As a core testing equipment in industries such as metals and building materials, the hydraulic universal testing machine's operational stability directly affects the accuracy of test data and production quality control efficiency. Scientific maintenance and upkeep can not only extend the service life of equipment (usually by more than 30%), but also avoid production stagnation caused by sudden failures. This article combines the structural characteristics of the equipment to sort out practical maintenance points and common problem solutions.

1、 Core points of daily maintenance (executed daily/weekly)

1. Hydraulic system: the "power core" of equipment operation

The hydraulic system is a high-risk area for faults, and special attention should be paid to the oil state and sealing performance: ① Check the hydraulic oil level daily to ensure it is between the tank markings, and if it is insufficient, replenish the same type of anti-wear hydraulic oil (recommended viscosity 46 #, in accordance with GB 11118.1 standard); ② Clean the return oil filter weekly. If the filter screen is found to be damaged, it should be replaced immediately to prevent impurities from entering the pump body and causing wear; ③ Check if there is any leakage in the oil pipe joints and sealing rings. If oil stains are found, wipe them off in a timely manner and replace the aging seals (it is recommended to use fluororubber material, suitable for high-pressure working conditions).

2. Electrical system: the "central nervous system" for safe operation

① Before starting up daily, check whether the power and signal lines are firmly connected, whether the plugs are loose or oxidized, to avoid poor contact and control disorder; ② Blow the control cabinet and touch screen heat dissipation holes with dry compressed air every week to remove dust accumulation and prevent component overheating; ③ Confirm that the emergency stop button and overload alarm device are functioning properly. When the emergency stop button is pressed, the equipment must be immediately powered off and stopped.

3. Mechanical structure: the "basic guarantee" for precise testing

① Clean the fixture teeth after each experiment, remove residual debris from the sample, avoid affecting the clamping accuracy, and regularly (weekly) apply lubricating grease (recommended lithium based grease NLGI grade 2) to the sliding parts of the fixture; ② Check for scratches on the rack rails, wipe them daily with a cotton cloth and apply rust proof oil to prevent oxidation and corrosion; ③ Confirm the accurate position of the limit switch to avoid overtravel impact during the test.

2、 Regular maintenance of key projects (monthly/quarterly/annual)

-Monthly inspection: focus on calibrating the force sensor (using standard weights for comparison, if the error exceeds ± 0.5% FS, professional debugging is required); Check the working status of the servo valve. If there is excessive pressure fluctuation, disassemble and clean the valve core.

-Quarterly maintenance: Replace the hydraulic oil filter element and take samples to test the oil contamination level (NAS level 8 or below is qualified). It is recommended to replace the entire amount of hydraulic oil that has been used for more than one year; Check the wear of the transmission gears and lead screws, measure the tooth clearance, and adjust or replace if it exceeds 0.2mm.

-Annual major maintenance: Invite professional technicians to conduct comprehensive calibration of equipment, including parameters such as force, displacement, and speed; Disassemble and inspect the hydraulic pump, measure the clearance between the rotor and the pump body. If it exceeds 0.15mm, it needs to be repaired or replaced.

3、 Common fault handling and prevention

1. Hydraulic oil leakage: It is often caused by aging sealing rings or loose joints. When dealing with it, tighten the joints first, and if ineffective, replace them with sealing rings of the same specification. The key to prevention is to avoid mixing oil and regularly check the oil temperature (not exceeding 55 ℃).

2. Inaccurate force value display: It may be due to sensor drift or amplifier failure. Restart the device for calibration first. If it is ineffective, check the sensor wiring or contact the manufacturer for calibration. Avoid severe impact on the sensor in daily life.

3. Clamping slippage: Due to tooth surface wear or insufficient pressure, slight wear can be polished on the tooth surface. In severe cases, the fixture needs to be replaced. Before testing, it is necessary to confirm that the clamping pressure has reached the preset value (usually ≥ 5MPa).

4、 Maintenance precautions

① The equipment needs to operate in a dry and ventilated environment to avoid dust and corrosive gas erosion; ② Hydraulic oil replacement requires emptying the old oil, cleaning the oil tank, and then injecting new oil to prevent the mixing of new and old oil from affecting performance; ③ Establish a maintenance ledger to record the content and time of each maintenance and overhaul, providing a basis for equipment lifecycle management.