JP5007134B2 - Parts polishing method, parts and plastic for polishing - Google Patents

Description

  The present invention relates to a technique for polishing a component whose main component is cemented carbide.

  Cemented carbide is an alloy obtained by sintering powder of hard metal carbide or the like, and is often used as a material for a cutting tool for metal processing because it has a low hardness reduction at high temperatures and is very difficult to wear. Patent Documents 1 and 2 disclose a tool processing method and a manufacturing method using such a cemented carbide.

  In recent years, as represented by digital cameras and mobile phones, demand for portable products tends to increase due to ease of use and convenience of movement. Along with the miniaturization of products, miniaturization of components constituting the products has progressed, and strict shape accuracy is required even for the fine components. In general, when trying to form small parts of the order of millimeters using milling, it is necessary to use a tool with a diameter smaller than the required shape. Hard alloy materials are used.

However, as the diameter of the tool is reduced, the cutting edge is remarkably difficult to form, and in particular, microchipping and polishing marks generated during the forming of the tool may remain on the cutting edge ridgeline. Therefore, it is desired to develop a polishing method for sharpening the cutting edge of a tool in order to improve the processing accuracy when the part is finely processed.
JP 2004-74313 A JP 2006-205327 A

  The present invention has been made in view of the above-mentioned circumstances, and the object thereof is to make a desired portion of a part mainly composed of cemented carbide used as a tool material or a mold material more flat. To provide technology.

In order to solve the above-mentioned problems, a method for polishing a part according to an aspect of the present invention is a method for polishing a part containing a cemented carbide as a main component to polybenzimidazoles, polycarbonates, polysulfones, polyethersulfones, polyarylates. A block selected from the group consisting of polyamideimides, polyetherimides, polyphenylene sulfides, polyether ether ketones, polyimides, polytetrafluoroethylenes, and mixtures thereof including copolymers Polish with plastic in contact .

  According to this aspect, it is possible to make a desired part of the part flatter than a method such as polishing with a grindstone or shot blasting. For example, by applying this method to a grinding tool whose main component is cemented carbide, unevenness such as grinding marks and microchipping of the edge of the cutting edge that occurs when a cutting edge is formed with a grindstone or the like can be made flatter. can do. Further, by applying this method to a mold having cemented carbide as a main component, the mold surface can be made flatter.

Another aspect of the present invention is a component mainly composed of a cemented carbide , polished in a state where the above-mentioned block-shaped plastic is brought into contact therewith. According to this aspect, for example, by using this part as a grinding tool, the processing accuracy of the material to be ground can be improved. Further, for example, by using this part as a mold part of a lens requiring high flatness, a high quality lens can be mass-produced.

Yet another aspect of the present invention provides polybenzimidazoles, polycarbonates, polysulfones, polyethersulfones, polyarylates, polyamideimides, which are used for polishing a cemented carbide-based component. A block-like abrasive plastic selected from the group consisting of polyetherimides, polyphenylene sulfides, polyether ether ketones, polyimides, polytetrafluoroethylenes, and mixtures thereof including copolymers. .

  According to this aspect, it is possible to flatten a desired portion of a component mainly composed of a cemented carbide as compared with an abrasive material such as a grindstone or silicon carbide particles.

  ADVANTAGE OF THE INVENTION According to this invention, the desired location of the components which have as a main component the cemented carbide used as a tool material or metal mold | die material can be made flatter.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. A suitable object of the component polishing method according to the present embodiment is a cutting component mainly composed of cemented carbide. Below, the grinding | polishing method is demonstrated to an example for an end mill as cutting parts.

  In addition, the cemented carbide which is the object of the polishing method according to the present embodiment is a composite material obtained by sintering carbides such as periodic table IVa, Va and VIa metals with iron-based metals such as Fe, Co and Ni. There is little decrease in hardness at high temperature, and it is very difficult to wear. Typically, tungsten carbide (WC) and binder (binder) cobalt (Co) mixed and sintered mainly in fields where wear resistance such as cutting and molds is required. Used in. In the following description, the case of a WC—Co alloy will be described.

  In addition to the aforementioned WC-Co alloys, WC-TiC-Co alloys, WC-TaC-Co alloys, and WC-TiC-TaC-Co alloys with improved oxidation resistance are also available as cemented carbides. It can be an object of a polishing method. Further, as a cemented carbide alloy, a WC—Ni alloy having a binder phase of Ni, or a WC—Ni—Cr alloy whose corrosion resistance is further improved by the addition of Cr can be used as a target for the polishing method.

  FIG. 1 is a schematic view showing a polishing method according to the present embodiment. The polishing plastic according to the present embodiment is polybenzimidazole (hereinafter referred to as PBI) having a chemical composition represented by the general formula (1).

  The PBI 10 shown in FIG. 1 is obtained by compressing a raw material powder by hot pressing into a plate shape. However, since the deteriorated layer remains in the portion in contact with the mold, this portion was removed and used as a 20 × 10 × 30 mm shape. As a characteristic property of PBI10, the hardness is as high as HRA50, and in particular, the tensile strength is 160 MPa equivalent to that of pure aluminum. PBI10 has the highest heat deformation temperature of 708K among the thermoplastic resins.

  A grinding tool to be polished is a two-blade square end mill 12 having a diameter of 1.6 mm, and a material thereof is an ultrafine particle cemented carbide. As a polishing apparatus, a small high-speed polishing machine of a three-axis linear motor drive system capable of mounting a square end mill to be polished was used. As shown in FIG. 1, the polishing conditions are as follows: the rotational speed (V) of the outer periphery of the square end mill 12 is 16.7 m / s, the feed amount per blade (Sz) is 4.3 μm / tooth, and the axial cut (Aa). : 50 μm, radial cut (Ar): 30 μm, and polishing was performed while supplying 0.5 MPa of dry air from the nozzle 14. In addition, what is necessary is just to select a rotational speed (V) suitably in the range of about 10 m / s-40 m / s.

  FIG. 2 is a view showing a state of a typical cutting edge before the molded square end mill 12 is polished by the PBI 10. FIG. 3 is a view showing a state of a typical cutting edge after the square end mill 12 is polished by the PBI 10 at a polishing rate of 16.7 m / s.

  From FIG. 2, a large number of grinding marks 17 generated during molding and polishing are observed on the cutting edge 16 before processing. Further, it can be confirmed that the microchipping 18 in which the WC particles have fallen off is generated on the cutting edge ridge line (bright and dark boundary region in the figure). On the other hand, FIG. 3 shows the cutting edge 16 after processing with a polishing distance of 400 m. As shown in FIG. 3, the cutting edge 16 is in an extremely flat state where the angular shape of the WC particles in the flank portion can be clearly confirmed. Further, the cutting edge 16 is not observed even at the cutting edge ridge line, and an extremely sharp cutting edge ridge line is formed by wear. Therefore, using the square end mill 12 polished by the PBI 10 can improve the processing accuracy of the material to be ground.

  Next, a mechanism for flattening the component by polishing with the PBI 10 will be described. There are two possible causes for the wear and flattening of the cutting edge of the square end mill 12 due to a reaction due to an increase in wear temperature and generation of wear powder due to decomposition of the PBI material. In order for the former to work as a main cause of wear, it is necessary to cause a reaction between WC and PBI material in the cemented carbide, but it is considered that a temperature of at least 1273 K or more is necessary for WC to chemically react. However, the PBI material has a glass transition temperature of around 710K and a melting point of 1273K or less. Therefore, there is little possibility of reaction due to an increase in wear temperature.

Therefore, in order to verify the possibility of generation of wear powder due to the PBI material used as the polishing plastic, the molecular structure on the wear surface of the PBI material by Fourier transform infrared spectroscopy (FT-IR-ATR) Analysis was conducted to examine composition changes. FIG. 4 shows that the FT-IR-ATR spectrum analysis was performed on the worn surface, the unworn surface, and the chips of the PBI material, and based on these values, the difference spectrum between the worn surface and the unworn surface (1445 cm ⁻¹ near benzene). It is a graph in which the C = C in-plane skeleton vibration of the ring is organized).

From FIG. 4, in the wear surface, 802cm ^-1 3-substituted benzene in the vicinity (P1 shown in FIG. ^{4), 700cm -1 (P2)} 2 -substituted benzene in the vicinity, ^{1280 cm} -1 (P3) near the imidazole ring, 1650 cm ^{- 1} Absorption band derived from N-H bending vibration or C = N stretching vibration near (P4) decreases, NH stretching vibration near 3400 cm ⁻¹ (P5), 2924 to 2853 cm ⁻¹ (P6 to P7) Absorption bands derived from CH stretching vibration are increasing. The peak near 3050 cm ⁻¹ (P5) is derived from the C═H stretching vibration of the benzene ring.

In addition, an absorption band derived from NH stretching vibration near 3400 cm ⁻¹ has appeared, and the amine component has increased. For this reason, the vicinity of 1650 cm ⁻¹ is considered to be C═N stretching vibration accompanying an increase in amine, and since this is decreased, it can be estimated that the C═N bond form of the imidazole ring is changed. This result is the same in the analysis result of chips. From these analysis results, there is a high possibility that the bond at the imidazole ring moiety is cleaved. From the above, molecular-level carbon wear powder and wear powder in units of benzene rings are generated, and it is clear that these fine wear powders contribute to the smooth wear of the above-mentioned cemented carbide. is there.

  Therefore, by using engineering plastics having a benzene ring and an imidazole ring, including PBI materials, as a polishing plastic, cemented carbide is the main component compared to abrasive materials such as grinding stones and silicon carbide particles. The desired part of the part can be made flatter.

  As polishing plastics having a benzene ring which is a kind of aromatic ring, polybenzimidazoles, polycarbonates, polysulfones, polyethersulfones, polyarylates, polyamideimides, polyetherimides containing the above-mentioned PBI Polyphenylene sulfides, polyether ether ketones, polyimides, and a mixture thereof including a copolymer can be used. Here, the “class” includes, in addition to the structure of the representative compound of each plastic described above, a structure in which a part of the structure is modified within the range of physical properties that can be used for the polishing plastic. For example, a derivative obtained by substituting a part of a compound such as an aromatic ring or a substituent of each plastic with another atom or a functional group may be used.

  Examples of the aromatic ring include a monocyclic aromatic ring such as benzene, a polycyclic aromatic ring such as polycarbonate, and a polycyclic heterocyclic aromatic ring such as benzimidazole. Moreover, polytetrafluoroethylenes etc. can also be used as a polishing plastic which does not have an aromatic ring. Further, instead of the imidazole ring, or a polishing plastic having an imide bond in addition to the imidazole ring may be used.

  As described above, the aromatic ring in each plastic may have a substituent, for example, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, and a propyl group, a methoxy group, an ethoxy group, and the like. Substituents such as halogens such as fluorine groups, chlorine atoms, bromine atoms, aryl groups such as phenyl groups and naphthyl groups, aralkyl groups having 7 to 12 carbon atoms such as alkoxy groups having 1 to 6 carbon atoms, benzyl groups, and the like. It is done. There may be a plurality of substituents, in which case the substituents may be of different types. These substituents may further have a substituent.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. Embodiments to which such modifications are added Can also be included in the scope of the present invention.

  For example, in the polishing method according to the above-described embodiment, the end mill is rotated at a high speed with respect to the fixed PBI material, but the PBI material may be rotated with respect to the end mill.

  As mentioned above, parts made mainly of cemented carbide polished with plastic are not only used for cutting tools such as end mills, but also for many uses such as surface finishing of lens molds and sharpening of cutting edge ridges of small diameter tools. Application to can be expected.

It is the schematic diagram which showed the grinding | polishing method which concerns on this Embodiment. It is the figure which showed the mode of the typical cutting edge before grind | polishing the molded square end mill by PBI. It is the figure which showed the mode of the typical cutting edge after grind | polishing a square end mill by PBI. FT-IR-ATR spectrum analysis is performed on the worn surface, unworn surface, and chips of the PBI material, and is a graph in which the difference spectrum between the worn surface and the unworn surface is arranged based on these values.

Explanation of symbols

  10 PBI, 12 square end mill, 14 nozzles.

Claims (4)

Parts made mainly of cemented carbide are polybenzimidazoles, polycarbonates, polysulfones, polyethersulfones, polyarylates, polyamideimides, polyetherimides, polyphenylene sulfides, polyetheretherketones Polishing in the state which contacted the block-shaped plastic selected from the group which consists of these, a polyimide, polytetrafluoroethylenes, and these mixtures containing a copolymer. The part is an end mill tool;
The component polishing method according to claim 1, wherein polishing is performed while rotating the end mill tool relative to the plastic. Polybenzimidazoles, polycarbonates, polysulfones, polyether sulfones, polyarylates, polyamideimides, polyetherimides, polyphenylene sulfides, polyetheretherketones, polyimides, polytetrafluoroethylenes, and A component whose main component is cemented carbide polished with at least one block-shaped plastic selected from the group consisting of a mixture containing a copolymer in contact with the plastic. Polybenzimidazoles, polycarbonates, polysulfones, polyethersulfones, polyarylates, polyamideimides, polyetherimides, polyphenylene sulfides, used for polishing parts mainly composed of cemented carbide A block-like abrasive plastic selected from the group consisting of polyether ether ketones, polyimides, polytetrafluoroethylenes, and mixtures thereof including copolymers.