Discussion on the processing method of equal notch

2022-08-12
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Discussion on the processing method of equally divided notch workpiece in radial tire vulcanizing machine

there is a kind of equally divided notch workpiece in the tire loading mechanism of radial tire vulcanizing machine of our factory. According to different product models, the forms of equally divided notch include straight groove, Archimedes spiral groove and circular arc groove. Each groove requires high precision and is difficult to process. Our factory has explored a set of mature processing methods from boring machine processing, lathe refitting Jiawang to CNC milling machine processing, which are now introduced to peers for reference. And more emerging new composite materials such as carbon fiber are also driving the growth of all composite materials

1 machining equal straight grooves with t612 boring machine

there is a part called fixed disc on our 1525 (Ⅱ z) radial tire curing machine, and its part sketch is shown in Figure 1. This part requires processing eight evenly distributed straight grooves, and the angular tolerance of any two adjacent grooves is required to be within soil 1 '

in order to meet the design requirements and ensure the machining accuracy of parts, the technologists analyzed and studied, and found a better method

1.1 analysis of processing technology

we use t612 boring machine for processing. The installation position is shown in Figure 2. 1 and 5, 3 and 7, 2 and 6, 4 and 8 in the eight slots are symmetrical to each other. Align and mill slots 1 and 5 according to the line to meet the requirements of the drawing, and drill a process hole I on the axis of slots 1 and 5 at the same time. Since slots 3 and 7 are perpendicular to slots 1 and 5, slots 3 and 7 can be processed on the boring machine to meet the requirements of the drawing, and a process hole II can be drilled on the axis of slots 3 and 7 at the same time. stay φ 1152 circumferential trial boring process hole III, when the difference between the distance a and B between II and III, III and I is less than 0.10mm, which is determined according to the requirements of the drawing, the position of slots 2 and 6 is found and the angular tolerance of slots 2, 6 and 3, 7, 2, 6 and 1, 5 is guaranteed to be within ± 1 '. Since slots 4 and 8 are perpendicular to slots 2 and 6, slots 4 and 8 can be processed on the boring machine to meet the requirements of the drawing

1.2 processing route

milling 1 and 5 slots -- drilling wettability (water level) experimental machine dumpling hole I -- milling 3 and 7 slots -- drilling dumpling hole II -- try boring hole III -- milling 2 and 6 slots -- milling 4 and 8 slots

1.3 processing process

(1) fasten the bending plate on the workbench after alignment, and fasten the positioning tire on the bending plate

(2) punch the table to find the outer circle of the positioning tire, so that the rotation center of the bell bar is in the center of the positioning tire, install the workpiece, level it with a cushion block and press it with a pressing plate (the inner hole of the workpiece and the outer circle of the positioning tire adopt clearance fit, and the outer circle of the positioning tire is positioned φ. 040)。

(3) move the boring bar horizontally, mill 1 and 5 slots to meet the requirements of the drawing, and drill the dumpling process hole I

(4) return the boring bar to the center of the positioning tire, move the boring bar vertically, mill 3 and 7 slots to meet the requirements of the drawing, and drill the process hole II to make the radius tolerance of I and II 0.04mm

(5) reset the boring bar according to hole I, loosen the pressing plate, rotate the workpiece, try boring process hole III, measure a and B with a caliper, when the tolerance of a and B is 0.10mm, drill hole III to meet the requirements of the drawing, and mill groove 2 and 6 to meet the requirements of the drawing

(6) the boring bar returns to the center of the positioning tire, moves the boring bar vertically, and milling slots 4 and 8 meet the requirements of the drawing

2 process equal Archimedes spiral grooves with C650

our 1525 (Ⅱ ZQ) vulcanizer has a part called fixed disc, and the part sketch is shown in Figure 3. This part requires to process 8 Archimedes spiral grooves

technical requirements: groove width, depth 22mm, surface roughness Ra12.5

spiral groove centerline equation ρ= 120+1.3325 θ

where ρ-- Pole diameter

θ-- Polar angle

after analysis, the technicians used C650 lathe to refit and process the workpiece, and achieved success

2.1 selection of machine tool

the motion forming Archimedes' spiral is composed of two simple motions, namely:

Ⅰ: Ray 0A rotates uniformly around 0 point (pole)

Ⅱ: point P on 0A moves in a uniform straight line on OA

according to the above analysis, I and II movements are easy to realize on the ordinary lathe. The workpiece can be installed on the chuck of the lathe and rotate at a uniform speed. The cutter is installed on the tool holder and moves at a uniform speed in a straight line with the action of the radial automatic tool walking mechanism. Therefore, it is decided to use C650 ordinary lathe to process Archimedes spiral groove

2.2 modification of machining system

because the relationship between the spindle speed of the ordinary lathe and the automatic tool walking mechanism is certain, it can not meet the requirements of machining Archimedes spiral groove. Therefore, reasonable modification of the processing system is the key. See Figure 4 for the processing system diagram

2.2.1 calculate the radial stroke of sharp knife

by ρ= 120+1.3325 θ, When θ= At 0 °, ρ= 120mm, when θ= At 360 °, ρ= 599.7mm

when the spindle rotates for one cycle, the radial stroke s of the milling cutter is

s=599.7-120=479.7mm

2.2.2 change gear calculation

c650 lathe, the maximum magnification of the screw pitch of the feed mechanism is 64, and the tool path of the radial screw of the tool holder is 1.6mm/r, so there is 264 × one point six × (b/a) · (c/b) =479.7

select za=27, zb=138, zc=127, m=2.25

2.2.3 transmission system modification

do not use the original machine tool main motor, cut off the power source, hoist a set of external power system next to the machine tool, and connect the power supply

the substitute external power system is composed of motor, reducer and pulley. The motor is 10kW, 1400r/min, and the scrapped C620 lathe spindle box is used as the reducer

i1=1:3-- speed ratio of belt pulley from motor to reduction gearbox

i2=1:63-- speed ratio of reducer

i3=1:1-- speed ratio from reducer pulley to change pulley auxiliary pulley

i4=1:45--c650 spindle box speed ratio

after the above modification, the transmission chain of the machine tool:

n=1400 · I1 · I2 · I3 · (b/a) · (c/b) · I4

=0.01r/min

<2.2.4 modify the tool rest

remove the upper tool rest, install a mirror cutting power head, make a small carriage, fasten the milling power head to the carriage, and then install it on the dovetail guide rail of the middle tool rest, and wedge it with a wedge iron

2.2.5 workpiece installation

clamp the outer diameter of the workpiece with the claw, drill 8 equal cutting holes on the workpiece in advance, and align the sharp knife with the cutting holes during milling, then milling can be carried out

the above modification method is simple, which ensures the consistency of the tracks of the eight spiral grooves and the stability of the quality. After processing, remove various accessories and install the original tool holder, the machining performance of the machine tool can still be restored, and the accuracy will not be affected

3 use tk6916 CNC milling machine to process bisection arc grooves. There is a part named rotary table on our new product 1145 (z) radial tire vulcanizer, as shown in Figure 5. This part is provided with six equally divided arc grooves, and the design requires that the indexing error of the track center should not exceed 6 ', so we use tk6816 CNC milling machine for processing

3.1 process preparation

(1) because the workpiece is thin, we will spot weld two pieces together for processing

(2) to check the processing procedure, draw a cross line before processing, and draw the notch line and φ 18h8 hole line

(3) the processing sequence is: drilling the cutting hole -- rough milling the notch -- fine milling the notch -- clamping dumplings φ 18h8 hole

3.2 programming, processing steps and process parameters

(L) selection of programming origin

φ The center of 506h8 inner circle is the programming origin, and the X, y, Z axis directions are shown in Figure 5. Calculate the coordinates of each machining point according to this coordinate system

set the coordinate origin with the statement G92 XO yo Zo *

(2) drill the lower tool hole at one end of each slot

this process is used as a subroutine o1007

adopt drilling cycle, such as hole Ⅰ g81 g98 x371.095 y-3.672 z-95r-45 F20 *

φ 18 drill out, the spindle speed is s08=125r/min, and the feed rate is f20=20mm/min

(3) thick mirror notch, unilateral allowance 1mm

this process is used as a subroutine o2007

the cutting depth in Z direction is 3mm each time, and the cutting of the thickness in Z direction of the workpiece is completed in 9 times. During programming, the main program calls the subroutine M98 p92007 for 9 times. Each time, the Z axis moves down 3mm and the coordinate system is set, so as to achieve the purpose of feeding 3mm in the Z direction each time

o2007

n1 G92 x0 Y0 Z0 *

n2 G00 G90 x371.095 y-3.672 *

n3 m08

n4 G01 z-28 F100 *

n5 G01 z-33 F15 *

n6 G03 x208.11 y190.57 R300 F70 *

n7 G00 Z0 *

(N4 ~ n7: rough milling I groove)

N8 G00 x188.72 y319.54 *

·

·

·

(N8 ~ N31: rough milling other grooves)

N32 G00 Z-3 *

N33 M09 *

n34 G00 x0 Y0 *

N35 M99 *

tool selection φ 20. Because the milling cutter with three edges is rough machining, the old milling cutter can be selected. The rotation speed is s10=200r/min, and the feed rate is f70=70mm/min

(4) finish milling notch meets the drawing requirements

this process is used as a subroutine 03007

use φ 10. The groove is machined to the size of the drawing with a three edge milling cutter, and the reverse milling is adopted

for example, when finishing Notch 1, the motion path of the cutting tool is s-, where S-1 is the reading tool compensation section, as shown in Figure 6

n2 G00 G90 x167.867 y222.577 *

n6 G00 G17 G42 x213.182 y201.446 H01 *

n7 G01 Z-32 F50 *

n8 g022, starting angle during installation x382.691 y-0.564 r312 F100 *

n9 G02 x359.509 y-6.776 R12 F20 *

n10 G03 x203.038 y179.649 r288 F100 *

n11 G02 x213.182 y201.446 R12 F20 *

n12 G01 Z0 F150 *

the spindle speed is taken as s12=315r/min, When machining r312 and r288 circular arcs, the feed rate is f70=mm/min, and when machining R12 small circular arcs at both ends, the feed rate is f12=12mm/min

(5) processing φ 18h8 hole

adopts drilling cycle:

g81 98 x220 y440 z-85 r-45

when drilling, the speed is taken as s08=125r/min, and the feed rate is taken as f15=15mm/min

take s02=25r/min as the rotation speed and f20=20r/min as the feed rate when making dumplings

4 summary

our factory uses t612 boring machine to process bisector straight grooves, and C650 lathe to refit and process bisector Archimedes spiral grooves, which all meet the design requirements and ensure the machining accuracy of parts. Good results have been achieved in the production process of recent ten years. Practice has proved that it is a good method for ordinary machine tools to process bisector notches. In recent years, NC machine tools have been used to process bisection curve grooves, which can directly get out of the curve path through programming and machine tool performance, making the operation simpler and the machining accuracy higher. This will be the development trend of processing bisection straight grooves and curve grooves in the future. (end)

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