JP4875810B2 - Fluorine resin bond grinding wheel and manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluororesin bond polishing grindstone used for polishing such as lapping and polishing, and a method for producing the same.
[0002]
[Prior art]
In recent electronic-related parts and mold-related parts, mirror surface processing is required, and high shape accuracy is also required in which there is no end sagging on the workpiece. Such precision machining has been difficult to achieve with conventional low-elasticity polishing pads, grinding wheels with shafts, and polishing tapes. In addition, mirror finishing with a grinder uses ultrafine abrasive grains such as metal bond grindstones, vitrified grindstones, and resin bond grindstones, so that a machine with a highly accurate mechanism is required.
[0003]
In general, mirror finishing on a production line can be classified into two types: a free abrasive grain method and a fixed abrasive grain method. In the free abrasive method, a large amount of slurry waste liquid is generated due to the use of a liquid, which causes environmental problems. On the other hand, in the fixed abrasive system, scratches (linear deep scratches) are likely to occur due to sandwiched pieces of abrasive grains or dust and dust after polishing between the grindstone and the workpiece.
[0004]
[Problems to be solved by the invention]
From the above points, scratches do not occur in mirror finishing, end face sagging does not occur on the workpiece, and polishing can be performed with high efficiency, and conventional polishing machines such as polishing machines and grinding machines can be used as they are. A medium elastic grindstone that can be used in an environmentally friendly fixed abrasive method is desired.
[0005]
This invention makes it a subject to provide the method of manufacturing the grindstone for fluororesin bond grinding | polishing which met such a request.
[0006]
[Means for Solving the Problems]
The present invention is a porous fluororesin bond mirror polishing grindstone characterized by mixing granules and abrasive grains prepared from fluororesin powder, press-molding the obtained mixture, and firing the obtained molded product It is a manufacturing method .
[0007]
Polishing grindstone manufactured Ri by the present invention process is a fluorocarbon resin bonded abrasive grinding wheel wherein the abrasive grains in the fluororesin porous are mixed.
[0008]
As abrasive grains used in the method of the present invention, diamond grains , cerium oxide grains , silicon oxide grains and the like are preferable.
[0009]
The fluororesin used in the method of the present invention is preferably PTFE (polytetrafluoroethylene), but other fluororesins can also be used.
[0010]
In order to manufacture the grinding wheel according to the present invention, powdery PTFE (25-30 μm) is granulated (70-700 μm), and the obtained granules are mixed with abrasive grains (0.3-30 μm) in the cold. Match. The mixing ratio of PTFE granules and abrasive grains is preferably about 8: 2 by weight, but this value is not limited. When the mixing ratio of the abrasive grains is too large, the adhesion between the PTFE granules and the abrasive grains is lowered. Thereafter, the mixture is pressure-molded into a grindstone shape, for example, a donut shape, preferably at a pressure of 20 MPa or more, and the molded product is fired in a high-temperature furnace, preferably at 360-380 ° C. for about 18 hours.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be specifically described based on examples.
[0012]
Powdered PTFE (about 28 μm) was granulated (about 400 μm), and diamond granules (about 25 μm) were mixed with the resulting granule in the cold. The mixing ratio of PTFE granules and abrasive grains was about 8: 2 by weight. Thereafter, the mixture was pressure-molded into a grindstone shape at a pressure of 35 MPa, and the molded product was fired at 370 ° C. for about 18 hours in a high-temperature furnace.
[0013]
Electron micrographs (500 × and 2000 × magnification) of the porous PTFE grindstone mixed with diamond abrasive grains thus obtained are shown in FIGS. 1 and 2, respectively.
[0014]
As can be seen from the electron micrographs of FIGS. 1 and 2, there are a large number of pores in and on the surface of the grindstone.
[0015]
FIG. 3 shows the single grain elastic characteristics of the grindstone at the processed surface contact portion. Six points on the surface of the grindstone were measured with a micro Vickers type indenter in the XY direction at a pitch of 3 mm. It is assumed that the high elastic point is near the high density and the low elastic point is near the hole. In this figure, the displacement corresponds to the grain size of the abrasive grains when the grindstone bites the abrasive grains. The high elastic modulus is about 13.7 mN / μm. For example, even if abrasive grains with a diameter of 10 μm drop off and bite into the ground surface again, the load is about 0.137 N per single grain. With such a load, there is no possibility that scratches will occur in ordinary electronic device materials.
[0016]
The surface of the electronic component was polished with a porous PTFE grindstone mixed with diamond abrasive grains, using the grindstone made of porous PTFE mixed with diamond abrasive grains obtained in the mirror surface processing experiment example.
[0017]
Experiment 1
Whetstone specifications: A donut-shaped whetstone having an outer diameter of 43 mm, an inner diameter of 29 mm, and a thickness of 7 mm. Particle size: 8-16 μm
Polishing conditions: Rotational speed = 450 rpm, Feed = 50 mm / min
The experimental results are shown in FIG. As a result, PV (difference between upper and lower waveforms) = 26.6 nm and Ra (surface roughness) = 3.8 nm, and a scratch-free ultra-mirror surface can be realized even with a larger particle size than conventional grindstones.
[0018]
The grindstone according to the present invention can be used not only for a fixed abrasive method, but also for a combination of a fixed abrasive method and a free abrasive method.
[0019]
【Effect of the invention】
In the present invention, porous fluororesin is used as the base of the grindstone, so that scratching does not occur in mirror finishing, end face sagging does not occur in the workpiece, and polishing can be performed with high efficiency. Mirror finishing machines such as grinding machines can be used as they are, and they can be used in an environmentally friendly fixed abrasive system.
[0020]
As the abrasive grains, any abrasive grains such as diamond, cerium oxide (SeO ₂ ), and silicon oxide (SiO ₂ ) can be applied.
[Brief description of the drawings]
FIG. 1 is an electron micrograph (magnification 500 times) of a cross section of a grindstone made of porous PTFE mixed with diamond abrasive grains, obtained in an example. In the figure, F represents PTFE, and D represents diamond grains.
FIG. 2 is an electron micrograph (magnification 2000 times) of a cross section of a grindstone made of porous PTFE mixed with diamond abrasive grains, obtained in an example. In the figure, F represents PTFE, and D represents diamond grains.
FIG. 3 is a graph showing single grain elastic characteristics.
FIG. 4 is a graph showing the result of a mirror surface processing experiment.

Claims (4)

A method for producing a porous fluororesin bond mirror polishing grindstone, comprising mixing granules prepared from fluororesin powder and abrasive grains, press-molding the obtained mixture, and firing the obtained molded article. The method for producing a fluororesin bonded mirror polishing grindstone according to claim 1, wherein the fluororesin is PTFE powder (25 to 30 µm) and the granules are (70 to 700 µm). Abrasive diamond grains, method for producing a fluororesin bonded mirror-polishing grinding wheel according to claim 1 or 2 is a cerium oxide particle and / or silicon oxide. A fluororesin bond mirror polishing grindstone manufactured by the manufacturing method according to claim 1 and having a large number of pores inside and on the surface .

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