Forming Of Sheetmetal using Reconfigurable Tool

Conventional sheetmetal forming use of tools which have to be fabricated each time a new shape is required results in long lead time, high tooling cost and waste of material.
The replacement of such conventional tools with ones that can be reconfigured each time a new product is required offers considerable advantage
There are ongoing contributions to the understanding of this technology

Mechanics & Equipment for sheetmetal forming using reconfigurable tooling

The mechanism of forming is similar to that of conventional dies since the ends of discrete elements are usually smoothened
Conventional sheet metal press is used and main difference is in toolings
As for conventional sheet metal forming, only one tool is required for operations such as stretch forming. The use of reconfigurable punch and die have also been investigated by researchers [16, 17] as illustrated in figure 3
There is a similarity in the technology of reconfigurable tool proposed by various researchers. Differences arise in the method of positioning and clamping the discrete elements and the method of smoothening the discontinuous surface of the tool
Contributions have been made by Nakajima [18] Pinson [19], Walczyk and Hardt [16], Papazian [20] (figure 4) and owodunni et al [17]

CAD/CAM system for sheetmetal forming using reconfigurable tooling

To reconfigure the tool, software to determine the position of the discrete elements and the control instruction for the actuator device or CNC machine used for positioning the discrete element is required (Fig. 5)

The positions of the discrete elements are determined by intersecting the surface model of the die/punch with a line which represents the centre line of the discrete element

The positions of the tip of the discrete elements are used as an input to the program which generates the instructions for the actuator device or CNC machine

It is possible to generate efficient toolpath by minimizing idle time of the positioning tool [17]

Accuracy & Economics of sheetmetal forming using reconfigurable tooling

The accuracy of the sheetmetal formed depends the accuracy with which the discrete elements are positioned, the smoothening of surface of the discrete elements and springback (Fig. 6)

It is possible to compensate for spring back and other size variations using techniques such as experimental determination of the deformation transfer function and FEA method [20]

Papazian et al [20] reports that a reduction to 1/8th and 1/3rd of the current tool fabrication cycle time and labour hour respectively is obtained

Owodunni et al [17], showed that it is possible to achieve great savings in the capital investment to the extent that the cost of a reconfigurable tool can be comparable to that of a conventional die

Research issues in sheetmetal forming using reconfigurable tooling

More investigations are needed to achieve low-cost positioning mechanism that are faster and for large scale tools

The limit on the size of small features that can be captured need to be considered

Efficient CAM system that will give more consideration to optimal planning is an important research issue

Experimental and numerical analysis of the mechanics of sheet metal forming using discrete elements also need to be investigated

Conclusions

Contributions in the research which have great potential for rapid manufacturing of sheetmetal parts have been reviewed

Reduction in cycle time and labour is possible for the reviewed technology

The possibility of having a capital cost for the technology comparable to conventional tooling has been demonstrated for prototypes.

Several research issues that will address the mechanics, the equipment, software, accuracy and economics of rapid sheetmetal forming were identified and discussed

Forming Of Sheetmetal using Reconfigurable Tool

Mechanics & Equipment for sheetmetal forming using reconfigurable tooling

CAD/CAM system for sheetmetal forming using reconfigurable tooling

Accuracy & Economics of sheetmetal forming using reconfigurable tooling

Research issues in sheetmetal forming using reconfigurable tooling

Conclusions

Acknowledgement