Application Cases

Experiment Name: Research on Ultrasonic-Assisted Polyurethane Blanking Process

Research Direction: Composite Materials

Test Objective:
Polyurethane blanking is a typical flexible die stamping technology. It uses an elastic pad made of polyurethane to replace the male and female dies in traditional rigid die sets,  the polyurethane elastomer pad with the metal mold to achieve blanking. The earliest flexible die stamping technology originated in the late 19th century and can, to some extent,  scratching issues during the blanking process. Subsequently, flexible die stamping technology has matured through continuous development and has been widely applied in industrial production and other fields. The most famous example is the aircraft panel manufactured using the Greene rubber pad forming method , demonstrating that this technology can be used to produce parts with high precision and few defects. Although flexible die stamping and micro-blanking technologies have relatively  mature) mechanistic research and applications, some problems still exist, such as: ① High alignment  precision) requirements for male and female dies, making alignment difficult; ② The polyurethane punching method lacks mechanical simulation to  solidify  the theoretical foundation; ③ Polyurethane punching has high requirements for die hole depth, often resulting in excessively large punched hole rollover zones. To address these problems, this paper mainly studies the following: ① Designs and builds a polyurethane micro-hole array blanking device and conducts single-factor blanking experiments; ② Investigates the variation of punched hole diameter and cross-section quality with sheet thickness, die hole depth, blanking force, and blanking speed; ③ Uses analytical methods to design a horn, performs finite element optimization, and conducts ultrasonic-assisted polyurethane micro-hole array blanking experiments to explore the optimizing effect of ultrasonic vibration on the blanking process.

Testing Equipment: Signal Generator, ATA-4052 Power Amplifier, Transducer, Horn;

Experimental Procedure:

Figure: Model of the Ultrasonic-Assisted Polyurethane Micro-Hole Array Blanking Device

The main modules include: an ultrasonic module composed of components such as a transducer and a horn; a die set module consisting of parts like a shank sleeve, upper die set, and lower die set; and a mold module comprising punches, a container die, ejector pins, and a polyurethane pad.

Figure: Physical Diagram of the Device

It can be seen that the transducer, horn, and punch are assembled into the ultrasonic module. The transducer and horn are connected using fastening bolts. The ultrasonic module is installed on the upper surface of the upper die set via the flange of the horn, with a positioning platform  located below the flange.

The experiment used a signal generator and an ATA-4052 power amplifier to form the ultrasonic power supply within the ultrasonic module, used to enhance the fixed-frequency high-frequency oscillation signal. The signal generator is a versatile dual-channel function/arbitrary waveform generator capable of outputting sinusoidal waveforms with frequencies up to 60 MHz and a sampling rate of 500 MSa/s. However, it has the problem of a relatively low maximum output signal amplitude, which cannot meet the amplitude required for processing. Therefore, it is paired with the ATA-4052 ultrasonic power amplifier to amplify its amplitude. The combined action of the two maintains a stable output of the ultrasonic vibration amplitude.

Experimental Results:

(1) This paper designed a polyurethane micro-hole array blanking device, designed and assembled an ultrasonic-assisted module, and conducted research on optimizing the polyurethane blanking process with ultrasonic vibration. It proposed, for the first time, a  special  process of sequentially completing rigid die blanking and flexible die punching within one stamping stroke. Through single-factor experiments, the influence  of die hole depth, blanking force, and blanking speed on the blanking process and workpiece quality were investigated, verifying the optimizing effect of ultrasonic vibration on the process and its role in improving blanked part quality.

(2) By designing and assembling the ultrasonic module and measuring the amplitude, it was found that the amplitude increases with the input amplitude of the power supply signal. Results from ultrasonic-assisted polyurethane micro-hole array blanking experiments showed that die holes with depths of 200, 300, and 400 μm could all be successfully punched, yielding blanked parts with micro-hole arrays. Ultrasonic-assisted blanking experiments were conducted by adjusting the power supply signal amplitude, and the punched hole cross-sections were observed. The results indicated that ultrasonic vibration improves the cross-sectional morphology of the punched holes, and as the amplitude increases, the proportion of the shear bright band in the punched hole cross-section increased from 57% (without ultrasonic vibration) to 81%, significantly improving the cross-section quality.

Figure: ATA-4052C High-Voltage Power Amplifier Specifications and Parameters