Sheet metal is one of the most essential materials used in almost all applications that surround us today. They are of different types with different properties, making their forming process and uses broad. Sheet metals are seen on automobile and truck (lorry) bodies, medical tables, airplane fuselages, and wings, roofs for buildings (architecture), and many other applications.
Choosing a specific forming process for a sheet metal depends on the required outcome. Many of the method explained below gives a similar result, but their cost may differ based on batch sizes, availability, and desired accuracy.
Today we’ll be looking deep into the different methods of sheet metal forming processes and how they are done.
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Sheet metals forming processes
Although there is a wide range of metal production services available, it is crucial to select the one that best suits your requirements while being affordable. The information provided here is all intended to assist you in carrying out that task. The various processes for sheet metal forming include the ones listed below;
Bending
bending is achieved when sheet metal is bent into the desired shape due to bending stress. It is bent so that plastic deformation can be reached, which prevents the metal from retaining its former shape.
Bending can be done with a V-die, thus v-bending. It is the common form of bending, giving a desired shape when used with a punch press. This bending can be used for creating flanges and corrugations. Another common method is edge bending, using a wiping die and a punch.
Rolling
this sheet metal forming process is performed to reduce the overall thickness of the metal sheet. It also makes the material to be more uniform. To achieve this, the material must pass through a set of rollers depending on the temperature (hot rolling or cold rolling). In hot rolling, the temperature for steel is around 1400 degrees Fahrenheit. This help to obtain a thickness from 1/16th of an inch to 5/16th of an inch. Whereas in cold rolling, the process is done at room temperature. The sheet may then be washed with acid and heat treated to get a good finish.
This process is also used to get a large-radii bends, instead of using press brakes for the bending. It helps to achieve a large uniform radius without the need for continuous manual work.
Decambering
sheet metal decambering is the removal of camber from sheet metal. A sheet metal, especially in strip-shaped parts, the horizontal bend is produced when it is flattened into sheets. This horizontal bend is removed flattening the edges to cut off the camber. The force is applied on deformed edges and not on the face, in order to push it into a straight form. This is usually performed on limited-length sections.
Punching
this process is a very common technique for cutting holes in sheet metals. It consists of a punch and a punching die, having a very small clearance between the two. If the two meet, that is, the punch and the die, the material is pressed between the two, and with enough force the hole is cut. this process is relatively inexpensive in large quantities and capable of punching holes in strips as well as sheet metal.
Holes of different sizes can be made but it is recommended that the diameter of holes should be greater than the thickness of the material. Usually on sturdy alloys, the diameter and the thickness of the punched material need to be different.
Deep drawing
this sheet metal forming process occurs if the shape of the sheet is changed to a desired shape in multiple stages with a series of dies. Deep drawing is considered if the depth of the shape formed exceeds the original diameter of the sheet. It is mostly used for large-batch production when converting sheets into different shapes like sinks, tanks, automobile parts, etc.
Expanding
expanding is when a sheet of metal passed through a perforating object, which cut and stretched the sheet into a pattern. A diamond-shaped mesh is used as it offers structural benefits than other shapes. It is commonly used for producing fences, platforms, catwalks, grating, etc. This process also offers a self-draining and strong product that can support the weight it is designed for. Products that undergo expansion is often seen where the passage of air or liquid is needed, but larger particle will be prevented from passing, e.g. sifting.
Curling
The curling method is implied when trying to form an edge on a ring on a sheet metal. It is also used to remove sharp edges and increases the moment of inertia near the curled end.
There is a difference between the two common edge curled edges and a tear-shaped hem. The initial edge is rolled into the formed circle in curling whereas, in a tear-shaped hem, the initial edge is still opened.
Curling is still classified into off-center and on-center rolls. where the off-center rolls have the center above the level of the sheet, whereas on-center rolls have the center at the same level as that of the metal sheet.
Wheeling
in this process, the English wheel is used to stretch and curve flat sheet metals into required shapes. The wheeling method requires highly skilled labor, making it expensive. However, the method cannot be used for mass production, it is mainly used for producing low-volume customized parts. It is also used for producing sheet metal parts for aircraft and car prototypes. This is done in stages and in each stage; the operator is expected to compare the form piece with the original shape.
Hydro-forming
hydro-forming process is the advanced way of shaping sheet metals into desired shapes like conventional shapes. It is done by placing the metal on a die, using a high-pressure fluid to shape the sheet. A good advantage of this sheet metal forming process is that more complex parts can be created in a short time frame. It is also cheaper as it requires less work. The process is also compatible with almost all materials such as stainless steel, brass, carbon steel, etc.
Ironing
this process is implied when the thickness of the sheet must be reduced in a certain area. It helps the manufacturer to obtain uniform wall thickness when deep drawing the products. Ironing is often done when producing soda cans, as they can need to be thinned at a predetermined thickness. 2 to 3 ironing processes with different dies are needed to create desired thickness in aluminum soda cans. The process is carried out with a combination of deep drawing.
Laser cutting
when cutting is mentioned in the sheet metal forming process, the laser is often used. in most cases, CNC machines are generally used to cut specific shapes. The process is precise and the finish is extremely smooth. As the is cut by laser flexibility is attained, which is one of its advantages. It is also possible to cut the metal sheets into extremely complex pieces using the process when needed.
Photo-chemical machining
this process is the control of corrosion on sheet metal parts as per requirements. It uses etchant and photo-resist to give the metal sheet its shape. This method was developed in the 60s which is a comparatively inexpensive method today. The good benefits of the process are that it can be used to cut any metal and it is ideal for mass production. Just as laser cutting, photo-chemical machining is extremely precise and offers a smooth finish. It is used in making fine meshes, apertures, flexible heating elements, metal gaskets, electrical contacts, and jewelry.
Press brake forming
the press brake forming makes a long sheet of metal get bent around a straight axis going through the material. The operation might look easy, but precision bending is a difficult task to carry out in this process.
Well, material properties may be considered along with the press and the tooling to perfect the amount of spring back. The press brake forming can be perfectly used for smaller parts which will make it suitable for smaller pieces along with large ones.
Incremental
incremental forming is a metalworking process that is carryout to give sheet metals a certain shape. Although, it is only viable with low volumes, as the product is formed in incremental steps. In this process, changes can be made to the product quickly without much hassle. the incremental method is more flexible. This process offers similar results to that of deep drawing, making punches and dies valueless.
That’s for this article “Sheet metal forming processes”. I hope you enjoyed the reading, if so, kindly comment and share with other students. Thanks!
