Sheet Metal Fabrication Software

[Rebbeca Schulke]

Learnhow to effectively design sheet metal parts. This guide starts with the basics and moves toward design best practices and advice on material selection, finishings and fastenings, with a focus on two sheet metal fabrication processes: bending and laser cutting.

Get an introduction to sheet metal fabrication. This section explains the sheet metal fabrication process, how precision sheet metal fabrication differs, the main advantages and disadvantages, as well as its common applications.

As there are many different ways of cutting and forming sheet metal, many specific tooling types are needed which can drive up costs. This is why developing a good understanding of the various sheet metal fabrication processes available is essential to producing the most efficient design for a particular application is essential.

The most basic form of sheet metal fabrication begins with a flat sheet of metal and a blueprint (usually a DXF or CAD file). This blueprint will serve as the instructions on how to cut, form, and finish the base material.

It could be as simple as a single bend to turn it into angle iron, or laser cut and bent at the edges to make computer enclosure panels. When these processes are combined, the material is first cut and later formed, followed by finishing and joining.

As the term sheet metal fabrication covers a wide range of processes and techniques, the advantages and disadvantages very much vary depending on the process. Below is a general snapshot of the benefits and drawbacks of fabricating sheet metal, but to have a more complete understanding of whether a particular sheet metal fabrication process is suitable for your application, more research into each individual process is needed.

In this article alone, fourteen types of sheet metal fabrication are mentioned. These varying techniques allow make it possible to create relatively complex parts by cutting flat sheets, bending parts into place and adding holes, slots, and notches cut in all the right places.

Together with the wide range of compatible materials and its ability to withstand (even thrive) in high heat, thermal conduction, electrical, and corrosive environments, sheet metal can be suitable for a diverse number of applications.

Each technique has limits that make combining different processes a necessity. This can be an advantage, but it can also create longer processing times. For example, a laser cutter cannot make tiny holes, so a drilling or punching process would have to be included.

Some processes, like stamping and roll forming, require custom tooling and equipment to be created to run the process. These custom tools can sometimes be very pricey and only profitable when manufacturing lots of parts.

Aerospace engineers used sheet metal for quite a few different lightweight and space ready parts. They create designs for the aircraft or spacecraft out of sheet materials including aluminum and steel, but also use other less common sheet materials like titanium, and tungsten.

Sheet metal has been one of the materials to really kick off the possibility of making automobiles since the beginning. This is due to the large sheet forming capabilities and the ability to make very strong framing out of such thin material.

The hood, the fender, the side panels, and the roof are all made from sheet metal that has been cut by laser and punching operations and formed in stamping processes. The frame and exhaust are both roll formed then bent into shape by CNC tube benders. There is a very vast range of automotive components being made that sheet metal fabrication paved the way for.

Healthcare has many unique constraints and demands when it comes to material selection, where sheet metal can be the material to choose in many of these cases.

If an MRI is the application, stainless steel and aluminum which are not affected by strong magnetic fields could be the material of choice. High precision tools can be made from sheet metal such as intricate surgery tools and scalpels. An added benefit is some of these materials are chemically inert for the human body and can be easily cleaned and sterilized.

Just take a stroll down the appliance section of the nearest hardware store and it is hard not to notice that almost every appliance is enclosed with sheet metal. Stainless appliances with a brushed finish are all the rage recently, where aluminum and powder coated steel have been popular since the dawn of appliances.

Although, it is not just the enclosure. Look inside the dryer and see the drum is also completely made of sheet metal, or the refrigeration system has copper capillary tubes that are sheet metal. Sheet metal has made a significant impact on almost all industries.

There are numerous ways of effectively cutting through sheet metal. This section will briefly cover the many different approaches to cut through sheet metal, split into two key groups: cutting with and without shear forces.

Laser cutting is a process in which a high powered laser beam is focused on a sheet material to heat and vaporize the material away.

Most commonly, emitted at a wavelength of 10.6mm (infrared), a CO2 laser is used to pierce through a variety of materials. Efficient, low cost, and productive - these are regularly used in the world of manufacture. A laser resonator creates the laser beam where it is still between 0.5-1.0" (12.7-25.4mm) in diameter. The laser then reflects off several mirrors and focused through a lens to a width of 0.006-0.016" (0.15-0.41mm).

A gas laser, typically oxygen or nitrogen, is then introduced into the system right before the laser exits the nozzle.

Plasma cutting works in roughly the same way in laser cutting, but is usually used on thicker pieces of metal where the surface finish is not as important. The plasma cutter can only be used on electrically conductive materials and works by creating an electrically charged beam of compressed ionized gas, which is known as the plasma.

The plasma is then shot through the cutter into the sheet metal and back to the grounding clamp to form a complete circuit. The material heats substantially and melts away while the compressed gas blows the excess material away. The result is a rough cut that has a large burr and oxidized zone around the cut.

Shearing is typically a process that involves cutting a straight line through the material and separating it into two separate pieces. It is similar to the straight edge paper cutting machine that is in most offices.

This process is usually used in order to obtain straight edges on a sheet of metal that has uneven or rough edges. This machinery uses hand power, hydraulics, electricity, or pneumatics depending on the thickness of material and length of the cut needed. The sheet of metal is placed on the die and support arms when the upper blade or punch places a large shearing force onto the material and cuts it. There is a small clearance between the die and the upper blade of about 5-10% of the sheet thickness in order to leave room for plastic deformation and fracture to occur properly.

Ideal application: High volume operations. Straight line cuts for softer materials that do not require a clean finish.

There are many different types of sawing operations that can be done to cut large pieces of tube or sheet.

Whether a band saw or another form of saw that uses a disc saw blade, they work by progressively cutting through the material using a sawtooth tool which makes a series of hundreds of small shear cuts on the material. Each tooth on the saw separates a small chip of material away from the material body through friction and shear forces.

Ideal application: Larger workpieces made from softer metals, where tolerance and finish is important. Can produce heavy burrs.

During the fabrication process, the sheet metal is usually first punched and cut in different ways and then followed by forming processes to make a nearly finished and realized product. Entire product chassis can be made in this way.

Not only is forming metal convenient, it also adds strength and stiffness to an assembly. In this section, we cover seven different ways to form sheet metal.

A process where a piece of sheet metal is placed onto a die with a specific geometry and the punch presses into the material to form the sheet metal to the die. Bending sounds easy and straightforward but it can be more complex than expected. For example, if the desired bend is a standard rounded corner, a 45 V-die is used. The material does not reach the inside of the V due to the thickness of the material and instead has a bend radius.

Protolabs Network offers sheet metal bending procedures using U-shape dies, V-shaped dies, or channel shape along the straight axis in more ductile materials.

Hemming can be a very useful technique when shearing processes are not available but a nice straightedge without burrs is necessary. Hemming bends the sheet metal upon itself like the hem on pant legs so that the exposed edge is a rounded feature to make the interior of the sheet metal seem like an exterior edge.

Hemming is at least a two stage process where a piece of sheet metal is bent and bottomed out into a V-die, then removed and placed into a flattening die to flatten the hem. Hemming is different from a curl because the raw edge is exposed.

Curling can also be a convenient process for a similar reason to hemming. It creates a nice rounded edge, but with curling the rough edge of the material is completely encapsulated within the curl. It can also be used for hinging applications.

Curling usually requires three steps in total where a piece of sheet metal is pressed into a circular die in two locations, then closed together with a circular punch.

Rolling sheet metal can be a single stage process where a thicker piece of sheet metal goes through as low as 2 (or as high as 20) hydraulically loaded rollers and compresses the sheet metal into a thinner sheet. If it goes through two or more rollers directly perpendicular to the sheet metal, the material is flattened to thinner material. With the usage of more rollers in different geometry and distances from each other the material can be shaped into different shapes.

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