US2884822A

US2884822A - Die press

Info

Publication number: US2884822A
Application number: US336387A
Authority: US
Inventors: Wilson Hugh Morton
Original assignee: International Nickel Co Inc
Current assignee: Huntington Alloys Corp
Priority date: 1952-02-13
Filing date: 1953-02-11
Publication date: 1959-05-05
Anticipated expiration: 1976-05-05

Description

3 Sheets-Sheet l Inventor l llllll @Il H. M. WILSON May 5,v 1959 DIE PRESS Filed Feb. ll, 1955 May 5, 1959 Filed Feb. l1, 1955 H. M. WILSON DIE PRESS 5 Sheets-Sheet 2' ,lo i

May 5, 1959 l H. M. wlLsoN 2,884,822

DIE PRESS Filed Feb. l1, 1955 5 Sheets-Sheet 3 ttorney United Stare Parent DIE` PRESS Hugh Morton Wilson, Newton Mearns, Scotland, assigner to The International Nickel Company, Inc., New York, N.Y.

Application February 11, 1953, Serial No. 336,387

Claims priority, application Great Britain February 13, 1952 1 claim. (ci. 78.-'18) This invention relates to deep die presses; that is to` say to presses in which one of two press surfaces is formed on the end of a punch and the other is formed at the bottom of a recess in a die, and in which when the press is closed the punch makes a sliding t in the recess and the press surface on the punch together with the surfaces ofthe die-recess, including the press surface at the bottom of the die-recess, define a totally enclosed cavity. Such presses maybe used for producing metal articles of precise shape, from hot blanks of approximately correct shape. To ensure precision in the shape of the final article, the blank is usually subjected to very high pressure by" which themetal is forced into contact with the entire area of the press surfaces. As a result, it may prove ditlicult toI remove the article from the recess after the plunger has been withdrawn.

' When tough metals for high temperature use, such as nickel/'chromium based alloys are being handled, the pressures are so high, for example 100 tons per square inch, that it is not feasible to provide ejector pins such as are frequently used in die-casting dies and the like in which pressures are comparatively low.

Itis anA object of the present invention to provide. fa deep die press in which an article can be subjected to high pressure and thereafter removed.

It is a further object to provide a method of deep die pressing articles of tough metal for high temperature use.

It is a more specific object to provide a deep die press for forming the blades of gas-turbines.

In carrying out the present invention the die is made in more than one piece, each piece carrying part of the press surface in the recess, and at least one piece is mounted to rock from a position it occupies during pressing to a position in which it or some other piece of the die breaks contact with an article in the recess, so facilitating removal of the article from the recess.

Preferably the rocking of two or more pieces serves both to break full contact of these pieces with the article and also to shift the article entirely out of contact with a stationary piece or pieces of the die. It may be sufficient to lift the article clear of the stationary piece or pieces.

Preferably the axis about which each piece can rock is such that the force to which the part of the die surface on the piece is subjected during pressing has a moment tending to hold the piece in position.

Preferably the rocking of each piece is effected automatically on the return stroke of the punch. This may conveniently be done by providing a lost-motion connection between a holder for the piece of the die and the part which carries the punch.

For many articles the die may be made in three pieces, namely a stationary central piece and two end pieces which rock to eject the article.

The invention has been particularly developed for use in the manufacture of double-rooted gas-turbine blades. The main steps n such manufacture are the hot rolling ICC of a billet to a dumbell-shaped' blank, hot pressing of the blank into a rough blade, and machining to final shape. Hitherto the pressing has not been carried out in deep dies because of absence of means for removing the rough blade from the recess of a deep die. Instead a series of pressing operations have been necessary in shallow dies with intermediate shearing operations to remove flashes No flashes occur in deep die pressing.

The preferred press for deep die pressing of a rough double-rooted gas-turbine blade from a dumbell-shaped blank will now be described in detail with reference to the accompanying drawings, in which: K l

Figure 1 is a half elevation and half section on the line l-I in Figure 2; Y

Figure 2 is a horizontal section on the line IIL-II in Figure l;

Figure 3 is a vertical section on a larger scale on the line III-III in Figure 2; and

Figures 4 and 5 are vertical sections showing some of the parts of Figure l in different operating positions. l

The press consists of a die mounted with its recess open upwards on a base plate 4, and a punch 6 mounted on a reciprocating stem 8.

The die 2 consists of a central piece 10 with a trough 11 in which the blade proper is pressed, and two end pieces `12 and 14 with

cavities

13 and 15 in which the roots of the blade are pressed. The punch 6 is complernentaryl to the whole composite die. The central piece 10 of the die is mountedin a holder 16 keyed at 18 to the base plate 4. One side ofthe trough is supported by a fixed abutment 20 on the holder while the other side is supported" by screws 22 passing through the holder. In addition the underside of the central piece has a shallow central recess l24 so that downward pressure on the bottom of the trough 11 counter-acts to some extent the tendency of the sides of the trough to spread under lateral pressure. .The -central piece is held down by clamps 26 screwed to the holder 16.

Each

end piece

12 and 14 of the die is mounted in an end face of a separate block-like holder 28 mounted to rock about a fixed horizontal shaft 30 which is transverse to the axis of the trough 11 in the central piece and is carried in two blocks 32 bolted to the baseplate 4. This shaft passes through the end of the holder remote from the

die piece

12 or 14, which has a bevelled face 34 to lit against a similarly bevelled end face 36 on the central die piece. Thus the end die piece in its holder can rock upwards about the shaft without jamming against the central die piece. The holder of each end die piece has a step 3S on its underside facing away from the centre of the die, and a strip 40 let into the baseplate serves as an abutment for this step. The force on the press face of the end die piece during pressing tends to rock the end die piece downwards, and this tendency to rocking is resisted partly by the abutment and partly by the engagement of the two

bevelled faces

34 and 36. In addition the abutment resists the axial component of the force.

The punch 6 is mounted in a further holder 42 screwed to the lower end of the main reciprocating vertical press stem 8. On this holder is mounted a crosshead 44 which can slide over two tie-rods 46, each pivotally connected at its lower end 48 to the top of one of the holders 28 for the end die pieces. Above the crosshead each tierod carries two lock nuts 50, and a washer 52 with a part-spherical under surface inserted between the lock nuts and the upper surface of the crosshead. A sliding guard 54 (shown in Figure l) is fitted to the holder 42.

In operation, a dumbbell-shaped blank of nickel/chromium based alloy is prepared by rolling preferably by means of an apparatus as described and claimed in my U.S. application Serial No. 180,750, filed August 22, 1950, now U.S. Patent No. 2,686,442. Before each blank is pressed, the punch 6 is moved to the position shown in Figure 1 and the heated blank is then placed in the recess in the die 2. The punch 6 is then forced downwards into the position'shown in Figure 4 and continues to move down until the blank has become so pressed that it entirely lills the remaining space between thepunch and the die.

j The punch is then withdrawn and on its return stroke is carried above the position shown in Figure 1 into the position shown in Figure 5. In this movement the crosshead 44 raises the tie-rods 46, thus rocking the two holders 28 for the end die pieces and lifting the rough blade 56 right out of the central piece so that it can be grasped lin tongs.- The punch is then moved downwards again far enough t o allow the holders 28 to rock back to theirV initial position, and is stopped to let the next blank be inserted. jxTo, elirninate anyrisk.of the roots of the rough blade jamming in the end die pieces, the side pressfaces of these pieces are flared in a horizontal direction at a small angle, say 2.

-..Since in deep die pressing there is no ash, the volume of the `blank determines the thickness of the rough blade. Accordingly, between rolling and pressing, each blank may need to be roughly machined to bring it to a definite volume. Moreover the blank is shaped, within the limits of .simple rolling and turning, so that the ow of metal inpr'essing is a minimum.

,"The blank is also shaped so that initially no metal touches the joints between the die pieces. This is to ensure that no metal escapes as ashes at the joints before the abutting faces are fully forced together by the pressure'in the die to resist penetration.

. After pressing, the blade will usually require nal light machining, but with skill in the pressing this stage may be omitted.

The procedure described in detail may be applied to the manufacture of single-rooted blade. The punch and die are modified in shape, one of the movable pieces of thedie forming the root while the other forms the tip of the blade. The press is supplied with mushroom-shaped blanks.

I claim:

A die press for forming an article by deep die pressing in a deep die recess comprising a reciprocal punch, a die capable of cooperating withy said punch to form a pressed article from a blank, and a mounting to support said die, said punch and die together forming an enclosed cavity when the punch is in the closedposition in the die, said die comprising a plurality of die pieces forming a die recess to receive a blank to be pressed by said punch, said plurality of die pieces comprising a die piece fixed to said mounting and two end die pieces pivotally supported -by said mounting to rock relatively to the ixedly-mounted die piece from a position permitting pressing of a blank'to a 4position serving to break contact between a pressed article and said fixedly-mounted die piece, and means to rock the` pivotally-supported die pieces to the die pressing position of the die pieces for forming a yblank into a pressed article in cooperation with the punch and then to rock the pivotally-supported die pieces to an open position of the die pieces for breaking contact between the pressed article and the ixedly` mounted die piece and lifting the pressed article partially out of contact with the pivotally-supported die pieces.

References Cited in the le of this patent UNITED STATES PATENTS 1,224,805 Stevenson May 1, 1917 1,266,963 Limont May 21, 1918 1,428,219 l Crawford Sept. 5, 1922 1,883,079 Strickland Oct. 18, 1932 1,942,666 Schwartz Jan. 9, 1934 2,158,434 ASchwartz May 16, 1939 2,275,174 Clements Mar. 3, 1942 2,302,674 Carter Nov. 24, 1942 2,540,457 Rice Feb. 6, 1951 2,541,544 Rahaim Feb. 13, 1951 2,680,286 Willgoos June 8, 1954 2,700,906 Allen Feb. 1, 1955