WO2015166589A1

WO2015166589A1 - Molten-glass-cutting shear blades

Info

Publication number: WO2015166589A1
Application number: PCT/JP2014/062204
Authority: WO
Inventors: 達雄林; 直樹横手; 亜希金子
Original assignee: 東洋ガラス株式会社
Priority date: 2014-05-02
Filing date: 2014-05-02
Publication date: 2015-11-05
Also published as: JP5652981B1; JPWO2015166589A1

Abstract

Provided are shear blades that are less likely to produce shear marks or top lines/top bubbles and can allow for longer intervals between shear blade replacements when gob-cutting. The molten-glass-cutting shear blades (1, 2) have hard layers (10, 20), which are harder than the base material and are provided only at the surfaces where the pair of blade edges will come into mutual contact. The blade back portions which come into contact with the glass and have no hard layer become worn in gob-cutting while the hard surfaces of the blade edges are preserved; thus, the shear blades are sharpened from the black back portions and the sharpness of the blade edges is preserved .

Description

Shear blade for cutting molten glass

The present invention relates to a molten glass cutting shear blade for cutting molten glass continuously supplied from a glass melting furnace.

In general, a glass product such as a glass bottle or glass tableware is a molten glass lump of a predetermined size obtained by cutting molten glass continuously supplied from a glass melting furnace with a pair of horizontal reciprocating shear blades. As a gob, it is dropped into a mold provided below and formed into a glass bottle, tableware or other glass product.
The shear blade has a flat curved concave shape as shown in FIG. 1, the blade tip has an acute cross section, and a pair of cutting blade portions intersect to cut the molten glass. The temperature is high at 1000 ° C. to 1400 ° C., and the cutting blade portion is also hot, so it is easy to wear. If worn, the cut end of the gob becomes defective, and this causes streaky shear marks to remain in the product. In the case of forming a glass bottle, as shown in FIG. 9, a streak 33 is formed on the top 30 or bottom 32 of the glass bottle, or a bubble 34 (particularly what can be formed on the top of the glass bottle is referred to as a top or top). ) Occurs and the product is defective.
Therefore, conventionally, in the inspection process following the molding process, these shear marks, top bars, and top bubbles are detected by a sensor to eliminate defective products, and when the detection rate exceeds a certain level, the production line is stopped and the shear blade Have been replaced. Frequent replacement of the shear blade involves a problem that the production line is stopped each time, resulting in a decrease in productivity and an increase in the cost of the shear blade.
For this reason, the cause of shear marks, celestial muscles, and bubbles is not necessarily clear except for obvious blade wear, but it is thought to be due to a decrease in shear blade cutting performance. Various proposals have been made from the surface of the shear blade material, the surface of the blade edge, and the like.

In terms of material, the shear blade is generally made of high-speed tool steel, super steel alloy, ceramic, or the like. For example, at least the cutting blade portion is made of a Co-based alloy having a specific composition (see Patent Document 1). ), A Ni-base-Cr alloy base material formed with Cr, Affi and Ti oxides in a mixed layer state (Patent Document 2), made of ceramics capable of electric discharge machining, and R0 at the cutting edge. .05-0.3mm rounded (Patent Document 3), with a cutting edge made of ceramic having a curved shape fixed to the lower step formed at the tip of a metal support as the shape and configuration of the cutting edge (Patent Document 4) and the like are known.

Japanese Patent Laid-Open No. 61-183431 Japanese Patent Laid-Open No. 03-242328 JP-A-1-148719 JP 63-55124 A

Conventionally, in gob cuts, shear blades are replaced when the number of rejects due to the occurrence of shear marks or the generation of top bubbles or streaks exceeds a certain number in the subsequent molding of containers and the like. Conventionally, various causes have been proposed as described above to maintain the wear and sharpness of the shear blade, assuming that the cause is the wear of the shear blade. However, a satisfactory solution has not yet been achieved.
Therefore, the present invention provides a shear blade that can suppress the occurrence of shear marks and the generation of bubbles and streaks more effectively than conventional methods by a simple method, and can increase the replacement interval of shear blades in gob cuts. With the goal.

The shear blade for cutting molten glass of the present invention for solving the above-mentioned problem is a shear blade for cutting molten glass that cuts molten glass continuously supplied from a glass melting furnace with a pair of blades, The base material is a shear blade made of a hard material, and a hard layer harder than the base material is provided only on a surface where a pair of cutting edges touch each other.
The hard layer preferably has a thickness of 5 to 50 μm.
The hard layer can be formed by discharge coating, plasma spraying, PVD method or the like.
Further, the hard layer is not particularly limited as long as it is a harder material than the base material. For example, if the base material is a high speed steel, tungsten carbide that is harder than the high speed steel, Boron, titanium carbide, etc. can be used.

According to the present invention, a hard layer that is harder than the base material is provided only on the contact surface side of the lower blade and upper blade of the shear blade, and the blade back portion that comes into contact with the glass does not have a hard layer, so Although it gradually wears due to repeated contact with the molten glass, the hard layer on the upper surface is maintained with less wear than the back of the blade, and as a result, the blade back is always ground and the sharpness of the blade edge is maintained. As a result, in spite of a very simple configuration, the shear mark and the ceiling can be used even for a long period of time, compared to the case where the hard layer is applied on both sides or the blade edge is made of a material different from the base material. There is no generation of streaks and sky bubbles, and productivity can be dramatically improved.

It is a top view of the lower shear blade of a pair of shear blades according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the upper and lower shear blades at a position corresponding to AA in FIG. It is the schematic diagram which has cut | disconnected the molten glass. It is a blade edge | tip sectional drawing of the shear blade which shows the abrasion state of the blade edge | tip of the conventional shear blade. It is sectional drawing of the shear blade which concerns on the comparative example which formed the hard layer in the blade edge | tip whole surface of a comparative example. FIG. 3 is a cross-sectional schematic view of a blade edge showing a state of wear of the blade edge of the shear blade of Example 1. 4 is a graph showing the wear state of each lower blade and upper blade in four sets of shear blades in Example 2. It is a graph which shows the abrasion state of each lower blade and upper blade in four sets of conventional shear blades. (A) and (c) show an example of the top bubble in the glass bottle, (b) and (d) show an example of the top line, and (e) shows an example of the shear mark on the bottom of the glass bottle.

1: Shear blade (lower blade)
2: Shear blade (upper blade)
5: Shear blade body 10, 20: Hard layer 11, 21: Virtual line representing wear surface 15: Molten glass lump 23 _1, 23 ₂ : Blade edge surface

In order to solve the above-mentioned problems, the present inventor examined the causal relationship between the occurrence of the top and top bubbles and the wear of the blade edge of the shear blade. The survey was used for 5 days to examine the occurrence of the top and top bubbles and the state of wear of the blade edge. FIG. 8 shows the result of measuring the wear state of the blade edge. This figure shows the cutting edge cross section of the center line of the shear blade in a state in which the lower blade and the upper blade are compared with each other. The x-axis represents the cutting edge axial distance and the y-axis represents the height direction distance. Is enlarged 10 times.
In FIG. 8, A and B show shear blades where a large amount of top and top bubbles are generated, and C and D are shear blades where the generation of top bubbles is small. However, when the cutting edge is worn, A, B and C, D There was almost no difference. In both cases, it was observed that the cutting edge was bent. Therefore, from this experimental result, it cannot be said that the occurrence of the top and top bubbles is caused by the wear state of the cutting edge or the cutting edge, and the conventionally proposed reduction of the cutting edge wear or cutting edge. It has been found that the measures to reduce (for example, make the cutting edge harder material) cannot prevent the generation of the top and top bubbles over a long period of time.

As a result of further research based on this knowledge, it was found that the cause of shear marks, celestial muscles, and bubbles is the sharpness of the blades rather than the blade wear and the blade droop. That is, the sharpness of the shear blade gradually decreases as the shear blade continues to be used. The reason why the sharpness of the shear blade deteriorates in a short time is considered to be due to the following phenomenon.
The high-speed tool steel SKH2, which is often used for shear blades, has sufficient hardness with Rockwell hardness HRC65, but softens beyond the tempering temperature of 650 ° C by cutting the gob between 1150 ° C and 1200 ° C. To do. Softened blades are easily deformed, and the blades become thin due to wear due to contact and rubbing between the blades, the deformation is promoted, and the surface per blade cannot be maintained. As a result, not only a gap is generated between the blades, but also the blade itself is worn and the cutting edge becomes rounded as indicated by a broken line 41 in FIG. As a result, it has been found that the cut of the gob is worsened and the cause of the occurrence of a shear mark in the product.

Based on this knowledge, in order to alleviate the phenomenon, an experiment was conducted with the idea of forming a hard layer on the blade edge contact surface 53 and the blade back surface 54 of the

blades

51 and 52 as shown in FIG. ).
However, the shear blade had a hard layer on the front and back, so that the wear rate of the contact surface and the blade back during cutting of the gob was reduced, and the replacement time could be slightly extended. Prior to the wear of the back part, the wear of the contact surface progressed, and as a result, the blade edge was worn and rounded, and a shear mark, a celestial streak and a sky bubble were generated, and the initial purpose was not achieved.

As a result of further research based on this phenomenon, surprisingly, the hard layer is provided only on the contact surface of the blade and the blade, and the hard layer is not provided on the back surface of the blade. In particular, it has been found that the occurrence rate of shear marks, celestial muscles, and foams can be reduced, and the replacement interval of shear blades can be increased, and the present invention has been achieved. The reason is not necessarily clear, but the following mechanism is conceivable.
In gob cutting, in FIG. 3, the wear resistance of the contact surfaces of the lower blade 1 and the upper blade 2 is maintained by the

hard layers

10 and 20, respectively. On the other hand, since the back surface of the blade in contact with the molten glass lump 15 does not have a hard layer, it gradually wears out due to contact with the molten glass as indicated by

virtual lines

11 and 21 in FIG. The amount of wear is kept low. As a result, the blade is always ground from the back of the blade, and the sharpness of the blade edge is maintained.
On the other hand, as shown in FIG. 5, when a hard layer is provided on the entire blade edge or both the front and back surfaces, only the contact surface side where the blades come into contact with each other wears, and the blade back side that comes into contact with the molten glass hardly wears. As a result, the grinding effect is lost, the smoothness is lost due to wear on the contact surface side, the cutting edge is gradually rounded and the cutting becomes worse, and as a result, a shear mark is generated on the gob.

1 to 3 show an embodiment of a shear blade according to the present invention, FIG. 1 is a plan view of a lower shear blade 1 of a pair of shear blades, and FIG. FIG. 3 is a schematic view of the molten glass being cut.
For the shear blade 1, a material used for a known shear blade such as high-speed steel, other alloy steel, cemented carbide such as WC, ceramic, or the like can be used as a base material of the shear blade body 5. And in this invention, as shown in FIG. 2, the

hard layers

10 and 20 harder than a base material are given only to the surface where a pair of blade edge | tips of the shear blade

main bodies

5 and 5 mutually contact, respectively, It is characterized by the above-mentioned. It is. The hard layers 10 and 20 are not particularly limited as long as they are harder than the base material. For example, if the base material is high speed steel, tungsten carbide, boron, titanium carbide, ceramic powder, or the like that is harder than the high speed steel can be employed. The hard layer preferably has a thickness of 5 to 50 μm, more preferably 15 to 25 μm. If the hard layer is thinner than 5 μm, the effect as the hard layer is thin, and if it is 50 μm or more, the effect as the hard layer is saturated, and conversely if the hard layer becomes too thick, the grinding effect decreases, so the above range Is desirable.

The hard layer can be formed by discharge coating, plasma spraying, PVD method, diffusion penetration into the substrate, or the like. For example, plasma spraying is less affected by heat on the substrate and can form a hard layer well. However, in order to improve the adhesion of the hard layer to the substrate, the surface of the substrate is roughened. It is desirable to apply. Further, the substrate is not limited to metal, and ceramic or the like can be used.

Example 1:
1. Shear blade configuration Base material: High-speed steel (SKH12)
Hard layer: A tungsten carbide layer having a thickness of about 20 μm was formed only on the blade contact surface by means of tungsten carbide discharge coating.
2. Gob cutting conditions Cutting speed: 11.5 cuts / minute (approximately 800,000 cuts over 5 days)
Gob temperature: 1160 ° C
Overlap: 1.3mm
Under the above conditions, the wear state and the sagging state of the cutting edge were observed after using the above-mentioned 5 days for cutting the gob. As a result, the wear / sag state of the cutting edge at the center position of the blade edge was worn about 0.9 mm in the horizontal direction after use from the state before use, but the sharpness of the blade surface was maintained, and the molded product In addition, the occurrence of shear marks, celestial muscles, and bubbles is stable at 0.2% to 0.4% even after repeated continuous cutting for 5 days, and it can be cut without problems without adjusting the shear blade. We were able to. And according to the present Example, it was in the state which can still be used enough after use for 5 days.
FIG. 6 schematically shows the state of wear of the cutting edge in the AA cross section of FIG. 1. The portion indicated by the broken line is the portion worn after cutting 800,000 times from the start of use, and the cutting edge of the shear blade main body 5 is shown. surface 23 ₁ before the start of use is a surface connecting the hard layer side (blade contact surface side) distal end a ₁ and the blade rear tip b _1, a cutting edge angle theta _1. By repeating the cutting of the molten glass from this state, the blade back surface 24 having no hard layer rather than the blade contact surface side repeats contact with the molten glass, so that the amount of wear is large, and the blade edge surface 23 connecting a ₂ and b _2. ₂ and the blade edge angle became a sharper θ ₂ . That is, the same effect as the grinding effect was achieved and the cutting edge became sharper. Note that the sharpness of the blade edge is maintained by satisfying the relationship of θ ₂ ≦ θ ₁ .

Example 2:
For the four sets of shear blades obtained under the same conditions, gob cutting was performed under the same conditions, and the wear and sharpness of the upper and lower blades of each set were observed.
1. Shear blade configuration Base material: High-speed steel (SKH12)
Hard layer: A tungsten carbide layer having a thickness of about 20 μm was formed only on the blade contact surface by means of tungsten carbide discharge coating.
2. Gob cutting conditions Cutting speed: 15.1 cut / min (about 1.3 million cuts in 6 days)
Gob temperature: 1145 ° C
As a result, as shown in the graph of FIG. 7, the four sets of shear blades were almost evenly worn, and the blade edge was not rounded and maintained in a sharp state. No increase in muscle or sky foam was observed. After 6 days of use, re-coating treatment was performed by tungsten carbide spraying, and the use was continued for 10 days (about 2.7 million cuts), but all 4 sets could be used without any problems. In the figure, the wear amount (g) was defined as the difference between the shear blade weight before the start of cutting and the shear blade weight after completion of 1.3 million cuts.

Comparative Example 1
The target is 800,000 cuts of molten glass in 5 days under the same cutting conditions as in Example 1 with two sets of shear blades made of the same base material and shape as in Example 1 except that there is no coating layer on the front and back surfaces of the cutting edge Disconnected.
As a result, from the start of cutting until the 2nd day, the occurrence of natural muscles and bubbles changed from 0.2% to 0.4%, but increased to 0.6% on the 3rd day. The overlap amount and tension of the blade were adjusted. As a result of the adjustment, the condition of the top and bottom bubbles temporarily decreased to 0.2-0.4%, but then increased again to 0.6%. Cutting with the blade was stopped. That is, according to Comparative Example 1, the blade edge was worn and deteriorated by use for 3 days, the sharpness was lowered, and the occurrence of the top and top bubbles increased. As for the other set, after the start of use, when the condition of the celestial muscles / foam bubbles rose to 0.6%, replacement was resumed with a new one. Since the occurrence of streaks and sky bubbles increased to 1%, the line was stopped and the shear blade was replaced.
About 0.15 mm of wear (vertical direction on the blade contact surface side) and roundness of the blade edge were observed after the cutting.

Comparative Example 2
A shear blade having the same base material and the same shape as in Example 1 was coated with tungsten carbide discharge coating on the entire blade edge as shown in FIG. 5 to form a hard layer having a thickness of about 20 μm. With the obtained shear blade, the molten glass was cut under the same conditions as in Example 1.
As a result, there was no occurrence of shear marks or top / foam bubbles on the product, but the blade state was about 0.2 mm of wear on the contact surface side blade edge, and the blade back side was due to contact with the gob No wear was observed. As a result, the blade edge was rounded, and who was observed.
In Example 1 and Comparative Examples 1 and 2 above, when the molten glass was cut in a weak and strong state of the shear blade, the blade contact surface after the completion of the above number of cuts, the wear state of the blade back, Table 1 shows the results when the sharpness of the cutting edge was observed. As shown in Table 1, in the case of Example 1, it can be seen that the sharpness of the blade edge is maintained as compared with Comparative Examples 1 and 2.

In the shear blade of the present invention, the base material is not limited to a metal material, and a ceramic material can also be used. The hard layer only needs to be a material harder than the base material. Since the molten glass can be cut well so as not to generate shear marks, celestial muscles, and bubbles, the industrial applicability is high.

Claims

A shear glass cutting shear blade for cutting molten glass continuously supplied from a glass melting furnace with a pair of blades, wherein the base material is made of a hard material, and the base material is formed only on a surface where the pair of blade edges touch each other. A shear blade for cutting molten glass, characterized in that it is provided with a harder layer.
The shear blade for cutting molten glass according to claim 1, wherein the thickness of the hard layer is 5 to 50 µm.
The shear blade for cutting molten glass according to claim 1 or 2, wherein the hard layer is formed by discharge coating or thermal spraying.
The shear blade according to any one of claims 1 to 3, wherein the base material is high-speed steel, and the hard layer is made of one selected from tungsten carbide, boron, and titanium carbide.