Pipe Bending Machine Lubrication Issues: Is Your Pump Working Properly?

If the lubrication system pump of a pipe bending machine malfunctions, the guide rails, lead screws, and gears will all be dry-blending. This may not be immediately apparent, but over time, it can lead to guide rail damage, bearing burnout, and repairs that will cost you dozens of cans of grease.

The lubrication pump not providing oil usually falls into a few main categories. Check the following in order.

Step 1: Check if the fuel tank has enough fuel.

This step is the simplest and easiest to overlook. If the fuel level is below the minimum mark, the pump will "dry run," making a loud noise but not pumping fuel. Open the pump station to check the fuel level; if it's below the lower limit, add fuel. Always add fuel through the nozzle; do not add fuel directly, otherwise dust and impurities will get in and cause problems.

Step 2: Check the fuel suction filter.

This is where the problem most likely lies. If there are impurities or sludge in the fuel, the fuel suction filter will be clogged, and the pump won't be able to draw fuel; either it won't pump fuel at all, or it will pump fuel in a sporadic manner. Remove the filter, check if it's clogged, clean it with kerosene or diesel, and then reinstall it.

Step 3: Confirm the fuel type is correct.

Using inferior fuel, fuel with the wrong viscosity, or contaminated fuel (whitened, emulsified, has an unusual odor) will also prevent the pump from working. If the fuel is already black or white, don't hesitate, replace it immediately and clean the fuel tank at the same time.

Step 4: Listen to the sound and check the pressure

Start the automatic lubrication system and listen to the pump's operating sound. If there's no sound, first check if the motor has power and if the wiring is loose. If the pump is running but the pressure gauge doesn't register a reading, disconnect the main oil line and plug the outlet to test the pressure. If the pressure gauge still reads zero even with the outlet completely blocked, the pump itself is faulty; if the pressure rises, the problem lies in the pipeline.

Step 5: Troubleshoot the Pipelines and Distributors

If the pressure returns to normal after plugging the pipe, then trace the pipeline downstream—check for a leaking oil pipe, a loose joint, or a clogged distributor. Another possibility is a blocked oil line, causing the pump to automatically alarm and shut down after a timeout. In this case, start with the distributor, loosening the plugs at each outlet one by one, and starting the pump to see which plug is not dispensing oil. That distributor plate corresponding to that line is the blockage point.

Step 6: Run a Circuit to Check for Lubrication Points

After stopping the machine, run a circuit around the guide rails, lead screws, and bearings—areas requiring lubrication. Touch them (be careful!). There should normally be an oil film. If a point is dry, it indicates a blockage in that oil line. If the automatic lubrication pump is pumping oil but the bearings aren't receiving grease, check the distributor plate for that line.

Step 7: Check the Settings—Is the Cycle Set Incorrect?

The lubrication pump is operated periodically by the control system. If the lubrication time is too short, the interval is too long, or the cycle parameters have been altered, the guide rail will not receive sufficient lubrication. Open the control panel and check if the lubrication time and interval are correct. Generally, lubricate for 16 seconds every 32 minutes, but refer to the equipment manual for specific instructions. If the lubrication time is too short, it will stop before the bearing is reached; if the interval is too long, the middle section of the guide rail will remain without lubrication.

Quick Summary: Six Key Points for Troubleshooting Lubrication Pump Faults

Is the oil level in the tank below the lower limit? If so, add oil.

Is the suction filter clogged? If clogged, clean or replace it.

Is the oil black, white, or emulsified? If it has deteriorated, completely change the oil and clean the tank.

Is there any unusual noise from the pump? Is the pressure gauge reading? If there is no sound, check the motor power supply; if there is sound but no pressure, perform a blockage test.

Are there any leaks at the pipe joints? Is the distributor clogged? If oil is not flowing from a certain point, check that line.

Is the oil injection time and interval set on the control system correct? If not, revert to the factory settings.

A hardcore solution for when a lubrication pump "plays dead": Dry-burn self-priming restart

When a CNC pipe bending machine has been idle for a long time, all the oil in the pipeline flows back into the pump, and air seals the oil passage. The guide rail oil pump motor is running, but no oil drips from the oil pipe for half a day. This situation is frequently encountered even after cleaning an oil tank. Operating method: Find a pressure-type grease gun and fill it with lubricating oil. Locate the oil pump and inject lubricating oil into the return pipe (note that the direction is to push into the pipe), forcibly filling the entire circuit with oil. The pump will then rebuild oil pressure and resume normal oil supply.

If the lubrication pump isn't working, the guide rails will just rub together. Take a minute each day before starting the machine to check the oil level and listen to the pump, test the pressure weekly, and randomly check a few lubrication points monthly—these small habits will result in smooth lead screws, clean guide rails, and the money saved from fewer maintenance calls could buy grease for years. The lubrication system is the lifeblood of a pipe bending machine; automatic doesn't mean neglecting it. The laziness you show in maintenance will eventually turn into repair bills.