JPH0224050A - Method and device for machine polishing with less surfacing affected layer to be generated - Google Patents

Abstract

PURPOSE:To extremely thin the thickness of a work affected layer and to increase the smoothness of the finishing surface thereof by pressing the rotating roll for polishing with an elastic material as its polishing face to the face to be polished by a specified pressure and polishing with feeding a specified polishing liquid to this pressing part. CONSTITUTION:A rotating roll (brush) 1 for polishing of an elastic material is pressed by the pressure of 3kg/cm<2> or less to the face to be polished of the body 2 to be polished. In this state, the face to be polished is smoothly subjected to polish finishing by this rotating roll 1 with feeding the polishing liquid contg. a fine abrasive grain of >=No.240 grain size at the rate of 15-60 for 100 liquid at wt.% to the vicinity of the face to be polished and the polishing rotating roll 1 getting into contact, namely to the pressing part of the rotating roll 1 from a mixture tank 4 with a stirring device 5, and the thickness of the work affected layer is extremely thinned.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of grinding or polishing the surface of a metal plate, etc., and an apparatus used therefor, particularly for X-rays in which it is necessary to prevent the occurrence of surface finishing degree ljtrM as much as possible. It can be advantageously used for preparing samples and samples for electron microscopy, and for grinding and polishing materials sensitive to strain such as Ts and magnetic steel plates.

<Conventional technology> Conventional equipment for grinding 1-polishing metal surfaces is equipped with an abrasive-containing whetstone or an abrasive-containing brush, and since the strain-affected layer extends several tens of micrometers from the plate surface, the strain layer becomes a hindrance. In this case, it was necessary to use strain-free polishing such as chemical polishing or electrolytic polishing after grinding and polishing.

Since such chemical polishing and electrolytic polishing are time-consuming and labor-intensive,
Distorted shape by mechanical polishing only! Various attempts have been made to obtain smooth polished surfaces with fewer layers.

As one of these techniques, a polishing method in which abrasive grains are contained in an elastic abrasive material (for example, polyurethane) is disclosed in JP-A-62-294131.This method significantly reduces the strain imparted to the surface. However, the depth of introduction of distortion is still quite large, and furthermore, it has drawbacks such as requiring a large number of passes to obtain a predetermined degree of smoothness.

Furthermore, in Japanese Patent Application Laid-open No. 60-25647, a brush roll containing abrasive grains is used to apply coarse and fine-grained wet sand! Qi! J
A method of polishing by spraying a solution containing a mixture of 1 and 2 on the brushing area has been disclosed, but although this method has better processing efficiency than the cited example above, it introduces a large amount of distortion, and furthermore, there are many scratches after finishing. It has the following drawbacks.

<Problems to be Solved by the Invention> The present invention provides a method for polishing the surface of a metal plate by mechanically polishing the surface to a sufficiently satisfactory level when polishing strain-sensitive materials, such as X-ray specimens or electromagnetic steel sheets. The purpose of the present invention is to provide a mechanical polishing method and apparatus that can reduce the thickness of the polishing material and increase the smoothness of the finished surface.

<Means for Solving the Problems> The present invention involves pressing a rotary polishing roll having an elastic material as the polishing surface against the surface to be polished with a pressure of 3 kg/c+f or less,
And fine abrasive grains with a particle size of 4240 or more are added to the liquid by weight ratio of 100
This is a mechanical polishing method characterized by polishing while supplying a polishing liquid containing a ratio of 15 to 60% to the pressing part, and which reduces the occurrence of a surface-treated altered layer. a mixing tank equipped with a rotating roll for use, a pressure control device for controlling the contact pressure of the elastic material against the surface to be polished, and a stirring device for maintaining a polishing liquid containing free abrasive grains in a uniformly mixed state; and the mixing tank. This mechanical polishing device is characterized by having a nozzle that supplies a polishing liquid to the vicinity of the contact between the surface to be polished and the rotary polishing roll, and which reduces the occurrence of a surface treatment-altered layer.

As a result of various investigations into the influence of polishing conditions on the depth of the work-strained layer, the present inventors found that the greater the vertical component of the force applied to the machined surface, the greater the work-strain. I came to know something profound.

Therefore, the present inventors conducted further studies and found that in order to prevent the layer from applying vertical component force to the machined surface, it is effective not to make the abrasive grains adhere to the abrasive material and to use an elastic abrasive material. The inventors have discovered that this allows for more effectively obtaining a polished surface with less process-affected layers.

FIG. 4 is an explanatory diagram schematically showing the distribution of stress applied to the surface of the material to be polished depending on the type of abrasive material.

FIG. 4(a) shows that conventional polishing is performed using a polishing roll that contains abrasive grains inside an elastic material and therefore has an uneven internal hardness, and that the normal force is large due to the dill caused by the abrasive grains. Same < (b) is an abrasive material with abrasive grains fixed inside, that is, an elastic material with uneven internal hardness is used, and since the elastic material absorbs the impact, the vertical force is small, and the horizontal force is mainly applied. Indicates that it will be processed. Furthermore, (C) uses free abrasive grains, and the abrasive grains are not fixed to the abrasive material, so the internal hardness of the elastic material is uniform, and the abrasive grains are bitten by the abrasive material. This shows that the rest is processed and polished using only horizontal force.

Further, in the present invention, it has been found that the surface to be polished can be polished by pressing the rotating body against the surface at a pressure of 3 kg/+j or less, preferably 1 kg/cd or less.

Next, the present inventors found that coarse abrasive grains not only cause a large vertical impact force but also generate many deep scratches that cannot be removed after polishing, impairing the quality of the polished surface.

As a result, the free abrasive grains used for such polishing were #240
If the grains are not as fine as above (JIS R6001), the surface altered layer will be thick, and preferably, the fine grains are 4,600 or more.

Incidentally, FIG. 5 shows the magnitude of machining strain detected magnetically, and H6 is the coercive force. As more strain is introduced, He becomes thicker (in Fig. 5, the ratio of H before polishing, (Hc, ): Hc (HcA) after polishing, HCA/) (cs indicates the degree of strain introduction). The roll material used is a polyurethane roll with a hardness of A60.If fine abrasive grains of 4240 or more are used, the increase in HcO will be small.

Next, the mixing ratio of free abrasive grains used in the method of the present invention with water must be 5 to 60 parts abrasive grains per 100 parts water. If it is less than 15, the polishing efficiency will be significantly reduced, and if it exceeds 60, it will be extremely difficult to maintain a homogeneous mixture of free abrasive grains and polishing liquid, and the particles will settle in the brush tank etc., interfering with operations. It comes to bring about.

However, when such free abrasive grains are mixed into a polishing solution and polished, there is a large variation in polishing ability.
As a result of studies conducted by the present inventors, it has been found that one of the causes of this variation is the variation in the mixing ratio of the polishing liquid and the abrasive grains. In other words, it was found that the cause of the variation was that if the abrasive grains were left to stand, they would form precipitates and the mixing ratio would change moment by moment.

Therefore, it is necessary to constantly stir the polishing liquid and the abrasive grains in the tank in which they are mixed in order to keep the mixing ratio constant.

The stirring means may be, for example, a propeller, but stirring by a propeller in the polishing liquid mixed with abrasive grains causes severe abrasion of the blade material, so stirring by gas is more suitable.

Another reason for the variation is that an elastic material is used as the abrasive material. In other words, the use of elastic materials is essential to reducing the machining-affected layer, but it expands with the rotation of the rolls, making it difficult to control the amount of cut into the surface to be ground, which causes variations. 0 In the present invention, the pressure on the surface to be ground is 3
By setting it to a constant value of kg/- or less, the contact area between the roll and the surface to be ground is made constant and variations are reduced.

Next, the present invention will be explained based on the drawings. 1 is a roll having an abrasive surface made of an elastic material. The material is a nonwoven fabric roll, a roll of polyurethane, or a thread diameter of 0.
A brush made of flexible nylon or the like with a size of 6 or less is suitable, but the material is not particularly critical as long as it is an elastic body.It is preferable that the elastic body has a hardness H5 (JrSA) of 60 or less and a compressive Young's modulus of 10' kg/cd. The following is preferable. The object to be polished 2 is fixed on a surface plate 3, and in this case, the surface plate and the object to be polished are moved to the right in the drawing, and the surface is ground or polished.

Reference numeral 4 denotes a device for dispensing polishing liquid mixed with abrasive grains.

Predetermined amounts of polishing liquid and abrasive grains are each charged into a mixing device (5). A mixing screw 6 is installed in the mixing device 11f5, and the screw is rotated only when adjusting the mixture, so there is no need to worry about wear.When the stirring is finished, the shutter 7 is opened, and the mixture of polishing liquid and abrasive grains is sent to the mixing tank 8. A stirring device 11 is installed inside the mixing tank 8 . If stirring is not carried out constantly, the abrasive grains will settle, causing a change in concentration.The stirring device may be a screw or the like, but in order to constantly stir, it is necessary to use air stirring or to separate a part of the discharged liquid. It is preferable to return the water to the tank and stir it using a strong circulating water stream. 9 is a valve for controlling the pouring amount, and 10 is a polishing W! This is a nozzle that supplies liquid.

The discharge rate is controlled by adjusting the pressure inside the tank with a valve 9A and controlling the discharge rate with a valve 9B. Figure 2 is a schematic side view when a continuous coil 2' is used as the object to be polished.
Fig. 3 is a view of the coil polishing device viewed from the direction in which the plate travels, and 12 is a pressure sensor. The pressure is kept constant by controlling the position of the rolls up and down.

Next, the present invention will be explained based on examples.

<Examples> Example 1 A test piece of low carbon steel after annealing was polished using a polyurethane roll. The polishing liquid used was water with W A #800 abrasive grains added at a weight ratio of 1O:1. The pressure during polishing is 3
The surface layer was removed at a rate of 1.2 g/cd. For comparison, the same surface layer removal of <1.2 m was performed using a #800 vitrified abrasive grinding wheel.The thickness of the process-affected layer in the case of polishing performed with the device of the present invention was approximately 1.84, In the case of a polishing wheel, it was 30-height.

Samples prepared using the apparatus of the present invention could be used for X-ray measurements as they were, but samples of comparative examples had to be chemically polished to remove the damaged layer.

Furthermore, when the pressure control device was released, the variation in the altered layer increased by +0.7 μm.

Example 2 Using a device according to the invention, 0,23 containing 3% silicon
The surface of a grain-oriented silicon steel plate with a thickness of ff111 was coated with #1000 Z in a JIS W1 type water-soluble polishing liquid using a nonwoven fabric roll.
Polishing was performed by adding r0t at a weight ratio of 10:1. The surface pressure of the roll during polishing was maintained at 300 g/cd. As a comparative example, a polishing device using an endless belt, emery #
Polished with 1000. Both surfaces were smooth, but the iron loss of the silicon steel plate using the device of the present invention was W. 0 at
．． It was 85W/kg. On the other hand, the comparative example is 1.34W/k
g, and was adversely affected by the process-affected layer.

The iron loss of silicon steel plate before polishing is 1. oOW/kg. The variation in iron loss depending on the presence or absence of a pressure control device is Δσ−0,
It became thicker (about 02W/kg).

Example 3 A stainless steel BA plate was used as a starting material and polished using a polishing apparatus according to the present invention. The material for the polishing roll is a polyurethane roll with a hardness of A60 at a circumferential speed of 1000 m/s.
The zero surface pressure used in minutes is 1 kg/c+a. As free abrasive grains, #600 alumina was mixed in a weight ratio of 30 parts to 100 parts of water. The mixed solution was constantly stirred to be homogeneous during operation in a stirring tank by a water jet. It was poured onto the surface to be polished at the same time, and both sides were polished at the same time. The polishing was completed so that Ra≦0.3 μm.

For comparison, a nonwoven fabric roll (hardness A30) containing #800 abrasive grains was used and finished to the same <Ra≦0.3 μm. When the depth of the processing alteration tank in both cases was measured by etching the surface after polishing, it was 10 μm in this example and 50 μm in the comparative example. has been significantly improved.

Example 4 A stainless steel BA plate was used as a starting material and polished using a polishing apparatus according to the present invention. For polishing, a nylon brush containing no abrasive grains with a thread diameter of 0.1 tw was used, and the surface pressure was 0.
It was adjusted to 5 kg/crl. #320 as free abrasive grain
Carborane term was mixed in a weight ratio of 45 parts to 100 parts of water. The mixed solution was constantly stirred to be homogeneous during operation in a stirring tank by a water jet. It was poured onto the surface to be polished at the same time, and both sides were polished at the same time. Polishing is Ra
It was finished so that it was ≦0.5 μ-.

For comparison, a polishing brush containing abrasive grains (#320) was used to achieve the same result of <Ra≦0.57+m. The depth of the damaged layer in both cases was measured by etching the surface after polishing, and it was found to be 15 μm in this example and 10 nm in the comparative example.
0 In this example, the introduction depth of the process-affected layer was significantly improved compared to the comparative example.

<Effects of the Invention> As described above, in the case of the apparatus of the present invention, it is possible to reduce the thickness of the process-affected layer as much as possible and to smoothen the surface of the polished material with little variation in a highly efficient and continuous manner. This makes it possible to quickly and easily polish materials that require strain-sensitive properties, such as X-ray specimens, surfaces of electrical steel plates, and metals for disk substrates.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view of the device of the present invention, Figure 2 is a diagram showing the case where the material to be polished is a continuous coil, Figure 3 is a view seen from the direction of flow of the material to be polished, and Figure 4 (a) . (b) and (C) are schematic diagrams showing the stress generation situation on the polished material due to II'R of the abrasive, and Figure 5 is a graph showing the abrasive grain size and the magnitude of strain as a ratio of coercive force. be. 1... Elastic roll, 2... Object to be polished, 2'... Object to be polished (continuous coil), 3... Constant
Board, 3'... Backup roll, 4... Mixing tank, 5... Abrasive polishing liquid mixing device, 6... Mixing screw 7... Shutter 8.
... Mixed liquid reservoir, 9A, 9B... Pulp,
IO... Output nozzle section, 11... Stirring peripheral air pipe, 12... Pressure sensor 13... Pressure control device.

Claims (1)

[Claims] 1. A rotary polishing roll with an elastic material as the polishing surface is pressed against the surface to be polished with a pressure of 3 kg/cm^2 or less, and fine abrasive grains with a particle size of #240 or more are added to the liquid in a weight ratio. 1. A mechanical polishing method that reduces the occurrence of a surface treatment-affected layer, characterized in that polishing is carried out while supplying a polishing liquid containing a ratio of 15 to 60% to 100% to the pressing part. 2. A rotating polishing roll with an elastic material as its polishing surface, a pressure control device that controls the contact pressure of the elastic material against the surface to be polished, and a stirring device that maintains the polishing liquid containing free abrasive grains in a uniformly mixed state. A mixing tank provided with the polishing liquid, and a polishing liquid from the mixing tank,
A mechanical polishing device that is characterized by a nozzle that supplies the polishing surface near the contact between the surface to be polished and the rotation roll for polishing, which reduces the occurrence of a surface-processed deteriorated layer.