CN-121972706-A - Method for adjusting low-frequency vibration hole making amplitude

CN121972706ACN 121972706 ACN121972706 ACN 121972706ACN-121972706-A

Abstract

The invention provides a method for adjusting the amplitude of low-frequency vibration hole making, which monitors the torque in the low-frequency vibration hole making process through a monitoring system and adjusts the amplitude through an amplitude adjusting module according to the change of the torque slope. First, a torque slope threshold k 0 at chip plugging is determined based on the machining material. And in the stable drilling stage, calculating torque average values in real time in a sliding window mode, calculating torque slope k according to two adjacent windows, and judging chip removal states in drilling according to k/k 0 . When k/k 0 is more than or equal to 1, the chip blocking exists in the drilling process, and k is reduced by increasing the amplitude until the amplitude A adopted is the optimal amplitude value after k/k 0 <1 is monitored. The invention can effectively avoid chip blocking in the drilling process and ensure that the amplitude reaches the minimum level, thereby being beneficial to improving the chip removal capacity of drilling and avoiding the excessive impact load caused by low-frequency vibration.

Inventors

CHEN YAN
HU LIANGTAO
ZHU QIANG
XU JIUHUA
FU YUCAN
SU HONGHUA
ZHAO ZHENGCAI
DING WENFENG

Assignees

南京航空航天大学

Dates

Publication Date: 20260505
Application Date: 20251105

Claims (5)

1. The method for adjusting the amplitude of the low-frequency vibration hole making is characterized by comprising the following steps of: 1) Selecting initial amplitude, and performing low-frequency vibration processing on a processing material by adopting a drill bit; 2) Determining a torque slope critical value k 0 when chip blocking is carried out according to a processing material, carrying out average value calculation on torque signals in two adjacent windows in a sliding window mode aiming at a stable phase signal after drilling, and obtaining a torque slope k of the two adjacent windows; 3) Judging chip removal conditions in the low-frequency vibration hole making process according to a slope ratio k/k 0 , and when k/k 0 <1 is monitored, obtaining an adopted amplitude A as an optimal amplitude value, and carrying out drilling processing according to the optimal amplitude value; 4) And calculating the time of the stable drilling stage of the drill bit according to the thickness of the processed test block material, wherein the amplitude of the drilling stage still continues to the final optimized amplitude value of the stable drilling stage for processing.
2. The method for adjusting the amplitude of a low-frequency vibration hole making according to claim 1, wherein the processing in the step 1) is specifically as follows: 1.1 According to the processed material, the structure and the material of the cutter and the processing parameters, the initial amplitude A 0 is selected and input to the amplitude adjusting module, and A c ≤A 0 ≤3*A c ,A c is the theoretical chip breaking amplitude; 1.2 The method comprises the steps of) drilling a material to be processed by a drill, extracting signals from the contact material of the drill tip, calculating the drill-in time of the drill according to the main cutting edge height h of the drill tip and the drill feeding quantity F, and removing the signals in the drill-in stage.
3. The method of adjusting the amplitude of a low-frequency vibration drilling process according to claim 1, wherein the size and the step size of the sliding window in the step 2) are set according to actual drilling parameters.
4. The method for adjusting the amplitude of the low-frequency vibration hole as set forth in claim 1, wherein the determination of the optimal amplitude value in the step 3) is as follows: 3.1 If the torque slope ratio k/k 0 of two continuous windows is more than or equal to 1, continuously increasing the amplitude value, setting an amplitude increment a, and if the torque slope ratio k/k 0 of two continuous windows is less than 1 after the amplitude is increased, processing the two continuous windows with the increased amplitude value to realize good chip removal in the drilling process and avoid too high impact caused by overlarge amplitude; 3.2 The amplitude A is iterated continuously in the hole making process by the set amplitude increment a according to the comparison relation between k/k 0 and 1, so that good chip breaking in the drilling process is realized, and excessive impact caused by low-frequency vibration is avoided.
5. The method of adjusting amplitude of a low-frequency vibration drilling process according to claim 4, wherein the amplitude increment a in the step 3) is set to be 0<a% or less than 50% A, and A is an amplitude value of a current drilling test.

Description

Method for adjusting low-frequency vibration hole making amplitude Technical Field The invention relates to the technical field of hole machining, in particular to a method for adjusting amplitude of a low-frequency vibration hole making. Background Materials such as titanium alloy and aluminum alloy have important roles in the aerospace industry because of the characteristics of high specific strength, low density, high toughness and the like. Bolting and riveting are the most common means of joining components in aircraft assembly, and the preparation of assembly holes is therefore one of the important tasks in aircraft assembly. However, serious chip blocking phenomenon can occur in the hole making process of materials such as titanium alloy, aluminum alloy and the like to deteriorate the hole processing quality and lead to the sharp reduction of the service life of a cutter, so that the assurance of clear chip removal in the hole processing process is of great importance. When the low-frequency vibration hole making technology is adopted to process the material, if the amplitude setting is too low, the smooth effect of chip removal is difficult to achieve, and when the amplitude setting is too large, huge impact is brought in the actual drilling process, so that the improvement of processing quality and the promotion of the service life of a cutter are not facilitated. Therefore, the method is favorable for realizing good chip removal only when the adaptive vibration parameters and machining parameters are selected, and the problems of poor hole machining quality and cutter breakage caused by chip blockage are avoided. The torque signal is found to be closely related to the chip removal state in the low-frequency vibration hole making test, when chip blockage occurs, the amplitude of the monitored torque signal is increased, and when chip removal is smooth, the torque signal is very stable, so that the torque signal can be used as a basis for judging the chip removal state. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a method for adjusting the amplitude of a low-frequency vibration hole, which can realize good chip removal and avoid excessive impact caused by vibration through amplitude adjustment, and can effectively avoid chip blocking in the drilling process and enable the amplitude to reach the minimum level, thereby being beneficial to improving the chip removal capacity of drilling and avoiding excessive impact load caused by low-frequency vibration. The invention provides a method for adjusting the amplitude of a low-frequency vibration hole making, which comprises the following steps: 1) Selecting initial amplitude, and performing low-frequency vibration processing on a processing material by adopting a drill bit; 2) Determining a torque slope critical value k 0 when chip blocking is carried out according to a processing material, carrying out average value calculation on torque signals in two adjacent windows in a sliding window mode aiming at a stable phase signal after drilling, and obtaining a torque slope k of the two adjacent windows; 3) Judging chip removal conditions in the low-frequency vibration hole making process according to a slope ratio k/k 0, and when k/k 0 <1 is monitored, obtaining an adopted amplitude A as an optimal amplitude value, and carrying out drilling processing according to the optimal amplitude value; 4) And calculating the time of the stable drilling stage of the drill bit according to the thickness of the processed test block material, wherein the amplitude of the drilling stage still continues to the final optimized amplitude value of the stable drilling stage for processing. Further improvement, the processing procedure of the step 1) is specifically as follows: 1.1 According to the processed material, the structure and the material of the cutter and the processing parameters, the initial amplitude A 0 is selected and input to the amplitude adjusting module, and A c≤A0≤3*Ac,Ac is the theoretical chip breaking amplitude; 1.2 The method comprises the steps of) drilling a material to be processed by a drill, extracting signals from the contact material of the drill tip, calculating the drill-in time of the drill according to the main cutting edge height h of the drill tip and the drill feeding quantity F, and removing the signals in the drill-in stage. Further improved, the size and the step length of the sliding window in the step 2) are set according to actual drilling processing parameters. Further improved, the specific process of determining the optimal amplitude value in the step 3) is as follows: 3.1 If the torque slope ratio k/k 0 of two continuous windows is more than or equal to 1, continuously increasing the amplitude value, setting an amplitude increment a, and if the torque slope ratio k/k 0 of two continuous windows is less than 1 after the amplitude is increased, processing the two continuous windows