Metal punching process: how it works and solutions

What metal punching is and how does the process take place? Discover more about Minifaber’s metal punching process and the metals we can work with.

Minifaber is a metal punching company that performs work on both large and small quantities, from consulting and design to punching operations. Thanks to our established expertise, we are able to meet the customer's needs to obtain finished and semi-finished products.

Here are the topics you will find on this page:

• What is metal punching? 
• How does the process take place?
• Metal punching machines
• Which metals can be processed?
• Minifaber, your partner for metal punching

 

What is metal punching? 

Metal punching is the process of impressing a form on a surface by pressure or percussion with a steel punch tool. In the metal punching process, the material is removed from a piece of sheet metal by applying a great enough cutting force. The metals that can be punched are different: steel, iron, copper, and aluminum. Everyone has their own hardness and needs adequate pressure to perform punching without imperfections. 

How does the metal punching process take place?

The process starts with cutting and piercing sheet metal up to 25-30 mm thick to create precision metal parts. The pressure exerted by the punch on the sheet metal initially results in plastic deformation of the material and then, when the applied stress exceeds the shear strength of the material, there is a severing of the fibrous structure (which is typical of sheet metal) of the material resulting in the physical separation of the part within the tool.

What are the main steps of the process?

• The cold metal stamping operation is carried out using dies mounted on presses. Specifically, it is carried out with a punch that, connected through a plate to the press slide, penetrates the die, cutting the sheet metal according to the shape of both the punch and the die (the contours of the punch and the hole in the die constitute the cutting parts that will operate the blanking). 

• The punched object falls under the die (and is picked up from there), due to the fact that the die has a section that widens from top to bottom.

• As it descends, the punch penetrates the sheet causing its fibrous structure to deform, and the sheet begins to penetrate the die. In this way, the sheet metal deforms, with rounding of the punched edges, in the upper contact areas with the punch and lower contact areas with the die.

• When the shear failure tension of the material is reached, a fracture surface is generated that separates the punched object from the rest of the sheet metal. Then the punch continues to push the punched piece inside the die until it falls out.

To ensure the correct positioning of the sheet metal above the die, there is a sheet metal guide system, and in the case of thin sheets, a sheet metal presser is also used to prevent the sheet metal itself, due to the stress caused by the punch, from bending and deforming during stamping, causing the production of deformed parts.

Metal punching machines

For the metal punching process, Minifaber uses TruMatic model automatic machines (punch press) by TRUMPF. The advantages of punching and laser cutting machining are combined in the TruMatic 7000 in a particularly profitable way. This high-end combination machine meets the most demanding requirements in terms of part quality, productivity, and flexibility. With the active die, scratch-free parts are obtained and maximum flexibility in forming is exploited. 

Our metal punching units enable us to manufacture small and large sheets, for small or large production needs. With numerical control (CNC) punch machines can cut and form complex metal parts in an easy, quick and safe way. The punching process is numerically controlled 24 hours non-stop and entirely managed by our technical department.

Which metals can be processed?

Minifaber can operate sheet metal punching on different metals, each with its own specifics: steel, iron, aluminum, and copper. Due to the fact that the fibers of the metal at the recision do not cut, but undergo bending, and by virtue of the elasticity of the material and the bending stresses that accompany the shear stress imparted by the punch, punching does not result in a precise cut of the edges of the workpiece or hole, but in a more or less pronounced burring depending on when the tool is sharpened and the type of metal and its crystal structure.

Steel and stainless steel metal punching

Minifaber can apply a metal punching process on steel and stainless steel. Due to the hardness of these materials, punching should be done by placing sufficient force throughout the process, without reaching the breaking point. 

Iron metal punching process

Iron is also a hard metal, which needs enough strength to be punched, limiting the smearing.

Aluminum metal punching

Unlike iron and steel, aluminum is a more ductile metal. This means that the metal punching process must be carefully programmed and checked.

Copper metal punching

Copper punching must take into consideration the breaking tension of the material, beyond which separation of the parts is caused. Also crucial is the use of special blocks to prevent unwanted deformation on the copper being worked, preventing the formation of sharp edges or irregularities.

Minifaber, your partner for metal punching

At Minifaber we are always available to evaluate any request from customers interested in developing a potentially significant business with us, providing them with our expertise in metal punching and forming. We mainly turn to structured companies, of medium and large size, operating both in the North American and international markets.