Understanding Metal Stamping
Metal stamping is a

cold-forming process that makes use of dies and stamping presses to transform sheet

metal into different shapes. Pieces of flat sheet metal, typically referred to as

blanks, is fed into a sheet metal stamping press that uses a tool and die surface

to form the metal into a new shape. Production facilities and metal fabricators

offering stamping services will place the material to be stamped between die

sections, where the use of pressure will shape and shear the material into the

desired final shape for the product or component.
This article describes the metal stamping process and steps, presents the types

of stamping presses typically employed, looks at the advantages of stamping

compared to other fabrication processes, and explains the different types of

stamping operations and their applications.


Basic Concepts of Metal Stamping


Metal stamping, also referred to as pressing, is a low-cost high-speed

manufacturing process that can produce a high volume of identical metal components.

Stamping operations are suitable for both short or long production runs, and be

conducted with other metal forming operations, and may consist of one or more of a

series of more specific processes or techniques, such as:


Punching


Blanking


Embossing


Coining


Bending


Flanging


Punching and blanking refer to the use of a die to cut the material into

specific forms. In punching operations, a scrap piece of material is removed as the

punch enters the die, effectively leaving a hole in the workpiece. Blanking, on the

other hand, removes a workpiece from the primary material, making that removed

component the desired workpiece or blank.


Embossing is a process for creating either a raised or recessed design in sheet

metal, by pressing the raw blank against a die that contains the desired shape, or

by passing the material blank through a roller die.


Coining is a bending technique wherein the workpiece is stamped while placed

between a die and the punch or press. This action causes the punch tip to penetrate

the metal and results in accurate, repeatable bends. The deep penetration also

relieves internal stresses in the metal workpiece, resulting in no spring back

effects.


Bending refers to the general technique of forming metal into desired shapes

such as L, U, or V-shaped profiles. The bending process for metal results in a

plastic deformation which stresses above the yield point but below the tensile

strength. Bending typically occurs around a single axis.


Flanging is a process of introducing a flare or flange onto a metal workpiece

through the use of dies, presses, or specialized flanging machinery.


Metal stamping machines may do more than just stamping; they can cast, punch,

cut and shape metal sheets. Machines can be programmed or computer numerically

controlled (CNC) to offer high precision and repeatability for each stamped piece.

Electrical discharge machining (EDM) and computer-aided design (CAD) programs

ensure accuracy. Various tooling machines for the dies used in the stampings are

available. Progressive, forming, compound, and carbide tooling perform specific

stamping needs. Progressive dies can be used to create multiple pieces on a single

piece simultaneously.


The Basics of Metal Stamping



Metal stamping

is a manufacturing process used to convert flat metal sheets into specific shapes.

It is a complex process that can include a number of metal forming techniques —

blanking, punching, bending and piercing, to name a few.


There are thousands of companies across the U.S. that offer metal stamping

services to deliver components for industries in automotive, aerospace, medical,

and other markets.As global markets evolve, there is an escalated need for

quickly-produced large quantities of complex parts.


Stamping Basics


Stamping — also called pressing — involves placing flat sheet metal, in

either coil or blank form, into a stamping press. In the press, a tool and die

surface form the metal into the desired shape. Punching, blanking, bending,

coining, embossing, and flanging are all stamping techniques used to shape the

metal.


Before the material can be formed, stamping professionals must design the

tooling via CAD/CAM engineering technology. These designs must be as precise as

possible to ensure each punch and bend maintains proper clearance and, therefore,

optimal part quality. A single tool 3D model can contain hundreds of parts, so the

design process is often quite complex and time-consuming.


Once the tool’s design is established, a manufacturer can use a variety of

machining, grinding, wire EDM and other manufacturing services to complete its

production.


Types of Metal Stamping


There are three major types of metal stamping techniques: progressive,

fourslide and deep draw.


Progressive Die Stamping


Progressive die stamping features a number of stations, each with a unique

function.


First, strip metal is feds through a progressive stamping press. The strip

unrolls steadily from a coil and into the die press, where each station in the tool

then performs a different cut, punch, or bend. The actions of each successive

station add onto the work of the previous stations, resulting in a completed part.



Multi-product inspection


A manufacturer might have to

repeatedly change the tool on a single press or occupy a number of presses, each

performing one action required for a completed part. Even using multiple presses,

secondary machining services were often required to truly complete a part.


Traditional machine vision solutions are designed to inspect only one item at a

specific point on the production line. This makes them unpractical for a sector

such as plastic

injection moulding, where the same production line can potentially make

various products that come in varying shapes and forms.


However, Inspekto TYPES?, one of the many apps that can be installed on the

S70, allows plastics manufacturers to overcome this issue. While traditional

machine vision solutions can only monitor one product at any given location on the

production line, an S70 system installed with TYPES? is able to inspect any number

of products — even tens or hundreds of different products — at that same location

on the line.


Emerging from the traditional constraints of one-product-per-solution, AMV

allows manufacturers to inspect a variety of items with one single system,

something that was unthinkable until recently.


Self-adjusting camera parameters


Another typical problem in this sector is achieving the correct lighting of the

parts to be inspected. Typically, injection moulds have smooth, highly reflective

surfaces that resemble mirrors. Additionally, moulds can be the same colour of the

plastic polymer, or can appear that way because of a lack of contrast due to

insufficient illumination of the inside of the mould.


Finally, moulding machines are built to be as compact as possible, so that they

will open just enough to eject the part, but not enough to guarantee adequate

illumination for visual QA.


All these challenges make inspection hard for traditional QA solutions, but not

for AMV systems, which are designed to self-adjust their camera parameters to

obtain perfect lighting, focus and contrast. In this way, the plastic parts can be

illuminated in a way that clearly differentiates one from the other, allowing the

system to perform effective visual QA in total autonomy.



An assembly line is a manufacturing process in which interchangeable parts

are added to a product in a sequential manner to create an end product. In most

cases, a manufacturing

product assembly line is a semi-automated system through which a product

moves. At each station along the line some part of the production process takes

place. The workers and machinery used to produce the item are stationary along the

line and the product moves through the cycle, from start to finish.




Assembly line methods were originally introduced to increase factory

productivity and efficiency. Advances in assembly line methods are made regularly

as new and more efficient ways of achieving the goal of increased throughput (the

number of products produced in a given period of time) are found. While assembly

line methods apply primarily to manufacturing processes, business experts have also

been known to apply these principles to other areas of business, from product

development to management.




The introduction of the assembly line to American manufacturing floors in

the early part of the twentieth century fundamentally transformed the character of

production facilities and businesses throughout the nation. Thanks to the assembly

line, production periods shortened, equipment costs accelerated, and labor and

management alike endeavored to keep up with the changes. Today, using modern

assembly line methods, manufacturing has become a highly refined process in which

value is added to parts along the line. Increasingly, assembly line manufacturing

is characterized by "concurrent processes"—multiple parallel activities

that feed into a final assembly stage. These processes require sophisticated

communications systems, material flow plans, and production schedules. The fact

that the assembly line system is a single, large system means that failures at one

point in the "line" cause slowdowns and repercussions from that point

forward. Keeping the entire system running smoothly requires a great deal of

coordination between the parts of the system.