Fast, accurate sheet metal inspection
To achieve consistent, reliable and traceable quality assurance for sheet metal measurement, 3D scanning and inspection offers a fast, accurate and resource-effective method.
Using industry-leading GOM 3D scanning systems, we provide a complete range of measurement and inspection services, from determining the sheet metal properties via accelerating tool-try-out and first article inspection, up to series-accompanying production control and trend analysis. All our highly-trained engineers have experience in producing a variety of industry-specific inspection reports.
3D Scanning Techniques
The high-resolution capture of 3D scan data is achieved through GOM's ATOS III Scan blue light fringe projection technology. For a single component, or for small numbers of parts, we offer a mobile 3D scanning service at your facility, which ensures that your production cycle has the minimal disruption possible. For batch inspection, our automated 3D scanning cell, the ScanBox 5120, allows for fast, accurate inspection, which provides information on accuracy and repeatability and informs the understanding of process variations.
What is sheet metal?
Sheet metal is defined as the thin, flat pieces of metal which have been formed using an industrial process. Popular sheet metals for forming processes are aluminium, stainless and mild steel, and are often used for architectural purposes. Physical Digital is able to accurately measure sheet metal formed by any of the following processes:
Bending occurs when a force is applied to a piece of sheet metal, causing it to bend at an angle to form the proposed shape.
Roll bending produces a cylindrical shaped product from plate or steel metals. The three roll benders “pinch” the flat workpiece between two rolls, bending it as it comes into contact with a forming roll, into a cylindrical form. It is then welded together to produce a cylinder and caps are then joined on to product tanks.
Deep drawing is a metal forming process where sheet metal is stretched into a chosen part shape. A tool pushes down on the sheet metal which forces it into a die cavity in the shape of the proposed part. The tensile forces applied to the sheet cause it to plastically deform into a cup-shaped part. These parts can have a variety of cross sections with straight, tapered, or even curved walls, but rectangular or cylindrical parts are most common.
Hydroforming is a process that is similar to deep drawing, in that the part is formed by stretching the blank over a stationary die. The force required to do so is generated by the direct application of extremely high hydrostatic pressure to the workpiece or to a bladder that is in contact with the workpiece, rather than by the movable part of a die in a mechanical or hydraulic press. Unlike deep drawing, hydroforming usually does not involve draw reductions - the piece is formed in a single step.
Stretch forming is whereby a piece of sheet metal is stretched and bent simultaneously over a die in order to form large contoured parts. Carried out on a stretch press, the sheet metal is attached to a carriage and securely gripped along its edges to be pulled by pneumatic or hydraulic force to stretch the sheet. Stretch forming is capable of shaping parts with smooth surfaces and very high accuracy.
Plasma cutting uses a focused stream of ionized gas, or plasma, to cut through sheet metal. The plasma flows at extremely high temperatures and high velocity and is directed towards the cutting location by a nozzle. When the plasma contacts the surface below, the metal melts into a molten state. The molten metal is then blown away from the cut by the flow of ionized gas from the nozzle. The position of the plasma stream relative to the sheet is precisely controlled to follow the desired cutting path.
Laser cutting uses a high powered laser to cut through sheet metal. A series of mirrors and lenses direct and focus a high-energy beam of light onto the surface of the sheet where it is to be cut. When the beam strikes the surface, the energy of the beam melts and vaporizes the metal underneath, and any remaining molten metal or vapour is blown away from the cut by a stream of gas. The position of the laser beam relative to the sheet is precisely controlled to allow the laser to follow the desired cutting path.
Photochemical machining, also known as photo etching, is a tightly controlled corrosion process which is used to produce complex metal parts from sheet metal with very fine detail. The photo etching process involves photo sensitive polymer being applied to a raw metal sheet. Using CAD designed photo-tools as stencils, the metal is exposed to UV light to leave a design pattern, which is developed and etched from the metal sheet.
Press brake forming
While using a press brake and standard die sets, there are still a variety of techniques that can be used to bend the sheet. The most common method is known as V-bending, in which the punch and die are "V" shaped. The punch pushes the sheet into the "V" shaped groove in the V-die, causing it to bend. If the punch doesn’t force the sheet to the bottom of the die cavity, leaving space or air underneath, it is called "air bending". As a result, the V-groove must have a sharper angle than the angle being formed in the sheet.
Roll forming is a metal forming process in which sheet metal is progressively shaped through a series of bending operations. The process is performed on a roll forming line in which the sheet metal stock is fed through a series of roll stations. The roller dies may be above and below the sheet, along the sides, at an angle, etc. As the sheet is forced through the roller dies in each roll station, it plastically deforms and bends. Each roll station performs one stage in the complete bending of the sheet to form the desired part.
Spinning, sometimes called spin forming, is a metal forming process used to form cylindrical parts by rotating a piece of sheet metal while forces are applied to one side. A sheet metal disc is rotated at high speeds while rollers press the sheet against a tool, called a mandrel, to form the shape of the desired part. Spun metal parts have a rotationally symmetric, hollow shape, such as a cylinder, cone, or hemisphere.
Punching is using a tool that is forced into a piece of sheet metal in order to shear or deform the material. Punches are available in many shapes and sizes and can be used for a variety of processes. Many punches are cylindrical and the punch diameter determines the size of the hole or pocket being formed.
Water jet cutting
Water jet cutting uses a high velocity stream of water to cut through sheet metal. The water typically contains abrasive particles to slice through the material and travels in a narrow jet at high speeds, around 2000 ft/sec. As a result, the water jet applies very high pressure (around 60,000 psi) to the material at the cut location and quickly erodes the material.
The shearing process is performed on a shear machine that can be operated manually or by hydraulic, pneumatic, or electric power. The blades used in these machines typically have a square edge rather than a knife-edge and are available in different materials, such as low alloy steel and high-carbon steel.
Hemming and seaming
Hemming is a forming operation in which the edges of the sheet are folded or folded over another part in order to achieve a tight fit. Normally hemming operations are used to improve the appearance of a part, to connect parts together, and to reinforce part edges.
Sheet metal stamping is the most common method of producing metal parts in the automotive industry due to its high production rate and low cost. In basic sheet metal stamping, a flat metal sheet is pressed to the desired shape between a die and a punch. The die is used to define the outside shape of the part, and the punch is applied to define the inside shape of the part.
Sheet metal is used in many manufacturing industries in the UK. Manufacturers, designers and production engineers need to be assured of the product’s quality and Physical Digital performs a vital role in inspection. If you have a sheet metal project for measurement or inspection, contact us or call 01483 750200 for a free quote.