Based on the research of the NC sharpening method of the helical tooth cutter, the method of obtaining the geometric parameters of the helical cutting edge is proposed. The design and development of the hardware and software of the economical CNC tool grinding machine control system for sharpening the helical tooth cutter are carried out. The technology was introduced.

1 Introduction

The helical tooth cutter refers to a cutting tool whose cutting edge is a spiral shape, such as a cylindrical milling cutter, an end mill and a spiral groove reamer. The sharpening of such tools is generally done manually by the process operator on the tool grinding machine by means of accessories. According to the spark, the grinding wheel is in contact with the teeth, and the amount of the backing knife is mastered by the hand feeling, and one tooth must be sharpened once. Therefore, the operator is required to be high, and it is difficult to ensure the quality of the sharpening, and the sharpening efficiency is not high. In this paper, the numerical control grinding method of helical tooth cutter is studied, and a small economical numerical control tool grinding machine is designed according to this, so that the numerical control sharpening problem of helical tooth cutter with unknown parameters can be solved.

2 CNC tool grinding machine drive system

In the transmission system diagram of the mechanical part of the CNC tool grinding machine, the Y and Z axes are the horizontal and vertical movement of the table; the X axis is the lifting movement of the grinding head; and the C axis is the rotation movement of the tool (workpiece). The grinding head can be adjusted to rotate around the X axis by hand; the grinding wheel and the tool are tilted up and down; the tool gearbox rotates in the horizontal plane.

3 control system hardware structure

The hardware structure of the control system uses the MCU 8031 ​​as the CPU. The system program is stored by the lower 7 bits of the P2 port and the 32KEPROM27256 extended by the P0 port. The lower 3 bits of the P2 port and the 2KRAM6116 of the P0 port are used to store data. The upper five bits of the P2 port are used for the address. Decoding, used to strobe LED display circuit, interface chip (8155, 8255), data memory (6116) and latch (273), P1 port is connected to stepper motor manual control circuit, stepper motor drive pulse signal is from P0 The port output is sent to the stepping motor driver via the latch (273); the PA port of the 8255 is connected to the system program start, pause button and working mode (parameter input mode, measuring mode, tool setting mode and automatic mode) transfer switch, PB The port is used for the tool spiral tooth measurement signal and other auxiliary function signal input, the PC port is used to output the auxiliary function signal; the PA port and the PC port of the 8155 are respectively connected to the row and column lines of the keyboard, and the PB port is connected with the sharpening tool type selection switch. .

4 helical tooth geometry measurement

When CNC sharpening, it is necessary to determine the correspondence between the axial feed of the tool and the circumferential feed. Since the helix angle β of the helical cutter and the guide are generally unknown during production, it is necessary to measure before sharpening. The relevant parameters of the spiral teeth. To this end, the helical teeth are unfolded in a straight line. Set the axial feed length (including the length of the grinding l1, the length l2 of the cutting edge and the length l of the grinding) to l, then the corresponding circumferential feeding arc length (including the grinding arc length s1, the cutting edge arc length s2 and the grinding arc length) S3) is s0. To determine the arc length s, the geometric parameters of a spiral line can be measured first, and then the arc length can be obtained according to a similar triangle.

For this purpose, before the sharpening, a measuring head is mounted on the grinding head, and the measuring circuit of the measuring head and the tool form a closed loop. In the measurement mode, in the measurement mode, the manual function is used to first make the measuring head contact with the cutter teeth, and then the tool is moved or rotated linearly, and 1 or 2 of the movement track of the measuring head relative to the tool is automatically recorded by the control system. The tool linearly moves the step number Z1 and the number of rotation steps C1, and converts the feed length input from the operation panel to the stepping motor number Ze according to the pulse equivalent of the Z axis, and uses the measured geometric relationship of Z1 and C1. The number of rotation steps of the C-axis Ce is obtained, and (Ze, Ce) is the end point coordinate of the straight line, and the linear interpolation and the rotation of the tool are linearly interpolated by the two axes.

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Tempered Glass

Tempered or toughened glass is a type of safety glass processed by controlled thermal to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tension. Such stresses cause the glass, when broken, to crumble into small granular chunks instead of splintering into jagged shards as plate glass (a.k.a. annealed glass) does. The granular chunks are less likely to cause injury.