EP1525927B1 - Combined punching and bending machine and machining process therefor - Google Patents

Abstract

The method consists of punching, forming, and tool change stages, and a lubrication stage for plate positions. Lubricant (8) is sprayed on the plate (2) to processed, esp. on its underside, by a spray device, which is positioned offset relative to the punch/forming tool in use at the time. In at least one plate position, between lubrication and forming/punching stages, at least one further processing stage in a different position is carried out. All processing stages not requiring a tool change, are carried out in sequence. The punching/forming machine (1) has interchangeable punching/forming tools (3) and a lubricant spray device (6) positioned below the plate. The machine is controlled by a computer program.

Description

The present invention relates to a method of processing a metallic sheet by means of a combined punching / forming machine, the method comprising the steps of stamping the sheet by means of a punch, "forming" the sheet by means of a forming tool (eg a tool for producing beading, threading or gills), "changing" of forming and stamping tools and "smearing" of sheet metal positions to be formed.

The forming of sheets is generally carried out with a forming tool, which consists essentially of two mold halves (punch and die). The mold halves are in contact with the sheet to be formed during the forming process, thereby exerting a force which causes the shape change of the sheet. During the forming, there is a relative movement between the sheet to be formed and the mold halves. In this case arise when the sheet metal to be formed on the mold halves frictional forces, which are reduced by the application of lubricant to the sheet metal or the mold halves to be formed. Since then, only the upper die (punch) could be lubricated during the processing of the sheet, since the lower die (die) was covered by the sheet and therefore was not accessible. For this reason, hitherto, the sheet underside outside the forming machine was manually lubricated at the processing positions to be formed, which was associated with high expenditure of time and an environmental impact by over-lubrication.

From DE-U-295 07 141 a method for processing a sheet by means of a punching machine is known, wherein the method, the processing steps "punching" of the sheet by means of a punching tool and "application of material These coatings are permanent coatings of the sheet, such as adhesive, insulation, sealing surface or wear protection coatings that are applied at the same time for punching ,

In contrast, it is the object of the present invention to further develop a machining method of the type mentioned in that the lubrication can be applied during processing on the sheet or that the processing is performed time-optimized.

This object is achieved by a machining method in which the lubrication by means of a laterally offset to the respective substitute punching or forming tool arranged spraying are applied to the plate and at least at a sheet position between "smearing" and "forming" this sheet metal position at least one processing step in a different position.

According to the invention, a lubricant, e.g. an air-oil mixture, sprayed at a distance to the working location of the forming tool to a sheet metal position to be formed and then moved this lubricated sheet metal position to the machining tool. The sequence of all processing steps is chosen so that the total processing time is as short or time-optimized and in particular shorter than in the case in which immediately after "smearing" a sheet metal position, this sheet metal position is transformed.

If the method also includes the processing step "smearing" of sheet metal positions to be punched, at least one processing step is preferably carried out at a different position at least at a sheet metal position between "smearing" and "punching" this sheet metal position. The sequence of all processing steps is chosen so that the total processing time is as short or time-optimized and in particular shorter than in the case in which immediately after "smearing" a sheet metal position, this sheet metal position is punched.

Preferably, a limited number of transformations or punching of non-lubricated sheet metal positions is carried out between the forming or punching of two lubricated sheet metal positions in order to optimize the number of lubrications. For example, it may be sufficient to lubricate only every second or third forming or punching.

In order to minimize the contamination of the machine by lubricants, only a limited number of repositioning should take place between lubrication and the associated forming or punching. Therefore, it is preferable to perform only a limited number of processing steps at other positions between "smearing" and "forming" or "punching" the same sheet metal position.

It is advantageous if in each case all processing steps that are possible without tool change, are performed sequentially and if a sheet metal position is formed or punched after applying lubrication.

• (a) Nur solche Blechpositionen stehen zur Auswahl, die ohne Werkzeugwechsel bearbeitet werden können;
• (b) Blechpositionen stehen zum Umformen bzw. Stanzen erst zur Auswahl, wenn sie zuvor geschmiert worden sind.

As a rule, the next sheet metal position to be machined is selected to be the one that can be reached most quickly starting from the current sheet metal position, if possible taking into account the following boundary conditions:

• (a) Only those sheet metal positions are available that can be machined without tool change;
• (b) Sheet metal positions are available for forming or punching only when they have been previously lubricated.

However, it is also possible to select lubrication positions of a next machining (after tool change) or even all lubrication positions which occur during the entire machining of the metal sheet as the next sheet metal positions to be machined.

Further advantages of the invention will become apparent from the description and the drawings. The embodiments shown and described are not as an exhaustive enumeration, but rather have exemplary character for the description of the invention.

Fig. 1

die erfindungsgemäße kombinierte Stanz-/Umformmaschine in einer schematischen Seitenansicht;

Fig. 2

die Draufsicht auf ein Blech, das an verschiedenen Positionen bearbeitet werden soll; und

Fig. 3

ein beispielhaftes Ablaufdiagramm für die Bearbeitung des in Fig. 2 gezeigten Blechs mittels der erfindungsgemäßen Stanz-/Umformmaschine.

Show it:

Fig. 1

the combined punching / forming machine according to the invention in a schematic side view;

Fig. 2

the top view of a sheet to be processed at different positions; and

Fig. 3

an exemplary flow chart for the processing of the sheet shown in Fig. 2 by means of the punching / forming machine according to the invention.

The combined punching / forming machine 1 shown in Fig. 1 comprises exchangeable stamping and forming dies for processing a sheet 2 which is moved in the machine 1 at the place of work of each substitute punching or forming tool 3 over, as indicated by a double arrow 4 is. The punching or forming tool 3 consists respectively of upper and lower punching or forming tools 3a, 3b, between which the sheet 2 is arranged. With 5 , the stationary receptacle for the lower punching or forming tool (die) 3b is designated. The forming tool is used for example for generating beads, thread passages or gills.

At a distance a (eg 100 mm) to the center of the lower punching or forming tool 3b, a stationary spraying device 6 with a spray nozzle 7 is arranged laterally on the underside of the sheet 2, a lubrication 8 , for example an oil stain, with to spray on a diameter b . The spray device 6 is connected via an electrically operable 2/2-way valve 9 with a pressurized oil reservoir 10 . By energizing the valve 9 oil passes under pressure to the spray nozzle 7 and is mixed there at the nozzle outlet with an air stream and sprayed onto the sheet 2. This air-oil mixture is sprayed at a distance to the working place of the substituted lower punching or forming tool 3b on a sheet metal position to be formed, and in the further course of processing this lubricated sheet metal position is driven to the punching or forming tool 3 for processing.

In FIG. 2, four processing positions P1 to P4 are shown on the sheet 2 by way of example, to be processed with the combined punching / forming machine 1. The positions P1, P4 are to be punched with a first punching tool and formed with a first forming tool and the positions P2, P3 punched with a second punching tool and formed with a second forming tool. The order of all processing steps is chosen so that the total processing time is as short as possible. Within the scope of this optimization, the fastest achievable next sheet metal position is determined based on the current sheet metal position (starting position). The time required for repositioning is calculated from the travel distance and acceleration along the travel axes. The sheet metal positions available for selection for the next sheet metal position may vary. Normally only sheet metal positions are available, which can be done without tool change. Sheet metal positions that previously require lubrication are not available until lubrication of this sheet metal position has occurred. Also, lubrication positions of a next machining (after tool change) or even all lubrication positions that occur during the entire machining of the sheet can be available for selection.

The diameter b of the sprayed point lubrication 8 is e.g. 30 mm. If larger areas or longer tracks, e.g. For a Nibbelbearbeitung be lubricated, the sheet is moved accordingly during the spraying process.

3 , the processing steps required for processing the sheet 2 are shown in a flowchart, wherein the order of the processing steps is optimized with regard to the shortest possible total processing time. For smearing a sheet position, the sheet 2 is moved until this sheet metal position is arranged above the spray nozzle 7. For punching and forming a sheet metal position, the sheet 2 is moved until this sheet metal position is arranged in the tool 3 accordingly. The individual processing steps are implemented in a control unit (computer) of the machine 1 controlling the method and processing of the sheet metal as a machining program (computer program or software).

First, with the first punching tool installed, the sheet position P1 is lubricated and punched with the first punching tool, followed by "smearing" the sheet position P2. Then, the sheet position P4 is lubricated and punched with the first punch, followed by "smearing" the sheet position P3. After the tool change to the second punching tool, the sheet metal positions P3, P2 are punched with the second punching tool. After the tool change to the first forming tool, the sheet position P1 is lubricated and reformed, followed by "smearing" of the sheet position P2. Then, the sheet position P4 is lubricated and lubricated with the first forming die and formed, followed by "smearing" the sheet position P3. After the tool change to the second forming tool sheet metal positions P3, P2 are punched with the second forming tool.

As a result of the position of the spray nozzle 7 which is at a distance from the punching or forming center by a, a dead zone is created on one side of the sheet which can not be lubricated. If machining operations are to be lubricated in this dead zone, machining can always be carried out alternately in the lubricatable and non-lubricatable regions. This ensures that there is still a sufficient lubricating film on the tool from the last lubricated machining.

Claims (7)

1. Method for processing a sheet metal (2) using a combined punching/forming machine (1), wherein the method comprises the processing steps of "punching" the sheet metal (2) using a punching tool (3), "forming" the sheet metal (2) using a forming tool (3), "changing" forming and punching tools (3) and "lubricating" sheet positions (P1-P4) to be formed,
   characterized in that the lubricants (8) are sprayed onto the sheet metal (2), in particular onto the lower side of the sheet metal, using a spray device (6) which is disposed at a lateral distance from the respectively mounted punching or forming tool (3), and, at least at one sheet metal position (P2) between "lubricating" and "forming" of this sheet metal position (P2), at least one processing step is carried out at another position.
2. Method according to claim 1, characterized in that the method also comprises the processing step of "lubricating" of sheet metal positions (P1-P4) to be punched and, at least at one sheet metal position (P2) between "lubricating" and "punching" of this sheet metal position (P2), at least one processing step is carried out at another position.
3. Method according to claim 1 or 2, characterized in that between forming or punching of two lubricated sheet metal positions, only a limited number of forming processes of non-lubricated sheet metal positions are carried out.
4. Method according to any one of the preceding claims, characterized in that, between "lubricating" and "forming or "punching" of the same sheet metal position (P2), only a limited number of processing steps are carried out at other positions.
5. Method according to any one of the preceding claims, characterized in that all processing steps which can be carried out without changing tools, are performed subsequently.
6. Method according to any one of the preceding claims, characterized in that a sheet metal position is formed or punched only after application of lubricant (8).
7. Method according to any one of the preceding claims, characterized in that the sheet metal position which can be reached within the shortest time from the current sheet metal position, is selected as the next sheet metal position to be processed.

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