Metal Punching

Punching is a metalworking process that involves applying high force to a tool and die to create a form or hole in a metal sheet. The tool, typically made from hardened steel or tungsten, can rapidly and repeatedly penetrate the sheet by either indenting it or shearing through it.

Punching is widely recognised as an efficient and cost-effective method for perforating sheet metal. It allows for the creation of holes or extrusions in different sizes and shapes, depending on the specific tools used and the geometry of the punch impacts.

Similar to sheet metal folding, laser cutting, or machining, the initial stage of our process begins in the office with DC’S programming team. Our punch programmers collaborate closely with the design team to maximize the efficiency of our punching machinery and material utilization.

Once the program and product route card are ready, the punch operator loads the appropriate material into the machine and initiates the program. The punch machine then proceeds to punch holes and shapes according to the programmed instructions for as long as the operator requires.

Automated equipment, such as the loadmaster, facilitates the loading of blank metal sheets onto the punch bed. The sheet is securely positioned by clamps beneath the punch head, and the machine selects the appropriate tool using an automated tool changer. The punching process begins, with waste material (referred to as a slug) falling into a designated compartment below the punch bed.

Once the sheet is fully processed, the punch machine automatically transfers it onto a waiting pallet. An operator then removes the waste sheet carcass and separates it from the usable parts (known as breaking out). The processed parts are either stored for subsequent processes or prepared for dispatch.

In the initial stage of punch programming, the programming department receives a nesting list from the planning department. This list contains details of the punch jobs scheduled for the day, including information such as part number, works order number, due date, and a route card specifying all manufacturing operations for each part (laser, punch, fold, weld, paint).

Next, the programming department receives the part model from the design department and imports it into Radan, a multi-part nesting software. Using Radan, the programmer arranges multiple parts on the sheet in a process called “nesting”. Taking into account the sheet size and required clearances between parts, the programmer optimizes the utilization of the metal sheet to maximize the production of parts.

Finally, the programming department generates the program in the form of a “block file” and transfers it, along with the product route card, to the punch machine operator. The operator then inputs the program into the designated machine for execution.

Punching is a versatile process that finds application in various industries. Apart from creating different perforated shapes, we can also incorporate countersinks, embossments, extrusions, and louvres.

One of the common applications for our punching operations is in electrical enclosures, where we create specific perforations and extrusions, along with inserts, before folding them into boxes.

We also produce high volumes of commercial vehicle steps and tread plates that require punched tread patterns for enhanced grip on the surface.

Moreover, we manufacture industrial computer server cabinets, which involve the production of perforated internal rails and components.

At DC Manufacturing, we punch a range of materials such as:

• Aluminium
• Alloys in thicknesses from 0.3mm to 8mm.
• Coated Steel
• Mild Steel
• Stainless Steel

When deciding between punching sheet metal and laser cutting, we carefully consider several factors to achieve the desired outcome. These factors include:

At DC Manufacturing, we prefer using laser cutting machines for materials over 3mm in thickness. While our punch machines can handle this thickness, limiting the material thickness helps extend the life of punch tools significantly.

Waste generation is an important consideration. Generally, laser cutting machines produce less waste compared to punch machines. The “clearance” (space required between shapes) in a punch nest is greater than that of a laser, resulting in more material wastage per sheet.

If you have any questions about CNC punching or other sheet metal processes, please don’t hesitate to contact us.