DD218845A1 - METHOD FOR FOLLOWING PROCESSING OF SHAPES FROM LEAD - Google Patents

Abstract

Process for the subsequent processing of sheet metal parts in multi-stage tools on presses that work as transfer presses. The aim of the invention is to reduce the production costs by capacitatively better utilization of the presses and increase their energy efficiency as well as - in new production facilities - to save investment and the production sites - to save investment funds and bring about production readiness faster. The task is to make it possible to use presses whose nominal pressing forces are smaller than the sum of the forces acting simultaneously on all the tool stages. According to the inventive solution, a same or cyclically repeating uneven number of shapes is simultaneously processed with the tool set, which corresponds to a rounded fraction of the sum of all work sequences. The shapes take a uniform distance from each other, which is the integer multiple of the center distance of the tool stages. The invention is applicable in the sheet metal processing industry, in particular for the production of larger sheet metal parts on presses of medium construction size. Fig. 3 a

Description

Title of the invention

Process for the subsequent processing of forman from sheet metal

v.

Field of application of the invention

The invention relates to a process for the subsequent processing \ 4on forms of sheet metal in multi-stage tools on mechanical or hydraulic presses, which are set up as transfer presses.

The method can also be applied to step conversion autors, in the following or follow-on composite tools - general cargo transport and used for circular workpiece transport.

Characteristic of the known technical solutions

In the preparation of the mechanized production of shapes to be machined from sheet metal in several sequences, a press is set under certain conditions, which is set up as a transfer press or can be set up. Your Nennpreßkraft must be greater than the sum of all the tool levels required simultaneously acting forces.

If the production of certain parts groups (pots, long forms, etc.) is to be prepared, the nominal pressing force will be determined by the total force of the largest, ie. H. the most voluminous part of this subgroup. *

, 1983 * 1043.98 ·

Thus, the press themselves, their location conditions (hall, foundation, etc.) and the resulting investments can be determined. In addition, the operating costs (energy consumption, etc.) can be seen. These highly productive systems - this is especially true for step-forming machines - but work in case of lack of follow-up orders with insufficient capacity or - too small forms - with unfavorable efficiency.

An example from the journal Umformtechnik 14 (1980) 1,

P. 11 - 15:

Set up was the mechanized production of a range of shelf trusses. The U-shaped parts have the same cross-section and are all made of steel strip 60 χ 1.5 mm »They differ in 7 different lengths, which are between 300 and 900 mm. The core of the system is a standardized press with a nominal force of 2500 kN. she has a

-1 stroke number of 50 min and a drive power of 22 kW.

All equipment used for the production mechanization of the system, including the feed unit for the belt, has its own drive and consumes additional drive energy. The tool, which can be adjusted to the different lengths of the workpieces, is 3-stage and requires about 80 kN for cutting and punching (1st and 2nd, step) and between 60 and 180 kN for bending (3 "step), depending on the length. The follow-up system delivers 12 pieces / min for parts up to 400 mm in length. This quantity decreases with the longest part to 7 pcs / min. Selection criterion of this press was obviously the table width. This does not contradict the abovementioned criterion of total force, but adds another selection criterion based on the tool size, which further increases the costs.

In many cases, the specified presses for the existing production facilities are too large and the project is abandoned entirely or in favor of transport-intensive cooperation.

Object of the invention

The aim of the invention is to reduce capacity by better capacity utilization of presses and increase their energy efficiency. In addition, investments in new equipment and / or equipment of production facilities should be saved and production readiness brought about more quickly.

Explanation of the essence of the invention

The object of the invention is to provide a method for the subsequent machining of forms from sheet metal on mechanized presses with multi-stage tools, which allows to use for it presses whose Nennpreßkräfte are smaller than the sum of the forces required by all tool levels simultaneously acting forces,

According to the invention, the object is achieved by simultaneously machining an identical or cyclically repeating unequal number of molds with the tool set, which corresponds to the rounded half, third or quartered number of the entire work sequences. The shapes take a uniform distance from each other, which is the integer multiple, but at least twice the center distance of the tool stages ^

A tilting moment occurring on the press ram during machining is virtually eliminated by applying a counter-torque, the force of which is applied with the greatest possible distance to the ram center.

The feeding movement of the output molds from the feeding station to the next tooling stage occurs every second, third or fourth ram stroke of the press.

At local topping of the output mold and first tool stage, the tool top of this stage engages the mold every other second, third, or fourth tappet stroke.

Based on the invention, for example, a transfer system for a two-stage tool set is charged only every other stroke, so that, changing per stroke, only one tool stage processes the forms. The press setting is made according to the larger 'single force of both tool levels. ,

Compared to the prior art can thus be used a smaller press with lower Nennpreßkraft. The unit performance is due to the higher stroke rate more than 50 % compared to a standard defined by the press "If the off-center force attack by the changing engagement of the tool stages exceeds the allowable size, according to another feature of the invention, a spacer with the greatest possible distance to the ram center relative to the engaging tool force between the table and plunger of the press or brought between corresponding tool elements. Due to the rigid or distance-dependent power meter equipped spacer the tilting moment of the plunger is almost canceled.

If the time available during a tappet stroke for supplying an initial shape, for example, to the feed station located outside the tool set is insufficient, the first pair of grippers carry out a transport movement only every second, third or fourth tappet stroke by being driven separately or temporarily from the rest Grab system is disconnected. If the feeding station now lies in the area of the first tool stage, a coupling piece between the plunger and the tool top part additionally ensures that the latter only engages the mold with the mold on every second, third or fourth push stroke.

By the latter features of the invention it is achieved that the press used works in the long stroke. This relieves clutch and brake systems in mechanical presses and generally reduces the expense of control and safety technology.

FIG. 2 B FIG. 3a FIG. 3b FIG. 4a

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embodiments

In the drawings show:

1 shows the prior art method for the subsequent processing of molds made of sheet metal, shown with two tool stages,

2a shows the method according to the invention for the subsequent processing of forms made of sheet metal, likewise shown with two tool stages - first working stroke,

as shown in Fig. 2a, but subsequent working stroke, ⁽

3a shows the method according to the invention for the subsequent processing, shown with three tool stages,

like Fig. 3a, but subsequent working stroke,

the transfer system for carrying out the method variant according to FIGS. 3a and 3b and its operating regime,

4b shows the transfer system according to FIG. 4a in shifted work phases.

In Fig. 1, two tool stages St ₁ and St are arranged on the table 2 of a press, in which the workpiece forms W ₁ and W _{2 are processed} simultaneously forming technology. In the area of the bottom dead center position of the tappet 1, the forces F ₁ and F_ occur which must be added to the total force F_ for press definition

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According to the invention, the machining of the workpiece shapes is carried out with the same tool arrangement as follows:

The workpiece shape W ₁ processed according to FIG. 2a initially with the force F ₁ in the tool stage St ₁ is brought to the stage St-, FIG. 2b for the subsequent stroke and further processed by the force F to form the workpiece W ₂ . Thus, the press is selected for the larger of the two individual forces, that is F ₁ . Their Nennpreßkraft is thus smaller than that of the press of the selected in Fig _t 1 example.

A further embodiment of the invention · according to Fig. 3a and 3b illustrates the process technology when editing with three tool stages and originating from the stage occupancy forces on the press ram including the compensation of the resulting tilting moments and - the example of the first tool stage - the uncoupling of the upper part during idle stroke purpose Time-saving for long-term tape inserts. In the first stroke shown in Fig. 3a, the tool stages St ₁ and St _{3 are occupied} by the workpiece shapes W and W ,.

The (different) forces required for shaping are represented by the length of the force arrows F and F. Above their distances to the ram center are the torques and thus calculate their difference, which finally acts as a tilting moment on the plunger. The compensation is achieved by the spacer D, which - introduced with the greatest possible distance to the ram center - in this hub generates the necessary counter-torque. At the same time d'as is at. This hub shown by the position of the coupling piece K coupled upper tool of the stage St. shown in operative position.

Fig. 3b shows the same tool at the next stroke.

The level St_ is occupied by the shape W_, which is transformed by the force F_. There is no tilting moment, ie the spacer D is made ineffective. Also, the coupling piece K has been removed, so that the lifting movement of the upper part of the stage St ^ is omitted and the supply of the new output form W_ can be performed. In terms of force, the sum of the forces F, F and F _Q acts on the first stroke and the greater single force F «» on the second stroke, according to which the press to be used is also determined.

In FIGS. 4a and 4b, the transfer system suitable for the three-stage tool according to FIGS. 3a and 3b, which was omitted there for reasons of clarity, is shown in its sequence of movements and the delivery phase of the new initial form with the upper part of the tool stage St ₁ disconnected according to FIG. 3b. In this case, Fig. 4a is the first stroke shown in Fig. 3a and Fig. 4b the subsequent stroke

associated with FIG. 3b. The respective upper half of the figures shows the position of the transfer system shortly after the beginning of the upward stroke of the press ram and thus the partial movement 3. The, partial movement 4 covers the working phase of the tools and completes the return stroke of the system in the new starting position shown in FIG. 4b above. The second partial movement 4 would therefore return to the position of the system shown in FIG. 4b and the subsequent partial movement 4 again into the position shown in FIG. 4a above.

To carry out the method, the usual structure of a 'transfer system, consisting of the mirror image arranged rails Sch with the grippers G ₂ and G ,, by the gripper G., which sits on the process-dependent auxiliary rails Sch, modified.

In the initial position in Fig. 4a above, in which the first ram stroke according to FIG. 3a has already taken place, is over, the tool stage St lying gripper pair G ₁ through the already processed workpiece W ₁ , as well as on the tool stage St 'the gripper G. _{3 occupied} with the workpiece W ₃ . After carrying out the partial movement 3 (FIG. 4a, bottom), with the auxiliary rail Sch, being locked to the rail Sch, the gripper G with the form W ₁ passes over the tool step St_ and the gripper G throws out the finished workpiece shape W_ , During the jerking of the system by the partial movement 4 takes place the uncoupling of the upper part of the tool stage St * and the further processing of the workpiece W ₁ in the tool stage St_ and it already begins the feed phase for the new output form Wg. The tool position corresponds to Fig. 3b. In the second part movement 3, the auxiliary rails Seh ,, unlocked and thus the gripper pair G _{1 separated} from the feed movement. It remains according to Fig. 4b, below the tool stage St stand, so that the insertion of the new output form W_ can be completed. At the same time, the workpiece shape W_ is transported by the gripper pair G_ from the tool stage St_ to St ₃ .

The next plunger stroke corresponds again to Fig. 3a, i. W and W and the renewed partial movement 4 represent the initial state according to FIG. 4a at the top again from the initial or workpiece shapes W and W_.

5 /. , '

Modifications of the movement sequence of the transfer system, e.g. by the own drive of the first gripper pair, are possible.

Claims (4)

invention claim 1. A method for the subsequent processing of forms from sheet metal by cutting, deep drawing, bending or the like, each mold is made locally successively in at least two work sequences in multi-stage tool sets on mechanized presses, characterized in that at the same time a same or cyclically repeating uneven number of shapes with the tool set corresponding to the rounded half, third or quartered number of all working sequences, while the shapes are evenly spaced, which is the integer multiple, but at least twice, the pitch of the tool steps. 2. The method according to item 1, characterized in that a tilting moment occurring during processing on the press ram by applying a (equal) counter-torque, the force attack is carried out with the greatest possible distance to the ram center, is almost canceled. 3. Method according to item 1 or 2, characterized that the feeding movement of the output molds from the feeding station to the next tool stage takes place every second, third or fourth ram stroke ♦, 4. The method according to item 1, 2 or 3, characterized in that the tool upper part of the first tool stage comes with every 2, 3 or 4 Stößelhub with the form for engagement. See .. ^ .. Soaps drawings