JPH09323124A - Press forming method and press forming die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify and miniaturize the structure of a press mechanism. SOLUTION: A lower die 11 is provided with inclined curved edges (guiding means) 16 and stoppers 17 and an upper die 12 is provided with rectangular curved edges (holding means) 19 which are along the outside of rectangularly bending parts 22. When a material 20 to be worked is lowered with the upper die 12, the tip edges 22A of the rectangularly bending parts 22 are inward guided and run against the stoppers 17, the rectangularly bending parts 22 are buckled so as to become a shape along the inclined curved edges 16 and the rectangular curved edges 19, and rectangular bended parts 23 are formed. Cam mechanisms for contacting and separating two curved edges from the inside and the outside to the rectangular bending parts are unnecessary, so the structure of the press mechanism is simplified and also miniaturized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an inwardly bent negative-angled bent portion at the tip of a right-angled bent portion that is bent and formed at a right angle to the edge of a plate-shaped workpiece. The present invention relates to a press molding method and a press molding die used therefor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, at the tip of a right-angled bent portion 1A, which is bent and formed at a right angle to an edge portion of a plate-shaped work piece 1, a negative portion bent inward is formed. Corner bending part 1B
In the case of molding, the following method has been adopted.

The work piece 1 having the right-angled bent portion 1A formed thereon is transferred to the press 2 shown in FIG. 9 and the wedge-shaped drive cam 3 is lowered to make the driven inner cam 5 provided on the lower die 4 into a right angle. At the same time as the bent portion 1A is approached from the inside, the driven outer cam 6 provided on the driven inner cam 5 is moved toward the right-angled bent portion 1A from the outside to bend the curved blade 5A of the driven inner cam 5 and the curved outer cam 6. The tip of the right-angled bent portion 1A is bent and deformed inward with the blade 6A to obtain the negative-angle bent portion 1B.

After the negative angle bent portion 1B is formed, when the drive cam 3 is retracted upward, the driven inner cam 5 and the driven outer cam 6 are bent by the elastic force of the return springs 7A and 7B to form the right angle bent portion 1A and the negative angle bent portion. Separate from 1B. Then, the driven inner cam 5 is moved to the negative angle bent portion 1 as shown by the chain double-dashed line in FIG.
Since it retreats to a position further inside than the tip edge of B, it becomes possible to take out the workpiece 1 on which the negative-angle bent portion 1B has been formed by pulling it upward.

[0005]

When the right angled bent portion 1A is pressed from the inside and the outside by the curved blades 5A and 6A to form the negative angle bent portion 1B as described above, the curved blade is bent. 5
Since a cam mechanism for moving A and 6A is required, there is a problem that the structure of the press mechanism becomes complicated and the size becomes large. As a countermeasure against this, it is conceivable to provide the curved blade 5A in a fixed manner. However, in order to take out the workpiece 1 after molding, it is necessary to retract it to a position inside the negative angle bent portion 1B, so that the cam A mechanism is required, and again, the complexity and size of the structure cannot be avoided.

The present invention was devised in view of the above circumstances, and it is an object of the present invention to simplify the structure of a press mechanism and reduce its size.

[0007]

According to a first aspect of the present invention, a negative angle fold that is bent inward is formed at the tip of a right-angled bent portion that is bent at a right angle to the edge of a plate-shaped workpiece. A press forming method for forming a bent portion, wherein a tip end edge of the right bent portion is brought into contact with a guiding means in a state where a right angle posture at a base end side portion of the right bent portion can be maintained. It is characterized in that it bends by being guided inward to form a negative-angle bent portion.

According to a second aspect of the present invention, in the first aspect of the present invention, the work piece is displaced in parallel with the right-angled bent portion while the right-angled blade is placed along the outer surface of the right-angled bent portion, By guiding the tip edge of the bent part inward by an inclined curved blade that is inclined with respect to the displacement direction and abutting against the stopper, the tip of the right-angled bent portion is formed into a shape that follows the right-angled curved blade and the inclined curved blade. It is characterized in that it is buckled to form a negative angle bent portion.
According to a third aspect of the invention, in the first aspect of the invention, the right-angled bent portion is held in a right-angled posture by partially projecting inward at a corner edge portion of the base end of the right-angled bent portion in the work material. By forming a reinforcement part and displacing the work piece in parallel with the right-angled bending part, the tip edge of the right-angled bending part is slidably contacted with a curved curved blade that is curved inward, so that the tip side of the reinforcement part It is characterized in that the portion is curved inward to form a negative angle bent portion.

According to a fourth aspect of the present invention, an inwardly bent negative-angle bent portion is formed at the tip of the right-angled bent portion that is bent and formed at a right angle to the edge of the plate-shaped workpiece. And a holding means capable of holding the base end side portion of the right-angled bent portion in a right-angled posture, and the right-angled bent portion along with displacement of the workpiece in a direction parallel to the right-angled bent portion. And a guide means for causing bending deformation by guiding the leading edge of the inside of the.

According to a fifth aspect of the invention, in the invention of the fourth aspect, there is provided a movable die for displacing the workpiece in parallel with the right angle bent portion with the right angle curved blade along the outer surface of the right angle bent portion. An inclined curved blade that is inclined with respect to the displacement direction of the movable die and guides the tip edge of the right-angled bent portion inward, and a stopper that the tip edge of the right-angled bent portion guided by the inclined curved blade abuts The present invention is characterized in that the negative-angle bent portion is formed by buckling the tip of the right-angled bent portion against a stopper to buckle the shape along the right-angled curved blade and the inclined curved blade. .

[0011]

According to the inventions of claims 1 and 4, in forming the negative angle bent portion, the right angled bent portion is not bent and deformed by sandwiching the right angled bent portion from the inside and the outside with bending blades.
Bending deformation is caused by bringing the leading edge of the right-angled bent portion into contact with the guiding means and guiding it inward. Therefore, there is no need for a cam mechanism to bring the curved blades into and out of the right-angled bent portion from both the inside and outside directions,
The structure of the press mechanism can be simplified and downsized.

In the inventions of claims 2 and 5,
By guiding the tip edge of the right-angled bent portion inward and abutting it against the stopper, the right-angled bent portion buckles and a negative-angle bent portion is formed. Since the right-angled bent portion is guided by the right-angled bent blade and the inclined bent blade during buckling deformation, the negative-angle bent portion can be formed at a predetermined angle. In the invention of claim 3,
The tip portion of the right-angled bent portion is guided inward along the curved bent blade to be gradually curved and deformed to form the negative angle bent portion. When curved and deformed, the base end side portion of the right-angled bending portion is held in the right-angled posture by the reinforcing portion,
The negative angle bent portion can be formed into a predetermined shape.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> A first embodiment of the present invention will be described below with reference to FIGS. The press mold 10 of the present embodiment includes a lower mold 11 fixedly provided on a floor surface (not shown), and an upper mold which is driven up and down by a driving mechanism (not shown) above the lower mold 11 (the structure of the present invention. And a movable type) 12, which is a requirement. Lower mold 11
A concave portion 13 that is open upward is formed on the upper surface of the. A pad 14 for receiving the work piece 20 from below and horizontally supporting the work piece 20 is fitted and mounted in the recess 13 so as to freely move up and down. The pad 14 is elastically compressed by a compression coil spring 15 provided in the recess 13. Is supported by.

Both sides of the concave portion 13 on the horizontal upper surface of the lower mold 11 are cut out in a V-shaped cross section. The inclined surface on the outer side of the cutout portion is an inclined curved blade (guide means which is a constituent of the present invention) 16, and the inclined curved blade 1
6 is guided to the inside by bringing the tip edge 22A of the right-angled bent portion 22 of the work material 20 into contact. Further, the deepest position on the inner inclined surface is the stopper 17, and the stopper 17 has a tip edge 22A of the right-angled bent portion 22 guided by the inclined curved blade 16.
Is struck.

The lower surface of the upper die 12 is a pressing surface 18 parallel to the pad 14, and the work material 20 is sandwiched and held between the pressing surface 18 and the upper surface of the pad 14. . At both end positions of the pressing surface 18 of the upper mold 12,
A right angle curved blade (holding means which is a constituent of the present invention) 19 is formed so as to project downward. The right-angled curved blade 19 forms a right angle with respect to the pressing surface 18 and extends along the outer surface of the right-angled bent portion 22 of the workpiece 20 placed on the pad 14.

On the other hand, the work piece 20 molded by the press mold 10 of the present embodiment is bent at right angles downward from both side edges of the flat top plate portion 21 by a press machine (not shown) in advance. It has a portion 22 and has a "U" shape as a whole. The dimensions of each part of the work piece 20 are set as follows. As shown in FIG. 4, the plate thickness dimension is t, and the radius of curvature at the buckling portion at the boundary between the right angle bent portion 22 and the negative angle bent portion 23 is t / 2,
The length dimension of the negative angle bent portion 23 is a, and the minimum vertical dimension of the region of the right angle bent portion 22 above the negative angle bent portion 23 is 2a, and the negative angle bent portion 23 and the right angle bent portion 22. When the maximum tilt angle with respect to is 45 °, t = 0.5 to 1.0
In the case of mm, the dimensions of a and t are set so as to satisfy a ≧ 10t, and in the case of t> 1.0 mm, the dimensions of a and t are set so as to satisfy a ≧ 4t. By setting the dimensions based on such conditions, the buckling deformation of the right-angled bent portion 22 described later can be favorably performed.

Next, the operation of the present embodiment will be described. Workpiece 20 having a right-angled bent portion 22 formed in advance
Are placed on the pad 14 as shown in FIG.
In this state, the tip of the right-angled bent portion 22 has an inclined curved blade 1
6 is arranged so as to point to a position closest to the outermost side. Further, both edge portions of the top plate portion 21 of the work material 20 are protruded to the outside from the pad 14 to be in a cantilever state,
There is a space between the inner surface of the right-angled bent portion 22 and the outer surface of the pad 14 that is slightly larger than the amount of the negative-angled bent portion 23 that protrudes inward from the right-angled bent portion 22 when it is formed. ing.

When the upper die 12 descends from this state, the pressing surface 18 of the upper die 12 abuts on the upper surface of the top plate portion 21 to sandwich and fix the work piece 20 between the upper surface of the pad 14 and The right angle bending blade 19 comes into lateral contact with the upper half region of the outer surface of the right angle bending portion 22. When the upper die 12 is further lowered from this state, the pad 14 and the work material 20 are lowered while the compression coil spring 15 is elastically contracted, and the tip edge 22A of the right-angled bent portion 22 contacts the inclined curved blade 16. Then, the tip edge 22A of the right-angled bent portion 22 is guided inward according to the inclination of the inclined curved blade 16, and accordingly, the right-angled bent portion 22 changes its posture as a whole to the inner side, and the right-angled bent portion 22 The leading edge 22A of the abutting portion comes into contact with the stopper 17.

In this state, the tip edge 22 of the right-angled bent portion 22 is
Although A cannot move further inward, a downward pressing force is applied to the right-angled bent portion 22 by the upper die 12, so that the right-angled bent portion 22 moves upward from the tip edge 22A by a predetermined dimension. It will buckle outward in position. When buckling, the upper half region of the right-angled bending portion 22 hits the right-angled bending blade 19 and the tip portion of the right-angled bending portion 22 hits the inclined bending blade 16, whereby the right-angled bending portion 22 is bent.
The shape of the right-angled bent portion 22 is determined while being restricted so as not to be deformed outwardly more than necessary. As a result, as shown in FIG. 2, the tip of the right-angled bent portion 22 is bent and deformed inwardly of the right-angled bent portion 22 along the inclined curved blade 16 to form the negative-angle bent portion 23, and The area of the right-angled bent portion 22 above the negative-angled bent portion 23 is held by the right-angled curved blade 19 in a right-angled downward posture.

After the negative angle bent portion 23 is formed in this way, as shown in FIG. 3, the upper mold 12 is retracted upward, and the pad 14 and the workpiece 20 placed on the pad 14 are retracted. Moves upward due to the elastic restoring force of the compression coil spring 15, and the negative angle bent portion 23 separates from the lower mold 11. In this state, the work piece 20 is lifted upward or horizontally moved in parallel with the right-angled bent portion 22 to move the pad 1
4 can be taken out. At this time, the right-angled bending portion 2
Since there is a predetermined gap between the outer surface of the pad 2 and the outer surface of the pad 14, there is no possibility that the negative angle bent portion 23 will be caught by the pad 14 when the workpiece 20 is lifted and removed.

As described above, in the present embodiment, as a means for forming the negative angle bent portion 23, the right angle bent portion is sandwiched between the inner and outer bidirectional bending blades to be bent and deformed as in the conventional case. Instead, the tip end edge 22A of the right-angled bent portion 22 is guided inward according to the inclination of the inclined curved blade 16 and abuts against the stopper 17 to buckle the right-angled bent portion 22. Therefore, not only the double cam mechanism for contacting and separating the two curved blades from the inner side and the outer side with respect to the right-angled bent portion but also no cam mechanism is required, and the structure of the press mechanism is simplified. It has been miniaturized.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. The press mold 30 of this embodiment includes a lower mold 32 fixedly provided on a floor surface (not shown) via a holder 31, and an upper mold that is driven up and down by a drive mechanism (not shown) above the lower mold 32. And 33. The lower mold 32 has a cylindrical shape that penetrates in the vertical direction, and is fitted and attached to the upper surface of the holder 31. A curved curved blade (guide means which is a constituent of the present invention) 34 is formed along the entire periphery of the opening edge on the upper surface side of the lower die 32. Curved curved blade 3
4 is a vertical surface 34A that is perpendicular to the upper surface of the lower mold 32.
And a horizontal plane 34B that is perpendicular to the inner peripheral surface of the lower mold 32.
And an arc surface 34C that smoothly connects the vertical surface 34A and the horizontal surface 34B.

In the lower die 32, a pad 35 for receiving the workpiece 50 from below and horizontally supporting it is mounted so as to be lifted and lowered by being guided by a bolt 36 screwed into the holder 31. . The pad 35 is biased upward by a compression coil spring 37 provided between the pad 35 and the holder 31, and is always held at a predetermined height by the engagement between the head of the bolt 36 and the inner bottom surface of the recess 38 of the pad 35. ing. Upper mold 33
Has a pressing surface 39 parallel to the pad 35,
Between the pressing surface 39 and the upper surface of the pad 35, the workpiece 5
0 is clamped and held. A holding portion 40 is formed on the lower surface of the upper mold 33 so as to project downward along the entire circumference. The peripheral portion of the pressing surface 39 and the holding portion 4
0 is closely contacted from the outside with a corner edge portion extending from the peripheral edge of the top plate portion 51 of the workpiece 50 to the right-angled bent portion 52. In addition, a plurality of protruding portions 41 that are aligned with the reinforcing portions 53 of the workpiece 50 described later are formed in a portion extending from the pressing surface 39 to the inner surface of the holding portion 40.

On the other hand, the work material 50 molded by the press molding die 30 of the present embodiment is bent downward at a right angle over the entire circumference from the peripheral edge of the flat top plate portion 51 in advance by a press machine not shown. It has a right-angled bent portion 52, and has a box shape with the lower surface side open as a whole. Top plate part 51
A plurality of reinforcing portions 53 are formed on the corner edge portion which is a boundary between the right-angled bent portion 52 and the right-angled bent portion 52 at predetermined intervals in the lengthwise direction. The reinforcing portion 53 is projected so as to be inverted inward with the same plate thickness, and the reinforcing portion 53 holds the right-angled bent portion 52 in a posture perpendicular to the top plate portion 51. ing. Further, the portion below the reinforcing portion 53 (on the tip end side) remains at right angles to the top plate portion 51 over the entire circumference, and by bending and deforming this portion, the negative angle bending portion 54 is formed. It is supposed to be molded. Next, the operation of this embodiment will be described. The workpiece 50 having the right-angled bent portion 52 formed in advance is placed on the pad 35. In this state, the tip edge portion (lower edge portion) of the right-angled bent portion 52 is fitted in the curved curved blade 34 and is in contact with the vertical surface 34A thereof. In addition, the region where the reinforcing portion 53 is formed in the peripheral portion of the top plate portion 51 protrudes from the pad 35 to the outside, and a negative angle fold is formed between the inner surface of the right-angled bending portion 52 and the outer surface of the pad 35. There is a space a little larger than the amount of the curved portion 54 protruding inward from the right-angled bent portion 52 when the curved portion 54 is formed.

When the upper die 33 descends from this state, FIG.
As shown in FIG. 3, the pressing surface 39 of the upper die 33 abuts on the upper surface of the top plate portion 51 to sandwich and fix the workpiece 50 between the upper surface of the pad 35 and the protruding portion 41 of the reinforcing portion 53. It comes to match the outer surface. When the upper die 33 further descends from this state, the compression coil spring 37 is elastically contracted and the pad 3
5 and the workpiece 50 descend, and the tip edge 52A of the right-angled bent portion 52 comes into sliding contact with the arc surface 34C of the curved bending blade 34. As a result, the tip edge 52A of the right-angled bent portion 52 is guided inward according to the arc shape of the arcuate surface 34C. At this time, the base end side (upper side) portion of the right-angled bent portion 52 is reinforced portion 53. As shown in FIG. 7, the portion on the tip side (lower side) of the reinforcing portion 53 is forcibly curved and deformed inward, so that the negative angle bent portion 54 is formed. It

After the negative angle bent portion 54 is formed in this manner, as shown in FIG. 8, the upper die 33 retreats upward and the pad 35 and the workpiece 50 placed on the pad 35. Moves upward due to the elastic restoring force of the compression coil spring 37, and the negative angle bent portion 54 separates from the curved bending blade 34. Then, after the upper die 33 retracts above the workpiece 50,
By raising the work piece 50 upward, the pad 3
5 can be taken out. At this time, the right-angled bent portion 5
Since there is a predetermined gap between the pad 2 and the outer surface of the pad 35, there is no possibility that the negative angle bent portion 54 will be caught by the pad 35.

As described above, in this embodiment, as a means for forming the negative angle bent portion 54, the right angle bent portion is sandwiched by the curved blades from both the inside and the outside to bend and deform as in the conventional case. Instead, the base end portion of the right-angled bent portion 52 is attached to the reinforcement portion 5
The tip edge 52A of the right-angled bent portion 52 is bent and deformed inward according to the arc shape of the curved curved blade 34 while being held in a right-angled posture by 3. Therefore, a cam mechanism for contacting and separating the two curved blades from the inner side and the outer side with respect to the right-angled bent portion is unnecessary, and the structure of the press mechanism is simplified and downsized.

Further, in the present embodiment, the reinforcing portion 53 is formed at the corner edge between the top plate portion 51 and the right-angled bent portion 52 to hold the right-angled bent portion 52 in a right angle posture. Therefore, as compared with the work material 20 of the first embodiment, the restrictions on the dimension setting are relaxed. <Other Embodiments> The present invention is not limited to the embodiments described above with reference to the drawings. For example, the following embodiments are also included in the technical scope of the present invention. Various changes can be made without departing from the scope of the invention.

(1) In the first embodiment, the side edge portion of the top plate portion protrudes from the pad to leave a space between the outer surface of the pad and the right-angled bent portion, so that the negative-angled bent portion is molded. Although the processed material can be pulled out upward and taken out, according to the present invention, a protruding portion is provided on the outer surface of the pad, and the protruding portion and the right-angled bending blade sandwich the right-angled bent portion. The configuration may be such that the tip edge of the right-angled bent portion is brought into contact with the inclined curved blade to bend and deform. With such a configuration, the right-angled bent portion is surely bent at the lower end position of the region sandwiched by the protruding portion and the right-angled curved blade. Therefore, the bending position of the negative angle bent portion can be easily set by changing the sandwiching area between the protruding portion and the right angle bent blade, and the degree of freedom in setting the dimension of the right angle bent portion is higher than that in the first embodiment. Becomes higher. If a protrusion is provided on the outer surface of the pad, the protrusion will be located above the negative angle bend, so the formed work piece cannot be pulled out upward, and It must be removed horizontally by moving it parallel to the fold. Therefore,
This configuration can be applied when the material to be processed has a "U" shape.

(2) In the first embodiment, the press forming machine for forming the negative angle bent portion on the workpiece having the "U" shape has been described, but the press forming die of the first embodiment is The present invention can also be applied to a press mold for forming a negative angle bent portion on a workpiece having a box shape in which a right angle bent portion is formed over the entire circumference. (3) In the second embodiment, the press mold for forming the negative angle bent portion on the box-shaped workpiece having the right angle bent portion formed over the entire circumference has been described. According to the press molding die of No. 2, the negative angle bending portion can be formed in the workpiece having a "U" shape.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state before forming a negative-angle bent portion in Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing a process in the middle of forming the negative angle bent portion in the first embodiment.

FIG. 3 is a cross-sectional view showing a state where molding of a negative angle bent portion is completed in the first embodiment.

FIG. 4 is an explanatory view showing the dimensions of a material to be processed formed in Embodiment 1.

FIG. 5 is a partially cutaway perspective view of a workpiece in which a negative angle bent portion is formed in Embodiment 2.

FIG. 6 is a cross-sectional view showing a process in the middle of forming a negative angle bent portion in the second embodiment.

FIG. 7 is a cross-sectional view showing a process in the middle of forming a negative angle bent portion in the second embodiment.

FIG. 8 is a cross-sectional view showing a state where molding of a negative angle bent portion is completed in Embodiment 2.

FIG. 9 is an explanatory view showing a forming process of a negative-angled bent portion in a press mold of a conventional example.

FIG. 10 is a perspective view showing a state before and after forming a negative-angled bent portion in a work material in a conventional example.

[Explanation of symbols]

 12 ... Upper mold (movable type) 16 ... Inclined curved blade (guide means) 17 ... Stopper 19 ... Right angle curved blade (holding means) 20 ... Work piece 22 ... Right angle bent portion 23 ... Negative angle bent portion 34 ... Curved bending Blade (guide means) 50 ... Workpiece material 52 ... Right angle bent portion 53 ... Reinforcing portion 54 ... Negative angle bent portion

Claims (5)

[Claims] 1. A press molding method for forming an inwardly bent negative-angled bent portion at a tip of a right-angled bent portion bent at a right angle to an edge portion of a plate-shaped work material. Then, in a state where the right-angled posture at the base end side portion of the right-angled bent portion can be maintained, the tip edge of the right-angled bent portion is brought into contact with the guiding means to guide it inside so that bending deformation occurs. A press-molding method, characterized in that the negative-angle bent portion is molded. 2. The work piece is displaced parallel to the right angled bent portion while the right angled blade is placed along the outer surface of the right angled bent portion, and the tip edge of the right angle bent portion is displaced with respect to the displacement direction. By inclining the inclined curved blade toward the inside and abutting against the stopper, the tip of the right-angled bent portion is buckled to a shape along the right-angled curved blade and the inclined curved blade to form a negative-angle bent portion. The press molding method according to claim 1, wherein the press molding is performed. 3. A reinforcing portion for holding the right-angled bent portion in a right-angled posture is formed at a corner edge portion of a base end of the right-angled bent portion in a work material by partially protruding inward, and the right-angled portion is formed. While displacing the work piece in parallel with the bent portion, the tip edge of the right-angled bent portion is slidably contacted with a curving blade that is curved inward, so that a portion closer to the tip than the reinforcing portion is inward. 2. A negative angle bent portion is formed by being curved.
The press molding method described. 4. A press molding die used for forming a negative angle bent portion bent inward at the tip of a right angle bent portion bent at a right angle to an edge portion of a plate-shaped work material. The holding means capable of holding the base end side portion of the right-angled bent portion in a right-angled posture, and the displacement of the right-angled bent portion with the displacement of the workpiece in a direction parallel to the right-angled bent portion. A press-molding die, comprising: guide means for causing bending deformation by abutting the leading edge and guiding the tip inward. 5. A movable die that displaces a workpiece parallel to the right-angled bent portion with a right-angled curved blade along the outer surface of the right-angled bent portion, and an inclination with respect to the displacement direction of the movable die. The right-angled bent portion is provided with an inclined curved blade that guides the tip edge of the right-angled bent portion inward, and a stopper to which the tip edge of the right-angled bent portion guided by the inclined curved blade abuts. 5. The press according to claim 4, wherein the negative-angle bent portion is formed by abutting the tip end portion of the blade against the stopper so as to buckle the shape along the right-angled curved blade and the inclined curved blade. Mold.