JPH03124334A - Forming method of powder can - Google Patents

Abstract

PURPOSE:To manufacture the products of smoothed inside surface without defect, e.g. pin hole, etc., by cold-drawing the pre-forming blank, drawing, machining and forming integrally at the time of forming powder can. CONSTITUTION:The pre-forming blank 10 which consists of the column type body 101 and the cylinder type body 102 is formed (process 1), the bottom part 20 and the body part 21 having inner wall surface fins 41, 42 are formed with the cold drawing (process 2), the truncated conical type drawn part 22 and the cylindrical type opening part 23' is formed with drawing (process 3), the finishing work of the drawn part 22 and the outer peripheral surface male screw 24 of the opening 22' is formed with lathing (process 4). In such a way the smooth surface without surface roughening on the inner wall surface of body is obtained and therefore the vessel without sticking of the minute powder to the inside wall surface at the time of discharging the contents is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a powder can, which is used to contain and cool powder, particularly fine plutonium powder.

A powder can, which is a container used to contain and cool such fine plutonium powder, is formed from a cylindrical can body with a bottom, and the inner wall surface of this can body is In order to release the heat generated from the fine powder, several cooling fins are formed to protrude radially from the inner wall of the can body toward the central axis, and the opening of the can body A cylindrical part with a small inner diameter is formed at the end as a part for taking in and taking out the fine powder, and for this reason, the open end part is made into a concave shape, and the outer periphery of the cylindrical part with a small inner diameter is formed. A male thread is machined on the surface. Furthermore, this can body is attached with a bottomed cylindrical lid having an inner diameter corresponding to the outer diameter of the can body in order to close the open end of the cylindrical portion having a small inner diameter. A female thread is machined on the inner circumferential surface of the cylindrical portion, which corresponds to the male thread machined on the outer circumferential surface of the small inner diameter cylindrical portion of the can body.

After storing the fine powder inside the can body in this way, the O-ring is placed under the interposition at the open end of the can body, and the lid is screwed into the male thread through the female thread. The fine powder contained in the main body is sealed inside the can main body.

That is, an example of a typical powder can having such a structure is shown in FIGS. 3 and 4 of the accompanying drawings. In the figure, reference numeral 1 indicates a powder can, and this powder can 1 is composed of a can body 2 and an M3.

First, among these, the can body 2 has a disc-shaped bottom 2°,
The cylindrical body 21 connected at the periphery thereof and the vicinity of the open end of the body 2I are narrowed so that the cross section has a truncated conical shape, and the aperture part 22 and its small diameter part. The opening 2. There is a male thread 2 on the outer circumferential surface of the
．． is turned.

On the other hand, the lid 3 is attached to the opening 2. of the can body 2. A cylindrical body 31 having an inner diameter approximately corresponding to the outer diameter of the body, a top 32 that closes one open end of the body, and an extension formed by extending the body 31 beyond the top 3□. At the end of this extension 33, an annular edge 34 is attached for mechanical handling. Note that the opening 2 of the can body 2 is located on the inner peripheral surface of the body 31 of the lid 3.
A female thread 3 corresponding to a male thread 24 turned on the outer peripheral surface of the
5 is turned.

Furthermore, several cooling fins 4+ and 42 are arranged at equal angular intervals from the inner wall surface of the body 21 of the can body 2.
It is formed so as to protrude radially toward the center. Note that in this example, cooling fins 4. ．． 42 have different lengths in the radial direction and are arranged alternately.

The powder can 1 having such a structure has a body 2. After storing the fine powder inside the opening 2. is closed with a lid 3 with an O-ring 5 interposed on the end face thereof, so that the fine powder can be contained in the powder can 1 and sealed tightly. That is, the lid 3 has a male thread 24 turned on the outer peripheral surface of the opening 2° of the can body 2, and a female thread 3. By screwing the lid 3 into the opening 2. of the can body 2. In this case, the bottom surface of the top 3□ of the lid 3 presses the O-ring 5 against the end surface of the opening 23 of the can body 2, so that the inside of the can body 2 is closed by the lid 3, and the outside is closed. It can be sealed against

By the way, powder cans having such a typical configuration, especially powder cans for storing fine plutonium powder, have defects such as pinholes on the wall of the body 21 of the can body 2. 2. When discharging the contents from the can body 2, the fine powder must not be
The bottom part 2°, the body part 23. Aperture section 22 and opening section 2. The inner wall is required to have a smooth inner surface.

Currently, the following two methods are mainly known for molding the can body of such a powder can.

In other words, 1.11 hill construction 2.1 and ■mameyu.A brief explanation of each of these is as follows.

1.11 Plate construction As shown in Figure 5 of the attached drawings, ■Bottom 2°■Inner fin 4. ．． The body part 2 integrally has a diaphragm 22 and an opening member 25 formed with two openings formed by turning a male thread 24. The members of the opening member 25 are separately produced and placed, and these members are welded. After assembling the welds by connecting them together (the welded parts are indicated by -), turning is performed.2. This is a method in which an integrally molded product is produced by molten metal forging and then turned.

However, powder cans formed by these known methods each have the following problems.

1. There is a concern that the contents may leak from minute defects such as pinholes that occur in the welded part of the L stop 1. 2. The roughness of the casting surface across the ridge is rough, and when the contents are discharged, there may be a slight leakage. The powder tends to adhere and remain on the inner wall surface of the can body and the circumferential surface of the fins.

Therefore, an object of the present invention is to provide a novel method for molding powder cans that can avoid the above-mentioned defects in products produced by conventionally known molding techniques.

:゛t・ In order to solve this problem, in the present invention, when molding the can body, which is generally composed of the bottom, body, constricted part, and threaded part of a powder can having a cylindrical shape, ( 1) A cylindrical body having the desired outer diameter and the required height of the body, and an outer diameter larger than the outer diameter and an inner diameter slightly smaller than the outer diameter on one end surface of the cylindrical body. and a cylindrical body having a necessary height. having an inner diameter equal to the outer diameter = 7- is inserted into the die, and the cylindrical body portion of the preformed material inserted into the die is provided with a forming surface corresponding to the desired internal cross-section of the body of the powder can. By subjecting the preformed material to a cold extrusion process using a punch, the cylindrical body portion of the preformed material is formed into a body having a desired inner cross section and outer shape, which is bottomed and has fins on the inner wall surface. and (3) a second intermediate semi-finished product in which a drawn part and an opening are formed by drawing the cylindrical part of the first intermediate semi-finished product by swaging. (4) forming a male thread on the outer circumferential surface of the drawn opening of the second intermediate semi-finished product;

夾-"L-" Hereinafter, the molding method according to the present invention will be explained in detail based on FIG. 1 of the attached drawings showing the outline of its implementation.

In FIG. 1, the molding steps according to the method of the present invention are shown as steps 1 to 4, and each step will be explained as follows.

(1) JJLl A cylindrical body 101 having the desired outer diameter D1 of the body of the powder can and the required height H, and an outer diameter larger than this outer diameter on one end surface of the columnar body 101. D2 and has an inner diameter d1 that is slightly smaller than the outer diameter D1 and has a required height H
(2): Molding a preformed material 10 having an integrally formed shape in which a cylindrical body 10□ having a cylindrical body 10 and a cylindrical body 10□ having a cylindrical body 10 and a cylindrical body 10□ having a 10, mainly the cylindrical body 101, is inserted into a die (not shown) having an inner diameter approximately equal to the outer diameter of the desired body, and the preformed material 10 inserted into the die is Mainly, a punch (see FIG. 4) having a forming surface corresponding to the inner cross-section (see FIG. 4) of the body 2I of the can body 2 (see FIG. 3) of the powder can is provided on the cylindrical body 10.
(not shown), the cylindrical body 10. The body part 2. has a desired bottom 2° and an inner and outer shape with fins 41 and 42 provided on the inner wall surface. (3) 2L'' By drawing the vicinity of the cylindrical body 102 of the first intermediate semi-finished product 11 by swaging, a truncated conical drawn part is formed. 2□゛ and the cylindrical opening 23 are molded into the second intermediate semi-finished product 12 (4) 21'' The drawn portion 22'' and the opening 2 of the second intermediate semi-finished product 12 are formed. ．． The finished powder product 1 is obtained by turning the outer circumferential surface of the opening 22'' to finish the drawing part 2□ and forming a male screw 24 on the outer circumferential surface of the opening 22''.

Incidentally, a product molded through molding steps 1 to 4 according to the method of the present invention is shown in a vertical cross section in FIG.

Since the molding method according to the present invention is carried out through the steps described above, it is clear that it exhibits the following effects. That is, 1. According to the method of the present invention, the powder can is integrally formed and there is no welded seam, so there is no concern that the contents may leak from minute defects such as pinholes that occur in the welded part, as in conventional welded structures. 2. According to the method of the present invention, the main forming is performed by cold extrusion, so there is no roughness on the inner wall surface of the main body, which is found in conventional molten metal forgings, and a smooth inner surface is obtained. Therefore, when the contents are discharged, the amount of residual powder caused by fine powder adhering to the inner wall surface of the main body is reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the molding process of the molding method according to the present invention;
FIG. 2 is a longitudinal sectional view showing a powder can molded by the molding method according to the present invention, and FIG. 3 is a vertical cross-sectional view showing an example of a conventionally known typical powder can. FIG. 4 is a cross-sectional view taken along line 1%'-4 in FIG. 3, and FIG. 5 is an example of a welded powder can manufactured by a conventional welding forming method. FIG. 1... Powder can, 2... Can body, 2o... Bottom, 2
1...Body part, 22...Aperture part, 2. ···Aperture,
2. ... Male thread, 3 ... Lid, 31 ... Body, 32
. . . top portion, 33 . . . extension portion, 3. ...Annular edge, 35...Female thread, 45,4□...Cooling fin, 1
0... Preformed material, 101... Cylindrical body, 102
...Cylindrical body, 11...First intermediate semi-finished product, 12...
・Second intermediate semi-finished product. 2

Claims (1)

[Claims] 1. In general, when molding a can body which is composed of a bottom, a body, a constricted part, and a threaded part of a powder can having a cylindrical shape, A cylindrical body having an outer diameter and a required height, and a cylinder having, on one end surface, an outer diameter larger than the outer diameter, an inner diameter slightly smaller than the outer diameter, and the necessary height. (2) Molding a preformed material having a shape integrally formed with a cylindrical body. The cylindrical part of the preformed material inserted into the die is subjected to cold extrusion processing using a punch having a forming surface corresponding to the desired inner cross section of the body of the powder can. (3) The cylindrical body portion of the molding material is made into a first intermediate semi-finished product having a bottomed body having a desired inner cross section and outer shape with fins provided on the inner wall surface. By drawing the cylindrical part of this first intermediate semi-finished product mainly by swaging, it becomes a second intermediate semi-finished product with a drawn part and an opening formed.(4) Drawing of the second intermediate semi-finished product A forming method characterized by forming a male thread on the outer peripheral surface of the processed opening through four steps. 2. The molding method according to claim 1, wherein in step (4), the outer surface of the drawn portion is also lathed to form the drawn portion with desired dimensions.