Research On Micro-hole Drills With High Accuracy

Spinneret plate is the core component in the manufacture of chemical fiber. Spinneret plate with high quality and accuracy is the dominant factor guaranteeing the fine spinning process and the quality of the produced fiber. In terms of spinneret plate, the most precise component is "micro-hole". The pattern, structure and accuracy of the "micro-hole" will affect the appearance, diameter and physical-mechanical properties of the produced fiber directly. Thus, the quality of micro-hole drill is crucial to spinneret plate manufacturers.This study systematically analyzed the current researches on micro-hole drills both at home and abroad, especially concerning about the micro-hole drills applied in spinneret plate and emphasizing on spade drills which play an important role in micro-hole drilling process. Firstly, the analysis of drill bit of spade drills was taken out. Combination of simulation with the software of DEFORM-3D, a powerful process simulation system based on the finite element technique, and orthogonal experiments were applied in the design of geometric dimensioning of spade drills. Thrust force (Fz) and torque (M) were set as indicators to evaluate the performance of spade drills. On basis of the above theoretical analysis, drilling experiments were conducted. The results of software simulation and actual drilling experiments were compared to obtain the optimized design of spade drill structures.Secondly, the technological parameters in the grinding process of spade drills were also studied in present research. The asymmetry of spade drills was considered. A novel grinding process was designed to fully amplify the function of grinding machine with high-accuracy. It provided strong theoretical support for improving the consistency and optimized design of spade drills. In addition, it was observed that the roughness of rake face of spade drills has obvious influence on the drilling processes. Grinding wheel was selected due to the cost performance upon the results of actual experiments.Then, a set of automatic test equipment with optical, mechanical and electrical integration, specially used for micro-hole drills of spinneret plate test was designed creatively. The motor system of this equipment was designed with motion control card, four shaft linkage precision platform and motor, automatic dislocation was taken out according to the positional deviation of the drills; image acquisition system was designed by the employment of image capture card, CCD, industrial lens and light source; and also the testing software of micro-hole drilling process was designed. The actual test of various spinneret plate micro-drills indicated that this control system was reliable, stable and fast. The accuracy of the test was±1μm and±0.5°in length and angle, respectively. The automatic test equipment of micro-drill in spinneret plate can take place of manual test, which could relieve the stress of testing personnel and result in higher test efficiency and accuracy. Therefore, the quality and consistency of micro-hole drills was guaranteed.Finally, the cutting parameters of spade drills in manufacturing process were optimized by the employment of combination of DEFORM-3D simulation and cutting experiments, thus, resulting in improved processing abilities of spade drills. In addition, it was suggested that the combination of pneumatic positioning device and blunt needle processing would lead to precise positioning in spade drill cutting process. Experiments certified that this method was feasible.