Automatic unit for hot molding and trimming of metal parts

An automatic unit for hot molding, e.g., forging or stamping, and subsequent trimming of metal parts. A molding press and a trimming press are served by two robot pairs. One robot of one pair delivers hot ingots to the molding press, the other pair of robots moves the part being molded step-by-step through successive stampings, and the other robot of the first pair delivers the fully molded part to the trimming press. The robots of the second pair move in mirror-image relation. The ends of the robot arms of the second pair are accommodated by depressions in the molds during the various stamping operations.

At the present time, molding or forging of metallic parts by means of 
mechanical presses is effected by a manual process. An operator at a press 
draws, with suitable tongs, an ingot or crop end coming from the furnace 
and heated to a suitable temperature (1200.degree. C.), positions the 
ingot with respect to a stationary mold part, at a first mold station, and 
then thereafter actuates the press to preform the part. Subsequently, the 
press ram is raised so that the operator, with the use of suitable tongs, 
seizes the preformed piece and passes it to a second mold station, and 
thereafter repeats the press closing operation. The final forming of the 
part is generally effected within a third and last station of the mold. 
After the third opening of the press, the part is manually withdrawn and 
sent to a trimming station by means of a suitable carrier. 
Each of the three actuations of the press, i.e., at the end of each molding 
cycle, the operator maneuvers a pedal control which actuates a device 
provided with one or more blowpipes which emit a mixture of water and 
graphite for cleaning, lubricating, and partial cooling of the mold. 
Thereafter, the operative cycle restarts. 
The manual cycle phases present evident drawbacks, such as: 
thermic irradiations, generated by the temperature of the worked part, 
reach the operator even if he is working at the distance made possible by 
the length of the tongs; 
vibrations to which the operator is submitted; 
fatigue of the operator, and related problems concerning the ergonomics of 
the particular working place; 
the noise produced by the operation which assaults the operator; 
ambiant pollution caused by the slag dust and the vapors generated by the 
vaporization of the liquid used for cleaning of the molding; and 
the intrinsic danger of the system comprising the various operations for 
the pedal actuation and manoeuvre of the part. 
The main object of the invention is to provide a totally automatic molding 
or forging unit wherein the repetitive cycle of the various operations is 
effected by automatons, i.e., "robots". The unit excludes completely the 
use of humans, except a specialized operator who controls an electronic 
central station from which the necessary impulses for the automatic 
actuation of the operative cycle are sent. 
With the stated object in view, one of the particular features of the 
automatic unit according to the invention resides in the various phases 
forming the operative cycle being effected by mechanical units which are 
controlled by appropriately programmed electronic microprocessors. 
More specifically, the automatic unit according to the invention is 
characterized by the press being served by four automatons, or "robots", 
located one on each side of the machine and operating sequentially so as 
to effect all the operations that, in the presently known technique, are 
made by human operators. 
Another particular feature of the unit according to the invention consists 
in two of the juxtaposed robots being operative to work in synchronism, 
interdependently, and effect the translation of the part from one to 
another station through which the molding cycle is effected. The other 
robot pair, an interlocking couple, is located perpendicular to the first 
pair and programmed to provide a robot which draws the block coming from 
the furnace and lays it on the stationary plane of the mold, the other 
robot being provided for drawing of the molded part, lifted from the mold 
plane, and carrying it between the planes of the trimming machine from 
which the trimmed part is sent to be heat treated. This robot provides 
further for drawing of the excess material coming from the trimming 
operation and discharging it onto the conveyor belt. 
Another particular feature of the unit resides in the two robots, one 
intended for drawing the block and the other for transporting the molded 
part to the trimming machine, being provided with a pair of arms, opposed 
at 180.degree. to each other. The arms are provided with pneumatically 
activated terminal pliers which may be operated in a reciprocating 
rotational movement around their own vertical axis within an angle of 
180.degree.. Both the operator robots which follow the part in the molding 
phases are provided with a single arm, having terminal pliers, capable of 
making reciprocating movements in a vertical plane. All the robots are 
capable of making translational movement of a programmed amplitude with 
respect to columns having a horizontal axis and parallel to the vertical 
frontal plane of the press. 
Another particular feature of the unit resides in the fact that in the mold 
upper and lower planes, in whose facing surfaces the negative shapes of 
the part to be molded are formed, on the sides exposed towards the 
operator robots, cavities are formed which are symmetrically juxtaposed 
and adapted to receive the ends of the terminal pliers carried by the 
robot arms. 
Another particular feature of the unit resides in the structure of the 
press frame which, in order to allow the access to, and manoeuvre of, the 
four robots, is open on all four sides.

With reference to FIG. 1, the unit comprises a frame 5 for a press ram 5a. 
The frame comprises four vertical columns 34, 35, 36, 37 (FIG. 4) 
delimiting four openings as respective symmetrical pairs 32, 32a and 33, 
33a adapted to allow the entry and the manoeuvre of the arms of two pairs 
of robots. 
The robot pair 23 and 26 is provided with single arms 24 and 27, 
respectively, terminating with pliers 24a and 27a which stand in one or 
the other of cavities 29, 30, or 31, as will be described below. Robots 23 
and 26 are movable step-by-step in the two directions indicated by the 
arrows, on parallel columns 25 and 28, respectively, having horizontal 
axes while their arms 24 and 27 are mobile in the two directions in a 
vertical plane. 
Robots 13 and 17, located perpendicular to robots 23 and 26, are each 
provided with a pair of arms 14, 15 and 18, 19, respectively. Each of the 
the robots is mobile on columns 16 and 20, respectively, having horizontal 
axes, and are angularly movable, about a vertical axis, with an alternate 
rotational movement along an arc of 180.degree.. 
Further, the pairs of arms 14, 15 and 18, 19 of robots 13 and 17 are 
telescopic whereby they may extend and retract for purposes which are 
described below. 
On one side of the press, beyond one of the angularly mobile robots, in the 
illustrated case the robot 13, a conveyor 12 brings in an orderly 
succession metallic blocks or billets A. The latter are heated at a 
suitable temperature and come through the chute 11, from the furnace 9, to 
which they are delivered by a suitable feeding device. 
Beyond the robot 17, at a suitable distance, a trimming press 6 is located 
and provided with a mold 21 in two parts with respect to which the arms 18 
and 19 of robot 17 manoeuver. 
The two pairs of robots are programmed in order to effect a series of 
movements and sequential operations comprising the working cycle. The two 
robots 23 and 26 move in synchronism and both groups of robots make the 
same movements and operations in a manner which may be defined as a 
"mirror-image" relationship. 
Robot 13 draws a billet A off conveyor 12 and lays it on part 8 (FIG. 3) of 
the mold. Robot 17 draws the part coming out of the last mold station and 
lays it between the parts 21 of the trimming machine 6. Therefore, the 
arms 14 and 15 of robot 13 and the arms 18 and 19 of robot 17 are 
connected to hydraulic and/or pneumatic devices which make them 
telescopically movable. 
Furthermore, all the unit kinematic parts are subject to automatic 
intervention control and security devices, capable of interrupting the 
operative cycle at any point of its activity, should any anomaly occur. 
The operation of the unit is as follows: 
The billet A coming from the furnace 9 arrives on the chain conveyor 12, 
which is provided with detectors to sense the presence and the temperature 
of part A. If billet A is at a suitable temperature, it stops against a 
checking device which is deactivated if the temperature of the piece is 
not as desired, or in the case where an unforseeable emergency occurs in 
the remaining parts of the unit; in such case, the part or billet A is 
rejected. 
During the normal course of an operative cycle, the terminal pliers of arm 
14 (or 15) which is in the open position and located over the billet A, 
receives a sequence control, whereby the common support of the two arms 14 
and 15 lowers and in succession, the pliers close on the billet A, lock 
it, and the support raises. The robot 13 rotates through 180.degree. and 
carries the billet A in front of the opening 33 of the press. At the same 
time, the pneumatic cylinder of arm 14 and the hydraulic cylinder of robot 
13 move forward inside the opening 33 until the billet A is brought to the 
position 29 (FIG. 1) onto the part 8 of the mold, laying it thereon. 
As soon as the terminal pliers of arm 14 leave the part A, the same arm 
rises and withdraws together with the robot 13. The arm 15, which in the 
meantime has assumed the position previously occupied by the arm 14, if it 
receives the operative instruction, repeats sequentially the movements 
just described for arm 14. The angular 180.degree. movement of the robot 
13 is reciprocating, whereby the angular movements thereof (and likewise 
for the robot 17) correspond always to working active phases. 
The pliers 24a and 27a of robots 23 and 26, during this phase, lie open in 
the cavities symmetrically opposed, formed in the two parts of the mold 
(FIGS. 1 to 3). The retraction of the arm 14 or 15 operates the descent of 
the ram 5a of press 5 together with the upper mobile part 7 of the mold 
which operates the first phase of the molding cycle producing the 
flattening of the billet (FIG. 2, part A1). As is known, the volume of the 
billet A is such as to be suitably excessive with respect to the volume of 
the cavities when the mold is closed so as to generate a part provided 
with a perimetric flashing 38 overflowing from the cavity and penetrating 
between the open ends of pliers 24a and 27a (FIG. 2). In the automatic 
sequence, the ram 5a rises; the pliers 24a and 27a close on the flashing 
38 while the corresponding arms 24 and 27 experience a lifting movement in 
the vertical direction; in a rapid succession the two robots 23 and 26 
move one step of such an amplitude as to bring the semi-manufactured part 
A1 to the second station. 
When that position has been reached, the arms of the robots 23 and 26 
lower, whereby their terminal pliers penetrate into the cavity 30 of the 
mold part 8. Subsequently, the pliers 24a and 27a open automatically while 
the ram effects the second descending stroke. When the ram 5a rises again 
automatically, the robots 23 and 26, by means of their respective arms, 
repeat the already described cycle whereby the semi-manufactured part 
arrives in the position indicated by A3 in FIG. 2. 
Then, the ram 5a of the press effects the third and last descent which 
concludes a molding cycle. When the ram 5a effects the re-ascending 
stroke, the pliers 24a and 27a rise together with the part A3 that they 
retain. Expellers 39 provide for detaching the part from the mold cavity. 
At the conclusion of this phase, the arm 18 or 19 of the robot 17, located 
before the opening 33a (FIG. 4), projects its terminal pliers to grasp the 
perimetric flash 38 of part A3. The pliers 24a and 27a open sequentially 
while the arm 18 or 19 of robot 17 retracts and the same robot moves in 
the direction of the trimming press 6. The robot advances to such a 
distance as to allow the arm which retains the molded part, after having 
effected an angular movement of 180.degree., to lay down the part between 
the planes of the press 21. Subsequently, the terminal pliers of the arm 
are opened and thereafter the ram of press 6 lowers and effects the 
trimming of the molded element. 
The molded element is automatically discharged into a container by means of 
a mechanism controlled by the ram of press 6. Thereafter, the ram of press 
6 moves up while the terminal pliers of arm 18 or 19 closes again on the 
sheared flash which is separate from the part. The arm then retracts, and 
when it reaches a position vertically over the conveyor 22, it releases 
the flash which is then discharged. 
The described cycle, wholly automatic, is accomplished within a very short 
time of about six seconds. 
All the phases of the cycle, including the sequential movements of the 
various members, are interdependent and controlled by one or more 
mocroprocessors. If more than one microprocessor is used, they are 
programmed to operate in synchronism. 
The movement of each kinematic member of the unit is subject to the control 
of proximity sensors, which provide the consent to the kinematic following 
phase only when the preceding one has been correctly actuated. Any 
eventual operation anomaly causes immediate stopping of the operative 
cycle. Concerning specifically robots 13 and 17, they are programmed to 
rapidly retract their respective arms from the press 5 area which receives 
the consent to effect the working stroke only when the retracting movement 
has been effected. 
The robot arms 24 and 27, which may be defined as operative robots because 
they provide the repetitive step-by-step repetitive translation of the 
workpiece, are provided with ducts for lubricating and washing the mold 
cavities. The activation of those ducts, in addition to being automatic, 
may be effected or protracted by the operator who can intervene with a 
remote control which temporarily interrupts the automatic cycle of the 
unit. 
The invention has been shown and described in preferred form only, and by 
way of example, and many variations may be made in the invention which 
will still be comprised within its spirit. It is understood, therefore, 
that the invention is not limited to any specific form or embodiment 
except insofar as such limitations are included in the appended claims.