Metal stamping is a great manufacturing method for sheet metal components and products. This guide will help you avoid basic mistakes and find success for your business
There is a wide range of manufacturing methods used by different industries across the world. However, metal stamping is emerging as a preferred option due to a number of reasons, especially as the demand for different metal components, parts and products has been on a steady rise.
It can be an intimidating concept, especially if you are stepping into the process for the first time. In this article, we will provide a complete guide that will help you know the essentials of the process and how to apply it successfully in your industry.
It is, in simple terms, a process of manufacturing metal components, parts, objects, products, and replicas of metal designs. Due to the rising demand for these parts, manufacturing methods have had to become both rapid and reliable while keeping up with higher supply demands. This is where stamping emerges as a favorable process to transform flat metal sheets into visually appealing shapes.
Stamping is also called pressing as it involves putting sheets of flat metal through a stamping press, either in blank or coil form. In the stamping press, there’s a tool and die surface that turns the metal into specific shapes. The press is the driver of a die. The piece part is the part created by pressing the metal sheet between the dies.
Before the metallic material is created, experts are required to draw up the tool using CAD/CAM technology. It’s of the utmost importance for these designs to be precise and accurate. It’s also crucial to note that a single-tool three-dimensional model may be made of hundreds of components. So, it is natural for the design process to involve some time-consuming sub-processes and complexities.
Designing a metal part generally involves the following processes:
Stamping techniques are of four major types, which are described below:
This type of stamping comprises a couple of stations, each of which has a distinct function. The metal strip is first passed through a press and then unrolled into a die press. This is the stage where each of the stations performs a separate cutting, punching, or bending function. The actions taking place in each station add to the work of the preceding stations, thereby creating a complete part. This type of stamping is ideal for creating metal components having complex geometrical specifications. They help manufacturers achieve lower labor costs, faster turnaround, higher repeatability, and shorter run length.
The deep draw stamping process requires manufacturers to pull a blank metal sheet into the die press through a punch, thereby shaping it as desired. The process gets its name from the fact that the depth of the sheet that’s drawn surpasses its diameters. In most cases, it proves more efficient and cost-effective compared to turning processes, where more raw materials tend to go into the making. Aircraft parts, automotive components, cookware and utensils, and electronic relays are made by deep draw stamping.
Four-slide stamping provides a range of benefits compared to the traditional pressing process. There are four slides, allowing the use of four different tools to complete bends simultaneously. Each shaft bends the material as soon as it is fed into a four-slide. The process is considered an ideal stamping process because of its versatility and efficiency. Manufacturers can make a number of complex parts if they can get this process right. Moreover, it proves quite a flexible option for metal parts that require frequent design alterations.
This type is ideal for manufacturers who wish to keep their upfront tooling costs as low as possible. Small projects or prototypes can be easily accomplished by following this stamping process. First, the blank is created, after which the manufacturer leverages a combination of tooling components and dies to punch, bend or drill metal parts. The small run size and customizable forming operations lead to a much higher unit charge. However, this is offset by the lower tooling expenses, which can make the process quite cost-efficient for projects that require a fast turnaround.
The steps involved in the stamping process may seem very complex, but having the right toolset can definitely ensure optimal results. Designing and producing the tool for creating the metal product is a crucial first step that manufacturers have to take. Read on to know more:
The initial tool is created following the stock strip layout, where a designer comes up with the metal strip and determines tolerances, dimensions, scrap minimization, feed direction, and other technical aspects.
The stamping process requires precision. Even the most complex of dies require repeatability. Wire electrical discharge machining (EDM) and 5-axis CNC mills can ensure tight tolerances even when cutting through hard tool steels.
During the stamping process, metal parts are subjected to heat treatment. This process is necessary to boost the strength of the parts and increase their durability. Hence, secondary processing equipment for grinding becomes crucial to ensure better surface quality and precision of finished parts. Also, a wire EDM shapes metal parts with a brass wire, which is electrically charged. This can cut through the most complex shapes, contours, and angles.
A stamping die is a precision tool that is capable of cutting and forming metal sheets into desired profiles and shapes after pressing them between components.
Stamping dies can be classified either as single-station or multi-station dies.
These dies are generally used for low-production, forming, and hand-fed single-cutting operations. These dies include both combination and compound dies. Combination dies are the dies that perform both cutting and non-cutting functions and incorporate them into a single press. A die that creates both cut and flange for metal blanks can be considered a combination die.
On the other hand, compound dies are capable of performing more than one cutting function in a single press. The use of compound dies is usually seen in the case of steel washer manufacturing, where the process requires multiple cuts on the metal.
Multi-station dies include transfer dies and progressive dies. In the case of these stamping dies, punching, cutting, and notching functions take place sequentially from the same set of die.
Transfer dies are essentially line dies timed together and spaced evenly in a single press. The distance between each pressing station or die that the piece part should travel is called the pitch. Contrary to single-station or progressive dies, multi-station dies transfer through traveling rails that are mounted within the press.
There’s another type of multi-station die called steel rule or knife dies. These dies were used for creating parts from softer materials, such as paper, leather, or cardboard. However, they are used in shaping metals, such as brass, copper, and aluminum.
In the case of steel rule dies, the steel strip used for cutting the surface is made to shape the metal as desired. The manufacturer cuts a slot into the die shoe to hold the material. The hardness and thickness of the material can help the manufacturer determine the thickness of the steel rule to make the cutting blade.
When it comes to the size of dies, the range can be from those palm-sized ones (used in manufacturing microelectronics) to those twenty square feet wide and ten feet thick (used for manufacturing auto body sides). Certain dies are capable of making more than one part per cycle. It is also important to note that the die size differs depending on the manufacturing method adopted to make piece parts.
To save cost on the stamping process, you should be careful about three main factors:
1. Material selection by considering alternative metals with properties best-suited to your application.
2. Production volume by aiming at producing more piece parts at once.
3. Secondary processes by using a manufacturer that also provides transport, additional fabrication, coating, finishing, treating, and packaging.
Metal stamping can be a complicated process depending on the nature of the application. However, as a beginner, you should be aware of the various fundamentals involved in the process. The ability to come up with a useful design depends on the choice of metal. You can choose to work with aluminum, stainless steel, or even cold-rolled steel to create high-quality metal parts and products.
Before choosing a metal, you should consider its grade, hardness, thickness, temper, weight, strength, tolerance, and corrosion resistance. Knowing the physical characteristics of each metal and determining its suitability to your application is the most important step that you as a manufacturer will have to take. When you get the initial steps right, the entire process falls into place.
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