WHAT TO LOOK FOR IN A METAL FABRICATION SHOP
When choosing a metal fabricator one must consider the different materials, industries served, machine capacity, the shop’s output capacity, and even which industries they are equipped to serve.
Experience: Well-established fabricating shops have a proven record of providing good service and products. Samson Metal Products’ facility has been providing excellent products and services since 1951.
Industries served: It is important to know what sorts of metal products or processes a fab shop typically focuses on, as they’ll be better suited to fulfill specific industry requirements. At Sampson Metal Products, we serve the automotive, aerospace, medical, food services, & security industries.
Machinery: For detailed projects, CNC machines are often the best option for a finely-detailed project, but manual machines are often necessary as well. If your end product is oversized, the size and load capacity of the machinery should be taken into account in choosing a shop as well. Metal fabrication relies heavily on precision and therefore rapidly evolving computer technology. CAD/CAM software are used to design the product layouts so that the CNC machine computers can be programmed to perform very specific tasks. Samson Metal Products can either program with your already completed CAD design files or prints, or you may work with one of our talented engineers to customize those for you!
Production type: When looking at machine shops, the volume output of products needs to be taken into account. Some shops are only low volume. Samson Metal Products can take on low and high volume jobs, as well as short term or long term product lines.
Materials The most common metal materials used to create precision sheet metal are steel and aluminum. Stainless steel is valued as sheet metal because stainless steel provides strength, durability, corrosion resistance, and easy cleaning. These qualities prove valuable in harsh environments and to the manufacturing, food processing, and storage industries. Stainless steel puts the most wear and tear on CNC machine bits when cutting so may be more expensive to mill. Aluminum is also popular because it is lightweight but offers compressive strength. Other metals used in fabrication shops include brass, copper, nickel, and titanium.
Types of Metal Fabrication
The process that cuts, shapes, or molds raw or semi-finished metal material into a final product is all under the umbrella of metal fabrication. These processes are done in fabrication shops, also known as fab shops. Some metal fabricators specialize in particular metals or processes. The main metal fabrication processes are folding, extrusion and machining.
Brake presses and folding machines crease metal by pinching it into a bend or fold by placing the workpiece between a punch and a die and applying pressure from the punch.
In the extrusion process, the workpiece is forced through or around an open or closed die. When forced through an open or closed die, the diameter of the workpiece is reduced to the cross-section of the die. When pressed around a die, a cavity is formed within the workpiece. Both of these processes generally use a metal slug or cylinder (a billet) as the workpiece, and a ram to perform the impact. The resulting cylindrical item product is often wiring or piping. The dies have different shapes to produce differently shaped parts. Extrusion can be continuous to create very long pieces, or semi-continuous in order to create many shorter pieces.
Steel fabrication commonly uses cold extrusion, impact extrusion is performed at room temperature and increases the strength of the part, making it stronger than the original material. When enough force is applied to the appropriate metal, it starts to flow into the available shape.
Hot extrusion is performed at an increased temperature, to keep the metal from hardening and to make it easier to push through the die.
Shaping metal by removing the unwanted material away from the desired shape uses a variety of techniques such as shearing, turning, milling, drilling, punching and welding.
Shearing takes place with one tool is above the metal and another one is located below the metal to apply pressure, and creates one long cut. By fracturing the metal as it cuts.
Turning uses a lathe to rotate the metal while a cutting tool moves in a linear motion to remove metal along the diameter, creating a cylindrical shape. The cutting tool can be angled differently to create different shapes. It can be done manually or with a CNC turning machine. CNC programming is usually used in order to program the lathe to cut in a very precise way so that parts fit together accurately.
Milling uses rotating multi-point cutting tools to progressively remove material from the workpiece until the desired shape is achieved. The metal is slowly fed into the rotating cutting tool, or the tool is moved across the stationary metal, or both the workpiece and the tool are moved in relation to each other. Milling is often a secondary or finishing process, but it can be used as the sole method of fabrication from start to finish. The different types of milling include face milling, plain milling, angular milling, climb milling, and form milling.
Drilling uses a rotary cutting tool with a drill bit, to cut a hole in the material. The drill bit presses against the metal while being rotated very quickly in order to create a round hole. A CNC punching machine fabricates holes in sheet metal by programming the hole size and spacing into the machine.
Punching uses uniquely shaped turrets on a punch press, which hit the metal through or into a die to create holes.
Stamping is similar to punching, except the press doesn’t create a hole in the metal, but an indentation. The machine does not force the metal through the die, but just raises it to form shapes, letters, or images in a metal panel or sheet.
Welding combines two or more pieces of metal together, through a combination of heat and pressure. This is a popular process because the pieces of metal can be any shape or size. Some of the popular welding techniques are Stick or Arc Welding, MIG Welding, TIG Welding, and Flux Cored Arc Welding.
Stick welding, also known as Shielded Metal Arc Welding (SMAW), uses an electrode stick that produces an electric current that forms an electric arc when in contact with metal. The high temperature of the arc welds the metal.
Metal Inert Gas Welding (MIG), or Gas Metal Arc Welding (GMAW), uses an externally supplied gas along with a continuous solid wire electrode to shield the metal from reacting to environmental factors so that welding is faster and continuous. The shielding gas also creates less welding fumes.
Tungsten Inert Gas Welding (TIG), also called Gas Tungsten Arc Welding, uses a tungsten electrode rod that creates a short arc to weld heavier metals, for heavy fabrication. This method requires a highly skilled welder, as the process is more difficult, but can it be used on most metals and for complex projects.
Flux Cored Arc Welding (FCAW) has a similar process and equipment as MIG welding. The wire electrode used contains a core that produces shielding gas, so a secondary gas source is not needed. This method is more portable than MIG or Stick welding but can’t be used on thinner metals.