JB-300WD Microcomputer-Controlled Low-Temperature Automatic Impact Testing Machine

Product Introduction:

The JB-300WD microcomputer-controlled low-temperature automatic impact testing machine is used to determine the impact resistance of metallic materials under dynamic loading, thereby assessing their behavior under such conditions. It measures the absorbed energy of the specimen by displaying on the dial the difference between the pendulum’s potential energy before impact and its remaining potential energy after impact. The maximum impact energy is 300 J, and it is supplied with a 150-J pendulum; the specimen cross-section is 10 × 10 mm. This instrument delivers substantial impact energy and is well suited for ferrous metals with high impact toughness, such as steels and their alloys.

This machine is an integrated unit for low‑temperature and impact testing, equipped with a dedicated pneumatic sample‑feeding system that automates sample delivery. It employs pneumatic end‑face positioning to ensure precise centering of the specimen, guaranteeing that, once the low‑temperature test is completed, the time from removal from the chamber to impact does not exceed 4 seconds—thereby enhancing both test accuracy and operational efficiency. Processes such as specimen cooling, temperature stabilization, temperature control, pendulum retrieval, pendulum suspension, sample feeding, positioning, and impact are all fully automated via electrical control. After the specimen is fractured, the residual energy is harnessed to automatically raise the pendulum, readying it for the next impact cycle. Consequently, this equipment demonstrates particular advantages in laboratories conducting continuous low‑temperature impact tests, as well as in metallurgical and mechanical manufacturing facilities that perform large volumes of such tests.

This machine is equipped with a computer and a printer, featuring dual‑control and dual‑display capabilities. It employs PLC‑based automatic control and measurement, calculating the rebound angle β of the pendulum after impact based on data acquired from an incremental encoder. The system automatically displays the rebound angle β, the energy absorbed by the specimen, and the impact toughness ak value. Data can be edited and test reports generated via the computer using dedicated data‑processing and control software; test data, the average energy of three trials, as well as test time and serial number, can also be stored and printed. Remote data transmission is supported. The computer screen provides a real‑time display of the cooling curve, enabling convenient monitoring of specimen cooling duration.

The impact body of this machine is made of cast steel, ensuring rigid stability throughout the test, strong impact resistance, and minimal deformation, thereby delivering accurate results and a long service life. Equipped with a high-torque clutch and a high-power motor, it operates smoothly and vibration-free during pendulum pickup and release. The low-temperature section employs cascade compression refrigeration technology, leveraging thermal equilibrium principles and recirculating agitation to achieve automatic, uniform cooling, stable temperature control, and precise temperature regulation of the test specimen.

This instrument is developed and manufactured in accordance with the national standard GB/T 3808-2002, “Verification of Pendulum Impact Testing Machines,” and performs impact tests on metallic materials as specified by the national standard GB/T 229-2020, “Metallic Materials—Charpy Pendulum Impact Test Method.” It also complies with JJG 145-2007, “Verification Procedure for Pendulum Impact Testing Machines.” By modifying its structural design and replacing relevant components—including the R8‑shaped blade—it can simultaneously meet the requirements of international standards such as ASTM E23, EN 10045, ISO 148, and ISO 83.

Technical Specifications:

Structural Overview:

The main components of this machine are:

Host machine, cryogenic unit, feeding mechanism, positioning mechanism, electrical control cabinet, microcomputer, and others.

1. Host: It consists of a housing, a transmission mechanism, a pendulum‑engagement and disengagement mechanism, an indicating mechanism, a pendulum, and an automatic pendulum‑raising signaling device, among other components.

1) Mechanical hanging and detaching swing section:

After pressing the “Raise Pendulum” button, the pendulum is raised and securely locked in place, with the safety pin extended. Pressing the “Automatic Feed” button initiates the following sequence: sample feeding → positioning → clamping → sample alignment. Next, press the “Retract Pin” button, followed by the “Impact” button to perform a single impact test. Once the specimen is fractured, the pendulum automatically swings back into position, the safety pin retracts, and the system is ready for the next impact test.

2) Designating Authority:

The indicator mechanism serves to display the absorbed energy of the specimen during testing and consists of a scale dial, pointer, and ratchet. This machine is microcomputer-controlled and features two independent reading systems, with test results simultaneously displayed on the computer.

3) Pendulum section:

The pendulum consists of components such as the pendulum bob, blade, pendulum rod, joint, plug, and hook. To facilitate the replacement of pendulums with different energy levels, a removal tool is included in the standard package.

2. Cryogenic system: It mainly consists of a refrigeration system and a low-temperature tank.

After turning on the power and the refrigeration switch, the high-temperature compressor starts operating. Once the conditions for starting the low-temperature compressor are met—typically after about 5 minutes—the low-temperature compressor automatically activates, and the refrigeration system enters its normal cooling mode. The refrigeration compressors run continuously; when the temperature inside the tank approaches the setpoint, the heating element in the cooling tank begins to supply heat according to PID control, compensating for the excess cooling capacity generated by the refrigeration system and maintaining a constant temperature.

3. Feeding Mechanism: After the specimen is cooled to the desired temperature in the low-temperature apparatus, it is swiftly and reliably delivered to the anvil support surface by this mechanism. The pneumatic feeding system consists primarily of a cylinder and a feeding device. The feeding motion is achieved through compressed air entering the cylinder, which drives the piston to propel the feed rod in a rapid forward stroke and a corresponding return stroke. The feed rod’s forward movement, retraction, and stopping are controlled by electrical signals generated by the pneumatic directional control valve and magnetic switches, which in turn govern the cylinder’s extension and retraction. By adjusting the position of the magnetic switches, the feed rod’s positioning and buffering speed can be finely tuned.

4. Positioning Mechanism: The specimen must be held tightly against the side of the anvil so that its notch is precisely aligned with the center of the pendulum’s axis. This close contact is ensured by the positioning mechanism. As the specimen is conveyed to the front anvil by the feed rod, a fixed spring plate pushes it forward, keeping it firmly pressed against the anvil’s side. Before the rear end of the specimen has fully disengaged from the spring plate and the front end has entered the rear anvil surface (by 2–3 mm), a magnetic switch on the pneumatic cylinder of the feeding mechanism sends a signal. The positioning cylinder then activates, triggering the positioning mechanism: its positioning rod moves into its working position, and the elastic push‑offs on the mechanism’s side press the specimen until its front end is tightly abutted against the positioning surface, thereby completing the specimen‑positioning process.

After the feed cylinder returns, the solenoid is reset upon receiving another signal, and the positioning cylinder mechanism moves away from the specimen’s locating surface to allow for impact.

5. Electrical Control System:

The machine’s electrical control system is a Panasonic PLC microprocessor‑based control system independently developed by our company.

Main equipment configuration:

1) One 300J host machine

2) One 150 J pendulum and one 300 J pendulum

American-standard blade R8, 2 pieces

3) Sample holder, one piece

4) Refrigeration temperature control unit, one set (mounted on the host machine)

5) Automatic feeding and positioning device, one set (mounted on the main unit)

6) One set of oscillating transmission mechanism (mounted on the main unit)

7) Automatic pendulum hanging device, one set (mounted on the main unit)

8) One branded computer

9) One brand A4 printer

10) One set of dedicated data processing and control software

11) Remover, one unit (for pendulum replacement)

12) Anchor bolts: four pieces

13) Safety protection device: one set (customizable fully enclosed guardrail)

14) Oil-free pump, one unit

15) Control cabinet, one unit

Brief Overview of the Experimental Procedure:

1. Taking the pose: Pressing the swing‑release button drives the turbine and worm gear via the motor; once the electromagnetic clutch is energized and engaged, it rotates the pendulum counter‑clockwise. When the pendulum reaches its designated position, the photoelectric proximity switch detects the signal, the safety pin locks into place, the electromagnetic clutch de‑energizes and disengages, and the pendulum is secured at the specified location.

2 Refrigeration: An imported compressor cascade system is employed to achieve the required test cooling. The test specimen is placed in a specimen chamber, which is then inserted into the refrigeration unit. Inside the refrigeration unit, cooling copper tubes encircle the specimen chamber, while a heating plate is mounted on the exterior of these tubes to regulate the cooling temperature. Once the desired temperature is reached, the heating plate maintains that temperature, leveraging the principle of thermal equilibrium to attain the setpoint.

3 Shipping Fee: The feeding system operates on pneumatic principles, using the reciprocating motion of a cylinder to push the specimen out of the refrigeration chamber and into the specimen gripper. Simultaneously, a positioning cylinder locks the specimen in its designated standard position on the impact support. The linear motion of the feeding mechanism is driven by compressed air entering the cylinder, which actuates the piston to propel the feed rod forward and return it to its original position. Forward, backward, and stop motions of the feed rod are controlled by electrical signals from the pneumatic directional control valve and magnetic switches, which in turn govern the cylinder’s extension and retraction. By adjusting the position of the magnetic switches, the feed rod’s position and buffering speed can be finely tuned.

4 Impacts: Once the specimen is in position, press the pin‑retract button to withdraw the safety pin. Then, press the impact button to release the pendulum, allowing it to fall freely and strike the specimen. The system automatically records the data. Utilizing the potential energy released upon impact, the control system acquires the signal, the motor drives the worm gear, the electromagnetic clutch engages, and the pendulum returns to its suspended position, ready for the next test.

5 software : The interface is as follows (real-time display of the cooling curve, with temperature and time shown clearly)