目的 探索剪切痕迹形态特征与造痕工具刃口形态结构之间的关系,建立一套根据现场剪切断头种类与细节特征推断造痕工具种类的方法。方法 选用10个品牌24种钳、剪工具共76把,采用直剪的方式,分别剪切紫铜丝、铝丝、铅丝、贯通地线、铁路线缆,比较观察剪切断头的侧面形态、峰角大小、立顶高度、立顶形态以及坡面反映出的刃侧加工花纹特征等,总结分析痕迹特征与造痕工具结构之间的内在关联性。结果 不同刃口形态的工具剪切断头侧面形态有较明显区别,工具刃侧不同的加工花纹会在断头坡面上有不同的特征反映,不同种类工具的刃顶厚度、刃顶形态、咬合角对剪切断头立顶高度、立顶形态及断头峰角大小有影响。结论 综合利用剪切断头侧面形、立顶高度、立顶形态、峰角大小、断头坡面上的工具刃侧加工花纹印压痕迹,同时结合现场具体环境可以有效提高工具种类推断结果的准确度与可靠性。

Objective To explore the relationship between cut marks’ characteristics and blade shapes of the tools that produce the marks, so as to establish an accurate and practical method to infer the type of tools based on macroscopical and microscopic manifestations of the cut marks. Methods 76 pliers and scissors from 10 brands of 24 specifications were selected to vertically shear the wires of copper, aluminum or steel, plus the cable that is specific for running through ground or railway communication. The comparison was made on the cut marks at their profiles, pinnacled angles, heights and forms of the top planes, as well as the enantiomorphous impressions of processed lines (or patterns) from different tools. Consequently, the intrinsic relevance was systematically and overall summarized between the cut marks and involved tools. Results There are obvious differences in the profiles of various broken ends cut by those tools bearing diverse blade edges. Both pinnacled angles and top planes of the cut marks are related to the blades’ specific processed lines (or patterns). And the impact was observed from the different tools of various blade-edges’ thickness/form and the occluding angles to the cut marks at their broken ends’ diameters (maximum opening distances) and patterns as well as the size of the pinnacled angles. In a word, all those characteristics (so far as observable and measurable) can be used to infer the types of tools. Conclusion In comprehensive utilization of the cut marks at their broken ends’ profiles, pinnacled angles, sizes, forms and the impressions of the blades’ processed lines (patterns), the types of tools can be accurately and reliably inferred with overall consideration of the concrete field conditions.