TOX PRESSOTECHNIK
EE: +358 50 5110203

Punching, Piercing & Shearing

  • Punching punch with stripper
  • TOX®-Punching System SHR
  • Piercing tong modular system
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Whether you need equipment  for piercing, form & pierce, notching, blanking, cutting, or shearing, TOX® can provide the punching solution to meet your needs.  In principle, it does not matter whether you want to process, whether it is sheet metal, plastics, cardboard, textiles or foils. Do you want closed or open cuts, forming cuts (even/planar and solid cut edges), single or several piercing holes with one stroke, or piercing + feeding + calibrating with a single stroke?

 

Our commitment to quality results in advantages for you:

  • Clean cut edges
  • Precise tool guidance
  • Minimal installation space due to integrated damping of cutting impact
  • Quick and quiet
  • Optimal scrap management

Punching Technology

According to DIN 8588, splitting or piercing is classified as the non-cutting mechanic separation of parts with the help of cutting edges. This procedure can produce high quantities of precise and complicated metal parts (or other materials) in a very short time.

 

This procedure is likely used for the further processing of semi-finished products like metal sheets, half-finished parts from automobile industries or plastic parts from the white goods industries.

Principal groups of piercing

Separation by cutting with steel, cutting with two approaching steels, and shearing.

Steel cutting

The separation by steels is characterized by the penetration of a wedge-shaped steel into the material and drifting it apart. Steel cutting is mainly used for treating soft materials and for trimming.

Cutting with two approaching steels

Contrary to steel cutting, two wedge-shaped steels penetrate the material. Pinching with a pair of tongs is an example for this kind of separation. This process is also mainly used for treating soft materials and for trimming.

Shearing

[1] Punch

[2] Piece part

[3] Die

[a] Die clearance

[F] Force

Shearing is the most frequently used process in industrial and commercial applications because it is very productive. This process occurs when two cutting wedges move (at least one) against each other. The material parts of the cutting surface are shifted against each other. This process needs three steps: 

  1. Elastic deflection
  2. Plastic flowing
  3. Cracking

Due to the cutting force, the sheet elastically deflects, is then plastically deformed and starts flowing. Finally, cracking takes place and the material breaks i.e. shears off. When shearing, generally a difference is made between the opened and the closed cut. An example for the open cut is the cutting off of a metal strip (like cutting with scissors). If the total cutting line is within the piece part, this will be a closed cut.

Die clearance

A correct die clearance is condition for an optimal shearing effect, high cutting quality and long serviceable life of the tools. The required die clearance specially depends on the shear strength and the thickness of the sheet. In the TOX®-Piercing Systems brochure, a table shows the values of the die clearance.

Sequence of a piercing process

1

The tool is mounted to a press or a piercing bow.

2

The upper tool with the cutting punch is moved towards workpiece by the drive

3

The spring-mounted stripper is positioned on the piece part, the springs are pressed together.

4

The cutting punch touches down, the drive further builds-up the force.

5

The cutting punch penetrates into the sheet, 1/3 deep into the piece part in case of optimal die clearance.

6

The piercing slug breaks through the die and causes the sudden release of the driving system. This release of pressure tension is also called “cutting impact”.

7

The punching slug is discharged.

A good cutting quality of the tool depends on:

  • the kind of tool guidance
  • the size of the die clearance
  • the kind of coating of the cutting element

The constructive configuration and operating mode of a cutting tool have a decisive influence on the production result. Among others, a differentiation is made according to their type of guidance. There are three essential types of guidances for cutting tools.

  1. Free cutting tools
  2. Plate-guided tools
  3. Column-guided tools or also guided upper tools, rams through guide rail/guide carriage

TOX®-Punching Systems

The well thought-out modular TOX® PRESSOTECHNIK system provides complete solutions for almost all punching applications. Select the appropriate components to configure the system suited to your application.

 

They are the basis for a press system, which can be combined in the System navigator.

In detail a system consists of:

 

Punching-System, Piercing-C-Bow
2

mounted on a C-Bow or Column press frame

3

having a tool coupling

4

The piercing tool set as subassembly or as subassembly in a C-Bow includes the stipping function.

5

The ram with guide rail and guide carriage or indexing slide is shuttling the punching punch to the sheet metal. It guarentees a clean, distortion-free contact with the sheet metal.

6

The special scrap discharge, slug removal unit, slug chute or slug suction depend on the press type and application. A reliable discharge of chips is a guarantor for a long life of the cutting elements and of the whole tool.

Calculation of punching machines

To define the size of a system the calculation of the cutting force is necessary.

 

Fs= ls x s x ks

 

Fs = cutting force

ls = cutting length

s = sheet thickness

ks = shear strength (approx. 0.8 x Rm)

Rm = tensile strength of the material

 

For the design of tongs or tool, a safety value of about 20 % must be added.

Bevel-ground steels can considerably reduce the cutting force. For roof-ground angles, 10° max.

If the total cutting force exceeds 25 kN, constructive measures must be taken.

Equipment for Punching Applications

We offer a range of machines for punching applications, including:

 

 

Let us know if we can help you to get a quote on this equipment.

Customer Projects with TOX®-Punching Systems
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Address

TOX® PRESSOTECHNIK OY
Lontoonkatu 9 B54
00560 Helsinki
Phone: +358 50 5110203
Fax: +358 50 5110203
Contact
EE: +358 50 5110203 Contact form
©TOX® PRESSOTECHNIK GmbH & Co.KG
 
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