Medical needles are widely used in medical treatment for injection or blood sampling purposes.^1–3 When the needle is inserted into a human organ, an insertion force is generated between the needle and the organ tissue. This force may influence the needle inserting direction^3–5 or increase pain.^5–10 Therefore, it is important to reduce or minimize it for achieving better medical treatment. The sharpness of the needle tip is closely related to the insertion force. Li et al.¹¹ polished the needle using the magnetic abrasive finishing technique and then measured the axial force—including tip cutting force, inner friction force, and outer friction force—during insertion of a hollow needle into a tissue-mimicking sample. The results showed that unpolished needles had a tip cutting force 22% higher than polished needles. Needle insertion in soft tissue is essentially similar to a knife cutting. The insertion force greatly depends on the needle tip’s cutting-edge geometry.^12–23 On the basis of the geometry of the needle tip and its fabrication method, two parameters—inclination angle and rake angle—are used to develop the mathematical models of needle.^12,14–18 Many studies have been conducted about the insertion force of needle.^21–31 Moore et al.²⁰ developed a predictive force model based on the inclination angle and the rake angle of a needle’s cutting edge to predict the insertion force and studied a novel needle cutting-edge geometry for end-cut biopsy and curved needle tips based on rake and inclination angles.^13–15 The rake angle is the angle of the rake face with respect to the perpendicular to the cut surface. It is believed that a larger inclination angle will lead to a lower cutting force and a larger rake angle will lead to a sharper needle edge.^{10,14,15,17,21}

中文翻译：

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新型刺血针医用针的几何形状和插入力建模

医用针头广泛用于医疗注射或采血目的。^1-3当针插入人体器官时，针与器官组织之间会产生插入力。此力可能会影响进针方向^3-5或增加疼痛。^5–10因此，为了获得更好的医疗效果，减少或尽量减少它非常重要。针尖的锋利度与插入力密切相关。李等人。¹¹使用磁力研磨抛光技术抛光针，然后测量将空心针插入模拟组织样本期间的轴向力，包括尖端切割力、内摩擦力和外摩擦力。结果表明，未抛光的针的尖端切割力比抛光的针高 22%。软组织中的针插入基本上类似于刀切割。插入力很大程度上取决于针尖的尖端几何形状。^12-23根据针尖的几何形状及其制造方法，使用倾角和前角两个参数来建立针的数学模型。^12,14–18关于针的插入力已经进行了许多研究。^21-31摩尔等人。²⁰开发了一种基于针尖端倾斜角和前角的预测力模型来预测插入力，并研究了一种用于端切活检的新型针尖端几何形状和基于前角和倾斜角的弯曲针尖。^13–15前角是前刀面相对于切削表面垂线的角度。据信，较大的倾斜角将导致较低的切割力，而较大的前角将导致更锋利的针边缘。^{10,14,15,17,21}