Research on Mechanical Impact Strength Test of Product Shells Based on LISUN Impact Testing Machine

Abstract:

Introduction

In daily use, lighting fixtures for household and similar purposes, household appliances and electronic equipment are constantly subjected to various mechanical impacts such as accidental collision, external contact and slight falling. Insufficient structural strength may lead to cracking, deformation and shedding of components, even exposure of live parts, resulting in safety risks including electric shock and mechanical injury. Therefore, standardized mechanical impact tests are indispensable in product research and development and ex-factory inspection.

Designed in strict accordance with international and national standards, the impact testing machine can accurately output quantitative impact energy corresponding to IK grades to simulate real impact loads in practical scenarios. The LISUN IK01-06 impact testing machine integrates six energy levels from IK01 to IK06 with integrated structure, convenient operation and excellent energy repeatability. It is widely applied in safety tests of lamps, household appliances and electronic accessories, acting as essential equipment for product compliance certification and quality control. Focusing on this impact testing machine, this paper conducts systematic research to provide standardized methods and references for mechanical strength tests of related products.

Working Principle and Structural Composition of Impact Testing Machine

Working Principle

Relying on the compression and instantaneous release of a built-in precision spring, the impact testing machine generates constant and repeatable impact energy acting on the sample surface to evaluate its mechanical strength.

Working process: The hammer rod is pulled to compress the spring to the locked position and store elastic potential energy. When the release mechanism is triggered, the spring releases energy rapidly and pushes the standard hammer head to impact the sample vertically at a specified speed. Since the mass of the hammer head, spring stiffness and compression stroke are all calibrated, the impact energy accurately corresponds to a certain IK grade, which ensures consistency and comparability of test results.

Impact energy is jointly determined by spring characteristics and the mass of impact components. All impact testing machine products from LISUN are calibrated by special calibration devices before delivery, so that energy errors are within the allowable range of standards, meeting the requirements of IEC 60068-2-75 and GB/T 2423.55.

Structural Composition

The LISUN IK01-06 impact testing machine is mainly composed of three parts:

• Main housing: including guide mechanism, energy adjustment knob, locking device and release button;
• Impact assembly: standard hammer head, hammer rod and impact spring;
• Adjustment mechanism: six adjustable gears for quick switching of impact energy corresponding to IK01 to IK06.
• Adopting integrated overall structure, the device is comfortable to hold and easy to operate, and a single impact can complete the assessment of one test point.

IK Grade, Impact Energy and Application Scope

IK code is defined by IEC 62262, representing the protection grade of equipment enclosures against external mechanical impacts. Higher grades correspond to greater impact resistance and higher impact energy. The LISUN IK01-06 impact testing machine covers IK01 to IK06, and the corresponding impact energy and typical applications are shown in the table below.

The LISUN IK01-06 impact testing machine supports quick switching among six energy levels: 0.14 J, 0.2 J, 0.35 J, 0.5 J, 0.7 J and 1.0 J, covering test requirements of most household lamps, household appliances and electronic products.

Main Applicable Standards of Impact Testing Machine

The impact testing machine is designed and applied in strict accordance with a series of international and domestic standards for mechanical strength tests of luminaires, household appliances, audio-visual equipment, plugs, sockets, connectors and instruments. The main applicable standards are listed in the following table.

All the above standards clearly specify that the impact testing machine shall be adopted to conduct impacts on vulnerable parts of products for specified times, and inspect structural integrity and safety performance.

IK01-06_Spring Impact Hammer IK Level Tester

Mechanical Strength Test Method Based on Impact Testing Machine

Test Purpose
By using the impact testing machine to simulate reckless operation and accidental collisions during practical use, the mechanical strength of product shells, lamp shades, handles, knobs, operating levers and indicator lights is examined to avoid unsafe damage, loosening or exposure of live components.

Test Conditions and Equipment

• Sample: fully assembled and under normal operating condition;
• Environment: normal temperature and pressure without obvious vibration and airflow;
• Equipment: LISUN IK01-06 impact testing machine;
• Calibration: periodic calibration with LISUN IK01-07-CAL calibration device.

Test Procedures
• Confirm the required IK grade and corresponding impact energy of the product, and adjust the impact testing machine to the corresponding gear;
• Fix the sample to simulate actual installation and working posture;
• Select impact points: shell surfaces, corners, joints, handles, knobs, lamp shades, indicator covers and other vulnerable parts;
• Press the impact testing machine vertically against the sample surface, pull the hammer rod to the locked position, and trigger release to complete one impact;
• Each test point is impacted once respectively, with separate tests on multiple key points;
• After impact, inspect the appearance, structure, function and safety protection performance of the sample.

Qualification Criteria

After the test by the impact testing machine, products are qualified only when meeting the following requirements:
• No cracking, breakage or shedding on shells, lamp shades and handles;
• No exposure of live parts with effective electric shock protection;
• No loosening of fixed components without influence on safe operation;
• Normal product functions without hidden dangers such as short circuit and failure;
•  The damage degree shall not cause human contact with dangerous components.

Product Advantages of LISUN IK01-06 Impact Testing Machine

1. Integrated multi-gears with wide applicability
One LISUN IK01-06 impact testing machine covers IK01 to IK06, meeting test requirements of multiple industries including lighting, household appliances, electronics, plugs and sockets, and reducing equipment investment.

2. Accurate energy output with high repeatability
Equipped with precision springs and standard impact components, the device features stable energy and small errors, and the test results are reproducible in compliance with standard requirements.

3. Simple operation and reliable safety performance
With vertical guidance and one-key release, the device is steadily held to avoid oblique impact; the reliable locking mechanism prevents false triggering.

4. Full compliance with global standards
It fully meets mainstream standards including IEC, GB, UL and EN, and can be directly applied for certification inspection and ex-factory quality test.

5. Calibratable and long-term stable performance
Periodic calibration is available with special LISUN calibration devices to maintain long-term precision and reliability.

Conclusion

The impact testing machine is essential standard equipment for mechanical strength and impact resistance tests of lighting fixtures, household appliances and electronic products. It can quantitatively simulate accidental impacts in practical use and effectively verify structural safety of product shells, handles, knobs, lamp shades and other components.

With integrated six-level standard impact energy, compliant design, convenient operation, stable energy output and wide application scope, the LISUN IK01-06 impact testing machine can carry out standardized impact tests on key product components.

Standardized tests by the impact testing machine can timely discover insufficient structural strength, eliminate safety hazards caused by reckless operation and accidental collisions, and ensure safe and stable operation of products throughout their service life. In product research and development, type test, quality control and international certification, mechanical impact tests centered on the impact testing machine are vital technical measures to guarantee product safety and compliance, with irreplaceable engineering and safety value.