阅读说明：本技术 一种密集孔群整体二次找正方法 (Secondary alignment method for whole dense hole group ) 是由 徐晓星 李家鲁 王立昆 刘银河 窦炳程 于 2020-07-30 设计创作，主要内容包括：一种密集孔群整体二次找正方法,属于机械加工技术领域,以解决现有的换热器管板孔群二次找正过程中,如果采用在摇臂钻上采用导柱钻头单孔找正,但导柱易划伤管孔壁,且坡口深度基于工人技术水平不可控,效率低,劳动强度大的问题,以及采用数控机床逐一找正单孔,找正精度高,但是单孔找正效率过低,不适用于密集孔群的问题。本发明包括以下步骤：S1、将管板竖直安放到数控机床的弯板上,根据加工管板上孔坡口深度误差(p,q),在管板上水平方向和竖直方向分布选取两点进行平面找正；S2、在管板加工的孔群中,选取四个孔,四个孔的中心连线形成平行四边形；S3、用数控机床上的三维测头确定四个孔中心的坐标。本发明适用于密集孔群的加工找正。(A secondary alignment method for an integral dense hole group belongs to the technical field of machining and aims to solve the problems that in the secondary alignment process of an existing heat exchanger tube plate hole group, if a guide pillar drill bit is adopted to perform single-hole alignment on a rocker drill, a tube hole wall is easy to scratch by a guide pillar, the depth of a groove is uncontrollable based on the technical level of workers, the efficiency is low, and the labor intensity is high, and the single holes are aligned one by adopting a numerical control machine, so that the alignment precision is high, but the single-hole alignment efficiency is too low, and the secondary alignment method is not suitable for the dense hole group. The invention comprises the following steps: s1, vertically placing the tube plate on a bent plate of a numerical control machine tool, and selecting two points in the horizontal direction and the vertical direction on the tube plate for plane alignment according to the depth errors (p, q) of the groove of the upper hole of the machined tube plate; s2, selecting four holes from the hole group processed by the tube plate, wherein the central connecting lines of the four holes form a parallelogram; and S3, determining the coordinates of the centers of the four holes by using a three-dimensional measuring head on the numerical control machine tool. The invention is suitable for processing and aligning the dense hole group.)

1. A secondary alignment method for the whole dense hole group is characterized in that: the method comprises the following steps:

s1, vertically placing the tube plate on a bent plate of a numerical control machine tool, and selecting two points in the horizontal direction and the vertical direction on the tube plate for plane alignment according to the depth errors (p, q) of the groove of the upper hole of the machined tube plate;

s2, selecting four holes from the hole group processed by the tube plate, wherein the central connecting lines of the four holes form a parallelogram;

s3, determining coordinates of the centers of the four holes by using a three-dimensional measuring head on a numerical control machine tool, wherein the coordinates of the centers of the four holes are sequentially A (x1, y1), B (x2, y2), C (x3, y3) and D (x4, y 4);

s4, calculating the coordinate (x, y) of the diagonal center point O of the parallelogram according to the coordinates of the four holes, namely

x＝(x1+x2+x3+x4)/4，y＝(y1+y2+y3+y4)/4；

S5, calculating an included angle theta between the central line of the parallelogram in the vertical direction and the y axis of the machine tool according to the coordinates of the central points of the four holes;

s6, when a hole group is machined, the numerical control program adopts a polar axis offset command, and the calculated included angle theta is substituted into the polar axis offset command;

s7, adjusting the axial hole feeding amount f according to the plane error a of the two points in the vertical direction in the step S1.

2. The method of claim 1, wherein the dense hole group integral secondary alignment method comprises: when the included angle between the two sides of the parallelogram is not equal to 90 degrees, the calculation formula of the included angle theta between the central line of the parallelogram in the vertical direction and the y axis of the machine tool in the step S5 is as follows:

θ1＝arctan((x3-x1)/(y1-y3))-60°；

θ2＝arctan((x4-x2)/(y2-y4))-60°；

the average value of θ is obtained by substituting θ 1 and θ 2 into the formula θ 1+ θ 2/2.

3. The method of claim 1, wherein the dense hole group integral secondary alignment method comprises: in step S7, the method of determining the hole axial feed amount includes: the hole group is divided into n rows, wherein the row number n is a/0.05, and the n is rounded up in a rounding mode, and the axial hole feeding amount f is a/n.

4. The method of claim 1, wherein the dense hole group integral secondary alignment method comprises: in step S1, the plane alignment error between two points in the horizontal direction of the tube sheet is less than or equal to | p |, and the plane alignment error between two points in the vertical direction of the tube sheet is less than or equal to | q |.

5. The method of claim 1, wherein the dense hole group integral secondary alignment method comprises: when the included angle between the two sides of the parallelogram is 90 degrees, and the parallelogram in the step S5 is a square or a rectangle, the calculation formula of the included angle θ between the central line of the parallelogram in the vertical direction and the y-axis of the machine tool is as follows:

θ1＝arctan((x3-x1)/(y1-y3))；

θ2＝arctan((x4-x2)/(y2-y4))；

the average value of θ is obtained by substituting θ 1 and θ 2 into the formula θ 1+ θ 2/2.

Technical Field

The invention relates to an aligning method of dense holes, and belongs to the technical field of machining.

Background

In recent years, the quality requirements of various large chemical design institutes and owners on core heat exchange equipment in chemical process flows are higher and higher, and particularly, the welding (pipe end welding for short) of a heat exchange pipe and a pipe plate is required, such as the requirement of pipe end welding seam RT flaw detection in a methanol reactor in the Dynees technology, the pipe end deep hole welding technology in a waste heat boiler and the like.

The quality of the pipe end welding depends on the groove processing precision, namely the shape and the depth of the groove and the concentricity of the pipe hole. The existing process flow is to firstly machine pipe holes on a deep hole drill to ensure the precision of hole groups and then to perform secondary alignment machining on grooves. In the past, the guide pillar drill bit is generally adopted to perform single-hole alignment on the rocker drill, but the guide pillar is easy to scratch the wall of the pipe hole, the depth of the groove is uncontrollable based on the technical level of workers, and meanwhile, the single-hole alignment efficiency is low and the labor intensity of the workers is high. The single holes are aligned one by one twice through a numerical control machine tool, the alignment precision is high, but the efficiency of the single holes is too low, so that the method is not suitable for dense hole groups; if other holes are aligned and processed for a single hole at a time, the accumulated deviation of the holes is too large, resulting in out-of-tolerance.

Disclosure of Invention

The invention aims to solve the problems that in the secondary alignment process of the tube plate hole group of the existing heat exchanger, if a guide pillar drill bit is adopted on a rocker drill for single-hole alignment, but a guide pillar is easy to scratch the wall of the tube hole, the depth of a groove is uncontrollable based on the technical level of workers, the efficiency is low, and the labor intensity is high, and single holes are aligned one by adopting a numerical control machine tool, the alignment precision is high, but the single-hole alignment efficiency is too low, so that the method is not suitable for dense hole groups; if other holes are aligned and processed for a single hole at one time, the accumulated deviation of the holes is overlarge, and the out-of-tolerance problem is caused, so that the integral secondary alignment method for the dense hole group is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a secondary alignment method for an integral dense hole group comprises the following steps: s1, vertically placing the tube plate on a bent plate of a numerical control machine tool, and selecting two points in the horizontal direction and the vertical direction on the tube plate for plane alignment according to the depth errors (p, q) of the groove of the upper hole of the machined tube plate;

s2, selecting four holes from the hole group processed by the tube plate, wherein the central connecting lines of the four holes form a parallelogram;

s3, determining coordinates of the centers of the four holes by using a three-dimensional measuring head on a numerical control machine tool, wherein the coordinates of the centers of the four holes are sequentially A (x1, y1), B (x2, y2), C (x3, y3) and D (x4, y 4);

s4, calculating the coordinate (x, y) of the diagonal center point O of the parallelogram according to the coordinates of the four holes, namely

x＝(x1+x2+x3+x4)/4，y＝(y1+y2+y3+y4)/4；

S5, calculating an included angle theta between the central line of the parallelogram in the vertical direction and the y axis of the machine tool according to the coordinates of the central points of the four holes;

s6, when a hole group is machined, the numerical control program adopts a polar axis offset command, and the calculated included angle theta is substituted into the polar axis offset command;

s7, adjusting the axial hole feeding amount f according to the plane error a of the two points in the vertical direction in the step S1.

Preferably, when the included angle between two sides of the parallelogram is not equal to 90 °, the calculation formula of the included angle θ between the central line of the parallelogram in the vertical direction and the y-axis of the machine tool in step S5 is as follows:

θ1＝arctan((x3-x1)/(y1-y3))-60°；

θ2＝arctan((x4-x2)/(y2-y4))-60°；

the average value of θ is obtained by substituting θ 1 and θ 2 into the formula θ 1+ θ 2/2.

Preferably, in step S7, the method for determining the hole axial feed amount is: the hole group is divided into n rows, wherein the row number n is a/0.05, and the n is rounded up in a rounding mode, and the axial hole feeding amount f is a/n.

Preferably, in step S1, the plane alignment error between two points in the horizontal direction of the tube sheet is less than or equal to | p |, and the plane alignment error between two points in the vertical direction of the tube sheet is less than or equal to | q |.

Preferably, when the included angle between two sides of the parallelogram is 90 °, and the parallelogram in step S5 is a square or a rectangle, the calculation formula of the included angle θ between the vertical center line of the parallelogram and the y-axis of the machine tool is:

θ1＝arctan((x3-x1)/(y1-y3))；

θ2＝arctan((x4-x2)/(y2-y4))；

the average value of θ is obtained by substituting θ 1 and θ 2 into the formula θ 1+ θ 2/2.

Compared with the prior art, the invention has the following beneficial effects:

the four-point center alignment method avoids the problems that the numerical control machine tool is low in single-hole alignment efficiency one by one, and the accumulated position error of only one single-hole alignment hole is large. Meanwhile, after the four-point center of the bronze drum is aligned once, the hole group can be processed together without being aligned again, and compared with manual alignment, the copper drum hole aligning device is high in efficiency and accurate in positioning precision.

Drawings

FIG. 1 is a front view of a tubesheet;

fig. 2 is a positional relationship between the vertical direction center line of the parallelogram and the coordinate axes of the machine tool.

Detailed Description

The invention will be described in further detail below with reference to the accompanying drawings: the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation is given, but the scope of the present invention is not limited to the following embodiments.