Sheet metal is produced by continuous rolling mills. Sheet metal essentially consists of an extremely thin sheet of suitable material, with a high surface area to volume ratio. It is sold as coils or as rolls. Sheet metal differs from plates by its thickness; typical sheet metal is less than 5 – 6 mm while steel plates are more than 6 mm in thickness. They differ in applications as well. While steel plates are used in the construction of boilers, turbines, etc. sheet metal finds applications in the automobile sector, trains, aircrafts, house appliances, computers, machined components, and so on.
There are various processes for sheet forming that include drawing, stamping or roll forming and a few others. Sheet metal manufacturing is mostly performed on a press and the parts are formed between two dies. Irrespective of the process used, the most important point to remember is that the aim of sheet metal forming is to modify its geometry without removing any material. The applied force stresses the metal (mostly steel) to plastic deformation (yield point). As the stress generated in the material continues to grow, the plastic deformation increases. This phenomenon is called strain hardening, and the sheet material deforms plastically, but does not fail. It is this property that is of most use in the industry, and why the use of sheet metal has been on the rise. Sheet metal is extremely ductile, can be carried easily as it can be folded, is lightweight, and is economical to use. Sheet metal parts are generally characterised by high strength, good dimensional accuracy, and good surface finish. They are used extensively in the automobile industry because of their ability to undergo plastic deformation and still retain their shape.
Here are a few examples of industrial sheet metals:
Sheet Metal Forming Analysis
Sheet metal comes in various sizes, forms, and properties. Each component that is formed from sheet metal needs to have specific qualities for it to be useful. For example, the requirement for a car fender is different from that of a beverage can. Metal forming simulation is useful in determining the attributes needed of a sheet metal, and computer simulation with the help of special software is an important aspect of the part forming process. Metal forming simulation makes it possible to detect errors and rectify problems like wrinkles or splits in parts, or possible effect of impact. Since powerful software tools (like Altair Inspire Form or PTC Creo efficient parametric tools to determine the suitability of the material, it is not necessary now to produce real objects to run practical tests. Forming simulation has become established in the automotive, aerospace and food industry since it is used to develop and optimize every sheet metal part. Sheet metal parts are solid models that can be represented in either sheet metal form or as a flat model using CAD. These parts are of uniform thickness and can be modified by adding features. Good sheet metal software analysis tool include features like bend analysis, springback and hemming. In addition, they also allow you to get information about the part, calculate its mass, and analyze the engineering. Such simulation tools are useful for the entire process chain of metal forming. A designer can analyze the formability of a sheet metal part at a very early stage, resulting in designs that are easy to produce. Process engineers can optimize various parameters using the simulation tool in the planning phase itself. Most software also provides fine tuning tools that allow tweaking of process parameters. The end result is a simulated product that is close to the real, optimal product. Since actual production comes at the last stage, simulation software saves both time and money for the manufacturing company.
Sheet metals play a crucial role in the automobile and the aerospace sector, and continue to be an important component of the manufacturing process in general. The material needs to be light enough so as to reduce fuel consumption, but at the same time be sturdy enough to withstand severe impact. A few desirable properties include:
A good sheet forming material needs to have adequate tensile and bending strength, yield strength, sheet and compressive strength, and hardness. In the era before sophisticated simulation tools were available, determining the perfect combination of material, thickness and the process used for forming was mostly a matter of trial and error. Companies spent a lot of money in developing a prototype physically and then test it under various conditions. Today's software has mitigated that need considerably. However, not every company has the tools or the means to opt for a proper metal sheet forming simulation software. Such companies rely on the expertise of engineering services provided by reputed companies from India, Singapore and other parts of the world for proper selection of sheet material and its related properties.