JPS6312744B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing machine for metals, hard plastics, etc., and more specifically for polishing nickel stampers for video discs that require optical surface precision, and especially for molding aspherical plastic lenses. The present invention relates to parts for a polishing machine for polishing the lens transfer surface of a mold and optically polishing the aspherical plastic lens itself.

Conventional optical polishing has long been used to polish glass lenses and prisms. However, these polishing methods are limited to flat and spherical surfaces.

In the field of optics, the question of how to polish aspherical surfaces has been desired for a long time, as is the establishment of a measurement method. This is because the aspheric optical surface has extremely great advantages, such as the ability to easily correct spherical aberration, and it also allows for the application of new optical technology.

Furthermore, in recent years, the range of optical uses for plastics has expanded, and for example, aspherical plastic lenses are being used for camera lenses, and hard plastics are being used for video disks, computer memory disks, etc. ,
In order to manufacture them, it is desired to establish a new optical polishing technology.

The reality of polishing in such fields is that, for example, in the case of molds for molding aspherical plastic lenses or molds for disc molding, the higher precision is required, the more difficult mechanical polishing becomes. Polishing is done by hand by skilled workers, which takes a long time to complete, making it inefficient and extremely expensive.

On the other hand, over the past few years, machine tools with dramatically improved machining accuracy have been developed, and a field called ultra-precision machining has emerged. Ultra-precision machining refers to, for example, suppressing the shape accuracy of processed products to an error of 3 μm or less. The reasons why such high-precision machining has been put into practical use are, firstly, that ultra-precision bearings such as air bearings and hydrostatic oil bearings have been put into practical use, and secondly, the fact that the position, dimensions, shape, etc. Laser interferometers have come to be used for measurements, and thirdly, the materials used for the cutting tools and grinding wheels used for processing include single-crystal diamond cutting tools, sintered diamond grinding wheels, and Borazone (which is said to be the second hardest material after diamond). For example, cutting and grinding tools made of cubic boron nitride have been developed.

These ultra-precision processing machines can process materials such as metals and plastics into products with high dimensional and shape accuracy. Then, if optical surface precision is required, by polishing the processed surface to a thickness of only a few μm,
It can be made into any optical surface you need.

However, when it comes to flat or spherical surfaces, mechanical polishing can be performed by applying the polishing technology for glass lenses or prisms as described above, but when it comes to aspherical surfaces or complex shapes, mechanical polishing can be performed. The reality is that polishing of mold surfaces, which is often the case, can only be done by hand. Hand-held polishing machines are used in some parts of manual polishing, but
For example, it is extremely difficult to finish a high-precision optical surface over the entire surface of a large workpiece by moving a small polishing jig in linear reciprocating motion (vibration) or rotating it over a large workpiece. It is a difficult and skilled job.

However, there are many aspects of the polishing mechanism that are still academically unresolved, and a lot of research is still being done on polishing glass lenses. Analysis of the polishing action of metals and plastics is also an area that still needs to be actively worked on.

As a result of many years of research into removal polishing of minute portions of precision machined surfaces, the inventor of the present invention was able to conduct a certain degree of analysis of the polishing mechanism. It is thought that the following four effects mainly occur in minute part removal polishing.

(1) Scraping action (2) Crushing action (3) Melting action (4) Recombination action The above four actions differ greatly depending on the material of the surface to be polished. For example, it was found that the recombination effect (4) does not work on plastics, but works more strongly on metals with a crystalline structure than on amorphous metals, and the effect is particularly pronounced at grain boundaries. It was also found that the melting effect of (3) is more pronounced when polishing plastics than metals.

In polishing work, an abrasive and a polishing liquid are interposed between the polishing jig and the polishing surface of the workpiece, but at this time, different relative I realized that I needed to give him some exercise. Furthermore, when crystal structures of different hardness coexist, ordinary polishing operations tend to produce so-called orange peel, where minute irregularities are seen at the grain boundaries. We discovered that by adding , a super-mirror surface can be obtained without causing tangerine skin, even for metals with such a eutectic multiphase structure.

More importantly, in the micro-polishing work targeted by the present invention, a new relationship has been discovered between the relative motion given to the three components mentioned above and the pressure given to the polishing jig.

That is, conventionally, when considering automatic polishing, in order to increase polishing efficiency, a method has been adopted in which the pressure applied to the polishing jig is increased and the relative movement is increased as much as possible. In this case, the polishing jig, the polishing material, and the polishing surface are rarely left in a free state, and in most cases, the polishing jig and the polishing material are firmly fixed. In other words, it is a method of polishing with a whetstone, sandpaper, polishing belt, polishing cloth, etc.

With such a polishing method, polishing efficiency can be improved, but precision polishing is difficult, and the shape accuracy of the polished surface is lost, resulting in a loss of optical value. In addition, the surface itself has countless fine scratches and is rough, which limits its optical use.

As a result of a detailed study of micro-polishing, the inventor found that
The polishing jig, the abrasive material, and the polishing surface are kept in contact with each other but in a free state, and the polishing jig captures some of the abrasive material and leaves it in a free state to some extent. Then, while applying constant pressure to the polishing jig, the polishing jig was polished at a relatively slow speed.
They discovered that extremely excellent polishing could be achieved by applying relative parallel movement between the two.

Due to the movement between the three, the polished surface becomes flattened little by little. Then, the abrasive material gradually breaks down into smaller pieces due to collisions with the polishing surface or collisions between abrasive materials. As a result, the polished surface becomes even more flat. In order to uniformly polish the entire surface of the workpiece, it is sufficient to move the polishing jig uniformly over the entire surface.

In such polishing, if the relative movement speed is increased, not only are deep scratches likely to occur on the polished surface, but also the amount of removal due to polishing increases significantly, causing the shape of the polished surface to be distorted. It has also been found that the accumulation of deep scratches gives the surface a tangerine-like appearance, making it impossible to obtain the final optical surface. Based on the above research results, the inventors of the present invention succeeded in completing a precision polishing machine suitable for removing minute parts, as described below.

According to the polishing machine of the present invention, the surface of a plastic or metal workpiece can be shaped into a certain shape, not only on a flat or spherical surface, but also on an aspherical or conical surface, or even a complex three-dimensional curved surface such as a horse's saddle. If the size is within this range, it is possible to finish the optical surface with high precision.

To summarize the present invention, polishing is carried out by attaching a polishing jig of an appropriate shape and material to the head plate of a rotating universal head that was originally developed. In other words, the disc-shaped head plate connects itself, the presser plate, the drive shaft, two guide plates fixed thereto, the guide ball sandwiched between the guide plates, and the guide ball and head plate. The rotating universal head is constituted by the guide shaft. The rotational force generated by the motor or the like is transmitted from the main shaft to the drive shaft, from the drive shaft to the guide plate, and from the guide plate to the guide shaft. The polishing jig is rotated by the force transmitted to the head plate by the guide shaft, and the polishing work is performed.

By using a universal head with such a design, it is possible to perform polishing by bringing an appropriately shaped polishing jig into contact with the polishing surface of the workpiece so that it is always parallel to the polishing surface.

A universal mechanism works for the inclination of the polishing surface. However, the ability of the universal mechanism according to this design to follow an inclined surface is limited to a rotation speed of approximately 600 RPM. The polishing rate according to the present invention is even for metals.
Since it is less than 300 RPM, there is more than enough rotation followability on inclined surfaces. Furthermore, changes in the height of the polishing surface of the workpiece can be accommodated by sliding the fitting portions of the hollow ends of the main shaft and the drive shaft. To adjust the polishing pressure, use the hollow parts of the two shafts.
This can be solved by inserting an appropriate compression spring, but if you want to adjust the polishing pressure more precisely,
A pneumatic or hydraulic pressure adjustment function may be provided on the main shaft or rotationally driven prime mover side.

The swing angle of the head plate with respect to the main shaft axis of the universal mechanism of this design is within 25 degrees at maximum. For this reason, if you swing the main shaft axis at an angle of less than 80 degrees with respect to the vertical direction,
Unless the curvature is very small, the polishing jig can properly contact and polish almost any three-dimensional curved surface.

Furthermore, in order to perform uniform polishing over the entire polishing surface of the workpiece, in the present invention, the stage on which the workpiece is placed is rotated extremely slowly and is also movable horizontally as desired. Depending on the shape of the workpiece, excellent mirror polishing can be achieved by simply moving the rotary stage horizontally without rotating it. However, the removal allowance for polishing (polishing allowance)
It was found that when the diameter exceeds 10 μm, subtle non-uniformity appears on the polished surface when the workpiece is rotated and horizontally moved only. To prevent this, the universal head to which the polishing jig is attached must be given horizontal movement (almost only in one direction) that is completely unrelated to the horizontal movement and rotation of the workpiece. I found out what I should do.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a cross section of the main shaft and universal head. The tapered upper end of the main shaft (1) in the figure is gripped by a rotating scroll chuck or the like to apply rotational force to the main shaft. It is convenient if the length of this part is made appropriately long because the height of the universal head can be adjusted according to the height of the workpiece. A drive shaft 2 has a spherical lower end and a hollow upper end, and the upper end is inserted into the hollow portion of the lower end of the main shaft.
A spline is cut in the middle of the drive shaft, and a flange is provided on the spherical side of the spline for fixing the guide plate 5 to the drive shaft. A claw of a guide shoe 8 fixed to the lower end of the main shaft is fitted into the spline, so that the drive shaft can slide up and down by the length of the spline without coming off the main shaft. Due to the engagement between the pawl and the spline, rotational force is transmitted from the main shaft to the drive shaft. The length of the hollow part of the main shaft that allows the drive shaft to slide up and down is a few centimeters longer than the length of the spline of the drive shaft, in addition to the length of the part where the main shaft and drive shaft fit together. Make it meter long. By doing this, even if a compression spring for increasing the polishing pressure is inserted into the hollow portions of the main shaft and the drive shaft, sufficient margin can be provided for the slide stroke. If the fitting tolerance between the main shaft and drive shaft can be kept small, the air in the hollow parts of the two shafts will act as a spring, and when it is desired to lower the polishing pressure, such as when polishing plastic, a compression spring can be used. Not necessary.

3 is a holding plate for holding the spherical portion of the drive shaft; 4 is a head plate which has the same role and is used to attach a polishing jig. Both are disc-shaped, with the spherical part of the driveshaft sandwiched between the hemispherical space in the center and held in place with screws and nuts at several places. However, in the presser plate, both the center hemispherical space and the surrounding hemispherical space for guide shafts, which will be described later, are partially cut out to allow each shaft to pass through. Thus, the two plates can rotate freely without coming off the spherical portion of the drive shaft, and can be tilted in any direction within a certain angular range with respect to the axis of the drive shaft. There are two or more (up to about four) spherical spaces at a certain distance from the center of the presser foot plate and the head plate, and in this part there is a guide shaft 6 which is cylindrical and has a spherical end. Pinch the spherical part. The cylindrical part of the guide shaft is sandwiched between two guide plates 5 attached to the flange of the drive shaft described above, and has a guide ball 7 which has a through hole in the center and rotates freely.
As shown in the figure, the through hole is made to have a sufficient length so that it does not come off the guide ball. Note that in the above embodiment, the drive shaft 2
In order to support the spherical part of the guide shaft 6, the presser plate 3 was fixed to the head plate 4, and two guide plates 5 were used to support the guide ball 7, but these mechanisms are similar to those described above. It is easily understood that other configurations are possible as long as a partially spherical recess can be formed that substantially surrounds the spherical part and the guide ball 7 so that they do not come off.

Thus, the head plate 4 can continue to rotate while maintaining a constant angle of inclination with respect to the axis of the drive shaft.

That is, if the polishing jig attached to the head plate has an appropriate shape, the surface of the polishing jig involved in the polishing operation can properly contact the polishing surface of the workpiece and perform rotational movement. When the head plate rotates at an angle to the drive shaft axis,
The guide shaft slides in the through hole of the guide ball in the axial direction, and the guide ball transmits rotational force to the guide shaft while making a sliding movement.

Reference numeral 9 in FIG. 1 is a guide pin for the compression spring. Again 1
The screw hole 0 is for a set screw for attaching a polishing jig.

By explaining FIGS. 2a and 2b, and FIGS. 3 and 4, the overall picture of the present invention should be understood.

Reference numeral 11 in FIGS. 2a and 2b is a rotary stage on which a workpiece is placed. The main shaft under the stage is bearing box 1.
It is fitted into the thrust and radial bearings in 2. A chain sprocket is also attached to the main shaft to rotate the stage. A small, high-torque, low-speed rotating motor 23 is attached to one corner of the main shaft bearing box, and another chain sprocket is fitted to the main shaft of this motor, and a second chain sprocket is fitted to the main shaft of the workpiece table. It is connected to the sprocket by a drive chain 24 to apply rotational force to the stage.

Moving shafts 13 and 13' for horizontally fixing the stage and horizontally moving the stage from side to side are passed through the bearing box of the main shaft of the stage. A thread is cut into the shaft 13' of these, and a nut is fitted into this thread, and the nut is fixed to the bearing box of the main shaft of the stage. By rotating the drive motor 14 of the shaft 13' in forward and reverse directions, the rotary stage can be moved left and right.

FIG. 2a is a schematic view of the stage viewed from above, and FIG. 2b is a schematic view of the stage viewed from the side. 2nd a
The figure clearly shows how the two shafts, ie, 13 and 13', which directly support the bearing box of the main shaft of the stage are arranged.

Of course, the support and movement axis in the above explanation,
In other words, the system 13 and 13' illustrated in the present invention is not the only and essential system.

The gist of this part of the invention is to cause the rotating stage to move horizontally, and the parts 13 and 13' are sliding bearings, and the drive is carried out by a chain type. However, there is no problem even if the system uses a pinion gear and a rack gear. This also applies to the subsequent explanations. That is, for example, regarding moving the rotary stage back and forth, and moving the polishing component according to claim 1 vertically and horizontally,
The method illustrated in this explanation is not the only essential one, but supporting and moving itself, whatever the method, is essential. Furthermore, the necessary conditions in the present invention are:
This means that the polishing component according to claim 1 is always used.

Now, in Fig. 2, in order to move the rotating stage back and forth, both ends of the two shafts 13 and 13' are supported.
Two movable bearings 15 for fixing are further supported by two longitudinally moving shafts 16 and 16'.
A thread is cut on the shaft 16', and a nut fitted onto the thread is fixed to the movable bearing 15 on the shaft 16' side. By rotating the shaft 16' drive motor 17 in forward and reverse directions, the rotary stage can be moved back and forth.

In this way, while rotating the stage, it can be moved from side to side and back and forth.

During polishing work, the length of time that the polishing jig remains on the polishing surface is controlled to be uniform over the entire surface of the polishing surface, for example by using a timer.
The motors 14 and 17 shown in FIGS. 2a and 2b may be driven by computer control.

18 in FIGS. 2a and 2b is the base of the entire polishing machine. FIG. 3 schematically shows only the main parts of the polishing machine when viewed from the side for convenience. Since the movement of the rotary stage has already been described, most of it has been omitted.

FIG. 4 schematically shows the polishing machine shown in FIG. 3 viewed from above, and the base 18 of the polishing machine shown in FIGS. 2 and 3 is omitted.

In FIGS. 3 and 4, reference numeral 19 denotes a motor for imparting rotational movement to the polishing component according to claim 1, which is suspended from the slider 21 by a hanger pin 20. 22 is the motor 19
The main shaft of the polishing part is gripped by a scroll chuck 25 attached thereto. As shown in FIG. 3, a polishing jig 26 is attached to the main shaft 1 of the polishing part, and a workpiece 27 placed on the stage 11 is polished. Figure 3 shows that the main shaft 1 of the polishing component is set almost vertically, and the universal mechanism of the polishing component is working against the inclination of the polishing surface of the workpiece. ing.

In the slider 21, the device for gripping the hanger pin 20 is rotatable in a vertical plane, so that the hanger pin can be stopped at any angle by the steady rest pin 28. By doing so, the operating range of the universal mechanism of the polishing component can be substantially increased.

As for the swinging mechanism of the hanger pin, by using a pulse motor or the like, the angle of the hanger pin, that is, the angle of the polishing part with respect to the vertical axis of the main shaft can be arbitrarily changed automatically even during polishing.

This greatly expands the capabilities of the universal mechanism for polishing parts, and as already mentioned, the polishing jig 26 can be used on almost any three-dimensional curved surface, except for those with very small curvature. Polishing work can be performed with proper contact at all times.

The slider 21 can be moved left and right on a slider movement shaft 30 by a slider drive motor 29.

Furthermore, bearings 3 at both ends of this slider moving shaft 30
1 and 31' are at the required height by the four pillars 32 and 32', 32'' that support them.
The slider moving shaft 30 is supported horizontally. Furthermore, these four pillars 32 and 32',
32'' is vertically fixed on front and rear bearings 34 and 34' fitted to two front and rear sliding shafts 33 and 33' placed on the polishing machine base 18.

The slider moving shaft 30 and the front and rear sliding shafts 33 and 33' are perpendicular to each other.

3 of the 4 pillars 32 and 32', 32''
2'' has a thread cut across about half the length of its upper part, and by rotating this support in forward and reverse directions using the vertical motor 35, the support can be fitted into the threaded part of the support. By the movement of a nut fixed to the bearing 31' of the slider moving shaft 30, it is possible to move the slider moving shaft 30 up and down while keeping it horizontal.In other words, as a result, the polishing part can be moved up and down. This is possible.

Further, the front and rear bearings 34 and 34' can be moved back and forth on the front and rear sliding shafts 33 and 33' by a moving motor 36. Overall, these mechanisms allow the abrasive component to be placed at any height and position, and its axis of rotation, that is, the main shaft, to be placed at any angle.

Furthermore, some key points regarding the actual production are as follows.

In FIG. 1, the main shaft 1 and the drive shaft 2 are preferably made of hard and durable tool steel.

The guide shoe 8, guide ball 7, head plate 4, etc. are preferably made of relatively soft materials such as brass or gunmetal, which have excellent sliding properties.

The rotary stage 11 in FIG. 2 needs to be made sturdy. The flatness of the stage is also important. It is also important to make the main shaft at the bottom of the stage strong. Third
The important thing in Figure 4 is that the slider 21
However, it is important to make the whole thing sturdy and precise so that it does not wobble during polishing work.

However, in the polishing work according to the present invention, the power required for the entire polishing machine is extremely small, and even when polishing a large mold, the power required is at most about 500 W, so it is sufficient to take this into consideration when manufacturing.

A suitable material for the hanger pin 20 is tool steel.

Second, the operating stroke of the front-rear sliding movement can be short. This depends on the technical factors of the polishing operation, and
It is sufficient to consider the strokes of

The third one refers to common knowledge, and the four pillars 32
and 32', 32'', and a mechanism for moving it up and down on the guide, bearings 31 and 3 are used.
In step 1', if the guide hole that slides into the support is not made accurately and firmly, for example, if the slider is at an uneven position on the slider movement axis and an uneven load is applied to the axis, the brake may fail. It works like this and becomes unable to move up and down properly.

To avoid this, it is better to make the length of the guide hole that slides into the support column longer, or to use a dovetail method instead of the hole method.

Examples will be described below.

Example 1 The size of the polishing parts shown in Figure 1 is determined by the overall height.
200m/m. Also, the diameter of the head plate is 80
m/m. (Figure 1 is the actual size) The base of the polishing machine, ie, 18 in Figures 2a, 2b, 3, and 4, is 600 m/m x
It was set at 450m/m. Overall height of polishing machine 650
m/m. The output of the motor for rotating the stage in Figures 2a and 2b is 5.3W, and the rotation speed is
Constant speed rotation of 8 RPM and clockwise rotation, the output of the motor 19 for rotating the polishing parts in Figures 3 and 4 is variable at 30W, and the rotation direction is clockwise, that is, the polishing jig and the polishing surface face each other. I made it rotate in the opposite direction.
All other drive motors for movement and sliding have an output of 30W, and are variable at a maximum of 150RPM using a speed reducer.

The loading table is made of stainless steel, and the thickness of the table is 20m/
It was set as m. In addition, the movement of the polishing work, sliding, and swinging of the main shaft of the polishing parts, that is, the set screw 28 incorporated in the slider 21 in FIGS. 3 and 4.
The control method for the mechanism that sets the swing angle is based on the shape of the workpiece and the performance required for the polished surface, such as a timer and limit switch method,
It is now possible to use any program control method using a microcomputer. In reality, it has been found that program control is suitable only for extremely complex mold polishing operations, and for most other polishing operations, a method using a timer and limit switch is simpler and has superior workability.

Using this polishing machine, molds for video discs are made.
No.600 by diamond compound abrasive.
Polished in the order of No. 1200, No. 1800, No. 3000, and No. 8000 (however, the numbers are the compound manufacturer's number according to the NBS standard of the abrasive grain).

Conventional manual polishing requires approximately one week of polishing time, with an average surface roughness of 0.05 μm and shape accuracy of 0.2 μm.
(for a diameter of approximately 350 mm), but according to this polisher, the average surface roughness was reduced in 10 hours.
0.005μm, shape accuracy 0.05μm.

Example 2 The back surface of a video disc stamper was polished using the polisher described above. The material is nickel and the thickness of the stamper is approximately 200 μm. No. 600~ with diamond compound as in Example 1.
Polished to No.8000 in 3 hours. The polishing cost is approx.
The average roughness of the surface after polishing was 0.01 μm, and the maximum roughness was 0.23 μm.

Manual polishing takes 5 days,
The occurrence of orange peel was unavoidable.

Example 3 Using the above polishing machine, the curvature is approximately 120m/m diameter
Concave polishing of the insert of a 40m/m lens mold was performed. The result of polishing using diamond compound up to No. 14000 was that N = 1 in the Newton fringe test, and the maximum surface roughness was 0.005 μm. Manual polishing was limited to about N4 in 4 days, but with this polishing, the above polishing could be done in 8 hours, and moreover, the same level of results could be obtained for all polishes. did it.

Example 4 Using the above polishing machine, a diameter of approximately 150 m/m,
We polished an aspheric lens for video projection made of cross-linked polymethyl methacrylate with a maximum wall thickness of approximately 35 m/m.

Using a special creamy cerium oxide as the abrasive material, the diamond bite surface is polished to an optical surface in about 15 minutes by ultra-precision machining.
Therefore, polishing was completed in approximately 30 minutes per lens, and the desired results were obtained.

In this case, no spring was used in the fitting portion between the main shaft and the drive shaft of the polishing component.

Furthermore, according to this polishing machine, it has been found that for workpieces made of the materials mentioned above, if the polishing time is longer than 20 minutes, the shape accuracy tends to be distorted.

Example 5 The universal mechanism of the polishing parts of the polishing machine described above is about half of the one described above, that is, the diameter of the head plate is 40 mm, and an aspherical lens with a diameter of 4 mm made of cross-linked polymethyl methacrylate is used. Polished. With this lens, we were able to focus the polarized beam of the He-Ne laser into a spot with a diameter of 4 μm.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the polishing part of the present invention, Fig. 2a
Figures 2b and 2b show parts related to polishing machine parts of the present invention, excluding the polishing parts and their peripheral equipment, Figure 2a is a plan view, Figure 2b is a side view, and Figure 3 is a part of the present invention. FIG. 4 is a side view of the main part, and FIG. 4 is a plan view thereof. 1... Main shaft, 4... Head plate, 11... Stage, 26... Polishing jig, 27...
…work.

Claims (1)

[Scope of Claims] 1. A main shaft that is gripped at its upper end and driven to rotate; the upper end is fitted into the lower end of the main shaft in an axial direction such that it can elastically slide relative to the main shaft, and a drive shaft that is rotatably inserted into the main shaft and has a spherical portion at its lower end; a guide plate that is substantially perpendicular to the drive shaft and whose center portion is fixed to an intermediate portion of the drive shaft; a plurality of guide balls rotatably supported on concentric circles of the guide plate and having a cylindrical through hole passing through the center; a shaft portion slidably inserted into the through hole of the guide ball; a guide shaft having a partially spherical recess in the center of its upper surface that contacts and substantially surrounds the spherical portion at the lower end of the drive shaft, and at a position on the upper surface corresponding to the guide ball; A partially spherical recess is formed in contact with and substantially surrounding the spherical portion at the lower end of the guide shaft, and rotatably supports the drive shaft and the spherical portion of the guide shaft. A polishing component comprising: a head plate having a polishing jig mounting portion on the opposite lower surface thereof. 2. The polishing component according to claim 1, wherein the polishing object is placed at a fixed distance from the polishing jig, and the polishing object is rotated and moved in a horizontal plane. Polishing parts with a stand. 3. In the polishing component according to claim 1, the main shaft is heated at 80°C with respect to the vertical direction.
A polishing part that can be tilted at an angle within 100 degrees and can be moved horizontally and vertically.