Angle grinder inspection

1. Inspection items
Grinding wheel safety inspection:
Strength test is crucial to ensure that the grinding wheel will not break and splash under high-speed rotation. Through high-speed rotation test simulating actual working conditions, observe the integrity of the grinding wheel. If cracks or fragments fall off, it is unqualified. For example, a high-quality grinding wheel should not show any signs of damage after running continuously for 2 minutes at a speed of 10,000 rpm.
Dynamic balancing detection cannot be ignored. Unbalanced grinding wheels can cause violent vibrations, affect operating accuracy and even damage the angle grinder. Using a professional dynamic balancing instrument for measurement, the residual imbalance is required to be controlled within a very small range, generally not exceeding 5 grams and millimeters.

Electrical performance test:
Insulation resistance test, measure the insulation resistance between the motor winding and the housing, and its value should meet safety standards to prevent leakage accidents. Usually the insulation resistance must not be less than 2 megohms, otherwise there is a risk of electric shock.
Grounding continuity test, for angle grinders with grounding devices, check whether the grounding line is good to ensure that the current can be quickly introduced into the ground in case of leakage to ensure personnel safety.

Mechanical performance test:
Speed ​​stability test, observe the speed fluctuation of the angle grinder under load and no-load conditions. Excessive fluctuation may lead to unstable grinding effect. The speed fluctuation is required to be controlled within ±5%.
Handle vibration test, measure the vibration amplitude of the handle through a vibration sensor. Excessive vibration will make the operator easily fatigued and difficult to operate accurately. Generally, the vertical vibration acceleration is not more than 2.5 m/s².

2. Test method
Special test of grinding wheel: use a special grinding wheel strength tester for high-speed rotation test; dynamic balance test uses a high-precision dynamic balancer to install the grinding wheel on the test shaft to measure the imbalance.

Electrical detection means: insulation resistance uses an insulation resistance tester to contact the motor winding and the housing to read the value; grounding continuity uses a grounding resistance meter to measure the grounding line resistance.

Mechanical performance measurement: speed stability is monitored in real time by a photoelectric speed sensor; handle vibration test fixes the vibration sensor at the key part of the handle to collect data.

3. Testing standards
In China, the standards are implemented according to GB/T 7442-2007 "Electric angle grinders", covering all aspects of mechanical, electrical, and grinding wheel specifications; internationally, IEC 60745-2-3 "Safety of hand-held power tools Part 2-3: Particular requirements for electric grinders, polishers and disc sanders" provides unified standards to ensure that the quality and safety of angle grinders around the world are comparable.

4. Significance of testing
For users, strictly tested angle grinders are safe and reliable, reduce operating risks, and ensure accurate and efficient grinding and cutting; for manufacturers, testing promotes the optimization of product design, improves quality, enhances market competitiveness, and promotes the steady development of the entire hardware tool industry.