What are Metal Stamping Dies and Its Functions?
Metal stamping dies are tools used to manufacture high-volume sheet metal components. The press on which the metal stamping dies are fixed, provides the force to close the precision metal stamping dies which shape and cut the metal into the desired components. Generally, stamping is performed using sheet metal materials with a thickness of .020 inches to .080 inches. This process can also be applied to plate stock with thickness’ approaching 1.000 inches or to foils as thin as .001 inches. The primary attribute of sheet metal material is formability. Formability can be defined as the materials ability to be bent, stretched, or drawn.
Although ductility is one factor that affects a parts overall shape and geometry, the die design too has an effect.
Metal Stamping Dies
The word “die” is a broad term that describes the tooling used to manufacture stamped components. A die set assembly consisting of a male and a female part work in conjunction with each other to form and punch holes in the stock. The upper half of the die set, which could be either the male or female and is mounted on to the press ram which delivers the stroke action. The lower half is attached to a bolster plate which is in turn secured to the press bed. To ensure alignment between the lower and upper halves of the die, set guide pins are used.
Sheet Metal Stamping Dies and its Process
The most common types of metal stamping dies carry out forming and cutting operations. Cutting dies shear sheet material into what is termed as a blank. After this process, these blanks are exposed to blanking dies which cut the entire edge of the component where the blank is stamped into a part. Punching is basically another function of cutting dies. Punching cuts off the slug from the metal stock to produce a slot or a hole.
Cutting dies are used to trim extra metal from around a shaped part. Other cutting operations along with hole punching require carefully maintained, specific clearances between the male component and the female component. The settings required for clearance is determined by both the temper and the stock thickness. Generally, as the stock thickness increases the die clearances too increase. As the softer stock is used the punch penetration into the sheet metal stock will correspondingly increase.
Forming is a term used to describe a stamped part whose contour and shape are reproduced directly from the shape and contour of a metal stamping die set. The main forming operations performed by metal stamping dies are bending, drawing, flanging, hemming, drawing or draw forming. These functions involve forcing a blank into a die cavity deeply and shaping it into the contour and shape of the punch sides and face. If the formability qualities are not sufficient, drawn blanks are subject to thinning, wrinkling and fracturing.
Multiple stamping operations could be performed within a single metal stamping die or at a number of die stations with a single stroke of the press. Single station dies can either be combination dies or compound dies. Basic cutting operations such as hole punching and blanking is performed by a compound die. Combination dies combine forming and shaping functions with cutting operations to produce components.
The moving dies create friction because of the resistance of the sheet metal stock. Therefore, lubrication is imperative for successful precision metal stamping. Lubrication ensures minimum contact between the workpiece and the tooling. This results in a longer tooling life, reduced tonnage requirements, and improved product quality. Lubricants may be water soluble, oil base or synthetic materials. These lubricants may be applied by roller or brush, drip, spraying, machine roller, flooding or even manually.
Die making is a beautiful blend of art and science. Precision metal stamping depends on metal stamping dies to produce parts. And we depend on those parts made by metal stamping dies for most of the objects we use in our daily life.