JPS5913934B2 - Can body neck-in processing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for netlining can bodies;
More specifically, the present invention relates to a method and apparatus for neck-lining a can body by applying ultrasonic vibration, which prevents troubles such as wrinkles in the neck-in portion.

Filling and sealing cans for carbonated drinks, juices, etc. can be divided into soldered cans, welded cans, adhesive-bonded cans, and seamless (squeezed and ironed cans) depending on the manufacturing method. The outer diameter of the double-sealed part is made to be approximately equal to or slightly smaller than the outer diameter of the can body by necking the can body, then forming a flange, and then double-sealing the rear end plate. There are many cases. This is not only due to its excellent design, but also due to the reduction in storage volume per can during packaging.
This is because it has technical and economical advantages, such as preventing dents in the can body due to collision between the double-sealed part and the can body during transportation, and saving material costs because the end plate can be small in diameter. . This netsukin processing of the can body was done, for example, in
As disclosed in No. 27, this is usually done by press-fitting the open end into the gap between the drawing die and the center die and drawing it into a predetermined shape (that is, reducing the warp). In this case, according to the experience of the present inventors, in the case of a seamless can with a thin body wall and where wrinkles often occur in the neck-in part 1, wrinkles are often generated in the neck-in part, and when the body wall part 2 is press-fitted during the neck-in process, wrinkles often occur near the bottom of the body wall. In order to prevent troubles above 3, which tend to cause buckling or deformation, lubricants are usually used to reduce the frictional force between the mold and the can body and reduce the pressing force, but in this case, the equipment itself Because it gets dirty (from paint, metal powder, dust, etc.), you have to remove the mold and clean it at regular intervals. 4 Even if you do that, you can't get a large drawing rate each time, so usually 2 There are problems such as the need for multiple drawing operations, which increases the number of steps and complicates the equipment. An object of the present invention is to solve the above problem, and in order to achieve this object, the open end of a cylindrical can body is narrowed so that the inner part of the can body is In a can body neck-in processing method that forms a tapered part toward and a neck-in part connected to the tapered part and which has a smaller diameter than the main part of the can body, the tapered part of the opening end and the part that should become the neck-in part In the neck-in processing method for can bodies, which is characterized by squeezing while applying ultrasonic vibration to the can body, and in the above-mentioned neck-in processing method, a relatively high power is applied to the opening end during drawing to form a taper in the initial stage of neck-in processing. To provide a neck-in processing method for a can body, which is characterized by applying ultrasonic vibrations of 1 to 100 mm, and then applying ultrasonic vibrations of relatively low output until the formation of the neck-in portion is completed.

Furthermore, the present invention provides for narrowing the open end of the cylindrical can body,
A can body neck-in processing device that forms a tapered portion inward from the main portion of the can body and a neck-in portion that is smaller in diameter than the main portion of the can body and connected to the tapered portion, the device comprises a drawing die and a center a holding mold having a cylindrical inner circumferential surface with an inner diameter substantially equal to the outer diameter of the can body; a ring shape having a tapered surface corresponding to the neck surface and a cylindrical inner circumferential surface connected to the tapered surface and having an inner diameter substantially equal to an outer diameter of the neck-in portion; a core mold having an outer peripheral surface having an outer diameter slightly smaller than the inner diameter of the core mold, and a locking mold having a locking surface connected to the base of the outer peripheral surface to define the height of the neck-in part. and an ultrasonic vibration element is fixed to the ring shape and/or the core mold, and the neck-in processing device described above, further comprising: The ultrasonic vibration element is provided with means for detecting the applied load and means for energizing or deenergizing the ultrasonic vibration element based on the detected value by the means, and the ultrasonic vibration is generated only while the aperture is being substantially performed. A net-in processing device for a can body, characterized in that an element is energized, and a net-in processing for a can body, characterized in that an ultrasonic vibration element is energized only while the drawing is substantially performed. The device further includes means for controlling the ultrasonic vibration output and a timer,
The ultrasonic vibrating element is energized only while the drawing is being performed, and relatively high-output ultrasonic waves are fed to the ultrasonic vibrating element during the drawing to form the taper at the initial stage of neck-in processing. There is provided a can body neck-in processing apparatus, characterized in that relatively low output ultrasonic waves are fed to the ultrasonic vibration element until the formation of the neck-in part is completed.

The present invention will be described below with reference to drawings showing embodiments of the invention. 1 and 2 show the state immediately before the can body 2 is inserted into the neck-in processing tool 1 and the neck-in processing is started.

The can body 2 is conveyed and held by the carrier 3 to a position where its axis coincides with the axis of the neck-in tool 1. Although not shown, when both open ends are to be tied in, as in the case of a can body for a three-piece can, a similar necked-in tool is provided on the left side of the figure. If there is only one open end, as is the case with can bodies for two-piece cans, the support for the can bottom is arranged on the left side of the figure.

The neck-in tool 1 includes a drawing die 4 and a center die 5.

The aperture die 4 has a holding die 6, a ring die 7, a spacer 8, and an ultrasonic vibrating element 9 consisting of an ultrasonic vibrator 9a and a horn 9b. The holding mold 6 has an inner diameter substantially equal to the outer diameter of the can body 2, and has a cylindrical inner peripheral surface 6a into which the open end 2a of the can body is inserted, and also has a ring mold 7 and a spacer 8. A recess 6b1 for accommodating the ultrasonic horns 9b and a hole 6c for accommodating a plurality of (six in this embodiment) ultrasonic horns 9b. The end opposite to the tip 6d is removably fixed to the support shaft 10. Therefore, when the ring mold 7 becomes worn out, it must be replaced. Repairs can be easily made. A tapered part 7a is provided on the inner surface of the ring mold 7, connected to the cylindrical surface 6a, and the opening end 2a of the can body is press-fitted into this tapered part 7a to perform a narrowing (diameter reduction). . The diameter of the ring-shaped cylindrical inner circumferential surface 7b defines the outer diameter of the can body neck-in portion 2c (FIG. 5). An ultrasonic horn 9b is screwed onto the outer peripheral surface of the ring shape at a position substantially opposite to the tapered portion 7a. The coil wound around the ultrasonic transducer 9a is connected to an ultrasonic oscillator 19. The support shaft 10 is configured to reciprocate in the axial direction in a constant cycle by a cam mechanism (not shown).
The center mold 5 consists of a core mold 11 and a locking mold 12, and the core mold 11 is fixed to the locking mold 12 by a presser bolt 13 via a stopper 14. 13 to the central shaft 15. central axis 15
is configured to reciprocate in the axial direction in a constant cycle independently of the support shaft 10 by a cam mechanism (not shown). The diameter of the outer circumferential surface 11a of the core mold 11 is slightly smaller than the inner diameter of the can body neck-in portion 2c (Fig. 5).
degree) small. The outer peripheral surface 12a of the locking mold 12 is the ring mold 7
The annular end surface 12b of the locking mold 12 between the outer peripheral surface 12a and the outer peripheral surface 11a of the core mold forms a locking surface 12b when the can body 2 is press-fitted. This defines the height of the neck-in portion 2c. A pressure detection element 16 is attached to the support shaft 10, and the pressure detection element 16 outputs an output when an axial load is applied to the support shaft 10 during neck-in processing.

After the output is amplified by the amplifier 17, the output is amplified by the comparator 1.
8 to a predetermined voltage (generally set to a low level). 19 is a switch circuit for the ultrasonic oscillator 20, and when the input voltage to the comparator 18 is higher than a predetermined voltage, the ultrasonic oscillator 20 is set to 0N, and when it is lower, it is set to 0F.
It is configured to be F.

Using the above-described apparatus, the can body 2 is tied in as follows.

The can body 2 is usually about 0.10 to 0.35 mw! Joining of side joints using soldering, welding, or adhesive methods from blanks made of low-carbon thin steel sheets such as thick tin-plated steel sheets, electrolytic chromic acid-treated steel sheets, or aluminum alloy sheet blanks. Alternatively, it is formed by a drawing and ironing method or the like.

Organic coatings are usually formed on the inner and outer surfaces. These can bodies 2 are first stopped at the position shown in FIG. 1 by the conveyor 3.
At that time, the entire neck-in tool 1 has at least the holding mold 6
The tip end 6d of the can body 2 is located outside the end surface of the can body 2. Next, with the locking surface 12b of the center die 5 located at the rear end of the ring-shaped tapered portion 7a of the drawing die 4 (the state shown in FIG. 1), the center die 5 and the drawing die 4 are simultaneously moved toward the left side of the figure. 1st
As shown in the figure, the open end 2a of the can body is inserted into the cylindrical inner peripheral surface 6a of the holding mold. Until then, ultrasonic transducer 9a
is not energized. Further, when the center mold 5 and the drawing mold 4 move to the left at the same time, the tip of the open end 2a of the can body is squeezed by the ring-shaped taper part 7a, as shown in FIG. Therefore, when a load of more than a predetermined value (generally set to a low value) is applied to the support shaft 10, the switch circuit 19 becomes 0N, and the ultrasonic horn 9b causes the open end to contact the tapered part 7a of the ring mold 7. Ultrasonic vibration is applied to part 2b. The output per ultrasonic transducer is preferably 500 W to 1 kW. If the output is lower than 500W, the effect of preventing wrinkles etc. will not be sufficient, while if the output is higher than 1kW, the heat generation will increase and the organic coating film (e.g. epoxyphenol coating film) applied to the can body 2 will burn. This is because problems such as this may occur.

There is no particular restriction on the frequency, and good results can be obtained at a frequency of about 10 kHz to 25 kHz, which is the frequency of normal ultrasonic processing. When the vibration direction is perpendicular to the axis of the can body 2 as in the embodiment shown in FIG. 3, the vibration is preferably about 2 to 10 pm. If it is smaller than about 2 μm, the wrinkle prevention effect will not be sufficient, and if it is smaller than about 1 μm.
This is because if it is larger than 0 pm, minute scratches are likely to occur on the processed surface. While being subjected to ultrasonic vibration as described above, the constricted tip of the open end 2a becomes the locking surface 1 of the locking die 12.
2b, as shown in FIG. 4, the center die 5 remains at that position, and only the drawing die 4 moves a predetermined distance to the left in the figure, and the ring-shaped cylindrical surface 7b and the core die outer peripheral surface 1
A neck-in portion 2c is formed between the neck-in portion 2c and the main body of the can body 2. At the same time, a tapered portion 2b is formed between the neck-in portion 2c and the main body of the can body 2.

The predetermined distance corresponds to the height of the neck-in portion 2c. In the above neck-in processing process, in the case of the conventional method that does not apply ultrasonic vibration, lubricant is applied to connect the ring-shaped tapered part 7a, the cylindrical inner circumferential surface 7b, the core-shaped outer circumferential surface 11b, and the can body. By reducing the frictional force between the open ends 2a, it was intended to prevent peeling of the coating film, the occurrence of vertical wrinkles in the necked-in portion 2c, and to prevent buckling and deformation in the case of a drawn can body. However, there is a limit to the friction-reducing effect of lubricants, and it is extremely difficult to completely prevent the above-mentioned troubles.In particular, the above-mentioned troubles are likely to occur with wear of the mold surface, so it is necessary to change the mold frequently. It didn't happen. However, when applying ultrasonic vibration according to the present invention, the above trouble does not occur even without applying lubricant, and the applied stress is also reduced, so there is less wear on the mold surface and the frequency of mold changes is reduced. It has been found that work efficiency can be greatly improved. After the formation of the neck-in portion 2c is completed in the above manner, the center die 5 remains at that position, and only the drawing die 4 moves to the right side of the figure as shown in FIG. 5, and the neck-in portion 2c is The ultrasonic oscillation stops because the load applied to the support shaft 10 becomes equal to or less than the predetermined value at the same time as it is removed from the drawing die 4.

Therefore, the ultrasonic vibration is applied only during the actual neck-in processing (approximately 1/12 of the entire process), which saves energy, prevents the temperature of the ring mold 7 from rising, and holds the ring mold 7 together. It is possible to prevent wear and tear on the contact surfaces with the mold 6, spacer 8, etc. Next, after the locking tool 21 engages with the tapered portion 2b of the can body 2, only the center mold 5 moves to the right in the figure, as shown in FIG.
is removed, and the can body 2 is sent to the next process by the conveyor 3. Next, the second can body is sent by the conveyor 3 to the position of the can body 2 in FIG. 6, and the drawing die 4 moves to the left in the figure, resulting in the state shown in FIG. The next netquin processing is performed as follows. FIG. 7 shows another embodiment of the present invention, in which a plurality of ultrasonic horns 9
b are screwed onto the rear end surface of the ring mold 7 at equal intervals so that their axes are parallel to the axis of the support shaft 10.

In this case, the ultrasonic vibration amplitude is preferably about 5 to 10 pm. This is because if it is smaller than about 5 μm, the effect of preventing wrinkles etc. will not be sufficient, and if it is larger than about 10 pm, there is a risk of scratches on the surface coating. For other configurations and effects,
There is no particular difference from the case in Figure 1. Further, as shown in FIG.
Since it is also supplied from 1a to the inner surface of the open end 2a of the can body, the effect of the present invention is further improved.

In the above examples, ultrasonic vibrations of the same energy were always applied during the neck-in process.

However, according to the findings of the present inventors, as shown in FIG. 9, during the stage until the drawing for forming a taper in the initial stage of neck-in processing is completed, that is, until the state shown in FIG. 3 is reached. A large load is applied to the can body 2, and thereafter the load applied during the formation of the neck-in portion decreases. Therefore, it is important to apply ultrasonic vibration pulses with relatively large energy for a short period of time in the above-mentioned initial period, and apply ultrasonic vibrations with relatively small energy thereafter, in order to improve energy efficiency and prevent paint film from seizing due to heat generation. Favorable from this point of view. FIG. 10 shows an embodiment of a circuit for applying such an initial high-energy ultrasonic vibration pulse. In FIG. 10, the output of the ultrasonic oscillator 20 is connected to a switch circuit 19, a resistor R
1. Input to the ultrasonic transducer 9a via the amplifier 21. R
2 and R3 are resistors connected in series to the negative feedback circuit of the amplifier 21, and a switch circuit 22 is connected in parallel to the resistor R2.
is provided. The signal from the comparator 18 is input to a switch circuit 19 and also to a switch circuit 22 via a timer circuit 23. When the input signal to the comparator 18 becomes higher than the predetermined voltage, the input signal to the comparator 18 becomes higher than the predetermined voltage.
The switch circuit 19 becomes 0N due to the output signal from 8, and the timer circuit 23 also becomes 0N. Based on the 0N signal from the timer circuit, the switch circuit 22 becomes 0FF for a certain period of time (usually a very short time on the order of 1/100 seconds). time), the timer circuit 23 becomes 0FF, and this 0
Based on the FF signal, the switch circuit 22 becomes 0N,
Further, each circuit is configured such that when the input signal to the comparator 18 becomes lower than the predetermined voltage, the switch circuit 19 becomes OFF. When the ring-shaped tapered surface 7a engages with the open end 2a and a load of more than a predetermined value is applied to the support shaft 10, the comparator 18 outputs an output, the switch circuit 19 becomes 0N, and at the same time the switch circuit 22 0
Becomes FF. Therefore, as shown in FIG. 11, an ultrasonic vibration pulse I having an energy amplified by (R2+R3)/R1 is input to the ultrasonic vibrator 9a, and comes into contact with the tapered surface 7a of the ring type 7. Ultrasonic vibration pulses with large energy are applied to the open end portion 2a by the ultrasonic horn 9b. When the opening end 2a has been constricted (tapered) to approximately the state shown in FIG. 3, the timer circuit 23 is activated and the switch circuit 22 is turned ON. Therefore, the ultrasonic vibration output applied to the ultrasonic transducer thereafter is reduced to R3/R1 times the output of the ultrasonic oscillator 20 (as shown in FIG. 11). The output of pulse I is usually 1 kW or more, and the duration is about 1 kW.
/200 to 1/100 second, and the steady output () is preferably 0.5 kW or less and 1/18 to 1/3 second. In the above example, the neck-in processing tool was moved to perform the net-in processing, but the same effect can be achieved by fixing the neck-in processing tool and press-fitting the can body into the tool. Needless to say, the present invention includes such embodiments.

According to the present invention, since ultrasonic vibration is applied to the open end through the mold when necking the open end of the can body, the applied stress and frictional force are reduced, and a lubricant is especially used. Even if the amount of neck-in (squeezing ratio) per one time is made larger than before, wrinkles in the neck-in part and buckling or deformation of the can body can be prevented.

Therefore, the neck-in process, which was conventionally performed in two steps, can be performed in one step, which has great advantages such as improved productivity and simplification of equipment. Furthermore, since there is less wear and tear on the mold, the number of times it must be replaced and re-polished can be reduced, resulting in great economic benefits such as improved production efficiency and reduced mold costs. In addition, since no lubricant is used, there is less contamination of the equipment due to paint, metal powder, dust, etc., and there is no need to remove and clean the mold at regular intervals, which also improves production efficiency compared to conventional methods. is remarkable. Furthermore, by configuring the device to apply ultrasonic vibration only during neck-in processing, it is possible to save energy and prevent temperature rise and wear and tear of the mold. This effect can be further improved by applying high-output ultrasonic vibration for a short time at the beginning of neck-in processing, and then applying relatively low-output ultrasonic vibration thereafter. Further, since the ultrasonic vibration element is directly fixed to the ring type and/or core type that receives direct load during neck-in processing, it has the advantage of high efficiency in applying ultrasonic vibration. Examples will be described below. Example 1 A welded can body with a diameter (outer diameter) of 53.13 mm and a height of 134.5 mm made of tin-plated steel plate with a thickness of 0.24 mm (phenol epoxy paint applied and baked on the inner surface, modified alkyd ink on the outer surface) is placed between a pair of opposing net-in processing devices of the type shown in Figs. is 50.72mm 1 penetration depth 6
．． 35m7! I processed it to make it L.

No lubricant was used. The ultrasonic output was 0.5 kW/horn, frequency 1.5 kHz, amplitude 5 μm, and the switch circuit 19 was activated to apply ultrasonic energy only during the neck-in drawing process. Even after 10,000 cans were continuously processed, no wrinkles were observed in the neck-in area. Comparative Example 1 Neck-in processing was carried out in the same manner as in Example 1, except that ultrasonic vibration was not applied and the wax-based lubricant was diluted with a solvent and applied to the processed area by roll coating.

After processing 10,000 cans, wrinkles were observed in the inner part.
When the work was stopped and the molds were inspected, significant scratches were found on the inner peripheral surface of the ring mold 7 and the outer peripheral surface of the core mold, and it was necessary to replace the molds. Example 2 Trunk wall thickness: 0.20mm1 Bottom thickness: 0.32m7! L1
Diameter (outer diameter) 53.05 m 1 L 1 Height 134.5 m 77
! The bottom part of the can body made of tin-plated steel plate (the inner and outer coatings are the same as in Example 1) is held by a holding device, and a device of the type shown in Fig. 8 (however, the number of horns is 9b and 97b), the opening end (thickness is the same as the trunk wall, 0.20m0) is connected to a diameter of 50.40mm.
1 push depth 6.35m77! Netsuquin processing was performed so that

No lubricant is used, and the ultrasonic output of both horns is 1.0k.
W/horn, frequency 20kHz, amplitude 8μm. The switch circuit 19 was activated to apply ultrasonic energy only during the neck-in drawing process.
Even after 10,000 pieces were connected, no wrinkles were observed in the neck-in part, and no buckling was observed in the body wall near the bottom. Comparative example
2. Net-in processing was carried out in the same manner as in Example 2, except that ultrasonic vibrations were not supported and a wax-based lubricant was uniformly applied to the processed portion.

Shortly after processing began, buckling occurred in the trunk wall near the bottom, and work was stopped. Example 3 Adhesive can body made of nylon 12 made of electrolytic chromic acid-treated steel plate (tein-free steel) with a thickness of 0.21 m1L (phenol epoxy paint applied and baked on both inside and outside surfaces)
Using a device having the control circuit shown in Fig. 10, an ultrasonic output of 1.5 kW/horn was applied for the initial 1/100 second of neck-in processing, and thereafter for 1/1 of the time until the end of processing.
Net-in addition was performed in the same manner as in Example 1, except that an ultrasonic output of 0.2 kW/horn was applied for 0 seconds.

After 10,000 cans were continuously processed, no wrinkles were observed in the neck-in area, no discoloration due to scorching of the coating film, and no peeling of the adhesive part during flange processing was observed. When the can body was subjected to neck-in processing under the same conditions as in Example 1, no wrinkles were observed in the neck-in part after 10,000 cans were processed, but peeling of the adhesive part was observed during flange processing. Five cases occurred.

Nylon 12 (melting point 17
This is thought to be due to the temperature (8°C) melting.

[Brief explanation of drawings]

FIG. 1 is a side longitudinal sectional view of a device according to a first embodiment of the present invention;
Figure 2 is a front view taken from the line H-H in Figure 1, Figure 3 is a side longitudinal sectional view of the device in Figure 1 showing only the tapered part of the can body, and Figure 4 is a net FIG. 5 is a side vertical cross-sectional view of the apparatus in FIG. 1 showing a state in which only the drawing die has been extracted from the state in FIG. 4; 6 is a side vertical cross-sectional view of the device of FIG. 1 showing the state in which the central die is removed from the state shown in FIG. 5; FIG. 7 is a side vertical cross-sectional view of the device of the second embodiment of the present invention; FIG. FIG. 8 is a side vertical cross-sectional view of the apparatus according to the third embodiment of the present invention, FIG. 9 is an explanatory diagram showing changes in the load applied to the can body as the neck-in process progresses, and FIG. 10 is the fourth embodiment of the present invention.
FIG. 11 is an explanatory diagram showing temporal changes in ultrasonic output in the fourth embodiment. 2... Can body, 2a... Open end, 2
b...Tapered part, 2c...Neck-in part, 4...Drawing die, 5...Center die, 6
...Retention type, 6a...Cylindrical inner peripheral surface,
7...Ring type, 7a...Tapered surface,
7b... Cylindrical inner peripheral surface, 9... Ultrasonic vibration element, 11... Core type, 11a...
・Outer peripheral surface, 12...Lock type, 11b...
- Locking surface, 16... Pressure detection element (means for detecting load), 19... Switch circuit (means for energizing/deenergizing the ultrasonic vibration element), 20... . . . Ultrasonic oscillator, 22 . . . Switch circuit (part of means for controlling ultrasonic vibration output), 23 . . . Timer circuit (time limit device).

Claims (1)

[Scope of Claims] 1. The opening end of a cylindrical can body is constricted to form a tapered part facing inward from the main part of the can body and a diameter smaller than the main part of the can body connected to the tapered part. A method for neck-in processing of a can body to form a neck-in portion, the neck of a can body being squeezed while applying ultrasonic vibrations to the tapered portion of the open end and the portion to become the neck-in portion. In-processing method. 2. Squeeze the open end of the cylindrical can body to form a tapered part that goes inward from the main part of the can body and a neck-in part that is smaller in diameter than the main part of the can body and connected to the tapered part. In the neck-in processing method for can bodies, relatively high-output ultrasonic vibrations are applied to the open end during the drawing process to form a taper at the initial stage of the neck-in process, and then ultrasonic vibrations of relatively high power are applied to the opening end until the formation of the neck-in part is completed. A method for neck-in processing of can bodies, which is characterized by applying ultrasonic vibrations of relatively low output during the process. 3. Squeeze the open end of the cylindrical can body to form a tapered part that goes inward from the main part of the can body and a neck-in part that is smaller in diameter than the main part of the can body and connected to the tapered part. A neck-in processing device for a can body includes a drawing die and a center die, and the drawing die includes a holding die having a cylindrical inner circumferential surface having an inner diameter substantially equal to the outer diameter of the can body. ,
a tapered surface connected to the cylindrical inner circumferential surface and corresponding to the outer circumferential surface of the tapered part; and a cylindrical inner circumferential surface connected to the tapered surface and having substantially the same outer diameter and inner diameter of the neck-in part. and a ring mold having a core mold having an outer peripheral surface having an outer diameter slightly smaller than the inner diameter of the neck-in part, and a ring mold having a core mold having an outer peripheral surface having an outer diameter slightly smaller than the inner diameter of the neck-in part. a locking mold having a locking surface for defining the height of the can body, and an ultrasonic vibration element is fixed to the ring mold and/or the core mold. Neck-in processing equipment. 4. Squeeze the open end of the cylindrical can body to form a tapered part that goes inward from the main part of the can body and a neck-in part that is smaller in diameter than the main part of the can body and connected to the tapered part. A neck-in processing device for a can body includes a drawing die and a center die, and the drawing die includes a holding die having a cylindrical inner circumferential surface having an inner diameter substantially equal to the outer diameter of the can body. ,
A tapered surface connected to the cylindrical inner circumferential surface and corresponding to the outer circumferential surface of the tapered portion, and a cylindrical inner circumferential surface connected to the tapered surface and having an outer diameter and an inner diameter substantially equal to the neck-in portion. The center mold is connected to a base of the outer peripheral surface, and the center mold has an outer peripheral surface having an outer diameter slightly smaller than the inner diameter of the neck-in part, and the center mold is connected to the base of the outer peripheral surface and has a height of the neck-in part. a locking mold having a locking surface for defining the ring shape, and an ultrasonic vibration element is fixed to the ring mold and/or the core mold; The ultrasonic vibration element is provided with means for detecting the applied load and means for energizing or deenergizing the ultrasonic vibration element based on the detected value by the means, and the ultrasonic vibration is generated only while the aperture is being substantially performed. A can body neck-in processing device characterized in that an element is energized. 5. Squeeze the open end of the cylindrical can body to form a tapered part that goes inward from the main part of the can body and a neck-in part that is smaller in diameter than the main part of the can body and connected to the tapered part. A neck-in processing device for a can body includes a drawing die and a center die, and the drawing die includes a holding die having a cylindrical inner circumferential surface having an inner diameter substantially equal to the outer diameter of the can body. ,
A tapered surface connected to the cylindrical inner circumferential surface and corresponding to the outer circumferential surface of the tapered portion, and a cylindrical inner circumferential surface connected to the tapered surface and having an outer diameter and an inner diameter substantially equal to the neck-in portion. The center mold is connected to a base of the outer peripheral surface, and the center mold has an outer peripheral surface having an outer diameter slightly smaller than the inner diameter of the neck-in part, and the center mold is connected to the base of the outer peripheral surface and has a height of the neck-in part. a locking mold having a locking surface for defining the ring shape, and an ultrasonic vibration element is fixed to the ring mold and/or the core mold; It is equipped with a means for detecting the applied load, a means for energizing and deenergizing the ultrasonic vibration element based on the detected value by the means, a means for controlling the ultrasonic vibration output, and a timer, so that the aperture is substantially reduced. The ultrasonic vibrating element is energized only while the neck-in process is being performed, and relatively high output ultrasonic waves are fed to the ultrasonic vibrating element during the aperture forming the taper at the initial stage of the neck-in process. A neck-in processing apparatus for a can body, characterized in that relatively low output ultrasonic waves are fed to the ultrasonic vibrating element until the formation of the can body is completed.