JPH0523968A - Polishing method and device - Google Patents

Abstract

PURPOSE:To provide a polishing method and device which is simple in structure and ease in handling and, moreover, capable of performing the automation of a finishing process in an easy manner. CONSTITUTION:This method is composed of having a work 6 with a concave work surface opening to the upper side, a tool 3 reciprocating in the vertical direction, and having a convex work surface formed into almost the same shape as the work surface of the work 6, a viscoelastic body 12 being held between the work 6 and the tool 3 and pressurized into deformation, and made up of kneading an abrasive grain, and two restoring devices 8, 14 adding some external pressure to the viscoelastic body 12 capable of overflowing to the outside as flowing from an interval between the work surface and the tool machining surface at the time of pressing the tool 3 to the work 6, and thereby restoring it onto the work machined surface. Accordingly, when the viscoelastic body 12 is pressed to the machined surface and made to flow therein, abrasive grains in the viscoelastic body cane to repeat an abrasive action on the work machined surface in consequence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and apparatus for polishing a surface of a workpiece which has been finished by electrical discharge machining or the like so as to have a finer surface roughness.

[0002]

2. Description of the Related Art In electrical discharge machining such as EDM machining (carving), an electrode having a shape substantially the same as the machined shape is gradually brought closer to a work (workpiece) to excite a discharge phenomenon between the two. This is a processing method for forming a work into a predetermined shape by removing the surface portion.

Although this electric discharge machining method has an excellent feature that an inner surface corner and a fine portion which cannot be machined by a rotary cutting tool can be easily machined, since an electric discharge phenomenon occurs spotwise, the surface to be machined of a workpiece is processed. The surface roughness has a certain limit by itself, and there is an unavoidable problem that the material of the surface to be processed changes due to heat during the electric discharge phenomenon.

For this reason, in the case where a further processed surface roughness is required as in the case of die manufacture, or when the change or alteration of the surface properties is disliked (therefore, that portion should be removed), after the processing, It is necessary to additionally perform finishing (polishing work) on the work.

[0005]

However, the above-mentioned finishing work is usually performed manually, and such work is extremely troublesome and troublesome. Or it may be partially mechanized, but its structure is complicated and expensive, and NC
Handling is complicated, such as having to create a program. Therefore, the advent of a polishing method and an apparatus capable of automating this finishing process with a simple structure and handling is desired.

[0006]

In order to solve the above-mentioned problems, a polishing method according to the present invention is characterized in that a viscoelastic body in which abrasive grains are kneaded is put into a concave processed surface opening on the upper surface of a work, Facing the tool having a convex processing surface having substantially the same shape as the surface to be processed, and performing relative reciprocating motion in the up-and-down direction between the work and the tool, and the tool and the work. And when approaching to a predetermined distance, the viscoelastic body flows through the gap between the machined surface of the tool and the machined surface of the work piece, and the abrasive grains in the viscoelastic body are projected on the upper surface of the work piece. Scrape while pressing the work surface of
When the tool and the work are separated from each other, the protruding viscoelastic body is returned to the concave work surface of the work, and the reciprocating motion and the returning operation of the viscoelastic body are repeatedly performed to form the concave shape of the work. The feature is that the surface to be processed is polished. Further, the polishing apparatus according to the present invention is a workpiece having a concave surface to be machined that is open upward, and a reciprocating motion in the up and down direction connected to a drive device above the workpiece, and the surface to be machined of the workpiece. A tool having a convex processing surface having substantially the same shape, a work piece and a tool, which is sandwiched between the work and the tool and deformed under pressure, and a viscoelastic body in which abrasive grains are kneaded, and the tool is pressed against the work. A viscoelastic body that flows from between the work surface and the tool processing surface at the time of pressing and can protrude to the outside, a returning device that applies external pressure to return the viscoelastic body to the work surface, and the tool moves upward. And a control means for timing the tool so as to descend when the returning operation of the returning device is completed, and the viscoelastic body has a surface to be processed of the workpiece. Flows while being pressed against Abrasive grains in the viscoelastic body is characterized by being configured so as to repeatedly rubbing the workpiece surface to be processed during that.

[0007]

The viscoelastic body is pressed by the vertically movable tool and flows between the work surface and the tool processing surface, whereby the work surface is effectively and satisfactorily rubbed. At this time, the viscoelastic body protruding to the outside is easily returned to the work surface by the returning device, so that this rubbing action can be repeatedly obtained, whereby a rational and economical polishing operation can be performed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side sectional view of an essential part of an embodiment of a polishing apparatus according to the present invention, FIG. 2 is a view seen from above along the line II-II in FIG. 1, and FIG. It is a figure. First, the basic structure of the illustrated embodiment device will be described with reference to FIGS. 1 and 2. What is arranged above the center is
The head 2 is connected to a vertical movement device (not shown), and a machining tool 3 is attached to the lower side of the head 2. On the lower side of the tool 3, a device body (not shown)
Workpiece (workpiece) mounted on the fixed base 5 of
6 is located. A plurality of pneumatically operated cylinders 8 are appropriately attached to the outer circumference of the work 6 via a base 9 so as to surround the work 6. A plate 14 for attaching the viscoelastic body 12 protruding to the outside of the work 6 to the original central portion is attached to the tip portion of the rod 10, which is the operating portion of these cylinders 8, in the processing step described later.

The work 6 has a recess 6a, which has been carved, in the center thereof, and the recess 6a having substantially the same shape as the outer shape of the tool is previously formed by another machining method (for example, die-sinking electric discharge machining). Next, the inner surface (work surface) of the recess 6a is formed with a certain degree of accuracy. A semi-solid viscoelastic body 12 having a predetermined degree of viscoelasticity and kneaded with abrasive grains is thrown into the work recess 6a.

The viscoelastic body 12 can be deformed with a small force when it is slowly deformed, but has a large repulsive force when it is rapidly deformed. Fluids that can differ. Therefore, when the viscoelastic body 12 is sandwiched between the tool 3 and the work 6 as described later and a predetermined pressure is applied thereto, the viscoelastic body 12 rubs the work surface of the work 6 in the compressed state and the tool 3 and the work 6 are rubbed. Flow through the gap with 6. At this time, since the abrasive grains move while being pressed against the surface to be processed, the extremely fine protrusions on the surface to be processed of the work are scraped off by the abrasive particles (that is, so-called abrasion). Due to the rubbing action due to the flow of the abrasive grains, the surface to be processed of the workpiece is finished to have extremely good surface roughness as a whole.

Silicon carbide, diamond, or the like can be used as the abrasive grains, and a resin material or the like having a predetermined viscoelasticity can be used as the base material. As a viscoelastic body, a commercially available product (for example, an abrasive (trade name, media) provided by Toyo Extrude Horn Co., Ltd.) can be simply used. Next, the processing steps in the apparatus of the embodiment will be described below with reference to FIG.

First, the tool 3 is gradually lowered by a vertical movement device (not shown) to narrow the gap between the tool 3 and the work 6, and when the viscoelastic body 12 between them is pressed, the viscoelastic body is pressed.
12 starts to flow outward (in the direction of the arrow) based on the characteristics described above (FIG. 3A). At this time, due to the flow of abrasive grains,
The work surface is properly rubbed. Then, when the tool 3 stops at a predetermined lowered position, the flow of abrasive grains also stops, and at this time, most of the viscoelastic body 12 protrudes into the work top surface portion surrounding the work recess 6a (FIG. 3 (b)). .

Next, the tool 3 is raised this time (FIG. 3 (c)). However, in this state, the viscoelastic body 12 does not return to the center of the work recess 6a due to its own viscosity, so this protrusion is generated. In order to forcibly return the viscoelastic body 12 to its original position, the cylinder 8 is driven to move the plate 14 at the tip of the rod and push the viscoelastic body 12 into the recess 6a (Fig. 3 (d)). ).

When the limit switch detects that the tool 3 has risen, driving of the cylinder 8 is started, and another limit switch indicates that the cylinder 8 has finished the returning operation of the viscoelastic body and has returned to the initial state. When it is detected, the tool 3 is lowered and the cylinder 8 is moved up and down.
Although not shown, the control means for controlling the timing of the return operation is constituted by a combination of these limit switches and a known sequence circuit.

One processing step is completed by the above series of steps. However, since it may not be possible to expect a sufficient rubbing effect by this alone, the series of steps (a) to (d) is repeated. Repeat as many times as you need. As a result, the work surface of the work 6 is transformed into a finished surface having extremely excellent surface roughness as a result of the above-described rubbing action due to the flow of abrasive grains being repeated many times.

As described above, according to the apparatus of this embodiment, it is possible to perform accurate polishing (scratching) without requiring manual work, although it has an extremely simple and simple structure. The system can be configured in a good manner, and the surface roughness of the work surface of the workpiece can be excellently finished, work efficiency and efficiency are dramatically improved, and the finishing process can be simplified and automated, which is rational and economical. is there.

The work 6 has a viscoelastic body 12 inside the work.
Has an inner surface (working surface) shape that returns (or easily returns), and an inner surface shape in which the viscoelastic body flows (or easily flows) along the inner surface of the work from the inside of the work, such as a concave work surface. In principle, it has a processing surface.
If so, for example, for a work having a hole penetrating vertically by wire electric discharge machining, if there is no bottom when it is desired to finish the inner peripheral surface of the hole with good surface roughness, Polishing work cannot be performed using the apparatus of this embodiment.

However, even for such a work, if a predetermined member (not shown) is applied to the lower side of the work to close the prepared hole, and a bottom is provided for convenience and temporarily, It goes without saying that processing can be performed by the apparatus of this embodiment. Further, for example, in the case where the work is formed by die-sinking electric discharge machining, it is possible to use the electric discharge electrode as it is (or after a certain surface treatment) as a tool in this embodiment. is there.

Further, in the present specification, the cylinder 8 or the like is used as a means for returning the viscoelastic body 12 protruding at the time of processing to the center of the recess, but the idea itself of the present invention is not limited thereto. It goes without saying that various modes can be considered instead. By the way, although it depends on the shape of the work surface (inner surface), etc., the viscoelastic body 12 does not always flow evenly on the inner surface when the tool 3 is pressed downward, and therefore the polishing state may become uneven. If there is such a change, for example, the vertical center axis of the tool 3 and the corresponding center axis of the work 6 are appropriately shifted (for example, sequentially in each of the above series of steps) to change the pressure pattern. A method can be considered. That is, in this way, the gap size between the tool and the work during machining becomes non-uniform, and the flow state of the viscoelastic body 12 changes or fluctuates.In other words, the polishing state can be controlled. By this, it is possible to easily and surely obtain a processed surface having a further excellent surface roughness.

[0020]

As described above, according to the present invention, a finished surface having a good surface roughness can be easily formed without depending on manual work, and work efficiency and efficiency are remarkably improved. Further, this makes it possible to automate the finishing process, has a simple structure, and is easy to handle, which is rational and economical.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part of an embodiment of a polishing apparatus according to the present invention.

FIG. 2 is a view seen from above along the line II-II in FIG.

FIG. 3 is a process drawing of an example.

[Explanation of symbols]

3 ... Tool 6 ... Work (workpiece) 6a ... recess 8 ... Cylinder 12 ... Viscoelastic body 14 ... Plate

Claims (2)

[Claims] 1. A viscoelastic body in which abrasive grains are kneaded is placed in a concave surface to be processed that is open on the upper surface of a work, and a convex surface to be processed having a shape substantially the same as the surface to be processed is provided above the work. A tool having is faced, and a relative reciprocating motion in the vertical direction is performed between the work and the tool, the tool and the work approach to a predetermined distance, the viscoelastic body and the processing surface of the tool. Abrasive grains in the viscoelastic body rubbed while pressing the work surface of the work while protruding into the upper surface of the work while flowing through the gap between the work surface of the work, and the tool and the work were separated from each other. Sometimes the protruding viscoelastic body is returned to the concave work surface of the work, and the reciprocating motion and the returning operation of the viscoelastic body are repeatedly performed to polish the concave work surface of the work. The polishing method characterized in that 2. A work having a concave work surface that opens upward, and a reciprocating motion in the up and down direction connected to a drive device above the work, and has a substantially same shape as the work surface of the work. A tool having a convex processing surface, a viscoelastic body sandwiched between the work and the tool, deformed under pressure, and kneaded with abrasive grains, and the work piece when the tool is pressed against the work. For a viscoelastic body that can flow out between the machining surface and the tool machining surface and protrude to the outside, a returning device that applies external pressure to return the viscoelastic body to the work surface, and when the tool is rising. A state in which the viscoelastic body is brought into pressure contact with the work surface of the workpiece by operating the returning device and controlling the timing such that the tool descends when the returning operation of the returning device is completed. When flowing with Polishing apparatus characterized by abrasive sex body in is constructed so as to repeatedly rubbing the workpiece surface to be processed.