Key Considerations for Cost-Effective and Accurate Custom Sheet Metal Fabrication Work

 Sheet metal is widely used for custom metal fabrication projects as it costs significantly less than machining cavities into metal blocks. Sheet metal used in custom metal fabrication projects can range in thickness from 0.4 mm to 6 mm. The selection of sheet metal for fabrication work depends on a variety of factors such as formidability, resistance, corrosion, weight, strength, and the overall cost.

Because sheet metal parts are manufactured from a single sheet of metal, the part must maintain uniform wall thickness. Sheet metal fabrication projects requiring more than one wall thickness may require reorientation and alignment of parts. Keeping the same bend radii across all bends makes the part more cost-effective. Making the bends in a single plane will prevent any additional reorientation. The spacing between the holes should be at least double the thickness of the sheet metal used.

Understanding K-factor and bend reliefs

K-factor is an important consideration for sheet metal fabrication works. It denotes the ratio of the neutral axis to the material thickness. The generic value of K-factor varies from 0.3 to 0.5. Its value changes with respect to the physical properties and thickness of metal. Bend reliefs are implemented where a bend extends on an edge in certain custom metal fabrication projects. It helps in controlling the unwanted metal deformation. Bend reliefs should be at least the same as the thickness of sheet metal in terms of width. It should be equal to or greater than the inside bend radius in terms of depth.

Cutting methods

Laser cutting is used in custom metal fabrication projects to cut metal sheets up to 8 mm in thickness. It results in a precise cut with a tolerance of just +/-0.005. A high-pressure water jet with abrasive particles is used to cut metal sheets up to 150 mm in thickness. Water jet cutting provides the same tolerance as laser cutting but the surface finish may vary, depending upon the parameters. Mechanical shearing is used in sheet metal fabrication projects to cut metal sheets into shapes for mass production. A die and punch are used to shear the sheet into the required shape. The forming limit of the sheet is considered in custom metal fabrication for developing a component. Drawing involves drawing of the blank metal sheet into a forming die using a punch to obtain a hollow or curved surface.

Other considerations for sheet metal fabrication

Offsets are used to create Z-shaped profiles in sheet metal parts. Notches need to be at least the material’s thickness or at least 1.016 mm, whichever is greater. Tabs must be at least two times the material’s thickness. Holes and slots should be a minimum of material thickness in diameter.

Brazing for a strong joint between dissimilar metals

The corners or opened edges are welded to maintain the strength and geometry of the component required for custom metal fabrication work. For parts made from aluminium and brass, brazing is used. A molten filler metal or braze alloy with melting point of above 450 degrees is made to flow into the joint. The filler’s melting point is always below the melting temperatures of the parts to be joined. The molten filler metal cools to join the workpieces together. Brazing is used in sheet metal fabrication works to obtain a strong joint between dissimilar metals. For the best results from brazing, the filler and parent materials should be metallurgically comparable and the joint design should incorporate a gap into which the molten braze filler can be drawn or distributed due to the effect of capillary action.

Brazing is widely accepted for custom sheet metal fabrication due to the flexibility and high integrity to which joints can be produced. It is one of the most widely used joining methods for a wide range of industrial applications. The welded sheet metal component needs to be surface finished to remove any sharp edges and provide the final product its cosmetic appearance. Surface finishing methods used in sheet metal fabrication include priming, sandblasting, jitterbugging, powder coating and hand grinding.

One-stop solution for your custom sheet metal projects

Brisbane Metal Products (BMP) provides a one-stop solution of all your custom metal fabrication projects as the leading fabrication shop makes use of the latest technology and tools for sheet metal fabrication, such as CAD/CAM software and CNC technology. This technology allows BMP to produce parts with high accuracy and precision. BMP has unmatched expertise in metal, wire, and aluminium fabrication with nationwide distribution capabilities. They have over 50 years of experience in custom metal fabrication work, and have provided expert service and project management to businesses around the world. As the entire project is Australia-based, you can be assured of the highest quality outcomes from a local business. Contact BMP for the best outcomes and cost-effective completion of your sheet metal fabrication projects.