Sheet metal is one of the most essential material 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 similar result, but their cost may differs based on batch sizes, availability and desired accuracy.
Today we’ll be looking deep on the different methods of sheet metal forming processes and how they are done.
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Sheet metals forming processes
While there is a great variety of metal production services on offer, the importance lies within finding the right fir for your needs while staying cost-effective. All the info below aims to help you do just that. The followings are the different types of sheet metal forming process;
Bending
bending is achieved when a sheet metal bent into desired shape due to bending stress. It is bent so that plastic deformation can be reached, which prevent 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 wiping die and a punch.
Rolling
this sheet metal forming process is perform 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 removing of camber from a sheet metal. A sheet metal, especially in strip-shaped parts, horizontal bend is produced when it is flattened into sheets. This horizontal bend is removed flattening the edges to cutoff 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 on sheet metals. It consists of punch and a punching die, having a very small clearance between the two. If the to 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 hole in strip 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 needs to be different.
Deep drawing
this sheet metal forming process occurs if the shape of sheet is changed to a desired shape in multiple stages with 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 sheet into different shapes like sink, tanks, automobile parts etc.
Expanding
expanding is when a sheet of metal passed through a perforating object, which cut and stretched the sheet into 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 undergoes expanding is often seen where passage of air or liquid is needed, but larger particle will be prevented from passing, e.g. sifting.
Curling
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 difference between the two common edge curled edge and a tear-shaped hem. The initial edge is rolled into the formed circle in curling whereas, in tear-shaped hem, the initial edge is still opened.
Curling are still classified into off-center and on-center roll. 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 metal sheet.
Wheeling
in this process, English wheel is used to stretch and curve flat sheet metals into required shapes. Wheeling method requires high skilled labor, making it expensive. However, the method cannot be use for mass production, it mainly used for producing low volume customized parts. It is also used for producing sheet metal parts for aircraft and car prototype. This is done in stages and 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. Good advantages of this sheet metal forming process is that more complex part can be created in 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 thickness of sheet must be reduced in certain area. It helps manufacturer to obtain uniform wall thickness when deep drawing the products. Ironing is often done when producing soda cans, as the can wall need to be thinned at a predetermined thickness. 2 to 3 ironing process with different dies are needed to create desired thickness in aluminum soda cans. The process is carried out with combination of deep drawing.
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Laser cutting
when cutting is mentioned in sheet metal forming process, 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 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 smooth finish. It is used in making fine meshes, apertures, flexible heating elements, metal gaskets, electrical contacts and jewelries.
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 be 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 use for smaller parts which will make it suitable for smaller pieces along with large ones.
Incremental
incremental forming is a metalworking process which is carryout to give sheet metals 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. incremental method is more flexible. This process offers similar result with 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!
