JP2004284333A - Mold for molding hollow body by injection molding machine and its molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that when an intake-manifold or the like is molded by an injection molding machine, strength of the portion where secondary welding injection is conducted is decreased, particularly the strength of a weld line portion is decreased, and a cycle time is increased by opening an undercutting mold forming a hollow body. <P>SOLUTION: The secondary injection is conducted on the welding surface having a rivet shape to achieve welding using shrinking force of the resin. The strength is increased by adjusting a rivet position to the welding line position or, if such adjustment is impossible, properly arranging a resin rich portion or a proper number of pins. The opening or closing time is decreased by dividing an inner core of a mold to remove the undercut and shortening opening and closing distance of the molding machine. In order to weld a vertically semi-circular portion becoming the hollow body to a flange, a part having a slidable side surface is advanced to prevent a void during the secondary injection. By the strength of the welding surface is enhanced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mold having a structure that can be formed by injection molding when resinating complicated-shaped products such as an intake manifold (distribution pipe for gas to an engine cylinder), which is a hollow integrated product of an automobile part, and does not require post-processing. The present invention relates to a mold and a molding method for completing an integrally molded product in the mold.
[0002]
[Prior art]
There are several conventional methods, and four typical methods will be described as follows.
[0003]
[Lost core method]
This method is used as a method of obtaining a plastic hollow molded body (intake manifold) as an automobile part. However, the inner core is made of a low melting composite alloy (composite alloy of lead, tin, antimony, etc.), and the core is required. It is molded by using another mold for shape production, it is inserted into this mold to form the main body, the molded product is taken out of this mold together with the composite alloy, and this is heated by high frequency heating to the alloy on the inner surface. Is melted and taken out to obtain a desired hollow molded body.
[0004]
Therefore, a low melting composite alloy is required as a core material, a core molding die of the alloy is required, labor for inserting into this die is required, high-frequency melting work of the molded product core part taken out together with the main body is required, further melting Equipment is required, which is troublesome, and the equipment costs are high, which inevitably leads to high costs.
[0005]
[Vibration welding method]
When forming a hollow body (intake manifold) as shown in FIG.
FIG. 1 is a bottom molded product of a main body having a flange, 2 is a top molded product covering 1 and is molded by a mold, taken out, put into a jig conforming to the shape, and opposed to each other to a vibrator. The upper and lower welding surfaces are welded by vibrating heat, but require technology.
[0006]
However, it has the following disadvantages, two molds are required, the molded product is deformed because the molded product is removed from the mold, and the molded product is warped, and the shape of R is uneven and it is difficult to fit. Burrs are likely to be generated on the inner surface, and it is necessary to inspect the burrs.At the same time, deburring work may be added in some cases. Also, a vibrator is required and equipment costs are required. The cost is unavoidably high because of the two-stage molding called vibration welding.
[0007]
【Mold cavity movement method】
This method is introduced in JP-A-7-186183, 7-186177 (Nippon Steel Works) and JP-A-8-11155 (Mitsubishi Rayon). However, since the molded product itself is moved, it is difficult to align the core, and there is no other way than to load the injection molding machine with an eccentric load.Especially for large products such as intake manifolds, this eccentric load can damage the tie bars of the molding machine. At the same time, there is a problem of connection, and at the part farther than the center part, burrs are apt to be generated due to this unbalanced weight. Further, at the welding part by secondary injection, the welding resin is mixed with 30% of glass fiber, so that the glass fiber Are aligned in a direction perpendicular to the flow, so that in the weld line, they are aligned in parallel with each other and glass fibers do not mix with each other. Strength strength by the glass fiber does not come out even out, therefore weld strength is decisive problem fall compared to the weld strength of the sliding method.
[0008]
[Mold core moving method]
This method is disclosed in JP-A-10-58487 (Nippon Steel Works) and JP-A-11-42670 (Toshiba), but the injection molding method for the cavity B is not illustrated in the description of the former 10-58487. This is a problem.Also, although such a simple shape describes a part of a complex-shaped molded product such as an intake manifold, it is impossible to form at all, and in the intake manifold, there is no inner core. There is usually an undercut, and it is often difficult to move the inner surface by removing the undercut first. In most cases, the biggest problem of both the above-mentioned Japanese Patent Laid-Open Publications (core moving method) is that the welding surface is similar to the cavity moving method. There is a decisive problem that the strength drops compared to the vibration method (the cause is the same as the cavitation movement method).
[0009]
In the present invention
FIG. 6
There is usually an undercut as shown in FIG. 10, which is removed by a clever method (described below). The core shape is "claim 2" of JP-A-10-58487, and the drawing direction can be determined from the drawing. For example, "a pair of semi-hollow molded products (A, B) cores are integral (20) and only in one horizontal plane direction."
FIG. 1 shows a molded article having a complicated shape and usually a sloping PL surface as shown in 1 (molded body lower surface having a flange) and 2 (molded upper surface article covering 1) shown in FIG. If the mold of the injection molding machine is opened by the methods of Japanese Patent Application Laid-Open Nos. 10-58487 and 11-42670, it is necessary to open the mold very large. Enlargement leads to an increase in cycle time and cost. Therefore, the following inner core is divided and the two-way moving method is devised, and the division is effective for undercut removal and structural processing.
[0010]
[Issue 1 to be solved]
When molding an injection hollow body, it is necessary to increase the welding strength of the welded portion on the inner surface of the peripheral edge of an intake manifold or the like to the level of the vibration method. Fiber-containing raw materials have particularly low weld line welding strength, and it is necessary to devise a mold structure and molding method corresponding to this.
[0011]
[Issue 2 to be solved]
Since there is always an undercut in the core, it is necessary to devise a method to remove this easily.
[0012]
[Issue 3 to be solved]
It is necessary to make the mold opening / closing distance of the injection molding machine as small as possible to reduce the cycle time.
[0013]
[Issue 4 to be solved]
FIG.
FIG.
FIG.
FIG. 12 It is necessary to devise a method of connecting the semi-circular part opposite to the vertical semi-circular part shown in the part and the simultaneously formed flange.
[0014]
[Issue 5 to be solved]
There is a need to devise several methods for improving reliability related to the above, but in the text, each part will be described separately.
[0015]
[Solution 1]
the above
In order to solve the problem 1, a molded product of a lower surface of a main body having a flange (in this case, a flanged component of an intake manifold) 1 and an upper cover 2 thereof.
The welding peripheral edges 11, 21 and the welding cross section of
FIG. 3 shows [3-1], [3-2], and [3-3], which increase the reliability of welding on this surface. A pin space having a rivet structure due to shrinkage during injection of a secondary welding resin. A hole 13 (a rivet space hole at the time of primary injection) and a rib 14 serving as a weir to prevent the welding resin from flowing into the inside are provided on the inner surface of the welding edge. 12 are provided, these details
FIG. 3 is an enlarged view of [3-1] [3-2] and its [3-3] assembly drawing.
FIG. 5A shows that [5-1] is before injection of the secondary welding resin, and [5-2], [5-3], and [5-4] show that the resin has entered the welded portion (hatched portion).
[0016]
However, until now we considered shrinkage as a matter of course in the primary molten resin injection, but in the secondary molten resin injection, we did not always take this shrinkage into account, so the larger the welding area was, Generally, the wall thickness is generally thicker and the shrinkage is larger, and the welding has been performed in the negative direction to reduce the strength.The countermeasures have been to increase the mold temperature and extend the injection time. Raising the mold temperature may be considered in terms of welding, but is problematic in terms of shrinkage, and prolonging the injection time involves entering a resin at a temperature (230-250 ° C.) much higher than the mold temperature. Therefore, considering shrinkage and fiber orientation, this is not a complete measure.
[0017]
The measures are
FIG. 11 shows a rivet-shaped space 13 formed by a sleeve pin method as shown in [11-1], which is filled with a resin by secondary injection and contracted to generate a contraction force in a vertical (up and down) direction. Further, [11-2] is only in the horizontal direction (lateral direction), [11-3] is in the horizontal direction and vertical direction (however, the pin shape is different from [11-1]), and [11-4] is as required The required number of square or circular pins smaller than the welding width (if necessary) and the required number of places required by hydraulic, air pressure, spring force, etc. It can prevent voids, increase the density, improve the degree of adhesion, and reliably increase the welding strength (including appropriate molding conditions).
[0018]
In particular, at the weld line generation location, as described above, the direction of the glass fiber is perpendicular to the resin flow, so that the weld line surfaces are parallel to each other. It is necessary to change the direction of this fiber because it does not come out. It is possible to intermix and change the direction of glass fiber by pressing pins vertically (vertically) and horizontally (horizontally). As it can be done, the strength is improved, and the resin density is also improved and the strength is improved.In some cases, only the vertical and horizontal directions are sufficient if necessary.Also, it is better to bring the weld line part to the rivet shape part, If it is difficult
FIG. 11 shows a resin reservoir formed on a PL surface (parting line) at the time of secondary molten resin injection as shown in [11-4], and a horizontal square or circular pin 20 and inclined pins 21 and 22 are installed. Pressing each other to measure the mutual incorporation of glass fiber and change of direction.If a resin escape part is required when the pin advances, install a piston with a spring at the rear at the appropriate place, and temporarily fill the resin with this part. After the pin retracts, the resin is returned by the piston reaction force.
[0019]
[Means 2 for Problem 2]
There are various ways to remove the undercut,
FIG. 6
As shown in FIG. 10, a clever method using a spring or magnet force has been devised.
[0020]
[Means 3 for Problem 3]
In order to shorten the molding cycle, it is necessary to reduce the mold opening of the molding machine, like the intake manifold
FIG.
FIG. 6
As shown in FIG. 7, since the molded article having a slope has a slope, the inner core portion is divided and moved in parallel and different directions (in this case, opposite directions) to make the mold opening / closing stroke of the molding machine approximately 30 to 50. %, The mold opening stroke can be reduced, the molding cycle can be shortened, the cost can be reduced, and the machining of the undercut part is easy by dividing the inner core. There is also an effect.
[0021]
[Means 4 for Problem 4]
How to connect the vertical semicircle to the horizontal flange
FIG. 6
FIG. 12 shows a solution by using a slide core.
[0022]
[Means 5 for Problem 5]
About this matter
FIG. 11 shows a rivet-shaped structure as shown in [11-2] and [11-3] in the primary injection.
In FIG. 10, the undercut of the R portion of the inner core is subtly removed by a spring method.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The present invention breaks down the wrong idea that increasing the welding area in conventional secondary resin injection increases the welding strength if the welding area is increased, and conversely increases the shrinkage by simply increasing the area. Use the shrinking force to make it the proper size and rivet shape, and in that part, increase the strength by applying vertical and horizontal pressure alternately, and consider the properties of glass fiber in the weld line part
[11] As shown in [11-4], by alternately performing the pressing operation of the pins, the mixing of the glass fiber and the change of the direction thereof are measured to improve the strength, and further, it is always attached to the intake manifold. Remove the undercut by a clever method, and divide the inner surface core and move it in parallel different directions (in this case, the opposite direction), reduce the mold opening distance of the injection molding machine, shorten the cycle time, and It is a method of connecting a vertical semicircular portion and a horizontal flange.
[0024]
[Features of product shape]
Product shape
FIG. 1 shows the following features.
[0025]
FIG. 5
FIG. 11 shows a rivet shape for improving the welding strength of the inner peripheral surfaces of the welding peripheral edges 11 and 21. A pin space hole 13 which is not filled with the welding resin at the time of the primary injection is formed, and this pin is retracted at the time of the secondary injection. Then, the rivet-shaped part is filled with resin, and the mold structure is designed to improve the strength by this contraction force.
[0026]
In consideration of shrinkage of the resin injected into the inner peripheral surfaces of the welding peripheral edges 11 and 21 of the intake manifold as shown in FIG. 1, a round pin is vertically formed on the rivet-shaped portion, and a square is formed at an appropriate position in the horizontal direction. Or devising a mold structure to increase the welding strength by installing a circular pin and applying compressive force to each other, and in a part where the rivet method can not be adopted, installing a pin in the horizontal direction and applying pressure, especially for the weak weld line part Press the pin alternately vertically and horizontally in the rivet-shaped part.If this weld line does not come in the rivet-shaped part, install a resin pool and several pins as necessary. In order to improve the strength of the welded part by intermixing glass fibers by moving forward and backward with each other, and to change the direction (the conventional practice has not focused on injection resin shrinkage for secondary injection). Concept, the strength improvement measures weld line portion of the glass fiber resin temperature, mold temperature increase was not considered much except injection times).
[0027]
By moving the divided cores having inner undercuts in parallel and different directions (in this case, in opposite directions) to reduce the opening and closing stroke of the injection molding machine, the cycle time is reduced and the mold processing is easier. Measured.
[0028]
FIG. 6
As shown in FIG. 12, this intake manifold may require a welded structure of a vertical semicircular portion and a horizontal flange, so a mold structure has been devised.
[0029]
Next two items
[Product shape]
[Mold structure and operation method] will be described.
[0030]
[Product shape]
FIG. 1 illustrates the shape of a molded product when forming an intake manifold.
FIG.
As shown in FIG. 2, in [2-1], reference numeral 1 denotes a molded product of the lower surface of the main body in which a flange is molded together, and reference numeral 2 in [2-2] denotes a component that covers it from the upper surface.
FIG. 3 is a cross-sectional view, and triangular fine irregularities 12 (high enough to melt and improve the welding force during the injection of the secondary molten resin) are formed on the inner surfaces of the welding edges 11 and 21 formed during the injection of the main body. , A space hole 13 having a rivet structure, and a projection 14 are further provided so that molten material does not enter inside.
FIG. 3 [3-3] shows a state in which the two molded articles face each other.
FIG. 4 is a sectional view taken along the line E of the molded product, and shows a state in which the molded product faces each other.
[0031]
FIG. 5 shows details of the unfilled inner surface welded part in [5-1], and molten materials in hatched parts in [5-2], [5-3] and [5-4]. It is considered to be effective.
[0032]
[Mold structure and operation method]
According to molding order
[Primary injection molding of hollow body],
[Secondary injection molding of inner peripheral surface of hollow body] and
[Formation of vertical injection welding part]
[0033]
[Primary injection molding of hollow body]
FIG. 6 is a cross-sectional view of the E mold in a state where the mold is closed (
FIG. 2E ₁ -E ₁ , E ₂ -E ₂ ) Indicates that the molded product and the cavities are opposed to each other with the inner core interposed therebetween. The necessary number of gates (eg, 51, 52, 53, etc.) are installed at the optimal positions in the main molded product, and the molten resin Is injected into the cavities to fill and form two opposing molded articles (primary injection molding is completed), but the inner core must be removed, but the inner split core 31 has 33 undercuts and the inner split core There are 34 undercuts in 32, you need to remove them first,
As shown in FIG. 10, when the inclined slide 37 retreats, the pins 35, 36 retreat in the direction of the arrow by the spring, and the undercut portions 33, 34 rotate inward about the 38, 39 and come off. Open the dies in the order of 61, 62, 63 to the minimum necessary.
FIG. 6 shows a process in which the body inner surface divided core 31 is retreating along a guide (omitted for simplicity) held outside the mold in the direction of 311. However, the inner core 32 is also required. Minimally open, retreat in the opposite direction 322, move in parallel different directions (in this case, the opposite direction), and the inclined slide 37 also retreats outward together with the core 32. After the retreat is completed, the mold advances again. Then, the PL surface (parting line surface) is matched, and the hollow body in the cavity is formed facing the cavity.
[0034]
FIG. 7 shows a state in which the main body split core 31 on the main body lower surface molded product 1 side is moving in the arrow direction 311. The upper cover 2 side split core 32 is also in the same state as the 1 side split core. The opening and closing distance of the molding machine can be reduced by about 1/3 to 1/2 by doing so.
[0035]
FIG. 8 is a cross-sectional view of the mold F (
FIG. 2F ₁ -F ₁ , F ₂ -F ₂ ) Indicates that the core inner surface divided cores 31 and 32
FIG. 7 shows a direction perpendicular to the cross-sectional view of the mold F, and moves in opposite directions at right angles to the sheet of FIG.
As shown in FIG. 9, the PL surface (parting line surface) moves forward and opposes, the inner core is pulled out in the same manner as described above, and a hollow body remains in the cavity.
[0036]
[Formation of secondary injection welded part on inner surface of peripheral edge of hollow body]
This is to inject a secondary welding resin into the inner surfaces of the peripheral edges 11 and 21 of the hollow body to complete the complete hollow body.
There has been a drawback that the welding strength is weaker than the vibration welding method as described above, but methods such as increasing the mold temperature to improve welding, increasing the injection pressure, and replenishing the shrinkage amount have been used. In terms of shape
FIG. 5 shows a [5-4] shape;
FIGS. 13A and 13B have tried shapes such as [13-1] and [13-2], but were unsuccessful. The reason for this is that if the welding area is increased, the welding strength is improved. The amount of shrinkage increases accordingly. Even if the injection pressure is increased, the temperature of the injection resin is higher than the mold temperature by 100 to 150 ° C or higher, and it has been overlooked that shrinkage always occurs. It is considered that the greatest cause is that they are arranged in a direction perpendicular to the direction and in a parallel direction.
[0037]
As a measure against this
FIG. 11 shows that a pin space hole 13 like [11-2] is formed by installing 15, 16 sleeve pins on the peripheral edge 11 as shown in [11-1], and the vertical lifting force is removed. As a result, the pin recedes to form a gap [11-2], and the gap is filled with the welding resin (hatched portion), and the rivet effect is generated by the shrinkage in the vertical direction. The pin 20 [11-4] having the dimensions is horizontally (laterally) pressurized by hydraulic pressure, air pressure, or spring force, and further the sleeve pin 15, 16 or [11-3] of [11-1]. The welding can be assured by pressing the pins 17 with each other. This operation is performed as necessary, and the strength state of the welding surface in one direction, vertical direction, horizontal direction, etc. Decided by It is.
[0038]
Especially when in the weld line area, the direction of the glass fiber is changed by the mutual pressing operation, which is effective in improving the strength. In addition, if the weld line is generated where the rivet effect appears, the operation in the vertical and horizontal directions Therefore, the strength can be easily improved. However, if the weld line cannot be generated in the rivet shape part,
FIG. 11 shows a case in which a resin stay is formed as necessary as shown in [11-4], and an appropriate number (three in the drawing) of square or circular small pins is arranged at an appropriate place as shown in the above figure. By moving forward and backward under pressure, the fiber orientation of the glass fiber is corrected, and the welding strength is improved. In addition, the cost is reduced as compared with the vibration welding method because the glass fiber is integrally formed in a mold. However, it is necessary to select appropriate resin temperature, mold temperature, and pressure.
[0039]
In order to obtain a flat surface such as [11-2], a sleeve type (two-stage device) as shown in [5-1] is required for the pin tip shape. What is necessary is just to use the stepped pin of type [5-3].
[0040]
[Vertical secondary injection molding]
This part
FIG. 2
FIG. 4
FIG. 6
FIG. 12 shows 40 parts as described in FIG.
FIG. 12 shows the operation, which is composed of a movable main body 50 and movable parts 41 and 42 and slide parts 45 and 46 installed thereon. And the movable body 50 stops at a predetermined position, and the movable body 50 advances in the forward direction 80. ₁ -N ₁₀ -N ₁₁ -N ₁₂ -N ₁ Line is N ₂ -N ₂ -N ₂ -N ₂ -N ₂ And the vertical semicircular portion can be formed. Next, in the case of secondary welding resin injection, a uniform gap 40 is required. ₂ If the arc is retracted in the backward direction 80 as it is, the center point N of the movable body 50 ₁₁ , 41 parts N ₁₀ Point, 42 parts N ₁₂ N at the point because the arcs are the same ₁₀ Point and N ₁₁ , N ₁₂ The distance between the points is greatly different, so that the resin cannot be secondarily injected with a uniform thickness. ₁ -N ₁₀ -N ₁₁ -N ₁₂ -N ₁ Must be made into a line of, with a structure devised for that
12 and [HH] cross section, the movable body 50 first retreats a little more, and the parts 41, 42 are moved outward with the centers of 43, 44. , The parts 45 and 46 advance in the direction of 70 to a predetermined position, the next movable body 50 advances and forms a gap 40 for resin injection, where the secondary welding resin injection is performed and the flange is formed. Welding progresses with
[0041]
Also in this part, insufficient welding due to shrinkage, glass fiber orientation, etc. can be considered. Therefore, after the injection is completed, if necessary, the movable body 50 is moved forward by 80, and the parts 45 and 46 are alternately pressed and advanced so that the gap due to shrinkage is obtained. In order to improve the welding strength by preventing adhesion, the parts 45 and 46 are retracted when removing the molded product, and then the movable body 50 is retracted.
Although it may be considered that it is impossible to advance the shrinkage prevention by looking at FIG. 12, it is added that the opposing portion is made of resin and has flexibility.
[0042]
【The invention's effect】
The present invention has the following effects by being executed as described above.
[0043]
Due to the shrinkage effect of the rivet effect on the inner surface of the welded peripheral edge and the vertical and horizontal pressurization operation by the pin (better in the case of vibration), if the weld line part occurs in the rivet shape part, the vertical and horizontal direction With the same pressurized operation as
FIG. 11 forms a resin reservoir as needed as shown in [11-4], arranges an appropriate number (three in the drawing) of square or circular small pins at appropriate locations as shown in the above figure, and pressurizes the pins. By moving forward and backward, the fiber orientation of the glass fiber is corrected, and the welding strength is improved. In addition, the cost is reduced compared to the vibration welding method because it is integrally molded in the mold.
[0044]
Since the inner core is operated in a different plane direction (in this case, the opposite direction), the opening and closing distance of the injection molding machine is reduced, so that the molding cycle time can be reduced and the cost can be reduced.
[0045]
Welding of vertical parts and flanges, which was impossible until now, is now possible
[Brief description of the drawings]
FIG. 1 is a plan view of a completed hollow molded article of an automobile part intake manifold according to the present invention.
[1-2] Completed product A1 arrow side view
[1-3] Side view of finished product
FIG. 2 [2-1] Lower body parts with flange
[2-2] Top cover parts diagram
[3-1] [3-1] [c] of two parts ₂ -C ₂ ] Cross section
[3-2] [c] of one part ₁ -C ₁ ] Cross section
[3-3] Partial sectional view of [c] before welding of 1 and 2 parts (before welding)
FIG. 4
FIG. 2 [E] Cross-sectional view of molded product (before welding)
[5-1] Peripheral view of welding (before welding)
[5-2] Welding diagram (rivet type welding diagram Pin upper surface is flat)
[5-3] Welding diagram (rivet type welding diagram Pin top surface is uneven)
[5-4] Welding diagram (normal partial welding diagram)
FIG. 6
FIG. 2 is a sectional view of a part E of a molded product (before facing a molded product).
FIG. 7 is a view in which the undercut 33 is removed and the inner core 31 of the part 1 is moving in the arrow direction 311. [Note] Note that the inner core 32 moves in the opposite direction 322.
FIG. 8
FIG. 2 is a cross-sectional view of a part F of a molded product F (the retracting directions of the divided cores 31 and 32 are opposite to the direction perpendicular to the plane of the paper).
FIG. 9
FIG. 2 is a sectional view of a part F of a molded product F (peripheral edge and before inner surface welding).
FIG. 10 is a structural view showing an undercut of an inner core.
[11-1] Sleeve structure for rivet welding (without filling of molten resin)
[11-2]-Riveted shape filled with welding resin and square or circular side pins (usually circular in this case) [Note] Be careful of the structure so that the rivet ceiling surface is flat
[11-3] Simple pin type structure (appearance is a problem) and square or circular side pins
[11-4] Intermediate G cross-sectional shape of the rivet portion, resin pool, and square or circular fine side pins
FIG. 12 is a view showing a structure of welding to a flange by secondary injection of a vertical semicircular portion.
FIG. 13 [13-1] Welded part shape (no significant effect)
[13-2] Welding section shape (no significant effect)
[Explanation of symbols]
1. Lower body molded product with flange
2. Top cover of the above molded product
11.1 Perimeter edge of part
21.2 Perimeter edge of component
12. Small irregularities on the welded part
13. Riveting holes
14． Rib to prevent molten resin from flowing to inner surface during secondary injection
15. Sleeve center pin for rivet formation
16. Sleeve liner for rivet formation
17. Rivet forming pin (integral pin)
18. Hollow of molten resin, square or circular pressure pin for density improvement
20. Square or circular slightly thin pressure pin for preventing cavities from melting and improving density
21, 22. Inclined pin for pressurizing operation
23.24 Inclined Pin Pressing Actuation for Riveting
25. Inclined block
26. Hydraulic or air cylinder
28. Resin pool
31.1 Parts core
311.1 Parts core sliding direction
32.2 parts core
322.2 parts core sliding direction
33.1 Parts core undercut
34.2 parts core undercut
Inclined block for removing 35, 36 undercut
37. Inclination block for 35, 36 operation
Undercut rotation center for 38, 33
Undercut rotation center for 39.34
40. Gap for injection of secondary welding resin between vertical part and flange
41, 42. Movable block installed on part 50
43,44. Center of movable block of parts 41 and 42
45, 46. Slide block
50. Moving parts
51, pin gate sprue
52, 53. Side gate sprue, runner
61, 62, 63. Mold opening
70. Sliding direction of slide block for forming gap 40 between vertical portion and flange
72. The movable direction of the movable blocks 41 and 42
80. Sliding direction of movable block between vertical part and flange

Claims (3)

[Fig. 5] In a hollow body molding die by an injection molding machine, [Fig. 5] A welding surface having an appropriate thickness and size is formed on the inner surfaces of the welding peripheral edges 11 and 21. 5-1] [5-3] is formed into a rivet shape, and circular sleeve pins 15 and 16 as shown in [11-1] in FIG. ], A circular pin 17 is provided to form a rivet-shaped space hole 13 during the injection of the primary resin, and is retracted during the injection of the secondary welding resin. The space 13 is filled with resin to form a rivet shape. Using the contraction force and applying pressure in the upward direction (the upper part is almost the same shape) directly using hydraulic pressure, air pressure, springs or the like, or using the inclined portions 23 and 24 at the bottom of the pin, and at the same time horizontal Square or circle from direction (side) Apply pressure such as oil pressure, air pressure, spring, etc. to the pins of each other, and perform these three directions of pressurization operation mutually, if necessary, only one direction, or two directions such as vertical and horizontal, and weak weld line Is set at the position of the rivet shape. If it is not possible, as shown in [11-4], if necessary, the PL surface (parting line surface) outside the molded body should have an appropriate shape. A resin puddle 28 is formed, and several square or circular pins 20 smaller (if necessary) smaller than the inner surface width of the peripheral edge and pins 21 and 22 having appropriate inclination angles are arranged at appropriate positions at the corresponding locations. The pressurizing operation moves forward and backward in the same manner as described above, and the mold is used to intermix glass fibers in the weld line portion and to change the direction, thereby improving the strength of the welded portion and preventing voids due to shrinkage, and preventing a decrease in adhesion. Structure and its Form method (含成 type conditions). [Fig. 6]
FIG.
As shown in FIG. 10, the undercuts 33.34 attached to the divided inner cores are removed inward around the centers 38 and 39, and the inner cores are opened to a minimum necessary shape. (In the opposite direction) or in the perpendicular direction (including the diagonal direction), and after the retreat is completed, the PL surface (parting line surface) is advanced, and the molded product of the cavity part, which becomes a hollow body, is opposed. A mold structure and a molding method thereof capable of greatly reducing the cycle time and facilitating machining of an undercut. FIG.
FIG. 12 shows a vertical semicircular portion or the like or a semicircular portion opposed to a part thereof, which is formed into a hollow body, by welding a flange formed at the same time to a semicircular portion. to _{2 -N 2 -N 2 -N 2 -N} 2 are brought into close contact with the arc _{N 1 -N 10 -N 11 -N 12} -N 1 by molding the body, outwardly movable body 50 during the secondary welding resin injection 80, and then the movable parts 41, 42 installed on the main body 50 are opened in the outward direction 72 around the pins 43, 44, and then the slidable parts 45, 46 are advanced in the 70 direction, and welding resin jettable gap _{40 (N 10 -N} 11 -N ₁₂ arc) is formed, a welding resin injected and filled in a gap therebetween, mutually pressurized further parts 45, 46 of injection after main body part 50 in the 80 direction Pressure advance to prevent voids due to shrinkage, Enhanced, mold structure and its molding method measures the strength improvement of the welding surface (含成 type conditions).

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