Types of metal forming in metal fabrication

• Forging: The shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed (i.e. cold, warm, or hot forging)

• Rolling: The process in which metal stock is passed through a set of roll to reduce the thickness is known as rolling. Rolling is classified according to the temperature of the metal rolled. If the temperature is above its recrystallization temperature then the process is known as hot rolling and if below then cold rolling.

• Extrusion: The process of creating objects of a fixed cross-sectional profile is known as Extrusion. A material is pushed or drawn through a die of the desired cross-section.

• Drawing: The process of forming sheet metal into shapes or stretched over a form is known as drawing. Deep drawing is a type of drawing where the depth of the part can be greater than its diameter. Deep drawing is generally done in multiple steps called draw reductions.

• Bending: The process of producing V-shape, U-shape, or channel shape along a straight axis in ductile material, most commonly Metal is known as bending. During bending, the workpiece is bent to form flanges, contours, curls, seams, corrugations and other geometries by means of applying force through hydraulic, pneumatic and electrical machines.

• Spinning: The process in which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part is known as spinning. Spinning can be performed by CNC lathe.

Metal Fabrication Methods

Fabrication includes several processes of manufacturing metal components by changing the raw material using various tools. Metal fabrication processes can be classified as cold, warm, and hot working depending on the temperature at which the material is processed. The factors influencing the metal fabrication process included the type of material being machined, the rate of production, the desired geometry and other physical requirements of the part. The emergence of CNC (Computer numerical control) technology brought automation and greater accuracy to these techniques.

Metal fabrication can be divided into the following categories:

1) Metal Forming: Any manufacturing process by which parts of components are fabricated by shaping or molding a piece of metal is known as metal forming.

2) Shearing: The process in which machines equipped to perform shearing action on metals cuts can create strips and free-form shapes for use in the manufacturing process, or shearing action can make holes within metal sheet to create ventilation covers or other specialized equipment from one metal sheet instead of distinct parts.

3) Material Removal: The process in which a cutting tool removes unwanted material from a workpiece to produce the desired shape. The workpiece is typically cut from the larger piece of stock, which is available in a variety of standard shapes.

4) Advanced Methods: There are some of the advance methods which are used for metal fabrication. They are

a) Laser Cutting: Laser cutting involves focusing a beam of high density energy on the surface of the workpiece. The beam evaporates portions of the workpiece in a controlled manner.

b) Electro Discharge Machining: Electro discharge machining is based on erosion of metal by spark discharges. This process can be used for machining any material which is an electrical conductor.

c) Wire EDM: The wire EDM or Electro Discharge Machining produces part shapes by cutting a metal work piece with a continuously moving wire by means of rapid, repetitive spark discharges. This process is used to cut thin and thick metal and is often used to make punches, tools and dies from hard metals.

d) Waterjet Cutting: In this process, the force of a water jet is used to cut material. The water jet acts like a saw and cuts narrow kerfs in the workpiece. Most of metals, plastics, fabrics, wood products, rubber, insulating material, leather, brick and composite materials can be cut using the waterjet process.

Laser Cutting

Laser Cutting:

Laser cutting is a cutting process that severs material with the heat obtained by directing a laser beam against a metal surface. Hence laser cutting is a technology that uses a laser to cut materials, and is typically used for industrial manufacturing applications. Laser cutting works by directing the output of a high power laser, by computer, at the material to be cut. The material then melts, burns, vaporizes away, or is blown away by a jet of gas, leaving an edge with a high quality surface finish.

Types of material used in Laser Cutting:

• Carbon dioxide laser (CO2): The CO2 laser produces a beam of infrared light with the principal wavelength bands. CO2 lasers are frequently used in industrial applications for cutting, boring, scribing, and engraving.

• Neodymium-doped laser (Nd): Nd lasers are used where high energy but low repetition speed are required around 1 kHz and also used for boring.

• Neodymium-doped Yttrium Aluminum Garnet laser (Nd:YAG): The Nd:YAG is a crystal that is used as a lasing medium for solid-state lasers. Nd:YAG lasers are frequently used in Medicine, Dentistry, Military and defense, manufacturing applications for very high energy pulses, boring, engraving, and trimming.

Methods to cut metals using Laser Cutting:

There are many different methods to cut metal using lasers. Some of the methods are vaporization, melt and blow, thermal stress cracking, reactive cutting etc.

• Vaporization Cutting: The process where a focused beam heats the surface of the material to boiling point and generates a keyhole. As the hole deepens and the material boils, vapor generated erodes the molten walls blowing eject out and further enlarging the hole. Non melting material such as wood, carbon and thermoset plastics are usually cut by this method.

• Melt and Blow: The process in which a high pressure gas is used to blow molten material from the cutting area, greatly decreasing the power requirement. First the material is heated to melting point then a gas jet blows the molten material out of the kerfs avoiding the need to raise the temperature of the material any further. Materials cut with this process are usually metals.

• Thermal stress cracking: The process a beam is focused on the surface causing localized heating and thermal expansion. This results in a crack that can then be guided by moving the beam. It is usually used in cutting of glass.

• Reactive Cutting: It is also known as burning stabilized laser gas cutting or flame cutting. The process in which oxygen torch with a laser beam as the ignition sources is used. It is mostly used for cutting carbon steel in thickness over 1mm. This process can be used to cut very thick steel plates with relatively little laser power.

CNC Router

What is CNC Router

A CNC router is a computer controlled tool for cutting various type of product such as wood, plastic, aluminum, steel and other kinds of metal. CNC routers comes in many configurations including the small home style known as “Desktop CNC Router” to the larger ones known as “Gantry CNC Routers” which are used on boat making facilities. Though there are many configurations, still most of the CNC routers have a few specific parts in common, likes CNC controller, one or more spindle motors, AC inverters, and a table. Generally CNC routers are available is 3 axis and 5 axis formats.

CNC router works like a printer. Work is composed on a computer and then the design or drawing is sent to the CNC router for the hard copy. As CNC routers are run and controlled by a computer, coordinates are uploaded into the machine controller from a separate program. There are basically two programs used, one to make designs and another to upload designs to the machine and run it. CNC routers can be run and controlled directly by manual programming, but the full potential of the machine can only be achieved if they are controlled from the file created by the CNC software (such as “CAD/CAM”).

Advantages of CNC routers:

1) Can be very useful when carrying out identical, repetitive jobs.

2) Produces consistent and high quality work and improves factory productivity.

3) Can reduce waste, frequency of errors and the time the finished product takes to get to market. For Example: CNC routers can perform the tasks of many carpentry shop machines such as the Panel saw, the spindle molder, the tunnel boring machine, and can also cut mortises and tennons.

4) Gives more flexibility to the manufacturing process.

5) Can be used in production of many different items, such as door carvings, interior and exterior decorations, wood panels, sign boards, wooden frames, moldings, musical instruments, furniture manufacturing and many more.

6) Can also make thermo-forming of plastics by simply automating the trimming process.

G Code-A Code used in CNC Programming

G-code is the common name for the most widely used numerical control program language. G-codes are also called as preparatory codes, and are any word in a CNC program that begins with the letter “G”. G-code’s programming environments have evolved in parallel with those of general programming from the earliest environments like writing a program with a pencil or typing it into a tape puncher to the latest environment that stack CAD, CAM and richly featured G-code editors.

Generally it is a code telling the machine tool what type of action to perform, such as:

• Rapid Move

• Controlled feed move in a straight line or arc

• Series of controlled feed moves that would result in a hole being bored, a work piece cut(routed) to a specific dimension, or decorative profile shape added to the edge of a work piece

• Set tool information such as offset

G-code began as a limited type of language that lacked constructs such as loops, conditional operators, and programmer-declared variables with natural-word-including names (or the expressions in which to use them). It was thus unable to encode logic; it was essentially just a way to “connect the dots” where many of the dots’ locations were figured out longhand by the programmer. The latest implementations of G-code include such constructs, creating a language somewhat closer to a high-level programming language. The more a programmer can tell the machine what end result is desired, and leave the intermediate calculations to the machine, the more s/he uses the machine’s computational power to full advantage.

CNC Plasma Cutting

What is Plasma Cutting?

Plasma cutting is a process of cutting steel and other metals of different thickness using a plasma gun. A plasma gun is also known as Plasma Arc or Plasma torch. Inert gas is blown at a very high speed out of the nozzle, and at the same time an electric arc is formed through that gas from the nozzle to the surface being cut, turning some of the gas into plasma. The generated plasma is sufficiently hot to melt the metal being cut and also moves so fast to blow away the molten metal from the cut.

Plasma cutting is used in different applications and is an effective means of cutting thin and thick materials alike, hand-held guns can usually cut up to 2 inch (48mm) thick steel plate, and stronger computer controlled guns can cut metals up to 6 inches (150mm) thick.

What is CNC Plasma Cutting Machine?

A CNC plasma cutting machine is an example of automatic and high efficiency cutting equipment. It is widely used in all kinds of Carbon materials, Stainless steel, Iron sheet, Aluminum sheet, Galvanized sheet, Titanium plate, and non-ferrous precision sheet metal cutting.

What is CNC Plasma Cutting Table?

CNC plasma cutting machines usually come with CNC Plasma cutting tables. The CNC plasma cutting table is a robotic table that incorporates the use of the hand help cutter. It is easy to maintain and also offer few additional features. Some of the features are listed below.

Features of CNC Plasma Cutting Table:

1) Variable speed and gears that can provide accurate motion in any direction
2) Rigid, yet lightweight parts that offer variable speeds of cutting and precise cutting with each speed
3) Some incorporate height capabilities to where the tip will not get hung up and in the end, no human interaction

Each manufacturer of a CNC plasma cutting table offers their own system to go with it. The computer software program, etc, is designed to work together with the table. As a whole unit, these systems can help to improve the business by offering unique capabilities which can be used to produce one of a kind masterpieces or specialty parts. The CNC plasma cutting tables offers repetitive capabilities that are precise with each and every cut. This type of computer numerical controlled technology and robotic technology that has been combined together to develop a system is absolutely unbelievable and unbeatable.

Some of the Advantages using this CNC Plasma cutting table:

1) Increase productivity while eliminating production costs and waste material cost.
2) Being able to use more of the materials by cutting all needed elements out of the same sheet.
3) Save the program for a specific project and can be used later with the assurance that the end product will be exact same as the one produced earlier.