DE8902955U1 - Device for producing die-cutting templates, particularly in the folding box industry - Google Patents

Description

The request relates to a device for producing punching templates, in particular in the folding box industry, for at least one punching table.

Folding box blanks or similar products are punched out in automatic punching machines using steel strip cuts, whereby usually several blanks are arranged flat next to each other in one plane and the punched material is fed in the form of sheets or strips. The punching force is built up between two parallel punching tables, whereby, depending on the design, the upper or lower table is moved towards the stationary counter table, and both tables can also move towards each other. The blanks of a knife arrangement "layout" are essentially punched out at the same time.

The machining accuracy of the punching tables, whose non-parallel nature is due to

a) machine faults,

b) one-sided loading (e.g. with smaller punching formats) and thus one-sided greater springing of the punching machine,

as well as the non-parallel nature of the cutting plates and trimming sheets on the one hand and/or the cutting knives on the other hand lead to that not all knives of a cutting die cut the material to be cut evenly.

!4-216.02

In order to force the cutting edges of the knives protruding at right angles from a trimming sheet into a single plane, non-cutting knives are backed with strips of hard paper of varying thicknesses - sometimes also thin strips of metal. These strips are glued to a so-called trimming sheet, which is provided with a drawing of the die contours and is arranged between two thin trimming sheets. The backing of the non-cutting or poorly cutting punching knives takes place in several passes, with the punching result being visually checked in detail in each case. With complicated layouts and a large number of cuts, this process can take several hours. This process is called punching trimming.

Knowing this state of the art, the inventor set himself the goal of developing a method and a device that would enable the time-consuming punching process to be carried out outside of the punching machine.

In DE-PS 31 33 462 of the applicant it was proposed that the creasing matrices and the make-ready sheets, which are also required for the production of folding boxes, be processed in an impression machine outside the punching machine, so that the latter no longer has to be shut down for such processes.

This impression machine is also suitable for carrying out the fur finishing outside of the punching machine.

M-216

The topography of the punching table of the relevant punching machine and its deformation under given load conditions should be recorded and reproduced on a known impression machine. Likewise, parallelism errors and load-dependent deformations of this impression should be compensated for using suitable equipment.

For this purpose, a device according to claim 1 is used, further features of which can be taken from the subclaims.

The recording of the punching machine on the one hand and the preparation of the printing machine on the other hand are carried out in the following steps:

Cleaning the table surfaces of the punching machine in question using a special cleaning machine;

Grid point measurement of the table distances under different loading conditions using a .;onfc>ined load and measuring device;

Determining and saving the distance differences;
Transferring the values to the printing machine ,

Then the table inaccuracies and deflections are measured using grid points under different load conditions on the impression machine - with the grid points arranged in the same way as those on the punch -

using a digital measuring device on the printing stamp. Now the difference values are automatically calculated and stored in the processor of the printing machine as an overlay on the value pairs of the punching machines.

When creating a punching preparation, according to the invention, the punching tools, i.e. the punching plate with the creasing preparation on it, a cardboard sheet to be punched, the punching form with the two preparation sheets lying on it and a neutral preparation sheet in between are picked up by the impression machine and loaded by the printing stamp in terms of raster points.

Using a measuring method described later, the initial height setting of the stamp is carried out with the load setting taken according to experience.

This offset height setting is changed by the difference values stored in the processor when the detent points are moved. The stamp recreates an image of the superimposed topographies and deformations of the tables of the punching machine and the impression machine.

The punching process can be carried out in the same way as on a punching machine.

According to the invention, the stamp distance is corrected during printing and the printing stamp is adjusted by means of a servo motor.

M-216.02

Advantageously, the computer is connected to a - preferably digital - length measuring device and to the servomotor for changing the length of the printing stamp.

The scope of the invention is to divide the impression ^area into several loading areas, which are determined by groups of cylinders; the pressure surfaces of several cylinders form one of the loading areas. The size and shape of each loading area can be changed by switching one or more cylinders on or off.

According to the invention, at least one measuring lance is also provided, which can be inserted into the gap(s) between the cylinder rows and interacts with a measuring point coding device between the cylinder rows.

It has also proven advantageous that the measuring machine

|t has a height-adjustable table in which the hydraulic system and the evaluation unit are integrated.

$ The printing machine is characterized by at least one

Pressure stamp with hydraulic cylinder and a pressure sensor with upstream actuating motor, where ti.

Pressure regulator and pressure sensor are connected to a computer,

U which in turn is connected to an optical data representation

^! &idiagr; can be connected.

Further features of the invention can be found in the claims.

M-216.02

Further advantages, features and details of the invention will become apparent from the ^following description of preferred embodiments and from the drawing, which shows:

Fig. 1: an oblique view of an impression
machine for processing cardboard
bogen Lür the production of folding boxes;

Fig. 2: an enlarged and elevated cross-section through a part of Fig. 1;

Fig. 3: the cross section according to Fig. 2 in modified Lac"? of individual parts;

Fig. 4: top view of an adapter of the impression machine;

Fig. 5: a section through Fig. 4 along the line V-V;

Fig. 6: a section through part of a punching machine;

Fig. 7: a schematic diagram of a compensation device on the impression machine;

Fig. 8: a schematic diagram of a value interpolation;

M-216.02

Fig. 9: the section through a

measuring device;

Fig. 10: a scheme with scanning fields;
Fig. U: a measuring transmitter;

Fig. 12: a compilation of

fixture parts.

According to Fig. 1, an impression machine 10 for producing punching templates outside of punching machines in the folding box industry or the like has a printing table 14 between two side walls 12 for receiving punching tools and adapters (not visible here).

In the selected embodiment, the printing table 14 is spanned by a crossbeam 16 that can be moved in the direction of the arrow x, from which an impression stamp 18 protrudes downwards for partially pressing the cutting die; the vertically movable impression stamp 18 can be moved along the crossbeam 16 by means of a carriage. These movements are controlled by a microprocessor 20.

A roller lifting system 22 and a roller guide 24 allow precise handling of the punching plate 30.

This impression machine 10 is used to process a make-ready sheet 29 outside a punching machine. A head 19 of the impression stamp 18 is connected to the

10

M-216.02 10

Now a tool 44 can be removed from the closing frame 31 and the mold plate 34 and transferred to an associated sheet punching machine (not shown in the drawing) with appropriately positioned tool holders and the trimming sheet 29 can be processed into a die; the impression points for the bending lines 38 (which can be created in some areas thanks to the stamping head 19) are then connected, the trimming sheet 29 can be - as shown

14 fixed punching plate 30, which consists of steel and has a laminated hard cardboard plate with a height of 0.6 mm on its surface as a trimming sheet 29. The punching plate 30 is loaded in

ji operating state a locking frame 31, which by, not $j

The lifting element shown moves vertically and – for example – by I

Clamping lever - can be fixed in under&c pressure position. |

is This closing frame 31 firmly surrounds a mold plate 34 as a U

Cutting die in which the folding box pattern is intended, |

which also include knives 35 for later cutting lines 36 and |

Punching elements 37 for sealing lines 38. On both sides of the |

Knives 35 and punching elements 37 are recognizable as spacers 39 ft rubber buffers.

If such a cutting plate 30 is fixed between the printing table 14 and the closing frame 31 guided in tool holders - after setting the make-ready format - and covered by a layer of tracing paper 41 and a protective sheet 42;

covered, the cutting die 34 is placed so that its \

Knives 35 and punching elements 37 produce impressions on preparation sheet 29 thanks to tracing paper 40.

11

M-216.02

in Fig. 3 at 45 for a punching process in the sheet punching machine ~ are removed down to the bending line teeth. The latter are then matrix parts for a cardboard sheet 46 to be deformed.

The horizontal movement of the stamp head 19, which is possible in two coordinates, as well as its stroke can be determined by a computer (not shown) which controls a network of pressure points in the minimum necessary number - saving energy and time.

The impression machine 10 is also used for the time-consuming preparation of the cutting die 34 itself.

Fig. '< illustrates a precision adapter 50 which allows a precise positioning of the punching tools. This adapter 50 is inserted into a selected recess 15 of the printing table 14 by means of a pin 52 and clamped there. The punching tool is then secured with the adapter 50, the upper part 51 of which is pivotably hinged.

A measuring program is installed which is used to

This program is used for basic settings.

Commissioning of a new machine the topography of the

printing table 14 and the deflection of table 14 and

Traverse 30 determined point by point at minimum, medium and maximum force, assigned to grid coordinates and saved.

Using an adjustment program, the corresponding hydraulic pressure is calculated based on the preselected piston force (empirical value) and set using the pressure control valve.

12

&igr;, _m

·

4-216.02 12

The exact height adjustment of the pressure stamp 19 is then carried out automatically at a selected point (reference point) of the punching (embossing) form, at which the preselected stamping force is achieved.

The individual points are approached using a travel program, whereby the stored quarters of the topography and the deflections - interpolated - automatically lead to different height settings of the pressure stamp 19 as a difference to the reference point, according to the set pressure.

After attaching a stamp extension, the minimum hydraulic pressure is selected and the program started - the pressure stamp 19 moves to the first point 1-1.

The ram stroke now starts. The pressure ram 19 remains under pressure. After calibrating the measuring device, the process is started so that the machine can automatically move to each ram point and store the associated measured stroke difference. Then the pressure ram 19 moves back to point 1 - 1. The average hydraulic pressure is selected, after which the average stroke difference value η is stored. After returning to the basic position, the pressure ram 19 moves back to point 1-1, after which the maximum hydraulic pressure is selected. Then the maximum stroke difference values are stored. After the measuring program has ended, the ram extension is removed.

To set the machine for printing, the pressure force is selected (empirical value) and the reference point

Li

M-216.02 13

by hand. The ram stroke starts and the pressure ram 19 now performs continuous strokes, whereby (in each case in the pressure-free phase) the stem length is sensitively increased by means of the servomotor 56 until the set pressure ram force is reached. The pressure ram 19 then remains at the bottom under pressure. Now the measuring device is calibrated and the machine is moved to the basic position.

If you want to create an impression, you select the travel program nn. The machine now carries out the program point by point, whereby the values are calculated or interpolated internally according to the set hydraulic pressure and the stored values of the topography and the deflections for the respective points, by which the stamp length is then adjusted using the servo motor 56. After the end of the program, the pressure force is corrected.

A scheme of the value interpolation can be seen in Fig. 8.

First, the dirty and rusty table surfaces 65, 66 of a stand-alone machine 67, partially shown in Fig. 6, are cleaned using rotating brushes 68 and the resulting dirt is removed using a vacuum cleaner 69. Previously, a measurement in the range of 1/100 mm was not possible, but cleaning now also allows this order of magnitude to be recorded.

A separate measuring machine is required for each punching format, in the embodiment selected in Fig. 9 with a hydraulic cylinder 70 with a height h of 30 mm, a diameter d of the piston 71 of 40 mm and a diameter e of the punch 19 of 50 µm.

14

&Mgr;-21&Iacgr;.&Igr;)? 14

176 hydraulic cylinders 70 are used here, which for 320,000 kp max. punching force of a so-called IV punching machine result in a maximum pressure on the hydraulic system of

320 000 x 4 = 144.68 145 bar.

4 ² xx 176

These 176 cylinders in eleven rows of sixteen cylinders each are connected by means of connecting channels, pipes and valves so that in the example in Fig. 8, load areas I to VI (each area is determined by two diagonals) can be selected according to the following configuration, in which the numbers of the load area(s) are arranged according to the size selected in each case

Load case (a): I

(b): I + II

(c): I + II t III

(d): I + IV

(e): I + II + IV + V

(f): I to VI.

Loading case (a) covers field I, loading cases (b) and (c) result in an enlargement of field I in the direction of the arrow. Loading cases (d) and (e) concern the lateral expansion of loading cases (a) and (b), while in (f) all areas are added together.

A measuring probe can be inserted into the gaps between the cylinder rows

76, which has a measuring head at the front end

77 and guides 78 for precise scanning of the punching table

15

M-216.02

The lance shaft 79 is provided with a longitudinal encoder 80. The ten measuring channels between the eleven cylinder rows are provided with a measuring point encoder device 81 at their entrance.

In Fig. 12, punching tables 14a, the cylinder unit 17, the hydraulic unit jj and the output unit ^10-12 can be seen.

^; The cylinder unit 17 is completely assembled and piped,

and connected to the required valves. This unit is pushed between the punching tables 14a and connected to the

, elements of the punching plate clamping. Then a

hydraulic umbilical cord to the hydraulic system and an electronic umbilical cord to the evaluation unit.

The hydraulic system consists of a pump with oil reservoir, etc., digital pressure indicator and precise, motor-operated pressure control valve as well as selector switches for the three pressure levels and selector fields for the six different

; _: loading areas.

U The evaluation unit includes the central control, the

JÜ printer unit, the storage unit, an interface to

I; Control of the impression machine 10 and a digital display

instrument that displays the measured table distance in &khgr;&khgr;,&khgr;&khgr; mm .

For optimal adaptation to the respective punch, the measuring machine is equipped with a height-adjustable table, in which the hydraulic system and

16

yi-216.02 &Igr;&Ogr;

the evaluation unit and the connection points are integrated. Above the table is provided with guides for the cylinder unit and the measuring lance.

Each standard format also requires a special cylinder unit, a measuring rod and a table. The insert for the measuring rod and the evaluation unit is the same and is adapted to the individual formats using software.

To measure and correct the (non-) _parallelism of the punching table, ie to measure the actual condition of the punching machine, the punch should be measured with the measuring machine using the information on the load area and the load height and the result printed out. The printout is then visually evaluated and the parallelism of the punching table is adjusted. The punch is checked again by measuring it again... and corrected if necessary.

The topography and deformation of the punching tables 65, 66 are measured for the load surfaces in three pressure (force) stages, namely 1/3, 2/3 and 3/2 of the maximum pressure. The measuring time is automatically determined by the coding devices mentioned when the measuring line 76 is advanced, and the measuring results are assigned to the individual grid points. The table distance differences are stored in relation to the smallest dimension as the zero dimension for each grid point. Eighteen difference values must therefore be stored for each grid point.

17

M-216.02 17

Since the pressure table 14 and traverse 30 bend in practice, compensation for the bending and parallelism errors is required. For this purpose, the hydraulic cylinder 17 for the stamp head 19 is connected to a pressure regulator 55 in the form of a hydraulic valve with a servomotor via a pressure sensor 54 for measuring the hydraulic pressure. In addition, the stamp head 19 is assigned a servomotor 56 and a digital length measuring device 58 - both are connected via lines 56a, 58a to a computer 60, which is also connected to the pressure sensor 54 and pressure regulator 55 via lines 54a and 55a. The computer 60 is provided with a screen device 62 and an actuating element - e.g. a joystick 63 -.

The measurement and storage of parallelism errors and deformations on the impression machine 10 then takes place in relation to the grid points. The values obtained according to the previous section are transferred to the memory of the impression machine 10 and can be called up there at any time after the punching machine and grid point.

To measure the bends and machining inaccuracies, the pressure ram 18 is fitted with a measuring shoe and the hydraulic pressure of e.g. 40 bar is entered digitally. After the movement has started, the pressure ram 18 moves over the grid point 1-1, makes a downward stroke and remains under pressure. The position of the digital length measuring device corresponding to this position is internally regarded as the "O" point, i.e. "0" is shown on the display.

Then the printing stamp 18 moves through all the raster points. The digital measuring device measures the stamp position achieved

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M-216.02 18

measured under pressure as a deviation from the "O" point, shown on the display in +^ 0.001 irtn and stored in a microprocessor based on the grid point.

The process is repeated with the hydraulic pressures §

of 85 bar and 130 bar, the measuring shoe is removed. S

For the impression process, the desired Steirpel force is set to A

Experience values are digitally preselected. Then van Carputer %

the corresponding hydraulic pressure is calculated and using 4

Servo valve and pressure sensor automatically adjusted. At the display ff

play the set punch force appears digitally. |

A suitable reference point M is marked on the die.

selected, which conveniently consists of a knife cross in %

the center of the die. Then the impression A

stamp 18 is manually moved over the reference point and the 3 stepper motor brings the pressure stamp 18 to its max.

possible low position. The pressure stamp 18 makes a depression ',,

downward stroke and remains at the bottom under pressure A. The digital i:

Length measuring device determines the position of the pressure t

stamp 18 above the printing table 14. The display shows the ab- ''-.

solute value &mdash; for example 37.262 mm &mdash; is displayed and O

stored internally. h

The pressure piston 18 makes an upward stroke and returns to the "home position", then a downward stroke until the piston in the hydraulic cylinder comes to a stop under pressure A. It remains in this position.

19

M-216.02 19

Using the stepper motor and the digital length measuring device, the punch is now adjusted to a height of C = B -0.2 (in the example: C = 37.262 - 0.2 = 37.062). The dimension C is now shown on the display (this process is not necessary when trimming).

Now the type of print (line, area, dots, etc.) is selected and the print is started. The print is made point by point. During the print, the stamp height is continuously changed by the corresponding correction values, whereby the adjustment is carried out by means of the stepper motor whenever the printing stamp 19 is in the upper position.

If the impression does not show the desired result, the stamping force can be varied and the impression process can be started again.

Claims (1)

1. Device for producing punching templates, particularly in the folding box industry, for at least one punching table, marked by a pressure rod with hydraulic cylinder, a pressure sensor with upstream pressure regulator (actuator), whereby the pressure regulator and pressure sensor are connected to a computer. 2. Device according to claim 1, characterized by the connection of the computer to a length measuring device and to the servomotor for changing the length of the pressure stamp. 3. Device according to claim 1 or 2, characterized in that several loading surfaces (I to VI) are each determined by a plurality of pressure cylinders. 4. Device according to claim 3, characterized in that each of the loading surfaces (I to VI) contains a plurality of cylinders in several rows and several rows. 5. Device according to claim 3 or 4, characterized in that the cylinders can be switched between different assignments to different groups or load areas (I to VI). M-216.02 ß. Device according to at least one of claims 1 to 5, connected by at least one measuring lance which is movable in the gaps between the cylinder rows and is connected to the recliner. 7. Device according to claim 6, characterized in that measuring channels with a measuring position coding device are provided between the cylinder rows. B. Device according to at least one of claims to 7, characterized by a measuring machine with a height-adjustable table in which the hydraulic system and the evaluation unit are integrated.