JPH0332574A - Manufacturing method for resin bond diamond or CBN wheels - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] A diamond or CBN wheel, as shown in FIG.
It is constructed by attaching a grindstone body 2. The grindstone body 2 in the resin bond wheel is formed by solidifying and molding diamond or CBN abrasive grains together with other fillers using a resin.

The present invention relates to a method for manufacturing this type of wheel.

[Prior art] A phenolic thermosetting resin is generally used as the main agent for resin bonding, and various filling powders are mixed with the bonding material powder, which is then mixed with diamond or CBN abrasive grains, filled into a mold, and processed. A grindstone body 2 having a predetermined size and shape is formed by applying pressure and heat.

The molding device is a mechanism that can also be called a breather molding device equipped with heating means. The molding temperature is 160°C to 200°C, the molding pressure is O*5 to 2 tons/-, and the press machine is 10 tons to 1000 depending on the size of the grindstone body to be molded.
Various capacities up to tons are used.

In the molding process, first, a mixed powder of bond material and abrasive grains is compressed under pressure, and as the temperature rises, the resin material becomes fluid and receives pressure, filling the space in the mold without any gaps. After maintaining the temperature necessary for polymerization and solidification for the necessary time, heating is stopped, and after cooling, the press is opened to take out the mold, and the molded product is taken out by disassembly.

During molding, a large amount of gas is generated from the resin material as the temperature rises. If gas remains in the molded product, it becomes bubbles, reducing the density and strength of the molded product, and sometimes gas pressure causes molten bond to flow out from gaps in the mold. To avoid this, a "degassing" operation is performed during the molding process. That is, the press is opened briefly to release pressure and eliminate gas. Gas escapes through gaps in the assembled mold. Repeat this operation several times intermittently.

The timing and number of degassing operations cannot be uniformly specified, depending on the bond composition, mold dimensions, structure, etc.
This will depend on the skill of the worker.

Due to the above-mentioned circumstances, it is generally not possible to obtain ideal characteristics in molded products. The characteristics of the molded product, that is, the grinding wheel body, are directly connected to the performance of the wheel, so the guaranteed performance of resin bond wheel products is set to a lower value than the ideal value, and it is unavoidable that the performance of the wheel wheel varies depending on the individual product. It is assumed that there is no such thing.

[Issues to be solved by the invention l111] 1 of the present invention! The problem is to provide a method by which resin-bonded wheels can be stably produced that guarantee the best performance.

[Means for Solving the Problems] It is impossible to prevent gas generation, and in order to prevent the above-mentioned adverse effects of gas, in the present invention, the entire molding process or a necessary part of the process is performed in a vacuum. It is something.

[For production] The operation of vacuum forming requires no explanation.

The generated gas is suctioned and discharged through the gap in the mold at the same time as it is generated, and does not accumulate in the molded body. This solves all of the problems mentioned above.

Table 1 shows the conventional method and resin bond with the same composition.
These are the properties of a molded article molded by the method of the present invention. The numbers in the table demonstrate that the method of the present invention significantly improves the specific gravity, hardness, and transverse rupture strength of the molded product compared to the conventional method.

Table [*Example] Since the molding temperature is up to 200℃ and the degree of vacuum is as low as 10-” Torr as shown in Table 1, it is difficult to configure the vacuum forming machine from the viewpoint of current vacuum technology. There isn't.

In the simplest configuration, as shown in Figure 1, the upper and lower 1%11
21 and 22 and the bellows 30 shape the height-variable sealed space and exhaust the inside.

111, the upper platen of the press is fixed to the base 15 by four pillars 13 and 14. A lower platen 12 is pushed up by a ram 17 of a hydraulic cylinder 16. Heat plates 21 and 22 are fixed to the upper and lower platens 11 and 12 via heat insulating plates 23 and 24, respectively.
The mold 25 placed between them is heated and at the same time press pressure is transmitted. The above configuration is equivalent to a molding machine generally used for conventional resin bond wheel manufacturing, and a bellows 3
0 (This is a configuration with additional vacuum equipment.

Note that the pressurizing means is not limited to the hydraulic cylinder 16, but various types such as an electric type can be used.

Metal rings 31.3 are attached to the upper and lower ends of the bellows 30, respectively.
2 and heat plate 21 through gaskets 33 and 34.
Hit 22. Further, an exhaust port 35 is provided in either of the rings 31 and 32, and is connected to a vacuum pump through an exhaust pipe (not shown).

Since there is a limit to the minimum height of the bellows when it is compressed, the first
In the configuration shown in the figure, the mold 25 must have a large height dimension T, which is a disadvantageous condition for heating the internal molded product by conduction from the heating plates 21 and 22. In addition, the press I/O requires a large stroke to open the press and push up the lower #32 of the bellows 30 to create a gap through which the height H of the mold can be passed.

As shown in FIG. 2, if the bellows 30 is placed in contact with the upper and lower platens 11 and 12 of the press machine, and the hot plates 21 and 22 are housed within the inner diameter of the bellows 30, the above-mentioned height restriction can be relaxed. There is no fear that the slats 33j34 will deteriorate due to heat.

However, the area of the platen becomes larger than the diameter of the mold 25.

Another method is to house the main parts of the molding machine in a vacuum container. FIG. 3 shows an example of a configuration in which a vacuum container 40 is fixed to the lower platen 12. Sliding portion 18 between lower platen 12 and columns 13 and 14
．． 19 vacuum seals, airtight doors for operating the inside of the container (not shown, the same applies hereinafter), etc., as well as power cotton for the heating plate, cooling head, and 4-clamp for the temperature measurement sensor, etc., penetrate the container wall. There are well-known methods and parts materials for airtightness, so there are no technical problems.

[Effects] Since the present invention performs the pressurizing and heating processes for molding a resin bonded diamond or CBN wheel in a vacuum, gases are suctioned out successively as they are generated, and do not interfere with the molding process. There are no air bubbles remaining in the molded product.

This eliminates the need for manual "venting" operations, and there is no influence from the surrounding air, so the best properties expected of the molded product can be obtained, providing a resin bond wheel f# that guarantees high performance. be able to.

[Brief explanation of drawings]

Fig. 1 is a front view of a vacuum forming machine implementing the manufacturing method of the present invention, Figs. 2 and 3 are partial front views showing other embodiments, and Fig. 4 is a front view of a diamond or CBN wheel. It is a diagram.

Claims (1)

[Claims] Resin bonded diamond or CBN characterized in that the pressurization and heating processes for forming the grindstone body are performed in a vacuum.
How to manufacture wheels.