Classification of progressive forming
Progressive forming is divided into negative forming and positive forming. Negative forming can form some parts with relatively simple shapes. It does not require a support model, but only a simple fixture. The sheet is clamped by the fixture, and then the forming tool head realizes layered processing according to the set program. After each layer is processed, the forming tool head drops a certain distance to process the second layer, and this continues until the end. During the processing, the fixture clamps the sheet and does not move.
Positive forming methods are used for parts with complex shapes. In the positive forming method, a support model is required. The shape of the support model must be consistent with the shape of the formed part. This support model is very different from the mold in stamping forming. The precision requirement of the support model is not very high, and the material selection is more flexible.
In this forming method, the support model is first processed, and the sheet is placed after the support model is processed. The subsequent processing steps are basically the same as negative forming. The difference is that in positive forming, after each layer of the forming tool head is completed, the pallet must drive the sheet and the forming tool head to move down the same distance together.
Characteristics of the incremental forming method
The forming ability of the sheet metal is improved during the incremental forming process. It can be seen from the forming limit diagram that the forming limit can be expressed as max minε+ε. Therefore, the sheet metal can have a larger deformation in the incremental forming process. The main disadvantage of incremental forming is the low forming efficiency. The relative time required to form a single part is relatively long. Therefore, how to improve its forming efficiency is also a very important prerequisite for its wide application.
The influence of forming angle on the surface quality of parts
It can be clearly seen from the formed parts that there is a great difference in surface quality between the gentle curved surface and the steep surface with a large forming angle. On the gentle curved surface, there are obvious tool head extrusion marks on the surface of the part, and the surface quality is poor; while on the steep surface, the surface quality of the part is good. This is the processing trajectory of the part when the forming angle changes under the condition of a given feed per layer. It can be seen that with the increase of the forming angle, the residual wave peak height of the part surface becomes smaller and smaller. However, the wave peak height of the surface corrugation of the actual processed part is much larger than the theoretical value at the gentle curved surface. With the increase of the forming angle, the wave peak height decreases rapidly, and the difference with the theoretical value becomes smaller and smaller.
Of course, the incremental forming method can form sheet metal parts with complex shapes. The forming only requires a simple support model. The formed parts have high precision and good surface quality. It takes less time for small batches of parts and saves money. It can meet the requirements of continuous innovative design, multiple varieties and small batches of products. If you need to customize incremental forming sheet metal parts in batches, you can choose to cooperate with Mulan Group. Mulan Group has professional sheet metal manufacturing capabilities and can meet customers’ needs for incremental forming. Mulan Group is a Chinese original manufacturer with complete certificates and qualifications. Welcome to contact us.
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