JPH01177924A - Manufacture of step roll - Google Patents

Abstract

PURPOSE:To simplify working processes by executing processes of cutting an outer diameter and circumferential grooves of material formed having a high rigidity layer of build-up welding along the outer circumference, of forming vertical grooves by cutting, and of forming small vent holes in the bottom of the grooves by a discharge process in series, while maintaining the high rigidity of the surface. CONSTITUTION:A process A of forming a layer of high rigidity build-up welding in the outer circumference, a process B of cutting its outer diameter, a process C of cutting circumferential grooves 73, a process D of forming vertical grooves 74 along the axis at constant intervals by cutting by one pass for one line, and a process E of forming small vent holes in the bottom of the grooves by a discharge process are executed in series, while the high rigidity of the surface of the material is maintained. By adjusting the thickness of the build-up welding, the layer of the high rigidity in the surface of a finished step roll 7 can be formed at a desired thickness, and because cutting and boring work are performed while maintaining the rigidity, a cutting process for compensation of distortion cause by a heat process can be eliminated, thereby processes can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing corrugated rolls for forming corrugated core paper (corrugator) of corrugated paperboard.

(Prior Art) A corrugated core paper of corrugated paperboard is processed into a corrugated shape by forming a tooth surface on the outer peripheral surface and passing the core base paper between a pair of mutually meshing corrugated rolls.

As shown in FIG. 9, the corrugating roll has a hollow large diameter portion (71) with small diameter shaft portions (72) protruding from both ends, and the large diameter portion has a vertical groove (72) extending over the entire length in the axial direction. ) 4) are formed at equal intervals in the circumferential direction, and furthermore, circumferential grooves (73) are formed at a predetermined pitch and perpendicular to each groove.

An air hole (75) is provided at the bottom of the groove for forcibly removing the core paper from the groove using air pressure.

This corrugated roll is required to have the following three mechanical properties: abrasion resistance, surface smoothness, and impact resistance.

Due to the ash content, the core paper has a scraping effect similar to fine sandpaper, and when the core paper passes between the corrugated rolls at high speed, the top of the corrugated rolls wears out, lowering the height of the step and shortening its service life.

The surface of the corrugated roll is required to have high hardness in order to withstand abrasion caused by the core paper.

Shishi "1Q" - Smoothness As with abrasion resistance, an effective means of reducing the abrasion and wear of the corrugating rolls caused by the core paper is to make the surface of the corrugating rolls as smooth as possible.

However, in the manufacturing process of corrugated rolls, gear cutting machines and tooth type grinders cut parallel to the axis of the corrugated roll, so cutting marks are created at right angles to the direction of movement of the core paper. Therefore, in order to finish the corrugated roll into a chevron shape, it is necessary to use abrasive grains as fine as possible in the grinding process to give the surface a smooth finish.

Chu 111 Minister 2 Hall! Hard foreign objects such as iron and stone are mixed in the core paper, and some quite large foreign objects can be found inside. When these hard foreign objects get caught between the corrugated rolls, a large impact is applied to the surface of the corrugated rolls.

Usually, the surface of the corrugated roll is plated with hard chrome, and the hardness of the plating layer is Hs95 or higher.

However, since the hardness of the base material itself is approximately Hs45, the hard chromium plating layer at the part where the foreign matter is caught is depressed by the impact of the hard foreign matter biting in the corrugated roll as described above, and surface peeling and chipping occur.

Corrugated rolls are required to have strength and toughness to withstand impact.

Corrugated rolls are manufactured by devising materials and processing methods to satisfy the above conditions as much as possible, and typically include hardened corrugated rolls and nitrided corrugated rolls.

The manufacturing method of the new hardened corrugated roll is as follows.

Finish turning the outer diameter of the material.

A circumferential groove (73) is formed in the material by turning.

A vertical groove (74) is cut by a bob machine.

Drill an air hole (5) using a drill.

The roll surface is quenched and tempered to increase surface hardness.

Finish grinding is performed on the vertical grooves (74).

Finish by applying hard chrome plating to the roll.

Corrugated rolls are made of expensive materials, so if their outer periphery wears out, they can be recycled and used again. The processing method for this recycled hardened corrugated roll is as follows: After annealing the material, the worn outer peripheral surface is turned to remove the tooth surface.

Perform sensual welding around the outer periphery of the material.

The material is softened and annealed.

From the next process onwards, the same manufacturing process as for the new corrugated rolls is carried out.

The purpose of performing tactile welding on the material is to compensate for the thickness of the turned material.

The material for corrugated rolls is generally JIS standard SCM440 (
Chrome molybdenum steel (Class 4) is used. SCM4
40 has high toughness and carbon content of 0.389g -0,
It is a material with good hardenability at 43%.

As mentioned above, since the material is quenched after gear cutting, increasing the quenching hardness will cause cracks and invisible cracks to occur, so the quenching hardness is kept around Hs70, and the quenching depth is about III+M.

After grinding to correct the bending and distortion of the rolls caused by quenching, hard chrome plating is applied to improve the surface slippage and create a hard film.

Since the recycled corrugating roll has a low base material hardness (around Hs45), as mentioned above, if the corrugating roll gets caught in hard foreign matter,
The impact causes the hard chrome plating layer on the surface to dent and the surrounding area to bulge.

In this case, the core paper may be torn if the surrounding bulges are not scraped off with a router or the like.

The manufacturing method of the nitrided corrugated roll is the same as the hardened corrugated roll described above, up to the step of drilling air holes, except that the surface hardness of the roll is increased by gas nitriding instead of hardening, and the roll is used without any post-processing.

In addition, in the processing of recycled corrugated rolls, the molten metal used during weld overlay is a material whose quality increases through nitriding, such as Nippon Steel Hard Co., Ltd.'s FVA-5B (carbon content of about 10.1%).
, 5-2 (carbon content 0.13%) are used, and these materials can be nitrided to create a hard surface with Hs of 90 or higher. However, the thickness of the nitride layer is 0.2~0.311
The hard nitride layer is 1 m long, and if lifting and grinding is performed on this thin nitride layer, the hard nitride layer will be scraped off.

Therefore, finish grinding is not performed after nitriding, so
Therefore, in order to prevent deformation during nitriding, it is necessary to completely remove internal distortion by complete annealing before nitriding.

When completely annealed, the hardness drops to about Hs45.

For this reason, even if the material surface is nitrided to form a surface layer with Hs of 90 or higher at rt'', the base is soft, and the hard but brittle thin nitrided layer on the surface of the corrugated roll peels off due to impact.

Peeling of the nitrided layer can be prevented by lowering the nitriding hardness, but in this case, the corrugated rolls become skewered more quickly due to insufficient hardness, resulting in a shorter life.

As mentioned above, hardened corrugated rolls and nitrided corrugated rolls do not fully satisfy the necessary mechanical properties as corrugated rolls, have high surface hardness and a thick surface hardened layer, and furthermore,
There has been a long-awaited need for a method for manufacturing corrugated rolls that can simplify the manufacturing process.

(Means for solving the problem) The present invention performs the necessary machining on a material subjected to high-hardness overlay welding while maintaining the surface hardness, resulting in a material with high surface hardness and a thick surface hardening layer. The purpose of this study is to clarify the manufacturing method of corrugated rolls that can be manufactured easily and the manufacturing process can be simplified.

In the present invention, the applicant proposes that since the performance of rolling rolls for steel manufacturing cannot be satisfied by quenching alone, a special roll with a high-hardness welding layer formed on the outer periphery is used, which can withstand severe usage conditions. Focusing on this, we considered applying this special roll to corrugated rolls for manufacturing corrugated paperboard.

The above-mentioned special roll has its outer periphery finished by turning to a desired diameter after high-hardness overlay welding, and it is known that turning can be performed on the high-hardness overlay welding layer.

However, it was necessary to research whether it was possible to process the vertical grooves and air holes in the corrugated roll without lowering the hardness of the built-up layer.

The hardness of the overlay layer is Hs80 or higher, and in gear cutting, materials with high tensile strength and high viscosity cannot be cut unless the hardness is Hs50 or lower.

Therefore, in view of the current situation where steel materials are easily cut with a thin disk-shaped grindstone, the applicant attempted to process vertical grooves using a grindstone.

Conventional common sense in grinding is that when the hardness of the base material is H57 (l), the maximum amount that can be ground in one pass is 5/100m, and if the hardness of the base material is Hs80 or higher, it is common sense that it is 2/100m. Yes, there was only that track record.

The applicant dared to carry out extensive experiments to break through the conventional wisdom, and succeeded in grinding and forming grooves with a depth of approximately 4.7+ua in one pass using a diamond or borazone-based rotating grindstone.

In addition, for the drilling of air holes, we focused on electrical discharge machining, which can be performed regardless of the hardness of the base material, and devised an electrical discharge machining device for drilling air holes in corrugated rolls, thereby efficiently drilling holes. succeeded in doing so.

The manufacturing method of the roll of the present invention includes a step of turning the outer diameter of a material on which a high-hardness overlay welding layer is formed on the outer periphery, a step of turning a circumferential groove on the material, and a step of grinding the material in one pass per thread. The process of forming vertical grooves extending in the axial direction at equal intervals in the circumferential direction, and the process of machining small diameter air holes at the bottom of the groove by electric discharge machining are carried out in a series, during which the high hardness of the material surface is maintained. Features (Operations and Effects) When performing high-hardness overlay welding on a material, the high-hardness layer on the surface of the finished corrugated roll can be formed to a desired thickness by adjusting the thickness of overlay welding.

Turning while maintaining the hardness of the high hardness layer on the roll surface.
In order to perform the perforation process, the rolls are hardened and
Grinding to correct warpage due to grinding to remove distortion caused in the material by tempering and quenching is omitted, simplifying the processing process.

(Example) In Examples, a method for processing recycled corrugated rolls will be described.

The corrugating roll is the same as that shown in Fig. 9 above, and the large diameter part (7
1) has a total length of 2000 mm, an outer diameter of approximately 400 mm, and 110 teeth. In addition, the corrugated roll (7) used in the implementation was an A flute (with the number of corrugations of the core paper being 36±3 per 30 cm).
JIS ``l 1516), and as shown in Figure 3, the tooth pitch is P9III11 and the tooth height H4.
, 68I, tooth ridge arc curvature rl 1.68mm, ? l
The I-base arc curvature r is 21.97, and the angle α formed by adjacent toothed teeth is approximately 49°.

Corrugated roll material SCM440 Overlay welding material NH-180 (product name) (Nippon Steel Hard Co., Ltd. uses a high-grade alloy material used for overlay welding and recycling of steel mill rolls, improved for corrugated roll recycling. The second Eli is a heavy grinding device that creates vertical grooves in a roll in one pass by grinding.

The structure of the grinding device itself is not much different from a conventional grinding device that performs a polishing process after gear-cutting vertical grooves.

Support stands (81) and (82) that rotatably support both ends of the roll (7) are provided at both ends of the base (8), and one support stand (81) is equipped with a rotary indexing device (not shown). is built-in.

A guide wall (83) is erected in the longitudinal direction of the base (8), a guide groove is opened in the lateral direction in the guide wall, and a grinding head (85) is slidably disposed in the guide groove. A traveling drive device (not shown) is connected to the head.

The rotating grindstone (80) is attached to the head (85) using the shaft (86).
) is arranged to be able to be raised and lowered, and the shaft is linked to a lifting device (not shown) provided within the head.

Further, a nozzle (87) for supplying grinding oil toward the grinding section 111 is attached to the head (85).

The grindstone (80) attached to the shaft (86) is
It is formed by electrodepositing borazone abrasive grains on the surface of a protrusion (sob) formed around the outer periphery of a metal disk (80a) with a diameter of 5601 mm and a width of 19 mm to correspond to the groove shape of the corrugated roll. .

Both sides of the protrusion (801+) correspond to the shape of the arcuate top of the tooth of the corrugated roll (7), and borazone abrasive grains are also electrodeposited on these parts.

FIG. 5 shows an electrical discharge machining device for forming air holes in corrugated rolls by electrical discharge machining.

The electric discharge machining apparatus of the embodiment uses a plurality of thin rod-shaped electrodes (4) to form circumferential grooves (7) arranged in parallel in the axial direction of a corrugated roll (7).
3) At the same time, as many air holes (75) as there are electrodes are bored on the top.
Each time the perforation is completed, the corrugated roll (7) is rotated by a predetermined angle by the rotary indexing device (6), and air holes (75) are sequentially perforated in the circumferential direction of the roll.

The device main body (1) of the electric discharge machining device includes a lifting drive device (10
), a long plate-shaped electrode support plate (2) is disposed horizontally, and a hollow spindle (21) is rotatably disposed vertically through the chain plate.

The arrangement interval of the spindles (21) is the circumferential groove ( ) 3 of the corrugated roll.
) corresponds to the interval.

As shown in Fig. 6, the lower end of the spindle (21) is provided with a collet chuck (22) that holds the rod-shaped electrode (4) in a removable and liquid-tight manner, and the upper end of the spindle (21) is provided with a rotating sleeve (26). Processing fluid supply tube (25) through
is connected.

The machining fluid supply tube (25) is the machining fluid supply device (53)
is connected to the spindle (21) to supply machining fluid into the spindle (21).

A rod-shaped electrode (
4) has a diameter of 3 to 3.5 mm and has a through hole (not shown) in the axial direction, and the machining fluid supplied to the spindle (21) is T! :, ejects from the tip of vfl(4).

A gear (23) is fitted and fixed to the upper part of the spindle (21), and the gear (23) (2) of the adjacent spindle (21)
3) They mesh with each other, and the rotary drive device (24) is linked to the gear of the spindle (21) at the end.

A guide plate (3) is provided below the electrode support plate (2) parallel to the chain plate so as to be movable up and down, and an elevating drive device (35) is connected to the guide plate (3).

A through hole (30) is formed in the guide plate (3) directly below each spindle (21), and a guide sleeve (30) is formed in the through hole.
31) is fitted and fixed, and the electrode (4) is slidably fitted into the guide sleeve (34).

Peripheral walls (32) made of an elastic material are formed to hang down from both longitudinal side edges and both end edges of the guide plate (3).

In the example, Zhou! (32) is made of closed-cell neorene sponge, and the lower edge of the hanging part from both ends of the guide plate (3) is hollowed out in an arc shape corresponding to the arcuate curvature of the large diameter part (71) of the corrugating roller. (32a).

Machining liquid supply ports (33
) is opened, and the machining fluid supply device (53) is connected to the supply port (33) via a hose (34).

A dish (5) is provided below the guide plate (3) as a processing liquid receiver.

The plate (5) of the receiver is formed into a rectangular shape, and the total length is the same as the corrugated roll (7).
) is slightly longer than the entire length of the large diameter portion (71) of the corrugated roll (7), and its width is slightly larger than the diameter of the large diameter portion () 1) of the corrugated roll (7).

In the receiver, the bottom surface of the dish (5) and the processing liquid supply device (53) are connected by a pipe line (51), and a strainer (54) is provided at the pipe connection part of the dish (5). There is.

There are bearing parts (61) (6) on both sides of the tray (5) that removably and rotatably support the shaft parts at both ends of the stepped roller (7).
1) is installed, and one of the bearings is a rotary indexing device i! (
6) is also used.

Incidentally, the electrical connection between the corrugated roll (7) and the electrode for electrical discharge machining is the same as known technology, so the explanation will be omitted.

Next, the processing procedure for recycled corrugated rolls will be explained.

(1) Annealing of the material A corrugated roll (hereinafter referred to as the material) whose tooth surface on the outer periphery is worn is annealed to soften the material, adjust the crystal structure, and remove internal stress.

(2) External turning of material Completely remove worn tooth surfaces by turning.

(3) High-hardness build-up welding (No. 111 ZA) The build-up welding material (NH-180) is applied to about 1
It is completely fused to the base material to a thickness of 0a+m, the hardness of the entire build-up layer is made I (sso~84) by precipitation hardening heat treatment, and the tensile strength is made to be about 183Kg/12.

(4) Outer diameter turning and circumferential groove machining (Fig. 1B) The excess welded metal is scraped off, the outer diameter is accurately finished to the calculated dimensions, and the circumferential groove (73) is further machined.

The turning process in the steps (2) and (3) above can be performed using a special cutting tool, and has already been carried out by turning the outer periphery of a rolling roll.

(5) Vertical groove processing (FIG. 1D) Next, vertical grooves ( ) 4) are formed by grinding in one pass per thread using the grinding device.

Grinding line f'I - Outside diameter of Borazon grinding wheel 5601111 Number of revolutions of Borazon grinding wheel 1480 rpm Grinding speed of Borazon grinding wheel (lateral movement speed of Borazon grinding wheel) 380 n+m/min Temperature of cooling oil 30~b Under the above conditions, 1 pass per thread Grind the vertical groove (74) with
Each time one groove is completed, the roll is rotated by one pitch of the groove by the rotary indexing device, and 110 grooves are sequentially processed.

(6) Air hole drilling process (Fig. 1D) Air holes (
75).

As shown in Figure 5, the receiver of the device is a corrugated roll (7) placed on a tray (5).
and connect the corrugating roll (7) to the rotary indexing device (6).

The guide plate (3) and the TiS support plate (2) are lowered, and the peripheral wall (32) hanging down from the lower surface of the guide plate (3) is pressed against the large diameter portion (71) of the corrugating roll (7).

Next, the processing fluid supply bag! (53), from the supply port (33) of the guide plate (3) and the tip of the rod-shaped electrode (4), the surface of the roll is surrounded by the peripheral wall (32) and the guide plate (3). Fill the space with machining fluid.

Is the spindle (21) not rotating in the above condition? ,
Gradually lower the electrode support plate (2) and at the same time lower the electrode (4)
An electric discharge is generated between the corrugated roll (7) and the corrugated roll (7), and an air hole (74) corresponding to the diameter of the electrode (4) is opened in the corrugated roll (7).

As the spindle (21) rotates, the electrode (4) rotates and discharges between it and the corrugated roll (7), so the electrode (4) does not bend and bite into the roll, and the air holes are drilled straight. will be established.

A tooth surface is formed on the surface of the corrugated roll (7), and even if the sponge peripheral wall (32) is pressed against the roll surface, it cannot be pressed completely liquid-tight, and the machining liquid leaks from the surface of the tooth surface. Since the liquid leaks, the supply of machining liquid from the electrode (4) and the supply port should be continued.

Nao, Zhou! (32) Prepare an outflow hole in advance to drain the machining fluid.
It is also possible to drain it out and circulate it.

Therefore, the machining fluid in the peripheral wall (32) is constantly replaced, and the machining fluid jetted from the tip of the electrode (4) also discharges molten waste from the machining area together with the machining fluid, so that the machining fluid is always clean. A good discharge condition is maintained in contact with the machining fluid.

Zhou! The machining liquid leaking from (32) flows along the surface of the large diameter part (1) of the corrugated roll (7), collects in the tray (5) in the lower receiver, and prevents the shaft at the end of the corrugated roll (7). Rotating indexing device!
It does not flow to the (6) side, and there is no need to consider waterproofing the indexing device (6) against the machining fluid.

The machining fluid dropped onto the tray (5) passes through a strainer (54), is cleaned, and is returned to the machining fluid supply device (53) for circulation.

When one row of holes is completed, the guide plate (3) and the electrode support plate (2) are raised, the corrugating roll (7) is rotated by a predetermined angle by the indexing device (6), and in this state, the above-mentioned Repeat the operation to perform the drilling process.

When the guide plate (3) is raised, the machining fluid in the peripheral wall (32) flows down the surface of the roll all at once, but even in this case, it does not flow out to the indexing device (6) along the shaft at the end. There isn't.

By repeating the above operations, the axial direction of the corrugating roll (7) and
A large number of air holes can be opened in the circumferential direction accurately and efficiently regardless of the hardness of the roll.

(7) Vertical groove finish grinding Although it can be used as a single-stage roll once the air holes have been drilled, in this example, in order to finish the tooth surface of the corrugated roll even more smoothly, the tooth surface is processed after conventional cutting groove machining. Similar to the polishing process, polishing is performed using a finishing rotating whetstone.

(8) Hard chrome plating processing In the embodiment, chrome plating is applied to the surface of the corrugated roll to form a hard plating layer with Hs of about 95 to 100 on the surface of the corrugated roll.

As described above, recycled corrugated rolls are completed using a processing method that changes the conventional processing process for recycled corrugated rolls.

With the processing method according to the present invention, when performing high-hardness overlay welding on a material, the high-hardness layer on the surface of the corrugated roll can be formed to a desired thickness by adjusting the thickness of the overlay welding.

In addition, even when hard chrome plating is applied to the surface of the corrugated rolls, the hardness of the material itself is high, so even if hard foreign matter in the core paper gets caught between the corrugated rolls, the plating layer will not dent like in conventional methods. There is no risk that the surrounding area will become excited.

In the present invention, in order to perform outer diameter turning, circumferential groove processing, vertical groove processing, and air hole drilling processing while maintaining the hardness of the high hardness layer on the roll surface, the roll is hardened and Grinding to remove distortion caused by hardening is not necessary, simplifying the processing process.

Figure 4 shows the shape of the tooth surface of the corrugating roll to form a B flute with 51±3 steps per 30 cm of wavy stepped portion of the core paper, and the tooth surface is formed in one pass per thread as described above. This is the cross-sectional shape of the tip of the Borazon grinding wheel.

Corrugated roll tooth pitch P 6.053 mm, tooth height H 2.4+m, tooth tooth circle? Ar 1.23+*m, groove bottom arc r21.5 (Ins, the angle between adjacent teeth is approximately 61
°.

Also, the grinding conditions for B flute are Borazon grinding wheel grinding 11
11 speed (lateral movement speed of Borazon grinding wheel) is 508 +n
+n/min, and the other conditions are the same as in the case of the A flute.

When carrying out the present invention, when grinding the grooves of the corrugated roll in one pass, it is also possible to rotate the borazon grindstone at a fixed position and move the roll in the axial direction. In short, it is possible to move the rotating grindstone and the roll relatively in the axial direction of the roll.

Furthermore, the present invention is not limited to the configuration of the embodiment,
Various modifications are possible within the scope of the claims.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the manufacturing procedure of corrugated rolls, Fig. 2 is an oblique view of the grinding device, Fig. 3 is a sectional view of the tip of the A-flute corrugated roll and Borazon grindstone, and Fig. 4 is the B-flute corrugated roll and A sectional view of the tip of the Borazon grinding wheel, Fig. 5 is a slope view of the electrical discharge machining device, and Fig. 6 is a front view of the electrode support part of the electrical discharge machining device.
Figure 7 is a slope view of the guide plate and surrounding wall, and Figure 8 is a slope view of the area near the guide plate and peripheral wall.
FIG. 9 is a cross-sectional view taken along the line ■-■, and FIG. 9 is an oblique view of the corrugated roll.

Claims (1)

[Claims] (1) The process of turning the outer diameter of the material with a high-hardness build-up weld layer formed on the outer periphery, the process of turning the material to form a circumferential groove, and the process of grinding the material with one thread and one pass in the axial direction of the material. The process of forming extending vertical grooves at equal intervals in the axial direction, and the process of machining small diameter air holes in the groove bottom by electric discharge machining, are carried out in a series, and the process is performed while maintaining high hardness of the material surface. A manufacturing method for corrugated rolls.