The stamping process is often confusing when the metallurgical process required for the product is determined by a stamping plant that is just getting started or a customer who is not very familiar with stamping.
Sipxmach recommends that when selecting a metal stamping process, priority is given to:
- Impact of stamping process on product function
- Specific design or functional requirements
- Production time and cost
- Suitable stamping sequence
Then goes this article body
Generally speaking, stamping can be divided into two categories: separation and forming
- Separation process: blanking, punching, cutting(segmentation), trimming
- Molding process: drawing, flanging, shaping, hole flanging, bending
- But, Cutting often be set as blanking process.
- And Shaping is little used, it just be used to adjust the details of the product at any step. Such as making a small R Angle, adjusting the flatness of the section, slightly adjusting the Angle of bending, and so on
When required, blanking is the first step of the stamping process.
It cut the larger sheet metal or coils into small pieces, to get manageable pieces.
In addition, blanking is also the last step of the stamping process, usually performed when a stamped metal piece be formed.
It separates the useful parts from the scrap, or it cuts the final product from the entire metal strip (common in progressive die stamping).
- Fine blanking
Fine blanking is a specialized form of blanking where there is no fracture zone when shearing.
This allows the process to hold very tight tolerances, and perhaps eliminate secondary operations.
Materials that can be fine blanked include aluminium, brass, copper, and carbon, alloy, and stainless steels.
If the stamping part requires slots, holes, or other cutouts, we can use punching(also called piercing).
Punching can be performed simultaneously with blanking, punches down the sheet metal in the shape of hole into waste basket.
Perforating is a punching that involves punching a large number of closely spaced holes, like a network sheet, but the material is not separated from the original sheet.
Drawing is the main stamping process in all.
Through the pressure action of the punch, the basic shape of the stamping parts is blanked out. That means, drawing make a flat metal formed into a metal with concave and convex shapes.
When the depth of the part is less than the primary opening, it is considered shallow drawing(Most used).
When the depth of the part is greater than the opening are deep drawing.
Lancing is a piercing operation in which the workpiece is sheared and bent with one strike of the die.
A key part of this process is that there is not reduction of material, only a modification in its geometry.
This operation is used to make tabs, vents, and louvers.
Obviously, bending means bending the metal at the desired angle.
The part after drawing, place it on a specially designed die and pushes against the part, get a required bend.
Because after bending, the structure and shape of stamping parts is easy to be destroyed by other stamping process, bending is after drawing.
- Air Bending. (flat bending)
Air bending is bending the flat surface of a part, often V-shaped. Leave a space between the punch and die larger than part thickness, and its bend will relaxes slightly when be released.
Air bending uses less power and pressure than other bending methods.
- Bottoming and Coining. (High strength bending)
Use anywhere from two to 30 times the pressure, and force the stamping parts fully into a tight-fitting die, get more permanent bend.
- NotchingNotching can be a beneft of a bending. Such as bending a corner in sheet or joining two tubes at a tee joint, notching one to fit closely to the other.
Forming creates the parts with multiple bends, such as U-bends and W-style in one step.
Draw a box is also forming process, it use more than 4 bending edge into a metal cuboid.
trimming is a process of cutting excess material around the perimeter of a part. It is often used to cut deep drawn cups or pools excess round edge from the part body.
Flanging is bending the metal plate along a straight line or curve more than 90°, is a special bending process.
In some cases, flanging is also used instead of trimming to deal with the edges of stamping parts.
In this case, the bending Angle is usually more than 180°, forming a closed U-edge.
9+1. Second-time stamping
A part after all stamping process may have defects on the inside and outside surface, so the parts need to be secondary processed.
The shaving process is a finishing operation where a small amount of metal is sheared away from an already blanked part, in order to provide a straight or smooth edge.
The parts after shaving can be shaved to an accuracy of up to 0.025 mm (0.001 in). And therefore shaving is frequently performed on instrument parts, watch and clock parts, and the like.
- Surface treament
Some stamping parts need to prevent rust or need a smooth appearance, so usually after stamping processing, physical polishing, material spraying or chemical treatment on the surface of the parts
There are many different processes involved in the stamping process, but there is no one best process, or even every process is necessary.
If you know the process well enough, you can better design the details of your stamping products.Minimize the scrap amount of your materials, save your production cost here, and improve the production efficiency while ensuring the quality. Looking forward to your inquiry!