JPH0585826U - Metal powder injection molding test piece - Google Patents

Abstract

(57) [Summary] [Purpose] In metal powder injection molding, to secure the accurate dimension measurement part of the test piece and to release it from the mold. [Structure] A straight portion for measurement is provided at a height of ⅓ of the thickness on the upper surface concave portion and outer shape portion of a disk-shaped test piece 1 having concave portions on the upper surface and the lower surface, and is connected to this straight portion to straighten the thickness. This is provided with a draft angle portion of 2 to 5 degrees, which is twice as large as the section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to the shape of a test piece that is required to accurately determine the shrinkage rate in injection molding using a metal powder of a raw material that has relatively little heat shrinkage and the shrinkage rate in the degreasing and sintering processes that are subsequent processes. .

[0002]

[Prior Art]

 Conventionally, as shown in FIG. 2, a draft angle of 0.5 to 5 degrees is applied to the entire circumference of both the inner and outer sides of the shape side surface. In this shape, as shown in FIG. 4, when the inner shape value was measured by the inner shape measuring tool 2 and the outer shape value was measured by the outer shape measuring tool 3, it was not possible to obtain an accurate numerical value. .

The draft around the entire circumference has become the mainstream in injection molding, and was designed in consideration of releasing the product from the mold.

[0004]

[Problems to be solved by the device]

 However, the conventional test piece shape has the following problems. When trying to determine the shrinkage rate with a test piece, there is a drawback in that an accurate dimension cannot be obtained because the slope portion is measured. As shown in Fig. 3, it is considered that the side surfaces of the test piece should be parallel to each other (hereinafter referred to as "straight part"), but the mold cannot be released from the mold and the test piece is destroyed.

Therefore, an object of the present invention is to secure a dimension measuring portion of a test piece and release it from a mold in order to solve such a conventional problem.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention has a configuration that has both roles by dividing the ratio of the portion required for dimension measurement and the gradient portion required for mold release from the mold as shown in FIG.

[0007]

[Action]

 In the shape configured as described above, a part of the side surface is straight, so that it becomes possible to accurately perform dimensional control during die processing.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional shape of a test piece of the present invention. The test piece 1 is a disk-shaped molded body having a thickness a and having a concave portion on the upper and lower surfaces, and a cylindrical outer peripheral surface. On the lower surface of the outer shape portion of the molded body, the surfaces facing each other are parallel straight portions (straight), and the dimension measuring portion 5 is formed. The inner surface of the recess lower surface and the upper surface connected to the straight portion of the outer shape form a draft portion 4 for facilitating release from the mold.

The draft has a shape in which both the outer shape portion and the inner shape portion are expanded upward, and has a gradient of about 2 degrees (tapering of about 4 degrees). In addition, the dimension in the thickness direction of the straight portion and the draft portion is (1/3) a for both the circular portion and the outer shape portion for the total thickness a of the test piece, and the draft portion (2/3 ) A.

Therefore, the thickness of the draft portion is twice the thickness of the straight portion. With such a shape, as shown in FIG. 5, the inner shape of the test piece 1 can be measured by the inner shape measuring tool 2 and the outer diameter of the test piece 1 can be measured by the outer shape measuring tool 3, respectively. As a result of the experiment, if the draft angle is at least 2 degrees, no problem in releasing occurs. Therefore, a range of 2 degrees to 5 degrees (4 to 10 degrees in taper) is usually applicable. It was also confirmed that the thickness of the draft portion with respect to the total thickness of the test piece with respect to the draft value should be about 2/3.

[0011]

[Effect of the device]

 As described above, this invention has made it possible to determine the shrinkage rate of metal powder or the like in injection molding and the shrinkage rate of degreasing and sintering, which are powder-specific post-processes. The shape of this test piece has the effect of reliably performing dimension measurement and mold release.

[Brief description of drawings]

FIG. 1 is a view showing a sectional shape of a test piece of the present invention.

FIG. 2 is a view showing a conventional test piece cross-sectional shape.

FIG. 3 is a diagram showing a cross-sectional shape of a test piece suitable for measuring dimensions.

FIG. 4 is a diagram showing a conventional test piece dimension measurement.

FIG. 5 is a diagram showing a test piece dimension measurement of the present invention.

[Explanation of symbols]

 1 Test piece 2 Internal measuring tool 3 External measuring tool 4 Draft slope section 5 Dimension measuring section (straight)

Claims (1)

[Scope of utility model registration request] 1. A test piece for measuring a shape dimension and determining a shrinkage rate in a test process of metal powder injection molding, comprising a disc having a thickness a and having concave portions on an upper surface and a lower surface, and the inner shape of the upper concave portion. Is a straight portion for measuring the height a / 3, a sloped portion for facilitating mold release from the mold is formed in the inner shape of the lower surface concave portion, and the outer shape portion has a height a / 3. A test piece for metal powder injection molding, characterized in that a straight portion 3 is formed, and a gradient portion is provided on the rest.