JPH07237124A - Surface processing method of mold - Google Patents

Abstract

PURPOSE:To provide a glass product whose glass surface has few defects by equipping a dry type blast process in which the unevenness of a mold surface is apt to become sharp peaks but a uniform oxidized film can be generated, and a wet type blast process in which the unevenness of the mold surface is dulled without damaging the uniform oxidized film. CONSTITUTION:In the case of the surface processing (blast) of a mold to be used for the glass products or the like of a TV cathode-ray tube panel and a funnel or the like in a high temperature press industry field, by firstly administering a dry type blast process using a dry type blast material whose grain diameter is #100-#1000 (JIS standard JIS R600), a uniform oxidized film is generated although the unevenness of a mold surface is apt to become sharp peaks. Next, by administering a wet type blast process using wet type glass beads whose grain diameters are #100-#220, the unevenness of the mold surface is dulled without damaging the uniform oxidized film. In this instance, blast pressure at each blast process is set preferably within the range of 0.5-5.0kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment (blasting) method for molds used in the field of high temperature press industry such as glass for TV cathode ray tube panels and funnels. The present invention relates to a surface treatment method for a die for extending the die life (die life).

[0002]

2. Description of the Related Art It is a well known fact that dry blasting and wet blasting exist in blasting methods. Conventionally, for the purpose of simplifying the process, the mold blasting is performed by selecting either a dry process or a wet process.

[0003]

However, in the wet-only process, it is not possible to pre-form a sufficiently strong and homogeneous oxide film on the surface of the mold, which prevents uneven high temperature oxidation during pressing. However, there is a drawback that the surface of the mold is easily roughened and the mold life is shortened.

Further, in the dry process only, the peak of the roughness of the mold surface is too sharp, and defects are generated on the glass surface.
Insufficient cleaning after blasting may cause contamination, that is, crushing and sticking of finely pulverized blast material to the mold surface, and residual due to adsorption.

[0005]

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and a wet type glass having a particle size of # 10 to # 220 (according to JIS standard JIS R6001). Surface treatment of a mold comprising at least two types of steps, a wet blasting step using beads and a dry blasting step using a dry blasting material having a particle size of # 100 to # 1000. It provides a method.

Further, in the present invention, it is preferable that the blast pressure in the wet blast process and the dry blast process is 0.5 to 5.0 kg / cm ² . If the blast pressure is less than 0.5 kg / cm ² , the mold surface is likely to have uneven stipple, which is not preferable. Further, if it is larger than 5.0 kg / cm ^2, the glass beads of the blast material will be crushed and the particle size distribution will change because the glass beads are repeatedly used, so the desired R _z (average surface roughness) Will not be obtained. Further, the plating layer (10 μm to 20 μm) on the surface of the mold is also peeled off, so 5.0 kg / cm ² or less is preferable.

Further, it is preferable that the first stage is the dry blast process and the second stage is the wet blast process.

[0008]

In the present invention, since the dry blast in the preceding stage of the plural blasting steps is dry, the surface of the die becomes hot and a uniform oxide film is formed. The oxide film, once formed, is very stable and provides a good protective barrier against the subsequent non-uniform oxidation action, ie non-uniform oxidation of oxygen. Therefore, the life of the die can be dramatically extended as compared with a wet single process without pretreatment.

Also, since this alone tends to cause surface defects of the glass due to the sharp uneven surface, a wet glass bead process in the subsequent stage is used to overcome this, thereby making the glass product a dull surface and providing a glass product having no defects. It can be molded.

[0010]

EXAMPLES Examples of the present invention will be described below. The conventional single-step wet glass bead process has a drawback that the mold life is inevitably short. Therefore, the mold life can be extended by combining this with a dry process to form a plurality of blast processes.

The multiple blasting process is preferably a two-stage blasting process, and the preferred combination of the two-stage blasting process is the first stage is dry and the second stage is wet. When press-molding glass, it is important that the irregularities on the die surface are moderately blunted, and if there are sharp peaks, it easily becomes a surface defect. Wet glass beads have a spherical shape,
The order as described above is preferable because it is suitable for making unevenness on the die surface dull. In addition, it is known that when the dry process is performed in the first stage, the uniform oxide film once formed does not lose its properties in the next wet process, and it is possible to achieve the intended purpose. Is.

Further, there is an effect that the contamination which may occur in the first stage can be washed and removed by bringing the wet process into the third stage.

However, in consideration of contamination, a dry blast material (# 600 to # 10) having a small particle size.
If No. 00) is selected, there is no problem even if the wet method is applied to the first step and the dry method is applied to the second step. This is because, in that case, the so-called blast function for producing roughness is achieved by the first-stage wet glass beads.

Next, the preferred blast material, its particle size and processing pressure will be described below. Garnet or alundum is preferred as the dry blast material. The reason for this is that since it has a sharp shape, it has a stronger effect of biting into the mold surface than a spherical shape, and energy transfer loss due to repulsion on the surface is small, so a uniform oxide film can be easily formed. Because. The particle size is preferably # 100 to # 1000 (according to JIS standard JIS R6001), and the blast pressure is preferably 0.5 to 5.0 kg / cm ² .

On the other hand, as described above, as the wet blast material, glass beads having a spherical shape suitable for blunting a sharp peak are preferable. The particle size is # 10 to # 2.
No. 20 is preferable, blast pressure is 0.5 to 5.0 kg
/ Cm ² is preferred.

The first stage uses # 150 dry blast material (alundum) and the blast pressure is 1.5 kg / cm.
^The dry blasting process was performed at ² . Specifically, using a dry blast device, the dry blast material was jetted from a distance of 0.3 m for 12 minutes toward the surface of a stainless mold (TV CRT glass molding plunger: male mold). The injection direction of the blast material was substantially perpendicular to the surface of the mold, and the dry blast treatment was performed by scanning the entire surface of the mold.

A wet blasting process was carried out in the second stage using # 80 wet type glass beads at a blasting pressure of 2.5 kg / cm ² . Specifically, a wet blast device (made by Fujikikai) was used to spray the wet glass beads toward the surface of a stainless steel mold for 20 minutes from a distance of 0.6 m. The injection direction of the glass beads is substantially perpendicular to the surface of the mold, and the entire surface of the mold is covered by 10 cycles per cycle.
Wet blasting was performed by scanning for 2 cycles of 20 minutes per minute. In the wet blasting process, glass beads are mixed with water as a solvent at a ratio of 30% by volume to form a dispersion liquid, which is sprayed toward the mold surface together with the solvent during the blasting process.

At this time, the mold (plunger) has its molding surface (convex surface) facing upward and is rotating at a rotation speed of 17 rpm. While rotating the mold, the blasting material was sprayed from above with three vertical guns from above, and the blasting material was sprayed from one horizontal gun also from the horizontal direction to complete the wet blasting treatment. The above-mentioned blasting treatment from the horizontal direction is performed in order to intensively treat the side surface of the mold, and is performed under substantially the same conditions as the blasting treatment from the vertical direction.

By performing the above-mentioned treatment, the life of the mold is extended to about 3 times or more of the conventional one. Further, by selecting an appropriate wet glass bead diameter and making it have an appropriate roughness, the mold life can exceed 10 times that of the conventional one.

[0020]

Industrial Applicability According to the present invention, the dry blasting step in which the unevenness of the mold surface is likely to have a sharp peak but a uniform oxide film can be produced, and the wet blasting in which the unevenness of the mold surface is blunted and the uniform oxide film is not damaged. By combining with the process, glass products such as TV cathode ray tube panels and funnels with few defects on the glass surface after press molding can be manufactured. In addition, it has resistance to uneven high temperature oxidation during pressing, and the contamination of the mold surface is eliminated,
It has an excellent effect that the life of the mold is dramatically extended as compared with the conventional one.

Claims (3)

[Claims] 1. A wet blasting process using wet glass beads having a particle size of # 10 to # 220, and a particle size of # 100 to # 100.
A surface treatment method for a die, comprising at least two types of steps, a dry blasting step using a # 1000 dry blasting material. 2. The blast pressure in the wet blasting step and the dry blasting step is 0.5 to 5.0 kg / cm.
^{2. The} term claim 1 surface treatment method of a mold according. 3. The first stage is the dry blasting process, and the second stage is
The mold surface treatment method according to claim 1, wherein the step is the wet blasting step.