JPH02127913A - Billet scalping device - Google Patents

Abstract

PURPOSE:To prevent a crack and a defect of a billet by providing two pieces or more of scalping dies on which a prescribed number of cutting edge parts are projected and provided radially in the front and in the rear on a billet through-port of a die, and constituting a cutting edge group for surrounding the whole outside periphery of the billet by two pieces or more of dies. CONSTITUTION:A first die 10 and a second die 11 on which a cutting edge 1 group is fixed and provided are attached to die holders 9, 9. On billet through- holes 12 of each die, six pieces of cutting edges 1 and notches 13 are provided, respectively. A first die 10 and a second die 11 are deflected in the periphery of an axis, and placed so that phases of each cutting edge 1 and notch 13 coincide with each other. A billet B is pressed by a piston rod 6, guided by a feed roll 7 and reaches a first die 10, about half of the surface is divided into six lines by the cutting edge 1 and the billet is brought to peeling. Subsequently, the remaining surface is brought to peeling by the cutting edge 1 of a second die 11, and a billet B' is transferred to the next process by the feed roll 7. In such a way, a load to the billet becomes about 1/2, a crack and a defect in the front and the rear end parts are scarcely generated, and also, chips can be discharged easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scalping device used for peeling billets before extrusion molding of aluminum building materials and the like.

[Prior art] The surface layer of a metal billet for extrusion molding is an oxide film or a segregated layer containing impurities, so if it is loaded into an extruder and molded as it is, the extruded product will not be formed. quality deteriorates. For this reason, as shown in Fig. 9, when billet B is preheated with billet heater H and pressed, a scalping device S is installed between billet heater H and extruder ■ before extrusion. surface layer is removed. Many methods and devices have been proposed for removing the surface layer of billets. For example, (a) Tokuko Sho [il-14891 publication, (b) Tokuko Sho 59-1
Those described in Japanese Patent Publication No. 486, (c) Japanese Patent Publication No. 81-15765, etc. are known.

The one described in the preceding example (a) has a diameter of 120 mm in the circumferential direction.
'By combining three cutting blades arranged at intervals,
After forming one continuous circular cutting edge, the surface layer of the billet is removed by forcing the billet through the circular cutting edge.

The prior example (b) differs from the prior example (a) in that the circular cutting blade is provided with notches here and there to prevent the cutting blade from being continuous.

In addition, in the case described in precedent example (c), the part from the front end of the billet to near the rear end is peeled with a high load, and the rear end of the billet is peeled with a lower load. It was designed to do so.

[Problem to be solved by the invention] In the case of prior example (a), as shown in Figure 10 (a),
When cutting into cutting edge 1 or billet B for the first time, billet B
Since the entire circumference contacts the cutting edge 1, the impact from the cutting edge is applied to the notched portion of the billet B, causing cracks 2 or defects 3 as shown in FIG. 11 to occur in this portion. Furthermore, when the cutting edge l comes off from the rear end of the billet B, the billet B is unable to support the load from the cutting edge l, resulting in a chip 3 at the rear end. If defects or cracks occur on the surface of billet B, air will be mixed into the extruded product, creating cavities or depressions on the surface, which is not desirable.

Furthermore, since the cutting edge 1 is circular, the chips 4 are connected in the circumferential direction to form a large annular body as shown in FIG. 10(b), making it difficult to handle and removing them from the device. . Then, the chips 4 curl in the axial direction of the billet B while being connected in the circumferential direction, so a considerable amount of force is required to curl the billet B, so it is necessary to apply extra force to peel it. This will require a lot of power.

In the prior example (b), notches are provided at various places on the circular cutting edge to prevent the cutting edge from being continuous, so the chips are divided into several pieces in the circumferential direction, which results in the cutting edge being cut into several parts in the circumferential direction There are no problems with chips.

However, even if the cutting edges are not continuous, all the cutting edges start cutting into the billet at the same time and come off from the billet's rear end at the same time. I have a problem. In addition, since there is a notch between the cutting edges, the billet surface layer is not removed and remains in the part corresponding to this notch, and these remaining surface layers are mixed into the extruded product, resulting in quality There is a problem not seen in precedent case (a), which is that it causes a decline in

In the prior example (c), breakage of the rear end of the billet can be prevented. However, since a high load is still applied when the cutting edge bites into the front end of the billet, there remains the problem that chips and cracks occur at the front end of the billet. Further, since the cutting edge is circular, there is a problem similar to that of the preceding examples (a) and (b) regarding chips.

In view of the problems of the prior art, the present invention has a relatively simple structure, has no cracks or defects in the front end and rear end of the billet, and can efficiently discharge chips. Furthermore, the present invention aims to provide a billet scalping device that does not significantly increase cutting resistance due to cutting.

[Means for Solving the Problems] The present invention provides a scalping die in which a predetermined number of cutting edges are arranged radially and inwardly at intervals at a billet through-hole of the die, and at least In this billet scalping device, two or more dies are disposed, and each independent cutting edge portion of at least two of these dies constitutes a group of cutting edges that surround the entire outer periphery of the billet.

That is, when two dies are provided, a plurality of cutting blade groups are fixedly installed on the first die at predetermined intervals, and a plurality of cutting blade groups in the first die are fixed on the second die. A group of cutting blades is fixed at a position corresponding to the interval between the billet and the billet, and the first group of cutting blades and the second group of cutting blades peel the entire circumference of the billet.

The appropriate number of cutting blades fixed to one die is 3 to 6.

In addition, if the width of the cutting edge fixed to the first die is wide, a third die is provided at a position after the second die, and the cutting edge fixed to the first die is attached to the third die. Provide a cutting edge with the same width as the blade.

In this case, the positions of the cutting edges of the first and second dies are slightly changed, so that the first die's cutting blade group cuts slightly shallowly, and the third die's cutting blade group performs further finishing cutting. Finally, the thickness is made the same as the thickness cut by the cutting edge group of the second die. By doing so, it is possible to avoid an increase in the load on the cutting edge group of the first die. Based on this idea, the number of dies can be increased as appropriate.

[Example] Examples will be described in detail based on the drawings.

FIG. 1 shows an example of this, which is equipped with a hydraulic cylinder 5 and a piston rod 6 for pressing a billet B, and the billet B is guided by a reroll 7. Two die holders 9 are fixed to the tie rod 8, and a first die has a group of cutting blades fixed to each die holder 9.9! 0 and the second die 11 are attached.

The first die 10 and the second die 11 are shown in FIG.
It is as shown in the figure. That is, each billet through hole 12 is provided with six cutting edges l and six notches 13. The length of the cutting edge l in the circumferential direction is the same as or slightly larger than the length of the notch 13 in the circumferential direction. The first die lO and the second die 11 are offset around the axis, and are arranged so that the phases of the cutting edges 1 and the notches 13 of each die coincide with each other.

The billet B is pressed by the piston rod 6, guided by the feed roll 7, and first reaches the first die lO, where approximately half of the surface is cut into the first die lO by the cutting blade 1 fixed to the first die lO.
It is peeled in strips, then reaches the second die 11,
The remaining surface of the billet B' is peeled off by the cutting blade (3) fixed to the second die 11, and the peeled billet B' is transferred to the feed roll 7.
is guided and transferred to the next process.

4 and 5 show modified examples of the die, in which a cutting edge 14 is fixed to a holder 15 with a bolt 16. In addition to being easy to mold with a die, this tool can be used for a long period of time by re-sharpening or replacing the attached blade 14.

FIG. 6 shows an embodiment that is particularly effective when deep removing the surface layer of billet B, in which a third die 17 is provided in addition to the first die lO1 and the second die 11.

As shown in FIG. 7, the length of the cutting blade 18 in the circumferential direction of the first die 10 and the third die 17 is longer than the length of the notch 19 in the circumferential direction. The cutting edge 8 of the first die 10 and the cutting edge 18 of the third die have the same blade width, but the cutting edge 18 of the first die has a smaller inner diameter than the cutting edge 18 of the third die. Make it large and peel it shallowly. That is, the first die 10 performs the first stage of peeling, and the third die 17 performs the second stage of peeling, so that the load on the cutting blade does not increase even if the skin is peeled to a deep depth of cut. I try not to.

FIG. 8 shows an example of the second die 11, and the relationship between the cutting edge 20 and the notch 21 is similar to that of the cutting edge 18 in the first die and the third die.
This is the opposite of the relationship between and the notch 19. That is, the length of the cutting edge 20 in the circumferential direction is shorter than the length of the notch 21 in the circumferential direction. Although this second die 11 makes a deep cut at once, the load does not increase because the blade width of the cutting blade 21 is small.

[Effects of the Invention] According to the present invention, after dividing and removing a part of the skin of the billet using the front die, the remaining skin can be removed using the rear die. Unlike when peeling, when the cutting blade provided on the die bites into the front end of the billet, and when it comes out from the rear end of the billet, the load from the cutting blade to the billet is 1/2 or 1/3. The possibility of cracks or defects occurring at the front and rear ends of the billet is greatly reduced. In addition, since the chips that are used to expel insects during peeling are divided into a number equivalent to the sum of the number of cutting edges of the front and rear dies, the cutting resistance caused by curling of the chips is small, and the chips are It can also be easily discharged outside.
It has the following effects.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an example of the implementation of the present invention, Fig. 2 is a front view of the die used in Fig. 1, Fig. 3 is a cross-sectional view taken along the line ■-■ of Fig. 2, and Fig. 4 is a modification of the die. The front view of Figure 5 is the v of Figure 4.
-■ Cross-sectional view, Figure 6 is a cross-sectional view of another embodiment, Figure 7 is a front view of the first and third dies in Figure 6, Figure 8 is a front view of the second die, Figure 9 1 is a schematic diagram of an extrusion molding process, FIG. 10 is an explanatory diagram showing the operation of a conventional billet scalping device, and FIG. 11 is a diagram showing a billet peeled by a conventional scalping device. B... Billet, B-... Peeled billet, H
... Billet heater I... Extruder, P... Extrusion molded product, S... Scalping device, ■... Cutting blade, 2... Crack, 3... Missing, 4... Chips, 5... Hydraulic cylinder 6... Piston rod, 7... Feed roll, 8
... Tie rod, 9... Die holder 10... First die, 11... Second die, 12... Billet through hole, 13... Notch, 14... Blade, 15... ...Holder 16...Bolt, 17...Third die, 18.
... Cutting edge, 19... Notch, 20... Cutting edge, 21...
・Notch.

Claims (1)

[Claims] At least two or more scalping dies each having a predetermined number of cutting edges protruding radially and inward at intervals at the billet through-hole of the die are arranged one behind the other, and
A billet scalping device characterized in that each independent cutting edge of at least two of these dies constitutes a cutting edge group that surrounds the entire outer periphery of the billet.