Faults

Electrical faults are the most common type of fault in radial drilling machines. The common troubleshooting methods are as follows:

1.The main shaft motor fails to start

This is the most common electrical fault. Follow these steps to troubleshoot: First, check if the main power supply is normal, if the main switch is closed, and if the fuse has blown. If the workshop trips or the fuse has burned out, restoring power supply and replacing the fuse can solve the problem. The second step is that if the main power supply is normal, check the start button: Press the button and listen for a sound of the contactor closing. If there is no sound, check whether the button contacts are oxidized or have poor contact, and whether the wiring is loose or fallen off. Grind the contacts or rewire them. The third step is that if the contactor can be engaged but the motor does not rotate and emits a "buzzing" sound, it indicates that there is a phase loss in the three-phase power supply of the motor. It is necessary to check whether the main contacts of the contactor are burned out and whether the motor terminal blocks are loose. Just deal with the parts with poor contact. If none of the contactors can be engaged, check whether the coil is broken and whether the thermal relay has tripped due to overload. If the thermal relay trips, it only needs to be reset. If the coil is burned out, replace the contactor.

2. The main shaft motor cannot be stopped

After pressing the stop button, if the motor still runs, this fault is most likely caused by the main contact of the contactor being welded and adhered. If the contactor has a large current for a long time and is disconnected, it is easy for the contact welding to fail to break. In this case, the contactor needs to be disassembled and the welded contact ground. In severe cases, simply replacing the contactor of the same specification can eliminate the fault.

3. The lifting direction of the rocker arm is reversed

When adjusting the lifting of the rocker arm, the direction is opposite to the indication of the operation button. This kind of fault is usually caused by the wrong phase sequence of the three-phase power supply after maintenance or the reversed wiring of the lifting contactor. It can be corrected simply by swapping the phase sequence of the two power supply lines or adjusting the wiring position of the contactor.

4. The clamping motor fails to start

If the column clamping motor does not work, first determine the scope of the fault: If it can start normally when the release button is pressed, it indicates that the fault lies in the clamping circuit. Check the contacts of the clamping button, the wiring of the contactor and the coil, and repair the parts with poor contact or broken wires. If the motor cannot be started whether it is released or clamped, check whether the fuse is blown, whether the motor wiring has come loose, and whether the winding is burned out. Eliminate them one by one.

Ⅲ. Troubleshooting Ideas for Common Mechanical and Hydraulic Faults

Mechanical and hydraulic faults are often related to wear, loosening and leakage. The common troubleshooting methods are as follows:

1. Various clamping mechanisms do not clamp tightly

It is a very common fault that the spindle box, column and rocker arm are not clamped tightly. The troubleshooting directions for different parts are different:

The spindle box is not clamped tightly: First, check the clearance of the 55° guide rail surface at the junction of the spindle box and the rocker arm. If the clearance exceeds 0.04mm, adjust the guide rail adjustment screw to control the clearance within the qualified range. If the clearance is normal, check whether the position of the clamping block is offset and whether the interference fit of the rhombus block is insufficient. If the rhombus block cannot stand up and self-lock, it will cause the clamping not to be tight. Adjust the position of the clamping block and the interference fit of the rhombus block. If it is a hydraulic clamping mechanism, it is also necessary to check whether the clamping cylinder is leaking oil and whether the oil pipe is damaged. Aging and oil leakage of the seal will cause insufficient oil pressure. Replacing the seal and replenishing the hydraulic oil can restore the clamping force.

The column cannot be clamped tightly: First, check if the spring plate screws are adjusted improperly. If the screws are adjusted too much, the column will be lifted too high, and the rhombic block will not be able to press the conical surface tightly. Readjust the screws, adjust the clamping force to the required range, and then tighten the nuts. If the screw still cannot be clamped tightly after adjustment, check the oil pressure of the hydraulic system. Insufficient oil pressure will cause the piston to fail to push the rhombus block into place. Adjust the oil pressure to the standard range. If the oil deteriorates, replace it with new hydraulic oil.

2. Spindle rotation failure

Abnormal spindle speed: If the speed fails to reach the set value or fluctuates, first check the V-belt of the main motor. If the belt is worn, loose or slipping, it will cause unstable speed. Adjust the tension of the tensioner pulley. If the belt cracks, replace it directly. When the belt is functioning properly, open the spindle box to check if the sliding gears are not meshing properly, if the positioning pins of the shift handle are loose, and if there are any impurities stuck on the gear tooth surface. Clean the impurities and adjust the position of the handle to ensure that the gears are fully meshed, and the problem will be solved. If all the above are normal, check the voltage of the main motor. Voltage fluctuations exceeding ±5% will cause unstable output power. Check the power supply line and repair the abnormal voltage.

Abnormal noise from the main shaft rotation: If the main shaft makes a "clunk" sound during rotation, it is mostly due to wear and damage of the main shaft bearings, peeling of the balls or breakage of the cage. Measure the radial runout of the main shaft with a dial indicator. If the runout exceeds 0.01mm, the bearings need to be replaced. If it is a uniform friction abnormal noise, check the lubricating oil level in the spindle box. If the oil level is too low or the oil quality has deteriorated, the gears will produce abnormal noise due to dry friction. Replenishing or replacing the lubricating oil can eliminate the abnormal noise.

3. Malfunction in the lifting of the rocker arm

If the rocker arm is stuck and heavy during lifting, first check the lubrication condition of the guide rail surface. If there is a lack of oil, replenish the guide rail oil. If the lubrication is normal, check whether the guide rail is deformed or whether the lifting lead screw nut is worn or stuck. If it is deformed, correct the guide rail; if it is severely worn, replace the lead screw nut pair. After the rocker arm is raised or lowered to the position, it should be clamped and shaken. Check the hydraulic clamping pressure, adjust the oil pressure to ensure the clamping force, and at the same time, check the gap of the clamping block and adjust it to the appropriate range.

4. The drilling accuracy has declined

If the hole position is offset or the hole diameter exceeds the tolerance after processing, first check whether the spindle box is clamped properly. Loose clamping will cause the spindle to shift during processing. If the clamping is normal, check the radial runout of the main shaft. If the bearing is worn, replace it. Check the tension of the drive belt again. A loose belt can cause unstable rotational speed and affect the feed accuracy. Adjusting the tension or replacing the belt can restore the processing accuracy.

Ⅳ. Conclusion and Record-keeping after Investigation

After the fault is eliminated, do not directly put it into production. First, start the machine and conduct a no-load test run to check if all actions are normal, if the clamping force meets the requirements, and if the processing accuracy is up to standard. Only after confirming that the fault has been completely eliminated can formal processing be carried out. At the same time, it is necessary to keep a good record of faults, documenting the fault phenomena, the troubleshooting process, and the solutions, to accumulate experience in handling faults. This way, similar faults can be resolved more quickly when encountered in the future.

In conclusion, troubleshooting for radial drilling machines is not as complicated as it seems. As long as the correct troubleshooting logic is mastered and the scope is gradually narrowed down from easy to difficult, the fault point can be quickly located. In daily production, proper maintenance and upkeep, regular inspection of the wear of vulnerable parts, and early replacement of aged seals and worn bearings can also reduce the probability of sudden failures and ensure the stable operation of equipment.