碳纤维增强复合材料单向层合板直角自由切削热特性试验

Test on thermal characteristics when orthogonally free machining carbon fiber reinforced plastic unidirectional laminates

为揭示碳纤维增强复合材料(CFRP)切削温度与切削要素之间的关系,采用直角自由切削对CFRP单向层合板进行了切削试验,并采用OMEGA-0.05mm高灵敏K型热电偶对切削温度进行测量,讨论了切削参数、刀具几何参数及材料参数对切削温度的影响。结果表明:对切削温度的影响程度由高到低的参数依次为切削速度、切削厚度、刀具后角和钝圆半径,切削参数对温度的影响效应不受纤维方向角的影响;不同于金属材料,CFRP纤维方向角对切削温度影响突出,顺纤维方向上的切削温度明显高于逆纤维方向上的,切削温度在θ=90°时达到最大值,且为θ=0°时的2倍;CFRP切削回弹对刀具后刀面与已加工表面的接触状况影响较大,从而影响切削温度,加剧了切削温度的各向异性特征,且第3变形区切削热对切削温度影响突出;CFRP切削温度范围窄,最大切削温度在300℃左右,将导致切削质量对温度变化更为敏感。

In order to reveal the relationship between the cutting temperature in machining carbon fiber reinforced plastic （CFRP） and the cutting factors, orthogonally free machining tests on CFRP unidirectional laminates were conducted. The cutting temperature was measured using OMEGA-0.05 mm K type high sensitive thermocouple. Discussions were made about the effects of cutting parameters, geometric parameters of tools and material parame- ters on cutting temperature. The results show that cutting speed, cutting thickness, relief angle of tool and blunt ra- dius, in the sequence of descending, have great influence on cutting temperature. The influence of cutting parame- ters on the temperature is not affected by the fiber orientation angle. Unlike metal materials, the cutting temperature is greatly influenced by CFRP fiber orientation angle. The cutting temperature cut along fiber orientation is signifi- cantly higher than that opposite fiber orientation. The maximum cutting temperature is present to the fiber orientation angle of 90° , and the cutting temperature at the fiber orientation angle of 90°is 2 times of that at the fiber orientation angle of 0°. The spring back of CFRP has great influence on the contact condition between the tool flank and the machined surface, which will affect the cutting temperature eventually. This has exacerbated the anisotropy of the cutting temperature. Moreover, the heat in the third deformation zone has prominent effect on cutting temper- ature. CFRP has a narrow cutting temperature range, maximum cutting temperature is about 300℃, which will make cutting quality more sensitive to temperature changes.