One of the most common sheet metal processing processes is material bending. This process is energy-intensive, and therefore, if there is no need for high productivity, then most often this work is performed on manual machines.
Manual bending
To begin with, any metal that undergoes bending has elastic properties. For this reason, during the processing of sheet metal, when a short-term deforming force is applied to the workpiece, the characteristics of the material do not always have time to be fully realized. In other words, after applying force to the metal billet, it will partially restore its original shape. In industry, they began to call it spring. It is also worth adding that the use of bending machines for sheet metal of a mechanical type, rather than manual, will not solve this problem, since the contact time of the punch with the workpiece will not change.
Compensation Methods
Certain methods have been developed by which it is possible to compensate for the effect of metal springing.
- The first method is to increase the angle of bending of the metal by the angle of spring. This method will be most effective if, before starting work with sheet metal, the characteristics and the grade of the alloy were precisely determined.
- In certain cases, a hydraulic bending machine for sheet metal is used. This addition makes it possible to withstand the raw materials under the influence of the load for a longer period, which significantly reduces the spring coefficient.
- Before being processed, the plates can be annealed. This operation significantly increases the plastic abilities of the material, but there is also a certain minus - a scale forms, which will have to be removed before proceeding with bending.
- Some punches or, in rare cases, dies are equipped with additional structural elements - notches or undercuts. The use of these devices significantly reduces the manifestation of plastic forces.
Varieties of technology
Naturally, in the case of using a manual machine for processing sheet metal, the force that can be applied to the workpiece is greatly limited by the physical capabilities of a person. For this reason, various technological methods for carrying out this procedure were invented.
- The first way is free bending with a non-profiled tool. When using this method, the workpiece is fixed using two supports that are located opposite each other. Deformation occurs with the help of a punch, which has a certain radius of the working area. This method is most often used for sheet metal processing, single-angle V-bending. The peculiarity of the technology is that for bending a minimum effort is required.
- Another method is calibrating bending. This process is carried out inside the matrix. From this it follows that the machine intended for processing sheet metal, therefore, should be equipped with a more powerful bed and table.
When metal bending is selected
The processing of such raw materials using the bending operation is selected based on certain factors.
- The capabilities that the machine has to carry out this operation.
- Depends on the brand of metal used in the production.
- Heavily dependent on device performance. It is important to understand here that sheet metal processing is most often required by flexible, cutting, punching, and other operations.
- The maximum forces required by a bending or milling machine to perform the desired operation are also important.
- An important selection criterion will be the accuracy with which the machine can cope with the task. This feature depends on the locking devices available on any bending machine.
Types of equipment for cold bending
The main advantage of manual bending was that during the processing process the protective coating does not peel off, and therefore a layer of paint, zinc, etc. is allowed. There is also a classification of machines for cold bending:
- An important factor is the width of the desktop. This factor determines the maximum width of the workpiece.
- It is also important to have equipment for cutting sheet metal. Most often, this role is played by an additional knife used for roller cutting of edges.
- Another important factor is the maximum value of the moment that is applied to the handle of the hand tool.
- In addition, the equipment is divided into classes depending on the drive that controls the movement of the slider. It can be a handle or a pedal. There are also combined types.
These options are a standard set. Leading manufacturers of this equipment are trying to provide it with the maximum number of additional options.
Additional processing methods
In production, there are additional processing methods that are considered simplified. Such methods include stamping with elastic materials, pressing operations, high-speed stamping, etc.
For example, if we consider stamping with elastic materials, then there are some peculiarities. The machine on which such an operation is carried out has only one metal working element — it can be a punch or a die. The second is made of rubber, plastic, polyurethane and liquid.
Suppose, as a metal part, the template used to lay the workpiece will be selected. This means that a rubber cushion will be used in the press slider, which will press the material to the template. It is worth noting that if the template is characterized by sharp edges, then the free edges of the workpiece are unbent, and then cut off along the cutting edge. Thus, it is possible to carry out cutting and punching of the material.
Sheet metal polishing
This process is designed to give an already finished product an aesthetic look, shine. In addition, this operation is also used in cases where it is necessary in the future to apply any additional layer of paint, protective substance, etc. to the surface of the workpiece.
This operation can be carried out in the following ways:
- mechanical or abrasive polishing;
- chemical treatment;
- electrochemical method;
- electrolyte-plasma method.
You can also add that the technology for some types of polishing does not require special equipment. For example, a mechanical method can be carried out independently at home. However, the natural minus is that a significant result or high quality grinding will not work.