Introduction
Deep drawing is a forming process used in the manufacturing of sheet metal components which require a profile with a large depth in comparison with its width. This process involves the shaping of a sheet metal blank into a desired shape using a punch and die assembly. The punch and die assembly of deep drawing includes a die having a circular hole in it and a punch tool which fits inside the die. During deep drawing process, the sheet metal blank is placed over the die and the punch is pressed over the sheet metal blank with the help of a press.
Deep drawing process involves three stages, i.e., drawing phase, redrawing phase, and trim phase. In drawing phase, the punch presses on to the sheet metal blank and forces it to take up the shape of the die as the blank gets thinner, resulting in a deep drawn part or component. After the drawing phase a portion of flash is normally seen at the edges of the drawn component which requires to be removed. This is done in the trimming phase which involves cutting out the flash from the edges of the drawn component. Finally, the redraw phase involves inserting the drawn component into the die of a smaller size and increasing the pressure to further reduce the size of the component.
The deep drawing process offers several benefits over conventional stamping methods as it increases the strength and accuracy of the component. By performing deep drawing on a metal blank, complex shapes with accurate dimensions can be produced in a single step. This method of forming is preferred in manufacturing components which require high precision and tight tolerances. Also, the deep drawing process consumes less energy and offers improved dimensional accuracy compared to stamping operations.
Deep drawing process has a wide variety of applications in the automotive, aerospace, and electronics industries. This process is used for manufacturing fuel tanks, car bodies, flat springs, and electrical connectors. It is also used for making circular baffles for fans, multipin connectors for electronics and cabinets, and other types of specialized components.
Deep drawing requires a high level of precision and requires higher forces to form the component,. Therefore, a specialized deep drawing die set is necessary for producing components with complex shapes and tight tolerances. The design of a deep drawing die set also plays an important role in producing components that meet the customer’s requirements.
Design Requirements
In order to produce complex components with tight dimensional tolerances, the design of the deep drawing die set must conform to certain design requirements. Here are some of the design requirements that must be considered when designing a deep drawing die set:
• A deep drawing die set must have a good fit between the punch and die. The punch must slide smoothly into the die, and the angles of the punch and die must match to avoid any binding.
• The clearance between the punch and die should be minimal as excessive clearance can lead to flash and burrs on the component.
• The surfaces of the punch and die must be well finished to minimize any wear and tear.
• The punch and die must have proper support at all points to ensure the accuracy of the component.
• The deep drawing die must have provisions for ejecting the component after each cycle.
• The deep drawing die must have proper lubrication channels to ensure smooth operation of the die set.
• The deep drawing die must have proper reinforcements to withstand the high forces involved in the process.
Design Considerations
There are several design considerations that must be taken into account while designing a deep drawing die set. Here are some of the design considerations that must be kept in mind while designing a deep drawing die set:
• The shape and size of the workpiece must be kept in mind while designing a deep drawing die set. The shape and size of the die must match the shape and size of the workpiece to ensure that the die can easily accommodate the workpiece.
• The wall thickness of the workpiece must be taken into account while designing a deep drawing die set. This helps determine the optimum clearance between the punch and die, and also helps determine the amount of force needed to draw the workpiece.
• The die should have a proper support structure which is robust and stiff enough to withstand the high forces involved in the process. This prevents the die from deforming under the high forces and ensures the accuracy of the component.
• The punch and die should have a minimum clearance of 0.005 inches to ensure a tight fit. The fit should also be such that there is no binding.
• The deep drawing die should have provisions for ejecting the component after each cycle. This helps reduce any chances of marks being left on the workpiece due to dragging it out of the die.
• The deep drawing process involves high forces which can lead to vibrations and decrease the accuracy of the component. To prevent this, the die must have provisions for dampening the forces to reduce the vibration and improve the accuracy of the component.
• The die must be properly lubricated to reduce friction and wear and tear of the die.
Conclusion
Deep drawing is a well-established process that is widely used in the manufacturing of complex components with tight tolerances. It offers several benefits over conventional stamping methods as it increases the strength and accuracy of the component. In order to produce components with high accuracy and tight tolerances, the design of the deep drawing die set is of utmost importance. The design of a deep drawing die set must match the shape and size of the workpiece, have a minimal clearance between punch and die, and have proper support, ejection, and dampening provisions. The knowledge of various design requirements and considerations is important in designing quality deep drawing die sets.
