Sheet metal fabrication is the process of creating metal structures and components by cutting, bending, and shaping metal sheets. Steel, aluminum, brass, copper, or titanium are the most common metals used in metal sheets.
The resulting sheet metal components can be used for a variety of purposes, including structural support, enclosures, and other applications. It has become increasingly popular for rapid prototyping due to its flexibility and relatively low cost compared to other manufacturing processes.
Sheet Metal Fabrication Techniques Used in Rapid Prototyping
Rapid prototyping creates a physical model or prototype of a product or part using computer-aided design (CAD) data. This process allows designers and engineers to test and refine their designs, identify potential issues, and make necessary changes before moving to full-scale production quickly and cost-effectively.
All sheet metal fabrication techniques can be used in prototyping manufacturing. The major sheet metal fabrication techniques involve cutting, bending, forming, stamping, and joining.
1. Cutting
Sheet metal cutting is a technique used in sheet metal manufacturing that is also known as shearing. There are multiple ways to cut sheet metal, but nowadays, computer technology is commonly used to achieve precise cuts. CNC (Computer Numerically Controlled) laser cutting and multi-tool CNC punch press are the most common methods used for sheet metal cutting.
2. Forming
It involves using mechanical tools, air or liquid pressure, magnets, or explosives to transform a flat metal sheet into the desired shape. Specialized forming techniques such as superplastic forming, press hardening, and hot forming are also available. Typically, one or more of these forming processes are utilized to create a rapid prototyping part made of sheet metal.
3. Stamping
Sheet metal stamping is a method used in sheet metal fabrication that involves utilizing a stamping tool or a die to transform the sheet metal into a desired three-dimensional shape using cold-forming techniques. The sheet metal stamping process can involve various techniques such as blanking, punching, embossing, bending, flanging, and embossing.
4. Joining
Once various sheet metal parts have been fabricated separately, they must be joined together, which usually requires welding. Welding is a process that involves partially or entirely heating or deforming the sheet metal part or heating and deforming it simultaneously to create a permanent connection. Various sheet metal welding techniques exist, including metal inert gas (MIG) welding, tungsten inert gas (TIG) welding, stick welding, plasma arc welding, laser and electron beam welding, gas welding, and others.
Another way to join sheet metal parts is through riveting or using hardware fasteners.
Advantages of Sheet Metal for Rapid Prototyping
Cost-effectiveness
Sheet metal is a type of thin and flat metal material with a uniform thickness of no more than 6mm. It is often less expensive than solid blocks of metal used in CNC machining no matter if the quantity is large or small.
Also, sheet metal can be easily processed into different shapes and sizes, which reduces material waste and production costs.
Short turnaround time
With computer-controlled machinery, sheet metal can be fabricated easily and quickly. Sheet metal fabrication often involves a streamlined workflow, with multiple steps in the process being performed in parallel. So the lead times are short.
Flexibility in design
With a wide range of materials and techniques that cut, bend, form, and weld sheet metals into complex shapes and geometries, sheet metal fabrication brings flexibility to design for engineers and designers. Also, custom tooling can be created to fabricate sheet metal into unique shapes or configurations that are not possible using standard tooling.
Challenges and Considerations in Sheet Metal Fabrication for Rapid Prototyping
1. Limitations of sheet metal fabrication for rapid prototyping
Material limitations
Sheet metal fabrication is typically limited to certain materials, such as steel, aluminum, copper, or brass. While these materials are widely available and have many desirable properties, they may not be suitable for all applications or design requirements.
Material thickness limitations
It is typically best suited for relatively thin materials, such as sheets of metal ranging from a few hundredths to a few millimeters in thickness. Thicker materials may require specialized equipment or techniques, which can be more expensive and time-consuming. Or you may need to turn to CNC machining instead.
Complexity of design
While sheet metal fabrication can produce complex shapes and geometries, there are some limitations to the complexity of design that can be achieved. For example, tiny features or intricate details may be difficult or impossible to fabricate with sheet metal, particularly when using traditional cutting, bending, and forming techniques.
Tooling limitations
Sheet metal fabrication requires tooling, such as dies, punches, and molds, to create the desired shapes and geometries. However, creating custom tooling can be expensive and time-consuming, which may be a limitation for rapid prototyping applications that require quick design iterations and changes.
Tolerance limitations
Sheet metal fabrication can produce parts with high precision and accuracy, but there are limits to the tolerances that can be achieved. Very tight tolerances may require specialized equipment or techniques such as CNC machining, which can be more expensive.
2. Material selection and design considerations
Sheet metal fabrication is always the optimal choice for metal products with a uniform thickness. The common sheet metal materials are usually steel, aluminum, and copper. However, the thickness of the sheet metal will affect its strength and stiffness.
Thicker sheets can provide more strength but may be more difficult to bend and form. Thinner sheets may be easier to work with but may not provide enough strength for the desired application.
Designing for sheet metal fabrication requires consideration of how the part will be made. Designers should consider factors such as the location and size of features, the number of bends and folds required, and the tolerances that can be achieved. This can help ensure that the final part is both functional and easy to manufacture.
The surface finish of the final part can affect its appearance, corrosion resistance, and other properties. Designers should consider factors such as the type of finish, such as painting or anodizing, and the roughness of the surface acceptable for the application.
Final Thoughts
With sheet metal fabrication, the rapid prototyping of metal products with uniform thickness can be cost-effective and fast, which helps engineers and designers speed up the product development cycle and save costs. Professional fabricators can easily have all the work done from fabrication to surface finishing.
