This month we continue our exploration of how we finish processed steel. With methods like plasma cutting, polishing, press brake cutting, sawing, and shearing, an experienced fabricator can create the perfect product to suit your needs.
Plasma cutting is an impressively precise and powerful way to finish processed steel. The cuts created are clean and meticulous, and the need for secondary processing is minimal. The method is efficient and relatively inexpensive. Plasma cutting can be used on even heavy metal plate, including stainless steel, alloy steel, carbon steel, brass, aluminum, and copper.
The process works by cutting through the metal in question with an accelerated stream of hot plasma. The plasma cutter expels a high-velocity stream of pressurized gas through a nozzle, and an electric arc created between the metal and an electrode within the nozzle ionizes the gas, forming an electrically-conductive channel of plasma. This cuts away at the molten metal. We perform plasma cutting at our Cd’A Metals and Norfolk Iron & Metal locations.
You cannot really finish processed steel until the finishing touch has been applied: polishing. Polishing is the process of using abrasives attached to a flexible backing to smooth, buff, and improve the overall surface finish of the material being processed. Abrasives serve different functions depending on their grit. Low-grit abrasives, rated 60 or 80 for example, remove gouges or nicks in the metal’s surface. On the other hand, high-grit abrasives at values of 120 or 180 refine the surface of the material.
Usually a series of abrasives of increasing grit are employed to enhance the physical appearance of your finished product. Polishing also improves the sanitary benefits of the material, making it an essential process for products destined for the food industry. We offer No. 3, No. 4, No. 4 Fine, No. 6, No. 8, and specialty finishes, all applied in-house at our Metalwest locations.
One step on the road to finish processed steel is shaping it into specified configurations. This is accomplished using a press brake. Press brakes can be operated hydraulically, mechanically, pneumatically, or electrically, and they are usually long and narrow so that large pieces of sheet metal can fit inside them. The metal is sandwiched between a punch and a die, and then pressure is applied to bend the metal.
Tonnage refers to the amount of force a press brake can apply, and the metric is how press brakes are rated. 100 to 300 tons is common, but tonnages of 3000 tons are not unheard of. Such press brakes have to be massive, as long as 50 feet long. In addition to different amounts of force, different press brakes also work at different speeds. The metal being molded makes a great deal of difference to the settings used.
Hydraulic press brakes provide high amounts of force, while electronic press brakes reduce the risk of leaks and minimize operating costs. They also work more quickly and accurately while taking up less space. Press brakes are used in a number of applications to finish processed steel, including automotive panels, furniture, airframes, and metal containers. We manage our press brake operations at our Norfolk Iron & Metal facilities.
Sawing is a way to finish processed steel, aluminum, titanium, copper, brass, bronze, and nickel alloys by cutting larger pieces into smaller ones. It is used across many industries, including architecture, aerospace, food processing, packaging, and biotechnology. We perform sawing at all our facilities: Cd’A Metals, Metalwest, and Norfolk Iron & Metal.
There are two major forms of sawing commonly used in manufacturing applications: band saw cutting and circular saw cutting. Circular saws spin as they cut but are designed to be rigid to reduce vibrations. This results in quick cuts that are still highly precise.
On the other hand, band saws are long and straight with metal teeth arranged to suit necessary functions. These teeth are bent slightly, and the cuts they make, while remarkably straight and uniform, are slightly wider than the blade itself.
Sawing can handle a high volume of cuts while reducing material waste due to closer tolerance cutting. The method offers rapid turnaround and high quality cut finishes. This generally cuts down on the amount of further finishing necessary to finish processed steel.
Shearing is a metal-cutting process that results in smaller pieces of sheet metal being cut out of larger flat or rolled stock. A shear machine moves the metal through, making straight cuts with large, sharp blades. The cuts made by shearing are clean and quick as they require no additional burning or melting of the metal. Because the blades are affixed and controlled by a squaring arm, the process has been compared to using large scissors.
Though shearing is better for softer metals like aluminum, bronze, and brass, it can be used to finish processed steel with higher-powered machinery. If the process is performed incorrectly, it will deform the metal. Shearing accommodates a high volume of cuts with very little material waste. We offer shearing services at our Metalwest and Norfolk Iron & Metal locations.