关键词: 蒙古栎, 多次切割, 纵向比较法, 横向比较法, 缝深, 缝宽

Abstract: [Objective] Aiming at cutting oak by laser, the influences of single and multiple cutting technology parameters on cutting seam width and depth were investigated, in order to provide theoretical basis to quickly determine the reasonable technical parameters according to the cutting effect requirements for production processing professionals.[Method] The technical parameters of laser cutting machine were used as influence factors, and the depth and width of cutting seam were set as the target of cutting effect. The longitudinal and horizontal comparison method were applied to observe the regularity of data change and proceed experimental data handling.[Result] The results showed that, in the case of single cutting, when lens height was F=3 mm, the seam width was about 0.2 mm; if F=7 mm, the width was about 0.1 mm; if F=11 mm, the width was about 0.3 mm. In the case of secondary cutting, if F=3 mm, the width was about 0.2-0.3 mm; if F=7 mm, the width was about 0.1-0.2 mm; if F=11 mm, the width was about 0.3-0.4 mm. In the case of three times cutting, if F=3 mm, the width was about 0.3 mm; if F=7 mm, the width was about 0.2 mm; if F=11 mm, the width was about 0.4 mm. It was observed that seam width was gradually reduced when lens height increased from 3 to 7 mm, but if the lens height was greater than 7 mm, the seam width began to increase, and the faster increasing rate was found. With the increase of cutting frequency, the seam depth increment became very small when the lens height was the same. Under the same conditions, the more the cutting frequency, the higher the absolute value of seam depth, and the increment of seam depth varied in each cutting. When the cutting speed v ≤ 100 mm·s^-1 and the light intensity was lower than 40%, the seam depth increment decreased with the increase of cutting frequency, i.e. the seam depth became smaller and smaller in each cutting. When the cutting speed v ≥ 100 mm·s^-1 and light intensity was more than 60%, with the increase of cutting frequency, the seam depth increment became bigger but the degree of increasing was relatively smaller.[Conclusion] The extremely significant factor that affecting the seam width was lens height F, when F was around 7 mm, the seam width was minimum, just about 0.1 mm. The seam width was increased when lens height was too large or small, and the growth rate increased quickly if the lens height was too large. Repeatedly cutting would lead the increase of seam width, but it would no longer change when achieved a certain degree. The seam depth increased with the cutting times, but the increasing degree reduced gradually at low and middle speed. The first reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 60% light intensity,the lens height is 7 mm. The second reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 40% light intensity, the lens height is 7 mm.The third reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 60% light intensity, the lens height is 4 mm.When large seam depth was obtained by cutting repeatedly instead of adjusting the lens height, the initial height of lens was F=5-6 mm, the light intensity was 50%-60%, and the cutting speed was less than 50 mm·s^-1. In order to obtain big seam depth,the multiple cutting technology with the lens height reducing gradually showed better quality and higher security in comparison with the single cutting method with low speed and high light intensity.

Key words: oak, cutting repeatedly, vertical comparison method, lateral comparison method, seam depth, seam width