JP3681848B2 - Round bars and lathe products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a round bar material and a lathe processed product, and in particular, a lathe that is different from a normal lathe machining apparatus that performs lathe machining with one end rotatably supported by a lathe chuck and the other end rotatably supported by a core push pad. Suitable for so-called CNC type automatic lathes (guide bush type, Swiss type CNC lathes, etc.) that, for example, support a round bar in a single-supported state so that it can be rotated and fed and perform lathe processing while sequentially feeding it. Technology.
[0002]
[Prior art]
Normally, in order to machine a so-called long bar material in lathe processing, a lathe device side chuck rotatably supports a part of the outer periphery of the round bar material, and is attached to the other end surface of the round bar material. On the other hand, centering is performed with a center drill or the like, and the machined center is rotatably supported by using a core pushing stand of a lathe device, so that both are supported. After this preparatory step, an apron on which a cutting tool is mounted is generally cut with a cutting tool while moving in the longitudinal direction of the round bar.
[0003]
On the other hand, a CNC type automatic lathe supports a relatively small-diameter round bar or pipe material in a single-supported state so that it can be rotated and fed, and a lathe while sequentially feeding the round bar to a cutting tool such as a cutting tool. Since the above-described center processing can be omitted and a small-diameter part that is difficult to perform center processing can be processed, it is preferably used.
[0004]
According to this CNC type automatic lathe, for example, in the case of continuous machining by unmanned automatic operation, fixing to eliminate core blurring is performed in order to improve the machining accuracy for a round bar material supported to be able to rotate and feed in a single-supported state. What is called a bush (guide bush) is used. Incidentally, a rotary bush type CNC type automatic lathe using a rotary bush that rotates in conjunction with a round bar has been put into practical use. According to this type of lathe, the machining accuracy is inferior to that of the fixed bush type because the lathe is more expensive than the fixed bush type and there is a slight amount of core blurring.
[0005]
Under the circumstances as described above, a fixed bush type CNC lathe is now widely used.
[0006]
With reference to the drawings, the fixed bush of the fixed bush type CNC automatic lathe will be described. FIG. 6 is a front view of the fixed bush, and is a view shown with the round bar 1.
[0007]
In this figure, the fixed bush 3 is formed with four split grooves 3a in a substantially cross shape as shown. In addition, the fixed bush 3 is provided with a hole 3n that is processed to be concentric with the outer diameter portion in the front-rear direction of the drawing. The hole 3n is continuously formed with the split groove 3a.
[0008]
The hole 3n is formed from an ultra-hard material such as tungsten carbide 3c, and can be sent out along the longitudinal direction of the round bar 1 by the fixed bush 3 by ensuring sufficient wear resistance. The round bar 1 which is held at a high speed and is rotated at a high speed in the direction of the arrow in the drawing is sequentially sent out to the cutting tool 12 shown by a broken line, so that lathe machining in a single-supported state can be performed without centering.
[0009]
That is, when lathe machining is performed, the gap between the hole 3n of the fixed bush 3 and the outer peripheral surface of the round bar 1 is set as small as possible, and lathe machining is performed so that the occurrence of core blur is extremely small and high accuracy. Lathe machining is feasible.
[0010]
[Problems to be solved by the invention]
As described above, lathe processing using a fixed bush is, for example, a free-cutting steel containing sulfur component, a metal material such as copper, and the outer peripheral surface thereof is in direct contact with the hole 3n, and By rotating at high speed, even if the calorific value increases, it is limited to metal materials or other industrial materials that can maintain a sufficient sliding state. In other words, the supplier of the fixed bush type CNC type automatic lathe does not guarantee anything other than good cutting metal materials such as free-cutting steel and copper.
[0011]
For example, in the case of titanium metal, which is extremely difficult to turn, a special cutting tool is prepared with a squeeze angle of the cutting tool set to about 20 degrees, and the peripheral speed of the round bar 1 is accurately controlled. In addition, it is known that a lathe can finally be processed while being sufficiently supplied and cooled by making the cutting fluid almost water-like.
[0012]
However, in the case of such a difficult-to-cut material, if the fixed bush 3 is used as it is, galling K as shown in FIG. 6 occurs.
[0013]
When such galling K is generated, the material to be cut becomes defective and galling K grows at an accelerated rate. For this reason, for example, in the case of unattended automatic operation, the operation must be forcibly stopped in the middle of the operation. In some cases, the device is destroyed, which causes a serious problem.
[0014]
Therefore, it has been common knowledge that difficult-to-cut materials cannot be turned with a fixed bush type CNC automatic lathe.
[0015]
Therefore, the inventors of the present application have studied and considered the cause of such galling K and found the following.
[0016]
That is, difficult-to-process materials such as pure titanium, titanium alloy, and stainless steel have a thermal conductivity of 0.05 (cal / cm / sec / ° C.) or less. This value is one digit or more lower than the thermal conductivity of the above-described free-cutting steel, copper, or other good-working material.
[0017]
From this, for example, frictional heat generated by rotation on the contact surface between the outer peripheral surface of the round bar 1 made of titanium bar material and the hole 3n of the fixed bush 3 is gradually stored in the bar material 1. As a result, it has been found that thermal expansion occurs, the outer diameter of the rod material 1 increases, melts, and partially sticks to the hole 3n, which is the cause of galling K.
[0018]
On the other hand, stick materials and pipe materials containing difficult-to-process materials are shipped or shipped by wrapping anti-rust paper, special paper, etc. at the time of factory shipment or long-term storage to prevent dirt and scratches or to prevent rust. Management is carried out on a daily basis, but extra man-hours are required for these operations, resulting in increased costs.
[0019]
A number of lathe processed products including a round bar material and a pipe material, in which a solid lubricating layer having a predetermined thickness is formed on the outer peripheral surface or the inner peripheral surface, have been put into practical use. In order to obtain such a product, first, after performing predetermined machining including lathe processing, masking of unnecessary portions of the formation of the solid lubricating layer is performed in order to form a solid lubricating layer at a desired portion. After the coating was formed, a finished product was obtained after drying and baking.
[0020]
Further, for example, Japanese Patent Application Laid-Open No. 54-137469 discloses a composition for drawing a steel material by utilizing the releasability of TFE (tetrafluoroethylene low polymer) of a fluoropolymer. Yes. According to this composition, although it seems to work effectively for ensuring the gloss of the surface after the drawing process, it does not contribute to the positive formation of the solid lubricating layer. Therefore, in this proposal as well, a separate process is required to form a solid lubricating layer having a predetermined thickness on the outer peripheral surface or the inner peripheral surface.
[0021]
As described above, since the number of man-hours is increased for forming the solid lubricating layer, an extra manpower is required for managing parts in the middle of completion, resulting in an increase in cost.
[0023]
Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a round bar material and a pipe material that do not require extra man-hours for preventing dirt and scratches or preventing the occurrence of rust. Yes.
[0024]
And it aims at providing the lathe processed product which formed the solid lubricating layer of predetermined thickness in the outer peripheral surface of the lathe processed product, the internal peripheral surface, or the external appearance surface at low cost.
[0025]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, according to the present invention, the guide bush installed and fixed on the main body side of the lathe machining apparatus is held so as to be capable of being sent and rotated along the longitudinal direction, It is a round bar material that is lathe processed in a single-supported state by being sequentially fed from the guide bush to the processing tool disposed on the main body side, and a solid lubricating layer having a predetermined thickness on the outer peripheral surface in advance. In order to reduce the friction in the holding state by the guide bush , the round bar is made of a metal material having a thermal conductivity of 0.05 ( cal / cm / sec / ° C. ) or less. It is characterized by being a difficult-to-work metal material of pure titanium or titanium alloy .
[0028]
Then, a guide bush installed and fixed on the main body side of the lathe machining apparatus is held so as to be able to feed and rotate along the longitudinal direction of the round bar, and to the processing tool disposed on the main body side from the guide bush. A lathe machined product in which lathe machining is performed in a single-supported state by sequentially feeding out, and a round bar material having a solid lubricant layer with a predetermined thickness formed on its outer peripheral surface in advance is used as a guide bush. In addition to lathe processing to reduce the friction of the holding state by leaving a solid lubricant layer , the lathe processing is performed by turning with a cutting tool, drilling with a cutting drill and grinding with a grinding device. In addition, a vertical end mill for grinding and processing the round bar material held at a predetermined angle by the guide bush with the rotation stopped. Further comprising a grinding device for, turning, holes, cutting, grinding is performed, the round bar material has a thermal conductivity of 0.05 (cal / cm / sec / ℃) The following metal material A solid material or tube material made of pure titanium or a titanium alloy that is difficult to process, and is characterized by leaving a second solid lubricant layer formed on the inner peripheral surface of the tube material. Yes.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0030]
FIG. 1 is a flowchart showing steps for forming a solid lubricating layer. In this figure, first, in step S1, a metal material having a thermal conductivity of 0.05 (cal / cm / sec / ° C.) or less, for example, pure titanium, titanium alloy, stainless steel, nickel alloy, Hastelloy (trade name) A batch of a solid or tubular round bar 1 having a predetermined diameter and a total length of Inconel (trade name) and other difficult-to-cut metal materials is prepared and accommodated in a tray.
[0031]
Following this, the process proceeds to step S2 and degreased with a solvent such as trichloroethylene or carbon tetrachloride or washed with water to remove surface stains and prevent coating unevenness and a decrease in the adhesive strength of the coating film described later. Like that.
[0032]
In subsequent step S3, sandblasting with alumina (60 to 120 mesh), liquid honing, or rough surface processing similar to these is uniformly performed on the surface including the outer peripheral surface and the inner peripheral surface.
[0033]
Thus, the physical treatment for the round bar is finished, and the process proceeds to step S4 where the surface is cleaned by flushing with high pressure air or washing with water. The above steps S2 to S4 are collectively referred to as a base processing step. In this step, any of the steps can be omitted as appropriate.
[0034]
Next, in step S5, the coating is stirred and the viscosity is adjusted by thinner or the like as necessary to prepare for coating.
[0035]
In step S6, a fluororesin-based paint containing PTFE (polytetrafluoroethylene) is uniformly applied by a method such as a spray gun, a roll coater, or dipping after the primer is applied as necessary.
[0036]
In subsequent step S7, preliminary drying is performed at 100 ° C. for about 30 minutes, and the process proceeds to the firing step in step S8. By this baking, baking is performed at 380 ° C. for about 30 minutes.
[0037]
Then, it progresses to step S9 and performs cooling. During this cooling process, sufficient durability to withstand the sliding of the fixed bushing can be ensured even with cooling at room temperature, but if the solid lubricating layer remains in the final product and the solid lubricating layer is exposed to high temperature or steam, it is baked. Later, if the water is immediately cooled, the durability is further improved.
[0038]
As described above, since the solid lubricating layer 2 is formed on the surface of the round bar 1, the product in this state is shipped from the factory. In addition, as a round bar material, there exists an external appearance surface including an outer peripheral surface and a side surface, and a pipe-shaped round bar material, Comprising: The solid lubricant layer 2 was formed not only on the outer peripheral surface but also on the inner peripheral surface. In addition, as long as the solid lubricant layer 2 formed on the round bar 1 is turned by a fixed bush type CNC automatic lathe, the material is not limited to the above difficult-to-work material, and may be a good-working material. .
[0039]
As this solid lubricating layer 2, fluorine resin, molybdenum disulfide, tungsten disulfide, graphite, boron nitride, polyimide, polyamide, PBI (polybenzimidazole), silicone resin , polysulfone, poly A combination of one or a plurality of ether-based and polyetheretherketone-based paints is used as appropriate, and the formation condition is that it is formed as thin as possible and does not break. Preferably, the solid lubricating layer 2 is set to 1 to 100 micrometers, so that brittle fracture does not occur in the holding state by the fixed bush, and the outer diameter tolerance of the round bar is kept within the general tolerance. It is good to make it.
[0040]
Next, FIG. 2 is a principle diagram showing how lathe machining is performed with a CNC type automatic lathe of a fixed bush type.
[0041]
In this figure, a hopper 5 for storing a large number of round bars 1 that have undergone the process shown in FIG. 1 is disposed behind the main body 10 of the lathe device, and the rounds stored in the hopper 5 are arranged. Each bar 1 is configured to be discharged downstream from the one located at the bottom.
[0042]
On the downstream side of the hopper 5, a portion in the middle of the discharged round bar 1 is gripped by the chuck portion 4 a as shown in the figure, and then rotated at high speed in the direction of arrow D 1 in the figure, and further in the direction of arrow D 2. In addition, a grip rotation feed mechanism 4 for feeding the round bar 1 at a constant speed is provided.
[0043]
Further, a fixed bush 3 fixed in the main body 10 is disposed downstream of the grip rotation feed mechanism 4, and an end 1a of the round bar 1 guided in the hole 3n of the fixed bush 3 is provided. It is configured to be held in a state of protruding to the outside of the main body 10.
[0044]
Referring further to the front view of the fixed bush 3 shown in FIG. 4, the fixed bush 3 is formed with four split grooves 3a in a substantially cross shape as shown in the figure. A hole 3n processed so as to be concentric with the outer diameter portion is formed continuously with the split groove 3a. The hole 3n is formed from an ultra-hard material such as tungsten carbide 3c, and can be sent out along the longitudinal direction of the round bar 1 by the fixed bush 3 by ensuring sufficient wear resistance. The round bar 1 that is held at a high speed and rotated at a high speed in the direction of arrow D1 in FIG. 2 is sequentially fed to the cutting tool 12 and the drill 15 so that lathe processing in a single-supported state can be performed without core blurring. It is.
[0045]
For this purpose, in preparation for lathe processing, a nut (not shown) is screwed into the screw portion 3b and gradually tightened so that the split groove 3a is narrowed by the component force generated in the taper portion 3P and fixed. The gap between the hole 3n of the bush 3 and the outer peripheral surface of the round bar 1 is set as small as possible. After this preparation, lathe processing is performed as will be described later, and high-precision lathe processing with extremely small occurrence of core blur can be realized. In FIG. 4, for convenience of illustration, there is a gap between the hole 3 n and the layer 2 on the outer peripheral surface of the round bar 1, but after preparation, depending on the accuracy of the workpiece. The required dimension (several micrometers to several tens of micrometers) is adjusted so that the gap is fine.
[0046]
On the other hand, the main body 10 includes a moving table 13 having a plurality of types of cutting tools 12, a moving table 16 having a drill 15 having different outer diameters, and a moving table 18 having different vertical end mills 17, respectively. It is provided so as to be movable relative to the main body 10. Further, the main body 10 is provided with a supply unit 14 for supplying a cutting fluid to the cutting unit and a tray 20 for storing the processed workpiece W.
[0047]
The control device 100 is connected to the above hopper 5, gripping rotation feed mechanism 4, each moving table and others via a signal line shown by a broken line. An input device 101 and a display device 102 connected to the control device 100 are connected to the control device 100. Used to execute an automatic lathe machining program.
[0048]
FIG. 3 is an operation explanatory view showing a state after starting an automatic lathe machining program for machining a workpiece W having a shape as shown in the figure.
[0049]
In this figure, first, a machining program for machining a workpiece W having a shape as shown in the drawing is input to the control device 100 using the input device 101 and the display device 102 in advance. Thereafter, when activated, the round bar 1 is first discharged from the hopper 5 in the direction of the arrow A, and the intermediate part is gripped by the gripping rotation feed mechanism 4 as shown in the figure. Further, the round bar 1 is held by the fixed bush 3 which is set so that the gap has a minimum necessary size by the above-described preparation, and starts rotating.
[0050]
Subsequently, for example, after the moving table 16 is moved in the direction of the arrow D5 in order to perform drilling with the drill 15, the hole is moved by moving in the direction of the arrow D6. Also, before and after this, after the moving table 13 is moved in the direction of arrow D3 and a desired cutting tool is selected, the cutting tool 12 moves in the direction of arrow D4 and stops.
[0051]
Thereafter, the round bar 1 is fed (arrow A1 direction) by the moving action of the gripping rotation feed mechanism 4 in the arrow D2 direction, and cutting is performed. At this time, the cutting fluid is supplied from the supply unit 14 to the cutting unit, but even a difficult-to-cut material can be cut without using a special cutting fluid or oil.
[0052]
By the above operation, the workpiece W having an arbitrary shape as shown in the figure is processed. Here, the moving table 18 provided with the end mill 17 is for cutting the round bar 1 that is stopped at a predetermined angle by a fixed bush. The end mill is used to cut key grooves, bolt heads, and the like. Since the shape portion can be appropriately processed, all desired products can be processed with one lathe device. A grinder or the like can be added as appropriate.
[0053]
Processing using the round bar 1 automatically supplied as described above is based on unmanned automatic operation in principle. Therefore, for example, if a difficult-to-process material such as pure titanium, titanium alloy, or stainless steel with a thermal conductivity of 0.05 (cal / cm / sec / ° C) or less is used as it is, a conventional round bar The frictional heat generated by the rotation at the contact surface between the outer peripheral surface of the material 1 and the hole 3n of the fixed bush 3 is gradually stored in the bar material 1 to cause thermal expansion, and the outer diameter of the bar material 1 As a result, there was a galling state in which the hole 3n was partially fixed, and the automatic operation was forced to stop halfway.
[0054]
However, referring again to FIG. 4, as the round bar 1, the solid lubricant layer 2 having a predetermined thickness is formed on the outer peripheral surface through the process described in FIG. 1. Since the holding state by the fixed bush 3 can be reduced and the lathe can be turned by the cutting tool 12 shown by the broken line while rotating at high speed in the direction of arrow D, heat generation due to friction can be prevented. As a result, even if it is a difficult-to-cut material, favorable processing becomes possible.
[0055]
FIG. 5 is a central sectional view of a lathe product. First, (a) shows a needle 200 obtained by cutting the metal titanium round bar 1 having an outer diameter of 6 mm by the above method. FIG.
[0056]
This needle 200 is a fine adjustment needle used as a needle of an ultrasonic scalpel for cataract surgery of a human eyeball, has a total length of about 35 mm, and an outer diameter of a tip portion of about 0.8 mm. It has a hole. Conventionally, in order to obtain such a needle 200, a dedicated cutting tool is prepared, and a large amount of dedicated cutting fluid is used to process each piece. Therefore, the processing cost is very high. It was. For this reason, it was reused by disinfecting it after use in surgery.
[0057]
Even such a needle 200 uses the lathes shown in FIGS. 1 to 4, and for example, a large number of metal titanium round bars 1 having a total length of about 200 to 250 cm are set on the hopper 5, By operating the lathe unmanned automatically and turning at a predetermined number of revolutions (around 2000 rpm), it becomes possible to manufacture a large amount of the lathe with high accuracy and at low cost.
[0058]
As a result, since it can be manufactured in large quantities at low cost, it can be handled as a so-called disposable product like a syringe, and hospital infections can be actively prevented.
[0059]
FIG. 5B is a central cross-sectional view of the roller 201, which is processed so as to leave the state where the solid lubricating layer 2 is formed, and only the portion 1c into which the bearing B is press-fitted is processed. is there.
[0060]
By processing in this way, a step of separately forming the solid lubricating layer 2 on the outer peripheral surface of the roller 201 becomes unnecessary. Furthermore, since the solid lubricant layer 2 is formed in advance on the round bar 1, there is an advantage that consideration for preventing dirt and scratches or preventing the occurrence of rust becomes unnecessary.
[0061]
FIG. 5 (c) shows a joint obtained by lathing a pipe 1 in which a solid lubricating layer 2 is formed in advance on both an outer peripheral surface and an inner peripheral surface of a pipe using the lathe shown in FIGS. 2 is a sectional view of a product 202. FIG. In this figure, only the threaded portion 1d is turned to leave the solid lubricating layer 2 on both the outer peripheral surface and the inner peripheral surface, thereby being resistant to rust and resistance to the fluid flowing inside. Products that can be reduced can be provided. In addition, the illustrated product can be obtained even by using a screw machining device or tool such as a normal NC lathe or general-purpose lathe.
[0062]
It has been described that the thickness of the solid lubricant layer 2 is preferably set to 1 or more and 100 microns or less so that brittle fracture due to holding and sliding of the fixed bush 3 does not occur. Since the joint part 202 having the screw part 1d that does not require special machining accuracy as shown in (c) can be machined in a light holding state, brittle fracture does not occur even if the thickness of the solid lubricating layer 2 is increased. It can be formed.
[0063]
Finally, in the above description, the case where the solid lubricating layer 2 is formed in advance on the round bar 1 side is mainly described. However, if necessary, the solid lubricating layer 2 is formed in advance on the hole 3n side of the fixed bush 3. In addition, a lathe process may be performed with the intention that the solid lubricating layer 2 of the fixed bush 3 is worn away immediately. Therefore, in this case, automatic continuous operation cannot be performed.
[0064]
【The invention's effect】
As described above, according to the present invention, it is possible to turn difficult-to-cut materials, which has been impossible in the past, with a fixed bush type CNC automatic lathe, and to prevent dirt and scratches or rust. It is possible to provide a round bar that eliminates the need for extra man-hours to prevent the occurrence of the above.
[0066]
And the lathe product which formed the solid lubricating layer of predetermined thickness in the outer peripheral surface of the lathe product, the internal peripheral surface, or the external appearance surface can be provided at low cost.
[0067]
[Brief description of the drawings]
FIG. 1 is a flowchart showing a process for forming a solid lubricating layer.
FIG. 2 is a principle view showing a state in which a lathe is machined by a fixed bush type CNC type automatic lathe.
FIG. 3 is an operation explanatory view showing a state in which lathe machining is performed by a fixed bush type CNC type automatic lathe.
4 is a front view of a fixed bush 3. FIG.
FIG. 5 is a central sectional view of a lathe product.
FIG. 6 is a front view of a conventional fixed bush.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Round bar material 2 Solid lubrication layer 3 Fixed bush 4 Grasp rotation feed mechanism 5 Hopper 10 Main body (fixed bush type CNC automatic lathe)
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Claims (8)

A guide bush installed and fixed on the main body side of the lathe machining apparatus is held so as to be capable of being fed and rotated along the longitudinal direction, and is sequentially fed from the guide bush to the machining tool disposed on the main body side. In a round bar material that is turned in a single-supported state,
In order to reduce the friction of the holding state by the guide bush by forming a solid lubricant layer of a predetermined thickness on the outer peripheral surface in advance , the round bar has a thermal conductivity of 0.05 ( cal / A round bar material characterized by being a difficult-to-work metal material of pure titanium or a titanium alloy, which is a metal material of cm / sec / ° C. ) or less . As the solid lubricant layer, fluorine resin, molybdenum disulfide, tungsten disulfide, graphite, boron nitride, polyimide, polyamide, PBI (polybenzimidazole), silicone resin, polysulfone, polyether The round bar material according to claim 1 , wherein a combination of one or a plurality of types of polyether type and polyether ether ketone type paints is used. In order to form the solid lubricant layer, a ground treatment step for the round bar material, a step of applying the paint of each system, a step of preliminary drying, a step of firing, and a step of cooling are sequentially performed. The round bar according to claim 1 , wherein By setting the thickness of the solid lubricating layer as small as possible and setting it to 1 to 100 micrometers, it is possible to prevent brittle fracture in the holding state by the guide bush and 4. The round bar according to claim 3 , wherein the diameter tolerance is kept within the general tolerance. A guide bush installed and fixed on the main body side of a lathe machining apparatus is held so as to be able to feed and rotate along the longitudinal direction of the round bar, and to the processing tool disposed on the main body side from the guide bush. It is a lathe processed product in which lathe processing is performed in a single-supported state by sending out sequentially,
As the round bar material, a lathe is processed so as to reduce the friction of the holding state by the guide bush by using a solid lubricant layer having a predetermined thickness formed on the outer peripheral surface in advance. The at least part of the solid lubricant layer is left , and the lathe processing includes turning with a cutting tool, drilling with a cutting drill , and grinding with a grinding device,
Furthermore, it further includes a vertical end mill for performing processing on the round bar material held at a predetermined angle by the guide bushing and a grinding device for performing grinding, and includes turning, drilling, and cutting. Processing, grinding,
The round bar is a solid material or tube material made of a metal material having a heat conductivity of 0.05 ( cal / cm / sec / ° C. ) or less and made of pure titanium or a titanium alloy difficult to process. A lathe processed product characterized by leaving a second solid lubricant layer formed on the inner peripheral surface of the tube material . As the solid lubricant layer, fluorine resin, molybdenum disulfide, tungsten disulfide, graphite, boron nitride, polyimide, polyamide, PBI (polybenzimidazole), silicone resin, polysulfone, polyether 6. A lathe product according to claim 5 , wherein a combination of one or a plurality of paints based on a polyether ether ketone paint is used. In order to form the solid lubricant layer, a ground treatment process for the round bar material, a process of applying the paints of each system, a preliminary drying process, a baking process, and a cooling process are sequentially performed. The lathe product according to claim 6 . By setting the thickness of the solid lubricating layer as small as possible and setting it to 1 to 100 micrometers, it is possible to prevent brittle fracture in the holding state by the guide bush and A lathe product according to claim 7 , characterized in that the radial tolerance is kept within the general tolerance.

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