Sawing Force Prediction Model and Experimental Study on Vibration-Assisted Diamond Wire Sawing

At a Glance

Metadata	Details
Publication Date	2022-11-19
Journal	Micromachines
Authors	Chenpu Zhang, Zhikui Dong, Yanheng Zhao, Ziliang Liu, Shang Wu
Institutions	Yanshan University
Citations	6
Analysis	Full AI Review Included

Executive Summary

This study introduces and validates a vibration-assisted diamond wire sawing (DWS) method applied along the wire speed direction to significantly improve the slicing of hard, brittle materials.

Core Value Proposition: Vibration assistance (0-50 Hz) is proven to reduce sawing forces and enhance surface quality metrics (Ra, Rz, TTV, and warp) compared to conventional DWS.
Modeling Achievement: A macroscopic sawing force prediction model was established for vibration-assisted DWS, accurately correlating process parameters (frequency, speed, tension) with normal (F_nv) and tangential (F_tv) forces.
Force Reduction: Increasing vibration frequency to 50 Hz resulted in an approximate 20% reduction in both normal and tangential sawing forces on HT250 ingots.
Quality Enhancement (Single-Wire): Vibration assistance stabilized the roughness and waviness profiles, reducing average Ra and Rz values across materials like HT250, stainless steel, and NdFeB.
Stability Improvement (Multi-Wire): For SiC and NdFeB slices, vibration significantly reduced the average values and standard deviations of Total Thickness Variation (TTV) and warp, indicating improved sawing stability and higher slice yield.
Mechanism Inference: The vibration is hypothesized to enhance the polishing effect of abrasive particles and improve chip removal, leading to better surface finish and reduced subsurface damage.

Technical Specifications

Parameter	Value	Unit	Context
Vibration Frequency (f) Range	0 to 50	Hz	Applied to the working table.
Wire Speed (v_τ) Range	0 to 20	m/s	Tangential speed of the diamond wire.
Feed Speed (v_n) Range	0 to 60	mm/h	Ingot feed rate.
Wire Tension (F) Range	20 to 40	N	Tension applied to the diamond wire.
Wire Radius (r) Range	0.05 to 0.15	mm	Diameter of the diamond wire.
Sawing Force Reduction (Max)	~20	%	Reduction in F_nv and F_tv observed at 50 Hz (HT250).
HT250 Average Ra Reduction	453 to 336	nm	Improvement in surface roughness with vibration.
SiC TTV Standard Deviation Reduction	0.0143 to 0.0031	mm	Significant improvement in multi-wire slicing stability.
NdFeB Warp Standard Deviation Reduction	0.0124 to 0.0074	mm	Improvement in slice flatness stability.
Materials Tested	HT250, Stainless Steel, NdFeB, SiC	N/A	Brittle and hard materials used for experimental validation.

Key Methodologies

The experimental study utilized a modified DX-2260 multi-wire sawing machine equipped with a specialized vibration-assisted platform.

Experimental Setup: Experiments were conducted on a DX-2260 multi-wire sawing machine integrated with a vibration-assisted platform consisting of a servo motor and an eccentric device.
Vibration Application: Simple harmonic vibration (0-50 Hz) was applied to the working table (carrying the ingot) in the direction parallel to the wire speed (tangential direction).
Force Measurement: A 3D force sensor was mounted beneath the working table to measure the normal sawing force (F_nv) and tangential sawing force (F_tv) during vibration-assisted single-wire sawing. Wire tension (F) was monitored using tension sensors on the guide wheels.
Model Verification: Orthogonal experiments were performed on HT250 ingots, varying vibration frequency (f), wire speed (v_τ), feed speed (v_n), and wire tension (F). Experimental force values (F_nvc, F_tvc) were compared against theoretical values (F_nv, F_tv) derived from the established prediction model.
Surface Quality Analysis (Single-Wire): Slices of HT250, stainless steel, and NdFeB were analyzed using a Bruker Dektak XT instrument to measure roughness (Ra, Rz), roughness profiles, and waviness profiles.
Geometric Quality Analysis (Multi-Wire): Multi-wire sawing experiments were conducted on NdFeB and SiC. The resulting slices were measured for geometric parameters: Total Thickness Variation (TTV) and warp, to assess overall stability and quality improvement.

Commercial Applications

This vibration-assisted DWS technology is critical for industries requiring high-precision, high-throughput slicing of extremely hard and brittle materials.

Photovoltaic Industry: Slicing crystalline silicon ingots into high-quality wafers with reduced TTV and warp, improving chip pass rates and production yield.
Electronic and Semiconductor Industries: Precision slicing of advanced brittle materials such as Silicon Carbide (SiC) and sapphire, which are essential for power electronics and LED substrates.
Aerospace and Defense: Machining hard materials like NdFeB (used in high-performance magnets) and other brittle components where minimizing subsurface damage (SSD) and maximizing surface quality (low Ra/Rz) is paramount.
Advanced Manufacturing: Optimizing the slicing process for any material where conventional DWS efficiency and quality are limited by crack propagation and high cutting forces.

View Original Abstract

Diamond wire sawing is the main machining technology for slicing various brittle materials, such as crystalline silicon, SiC, and NdFeB. Due to their high hardness and high brittleness, as well as the ease with which the surfaces of machined materials are damaged, it is difficult to further improve the sawing efficiency and the surface quality based on research conducted on the original machining method. In this paper, a vibration-assisted diamond wire sawing method is proposed. We analyzed the impact of load on the ingot, motion trajectory, and sawing depth of the abrasive particles, and a macroscopic sawing force prediction model for the vibration-assisted sawing method was established and verified via experiments. Based on the single-wire-sawing experiment and prediction model, the influences of the vibration parameters and sawing parameters on the sawing force were determined. The influences of vibration assistance on the surface quality, including the roughness profile, waviness profile, thickness profile, Ra, and Rz, were explored through single-wire-sawing experiments, and the influences of vibration assistance on the geometric parameters of slices, such as the total thickness variation (TTV) and warp, were explored through multi-wire-sawing experiments. It was found that vibration-assisted sawing can reduce sawing force and improve surface quality.

Tech Support

Original Source

DOI: https://doi.org/10.3390/mi13112026

References

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