JPH02104467A - Method of cutting unnecessary parts of molded product and structure of the same cutting part - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is applicable to die casting products, low pressure casting products, double weight casting products, plastic mold casting products, sand mold casting products, ceramics, sintered products, etc. How to cut out unnecessary parts (runners, overflows, etc.) from molded semi-finished products (molded products) for the transportation of a wide range of molded products, such as compact metals, and
This relates to the structure of the cut-out portion.

[Conventional technology]

For cutting unnecessary parts of molded products, see Japanese Patent Application Laid-Open No. 56-990.
No. 71 discloses a method and apparatus for cutting and removing unnecessary parts of a cast product.

In the above-mentioned known technology, the part to be cut has a shape with a certain thickness dimension, and a pair of single-edged cutters is used so that the stress generated during cutting is applied only to the removed part.

[Problem to be solved by the invention]

Defects such as cavities and hot spots in die-cast products are mostly caused by the entrainment of air in the molten metal and insufficient pressure on the product. To prevent this, it is necessary to The most reliable and inexpensive method is to increase the area of the casting gate and reduce the flow rate of the molten metal passing through it in order to alleviate the wiping change. In addition, thick gates are advantageous for flow analysis applications. However, when cutting this thick gauge 1-, the above-mentioned known technique (Japanese Unexamined Patent Publication No. 56-99071) has problems with the life of the blade and the unevenness of the cut surface. Furthermore, if a saw blade is used, the cut surface is relatively smooth and the cut can be made with high precision, but there are problems in terms of efficiency and cost.

The present invention has been made in view of the above circumstances, and is capable of cutting and removing unnecessary parts of a wide range of general molded products with high precision, high efficiency, and low cost, and also provides cutting with excellent quality of the cut parts. It is an object of the present invention to provide a method and a cutting section structure for applying the above method.

By applying the present invention, it is also possible to reduce the occurrence of internal defects (casting defects) in molded products.

[Means for Solving the Problems] The cutting method of the present invention, created to achieve the above-mentioned object, cuts the boundary between the part to be used as a product (hereinafter referred to as the product part) and the unnecessary part to be cut and removed. A tapered surface is formed in the direction of opening from the cutting location toward the product, and the cutting location is sheared with a double-edged cutter.

Further, the cutting part structure of the present invention created to carry out the above-mentioned method of the invention has a tapered surface that opens toward the product part in a part closer to the product part than the cutting part.

[Effect]

As in the above cutting structure, if a tapered surface is provided closer to the product part than the cutting point and opens toward the product part, (i) Not only a single-edged cutter but also a double-edged cutter can be used as a separate cutter. Does not cause any problems.

(it) The change in the area of the flow path from the taper portion to the product portion is not sudden, the flow of the molten metal becomes smooth, and the occurrence of internal defects in the molded product is suppressed.

(Mountain) As described in item (i) above, by using a cutter with a long blade, the precision of the cutting surface is improved, the useful life of the cutter is extended, and the cutting efficiency is improved.

V) The part surrounded by the tapered surface that opens toward the product is thick and prevents early solidification, making molding work easier and suppressing the occurrence of internal defects.

〔Example〕

Figure 1 shows a case in which the cutting part structure of the present invention is applied to die casting.
It is an explanatory diagram of an example.

FIG. 2 is an explanatory diagram of a conventional example shown for comparison.

Common to both figures above, 1 is the runner part, 3 is the product part, and 4
is molten metal.

The gate portion 2 of the conventional example (FIG. 2) was configured to be as narrow as possible in order to facilitate cutting.

The gate portion 2' of this example (FIG. 1) is configured to be wider than the gate portion 2 of the conventional example. Then, a tapered surface 6 that opens from the gate portion 2' toward the product portion 3 is provided.

In the flow of the molten metal shown in FIG. 2 (conventional example), the flow path suddenly becomes wider when it flows into the product part 3 from the gate part 2, so that a large amount of entrained air 5 is mixed in.

The flow of the molten metal in FIG. 1 (embodiment) gradually widens from the gate portion 2' through the tapered surface 6 and flows into the product portion 3, so that the entrainment of air 5' is reduced.

Moreover, since the wall thickness near the taper portion 6 is large, there is no risk of preventing the flow of the molten metal due to premature solidification.

3 to 5 are explanatory diagrams of the cutting method of the present invention.

Figures 3 to 5 show the solidified state of the molten metal.
In other words, the runner section 1 is an unnecessary section.

Figure 3 is an explanatory diagram of the principle and is for convenience of explanation.

Only the lower blade 7 is depicted, and the upper blade (described later with reference to FIGS. 4 and 5) is omitted.

10 in the figure is a base, and on this is a molded product (workpiece) (
In this example, a lower reference mounting table 12 is provided on which an unnecessary part (runner part) 1 of a die-cast product is placed.

The mounting table 12 is supported by a spring 9 on the base 10, and unnecessary parts (
The structure is such that when a load F is applied to the runner part) 1 from above, it moves downward.

A lower blade 7 is fixedly disposed in a part corresponding to the cutting part (gate part) 2 between the lower reference mounting table 12 and the product part 3,
The lower blade 7 has a cutting edge 7a facing upward, and both sides 7b and 7c of the blade are sloped almost symmetrically. Then, when a load F is applied from above to the unnecessary part (runner part) 1 (in reality, this load is applied by the upper reference a holder 13 (Fig. 4) when the upper blade 8 is lowered) lower side j! The iS mounting table 12 moves downward.

As a result, the cutting edge 7a of the lower blade 7 is at the lower reference t! i, i The state is such that it protrudes above the upper surface 12a of the stand 12 by a maximum predetermined height, that is, the thickness I of the cut portion (gate portion) 2 of the workpiece (a height l that is less than 1/2 of the thickness I).

The unnecessary part (runner part) 1 is placed on the upper surface 12a of the lower reference mounting table 12, and a load F is applied from above to the unnecessary part (runner part) 1, thereby lowering the lower reference mounting table 12. Cutting edge 7a of lower blade 7 into unnecessary part (runner part) 1 and product part 3
Insert the cut part (gate part) 2 from the bottom surface between.

Since the biting lower blade 7 has the above-mentioned configuration (dimensional protrusion), in the cutting biting state as shown in Fig. 1,
The slope 7b faces the unnecessary part (runner part) 1 side, and the slope 7c
faces the product section 3 side. For this reason, the stress associated with shearing is applied to the product part 3 side and the unnecessary part (runner part), as shown by the additional arrow.
1 acts symmetrically in the outward direction on both sides. The product part 3 is not supported, and the unnecessary part (runner part) 1 is placed on the lower reference mounting table 1.
2 are elastically supported, so that both can be moved outwardly from the cutting part (gate part) 2.

FIG. 4 is an explanatory diagram of a cutting operation as an embodiment of the method of the present invention.

The upper blade 8 and lower blade 7, which are double-edged cutters, have their cutting edges 8a.
, 7a are placed directly facing each other.

The upper reference mounting table 13 is the same as the lower base mounting table 1 described above.
It has a structure symmetrical to that of the lower reference mounting table 12, is elastically supported by a spring 9, and has functions similar to those of the lower reference mounting table 12 in terms of its rolling ability and flexibility.

Therefore, when looking at the relationship with the workpiece and the mounting table, the action of the upper blade 8 is similar to that of the lower blade 7.

Because of this configuration, the stress generated in the cutting part (gate part) 2 by the upper blade 8 and lower blade 7 is
Since it is symmetrical with respect to the axis passing through a and 8a, the cutting crack 14 also runs approximately on this axis, resulting in a flat cut surface with few irregularities, and it is difficult for the cutting crack to occur. In addition, the forces applied to the lower blade 7 and upper blade 8 are applied almost symmetrically with respect to this axis (an imaginary line passing through the cutting edges 7a and 8a), so the components perpendicular to the cutting direction become compressive forces and cancel each other out. As a result, there is no great burden on both blades 7 and 8.
The durability of both blades 7 and 8 is extended and even thick gate parts 2 can be cut economically.

FIG. 5 shows the state of completion of cutting in the embodiment of FIG. 4.

FIG. 6 shows an embodiment different from the above, in which one double-edged cutter (upper blade 8) is provided. 7' in the figure is a cutting table member provided in place of the lower blade 7 in the previous example. This example also provides the same functions and effects as the previous example.

The following effects were confirmed in cutting unnecessary parts of the die-cast molded products according to both of the above examples.

(B) New functions With the conventional pre-trimming method, it was difficult to cut gates with a thickness of 2m or more on a mass production basis, but according to this example, it is now possible to cut gates with a thickness of 5m. Ta.

(b) Improved performance and efficiency According to this example, the thick gate and tapered part can alleviate changes in the cross-sectional area of the molten metal flow path during forming, and also facilitate the application of flow analysis when determining casting plans. , the amount of air entrained in the molten metal could be reduced. In addition, the thick-walled gate solidified more slowly in the gate area than the thin-walled gate, which prevented a drop in molten metal pressure in the product area.

As a result of the above, the quality of die-cast products could be improved.

(c) Economical efficiency According to this embodiment, the quality of the die-cast product is improved, resulting in the defect rate of cavities, hot spots, etc. discovered during casting, U finishing, rock machining, assembly, etc. decreased. Furthermore, the unevenness of the cut surface was reduced compared to the conventional example, and the casting process was also shortened.

Such effects can be expected not only for die-cast products but also for molded products in general.

〔Effect of the invention〕

As explained above, according to the cutting method of the present invention, unnecessary parts of a molded product can be cut and removed with high precision and high efficiency, and the cutting cost is low.

Furthermore, it also has the secondary effect of smoothing out the vortex flow in the molded product and suppressing the occurrence of internal defects.

Moreover, according to the cutting part structure of the present invention, a tapered surface is formed in the direction of opening from the part to be cut to the product part, so it is suitable for carrying out the above method.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the basic principle regarding the method and structure of the present invention. FIG. 2 is an explanatory diagram of a conventional example for comparison with the above explanatory diagram. 3 to 5 show an example of the cutting method according to the present invention using an embodiment of the cutting structure according to the present invention, FIG. 3 is a partial explanatory diagram, and FIG. FIG. 5 is an explanatory diagram of the state in which cutting is completed. FIG. 6 is an explanatory diagram of an embodiment different from the above (FIGS. 3 to 5), and corresponds to FIG. 4 in the previous example. 1... Runner part (unnecessary part), 2.2'... Gate part (cutting part), 3... Product part, 4... Molten metal, 6... Taper part, 7... Lower blade , 7a...Blade tip, 7b, 7c...
...Slope, 8...Upper blade, 8a...Blade tip, 9...Spring, 10...Lower base, 11...Upper base, 12...
・・Lower reference mounting table, 13 ・・Upper reference mounting table, 14
...Crack, F...Load. Agent Ben R+ zh Jll 'fa ”A
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Figure 5 q 10 '7

Claims (1)

[Claims] 1. A method for cutting an unnecessary part of a molded product, characterized in that a tapered surface is formed in a direction that opens from the cutting part toward the product part, and the cutting is performed with a double-edged cutter. How to cut unnecessary parts of molded products. 2. The method for cutting an unnecessary part of a molded product according to claim 1, wherein the molded product is a die-cast product, and the unnecessary part is a runner or an overflow. 3. A structure for cutting an unnecessary part of a molded product, characterized in that a tapered surface is formed in the cutting part of the unnecessary part of the molded product in a direction that opens from the vicinity of the part to be cut by the cutter toward the product part. 4. The molded product is a die-casting product,
4. The structure for cutting an unnecessary part of a molded product according to claim 3, wherein the unnecessary part is a runner or an overflow.