Bending Machine (flat metal bending)
A bending machine is a metal-forming machine tool (DIN 8586), whose purpose is to make bends in a workpiece. A bend is generated by means of a tool in the course of a linear or rotational movement of the workpiece. A detailed subdivision can be made on the basis of kinematics.
- 4.1 Operation of the electronic angle measurement
- 4.2 Functionality of the stroke measurement
- 6.1 Networking with a punching machine (example)
CNC bending machine
In modern CNC bending machines, a special emphasis is placed on low set-up times and flexibility. They are powerful bending machine with which individual parts and small series can be just as cost- turn as serial parts.
Universal Bending Machines - Modular design
The universal bending machine consists of a base machine can be equipped with little effort and used for a variety of bends. The tool change is possible via a simple plug-in system in few seconds. For the basic machine includes NC stop, work table, and Windows software. The modular design allows the low-cost entry into the bending technology, since the machine is expanded without tags after the initial investment, that is, the basic machine provides the bending stroke, the tool determines the type of bend.
Bending Tools
In the bending tools is distinguished mainly by the type of deflection produced. They can be designed such that the bending angle by means of a reference bend is adjusted. With CNC machines, the bending angle of the machine in a stroke is converted or the bending tool itself is provided with an angle sensor.
Standard bends
Standard curves are all the bends that have no unusual geometry. The bend is (relatively) far away from the material ends, so that sufficient space exists to support the tool. The distance to a second bending is large. It is used as a so-called punch tool with an electronic bending tool or a mechanical bending prism.
U-bends
In U-bends more bends very closely spaced are generated. This, instead of a punch, a bending mandrel is used, the contour of which is substantially narrower.
Floor bends
A bending tool is used, when two bends are to be generated with a small distance from each other simultaneously.
Edgewise bending
The edgewise bending tool is used, if the bend axis is parallel to the narrow side of the workpiece.
Torsional deflections
Using a Torsionsbiegewerkzeugs the workpiece is rotated along the longitudinal axis.
Angle measurement and Springback Compensation
To order individual parts and small series can turn just as economically as production parts is an angular measurement with springback compensation helpful. With the use of electronic tools is achieved bending accuracy of ± 0.2 ° by the calculated springback compensation as early as the first part. At the stroke measurement is a table of bending factors in the machine control is defined for each type of material.
Operation of the electronic angle measurement
In the bending prisms with electronic angle measuring twist when bending two flat pins. The measurement accuracy is 0.1 °. From the measured values then the computer calculates the required Nachbiegung. Regardless of the material springback is compensated. The high angular accuracy of ± 0.2 ° is achieved already at the first workpiece without rework.
Operation of the stroke measurement
There, where bending prisms with integrated angle measurement can not be inserted because of their size, eg if there is insufficient distance between two bends, and bending prisms can be used without angle measurement. For this purpose, can the control of angle measurement switch to stroke measurement. In this method, the stroke of the bending ram in millimeters, and thus the penetration depth of the die can be selected in the prism. The setting accuracy is 0.1 mm. The hub for the Nachbiegung then omitted. The further development of the lifting system also allows to specify an angle which is converted with the aid of a lift curve stored in a hub. The bending accuracy depends in this case on several factors such as material thickness, hardness, etc., which may vary from workpiece to workpiece.
Programming and operation
Programming is done via a computer with a Windows-based software, which is part of the machine or connected via a network with this. If a new program can be created design data imported or entered via mouse and keyboard. With a graphical user interface, you do not need prior knowledge of CNC programming. Programming errors are easy to detect. Programs are ideally stored in a database in order to find it again quickly search and sort options. If a bending program called, the software automatically checks the program for possible collisions. Operator errors are thus largely excluded.
After a short time the program are aware of any important data. The program calculates the work piece and displays it on the screen. The operator sees on the screen, as the material is inserted into the machine. Side stop and tool position (symbolic ) are shown. The extended length is known before bending. Time-consuming try and set up accounts so that all tolerances are observed already with the first blank.
Networking with the entire production chain
Much organizational effort and interface management can be saved if the bending machine with the preceding and trailing production steps is linked. To network with other machines and external workstations on possible, common interfaces need to be created.
- A software for simultaneous programming of subsequent steps, such as CNC punching machine.
- With a standard industrial PC on Windows platform, the machines are networked with each other easily.
- Integration of various machines to a central database for storing the program data on servers.
- Software interface for example DXF
Networking with a punching machine (example)
If workpieces are bent, holes were made in the work you want to put it in a module can in the previous step usually. For this purpose, a punching machine can be used. In this way, the entire workpiece can be prepared with a program for the CNC manufacturing. This is a very simple and economical workflow.
Literature and References
- M. Weck: Machine Tools machine types and applications. 6th edition Springer Vieweg Verlag, 2005, ISBN 3540225048th