Rompa Group offers a wide variety of technologies around the world at different production sites. We always keep the finished product in our minds during the whole production process.
These are the technologies we currently offer:
- Injection molding
- Metal Injection Molding (MIM)
- Assembly (ESD)
- Decorating and Finishing
In this week's article we dive deeper in the processes and considerations of stamping, also called metal stamping. In a recent article we explained to you what the definition of stamping is, how metal stamping works and what the pro’s and con’s are. You can read this article here
Before we start with complex processes of metal stamping, let's give you some basics. Stamping means that a metal sheet is placed into a stamping press. The press presses the sheet into a desired shape. Sounds easy, right? Yes, but the possibilities are endless! Think about punching, coining, bending, blanking, embossing, flanging and many other stamping techniques.
Nine basic processes for metal stamping
It always starts with a design. At Rompa Group we take many considerations into account and aim for a high-end design, whether this is for a complex part or straightforward part. There are nine basic processes involved in the actual stamping of metal parts, excluding phases such as design and prototyping, which are required prior to stamping.
Blanking is the initial stage in the stamping process if and when it is required. Blanking is the process of breaking down huge metal sheets or coils into smaller, more manageable pieces. When a stamped metal component is to be drawn or shaped, blanking is frequently done.
Piercing can be used to create slots, holes, or other cuts in a part. Piercing punches the required shapes out of the metal sheet and can be done simultaneously with blanking.
Bending is a process that is very self-explanatory. The part-in-progress is put on a specially built die, where a ram pushes against the metal to bend it. Because punching an already bent piece of metal causes the entire portion to deform, bending is done after drawing.
When a punch into a die bends the flat surface of a part into a V-shaped bend, this is known as air bending. The space between the punch and the die is bigger than the thickness of the metal, resulting in a bend that somewhat relaxes when the component is released. Air bending requires less force and power than other bending techniques.
In the metal stamping process, the actual stamping is called drawing. A punch pushes a piece of metal through a die, forming the part's basic shape. Shallow drawing refers to sections with a depth less than the principal opening; deep drawing refers to parts with a depth higher than the opening.
Bottoming and coining
Bottoming and coining are bending procedures that are similar to air bending except that the material is pressed fully into a tight-fitting die, resulting in a more permanent bent.
Pinch trimming is a method of separating a piece of metal from scrap metal by cutting it off the metal sheet. The metal is pressed against a flat vertical surface in an unusual procedure. It's commonly, but not always, used to cut deep drawn round cups from a sheet of paper.
Lancing is a sort of metal cutting that is used to create vents or tabs. A portion of a part is cut on three edges and bent at the same time. This not only generates the essential opening or hook-like feature, but it also removes the need for scrap collection or further machining.
Forming, like bending, bottoming, and coining, is a bending process. In one step, it makes pieces with multiple bends, such as U-bends.
What type of stamping?
We then start with the stamping method. There are several different types of metal stamping techniques. They are called: progressive, fourslide and deep draw. Below we explain each of these methods individually.
Progressive Die stamping
There are several stations in the method, each with its own role. Strip metal is put into a progressive stamping press first. The strip unrolls smoothly from the coil into the die press, where each station executes a distinct cut, punch, or bend. Each subsequent station's activities build on the work of the prior stations, resulting in a finished portion.
Deep Draw Stamping
Deep drawing is the process of punching a sheet metal blank into a die and forming it into a shape. When the depth of the drawn part exceeds its diameter, the procedure is referred to as "deep drawing." This method of forming is good for producing components with many series of diameters and is a more cost-effective alternative to turning techniques, which normally use up more raw materials.
Fourslide, also known as multi-slide, is a technique that requires horizontal alignment and four different slides; in other words, four tools are used to shape the workpiece at the same time. Even the most complex pieces may be developed with this method, which allows for detailed cuts and complex bends. This technique has several advantages compared to the regular stamping process. It is a better choice for producing more complex parts and has more flexibility for changes in the design. Four different tools per slide can be used that results in multiple bends in the part.