Research in China has tried to assess how lateral vibrations in diamond wire saw can increase the notch losses in the production of solar wires and have developed a predictive model than allegedly helps to reduce them. Their analysis showed that, with constant saw parameters, smaller waffles suffer from a larger surplus core loss.
Researchers from Chinese Shandong University have proposed a new methodology for the quantitative prediction of surplus core loss caused by lateral vibrations of diamond wires cut in the production of solar wanders.
Kerf is the crystalline material that is wasted when a solar -inot is cut into waffles.
“The notch loss model outlined in our research can predict the uniformity of the thickness of silicon waffers, which can help arrange the thickness of thinner silicon waffles in the future and offer a new perspective for the study of fracture of photo -Silicon waffles,” PV -Magazine.
The researchers warned the newest Diamond wire saws used in the PV industry can work faster than in the past, which increases the vibrations during production. They also explained that the diameter of the sawded wire becomes thinner while the wire span increases, which increases the lateral vibrations. Both combined effects can in turn result in a larger cereficiency loss and a lower wafer thickness.
The lateral vibration of the sawdow will indirectly weaken the fracture strength of the silicon wafer, resulting in an increase in the break speed during the sawing process and subsequent cleaning and transport, “they explained further.” That is why it is very important to study the excess notch loss. future.”
The scientists initially investigated the lateral vibration dynamics of the diamond sawing board during the sawing process under continuous excitation at both ends of the sawing council. They then studied the friction damping effect in the sawing notch.
Moreover, they used the finite difference method, which is often used to solve differential comparisons, to resolve their model numerically. They also diminish the gear signals of the vibrations and the relocation signals to assess the lateral vibration characteristics of the sawing wire.
Finally, the academics developed their modeling via the Hertz contact theory, which describes the distortion and stress distribution when two non-compliant, elastic and smooth bodies make contact. They also apply the principle of preservation of Momentum, which states that the total momentum of a closed system remains constant over time.
To validate the predictive model, the research team has performed three groups of sawing experiments with a SH300 machine tool supplied by Shenghai Numerical Control Co., LTD, China. The diameter of the sawded wire used was 350 urn and the wire speed varied from 1,000 m/min to 1,400 m/min.
The experiments showed that Kerf loss caused by the lateral vibration is mainly due to the vibration bronze signal of the main saw phase, where the vibration bronze signal is stable. Moreover, the researchers discovered that KNERF -loss is decreasing with a higher wire tension and a lower wire span, while it increases somewhat with a higher wire speed.
The analysis also showed that, with Constant saw parameters, smaller waffles suffer from a larger surplus core loss.
“The greater the excess notch loss, the greater the irregularities in the thickness of the silicon waffle,” the scientists emphasized. “For photovoltaic monocrystalline silicon waffles, considerable thickness eviance is unacceptable.”
They also emphasized that lateral vibrations mainly influence the edges of the waffles, which increases the risk of cracks.
Their findings are available in the newspaper “Prediction of surplus noise loss in diamond wire saw based on vibration bronze signal measurement and processing“Published in Measurement.
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