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SHEET METAL FABRICATION
THE ULTIMATE GUIDE
Sheet metal fabrication takes thin, flat, and bendable sheets of different types of metal and cuts, bends, and assembles them into a variety of products. Before this happens, you must decide what material, process, and finishes are best suited to your end goals and needs. This guide is designed to help you make some of those key decisions.
SHEET METAL DESIGN GUIDE
BODASHEET METAL ENGINEERING
Choosing the right sheet metal fabrication process
There are many different options when using sheet metal to fabricate a product. Some processes are better suited to different uses, schedules, and budgets. Below we outline some of the most common sheet metal fabrication processes along with their advantages and disadvantages.
Lead Time Process Custom Minimum Thickness from CAD Best used for Precision tooling order (mm) to 1st Level required quantity production
Small to large parts 1 to Less 0.5mm to Laser with every geometry +/- 0.12mm No 10,000 than 1 20.0mm cutting possible. units hour
Small to large parts 1 to Less CNC sheet with straight angle 0.5mm to +/- 0.18mm No 10,000 than 1 bending geometry, multiple 20.0mm units hour bend possible.
Small to large parts No unless with most geometry 1 to Less CNC 0.5mm to special available, good for +/- 0.12mm 10,000 than 1 Punching 4.0mm* form parts with multiple units hour required holes and embossed.
High volume Yes from 10,000 Less production with tight 0.5mm to 250 USD Stamping +/- 0.12mm units and than 1 tolerances, restricted 4.0mm* to 100,000 above hour geometry. USD+
Thin material with simple geometry 1 to Less 0.5mm to Shearing (straight lines) and +/- 0.50mm No 10,000 than 1 4.0mm* low tolerances units hour requirements.
* Higher gage may result in deformation or reduce precision
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BODASHEET METAL ENGINEERING
CO2 or Fiber Laser Cutting
Laser cutting uses a laser to cut sheet metal into the required shape. There are two broad categories of laser cutting: fusion cutting (melts material and add high pressure gas to sheer the melted material away) and ablative laser cutting (pulsive laser removing material layer by layer). Today’s lasers are either CO2 lasers or fiber lasers. CO2 lasers use infrared light to cut materials. They cut faster and leave a smoother surface finish when cutting thicker materials. A fiber laser is a single mode beam which direct higher power density to the sheet metal. The process is faster and well suited to applications that have a very narrow weld seam.
Advantages Disadvantages
Faster and more efficient than traditional Potential for structural changes to the material • • cutting methods with a smooth surface finish. impacting the final product. Highly accurate, precise results Not all metals can be cut by lasers (reflective • • accommodating tight tolerances. material for example will require a fiber laser). A custom die is not required. Requires adjustment when using sheet metal • • Each piece is individually cut so changes can with varying thicknesses. be made, or errors corrected easily. Work hardening of the edges may require • Works on a wide variety of metals and other additional processing before treatments like • materials. powder coating or painting. Accommodates a variety of material Other cutting methods may be better options • • thicknesses and diverse shapes. for long production runs. Go-to process for several industries. • Well suited for metal annealing, etching, and • engraving for serial numbers, barcodes, part marking etc.
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BODASHEET METAL ENGINEERING
CNC Sheet Bending
CNC sheet bending uses a CNC press brake or CNC folder to bend metal into two or three- dimensional shapes. This process can bend large or small sheets of metal, fabricating high quality pieces quickly. CNC sheet bending is also used to adjust a finished or near-finished product. Dies are available for standard angles and operations so custom tooling may not be required.
Advantages Disadvantages
Highly accurate process ideal when high The process can cause indentations or • • precision is required. scratches on the product. Can produce large volumes in a short time. Can be labour intensive. Low cost for production and minimal Custom tooling is required for specialized •• •• tooling costs. bending projects. Suitable for high or low volume production. Bends need to be in a position on the sheet • Can create multiple, custom shapes metal where there is enough material to fit •• through a series of bending processes. into the equipment without slipping. Standard punches and dies available Fractures can occur when hard metals are • • including in V and U shapes bent parallel to the rolling direction of the sheet metal. Holes, slots, or other features close to the • bend can become distorted.
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BODASHEET METAL ENGINEERING
Stamping
Stamping is the process of using a mechanical or hydraulic stamping press to create an indentation in the metal to bend or shape it. It’s commonly used for forming shapes, letters, or images on the sheet metal, but is also used for processes like bending, stretching, hemming, flanging, and curling for more complex projects. Stamping presses can mold metal into more complex forms – including four-sided forming. Metal coining for items like coins or small parts for electronics is also possible. Customized dies are created for individual projects.
Advantages
Faster and cost-effective production for large • volume production. Accuracy and precision for complex shapes and • producing identical pieces. Once the die is created, can produce large • volumes quickly. Well suited for small parts requiring • micro-precision. Versatile process that can include punching, • blanking, embossing, flanging, bending, or coining Scrap leftovers can be recycled. •
Disadvantages
Higher pre-production time to make a custom die • Changes once the die is created are costly and • impact the schedule. Errors in the die result in errors with entire • production. Pieces may require additional processes including • deburring, tapping, reaming, or counterboring. Less cost effective for smaller order production Must use materials that are malleable enough to •• form without breaking.
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BODASHEET METAL ENGINEERING
Shearing
Shearing is the application of enough force to cause the sheet metal to fail and separate in the location of the desired cut. The shearing force is applied by either a punch, a die, or a blade. This process is typically used for straight line cuts but can also produce angled cuts.
Advantages
Can produce very long, straight lines on sheet • stock.
Works well with soft metals. • Cost effective for high output projects. • Good choice for cutting small lengths or • different shaped material.
Disadvantages
Limitations in the type and intricacy of the • cuts (used mostly for straight cuts).
The process can create burrs or other • imperfections on ends.
Not suitable for all material like hard metals •• or material with large diameters.
Slower and less precise than other cutting •• methods.
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BODASHEET METAL ENGINEERING
CNC Punching
Sheet metal is cut using a punch press to push the material into a die to create holes or cutouts. The CNC punch machine can also be used for secondary processes like tapping, blanking, forming, extruding, and deburring.
Advantages Disadvantages
Stronger cutting power than some other Not well suited for complex shapes. • • methods making it suitable for a wide Edges will have burrs and may require • variety of metals. secondary finishing. Fast and cost-effective way for punching Diameter of the holes generally shouldn’t be • • holes, squares, slots, notching or other smaller than the sheet metal gauge. shapes into flat metal. Well suited to medium to large quantities • Good precision and uniform cuts Multiple standard punches available for • different requirements. Can produce intricate designs using • overlapping cuts or 3D forms such as dimples or countersinks.
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