{"id":22912,"date":"2025-11-23T19:29:12","date_gmt":"2025-11-24T03:29:12","guid":{"rendered":"https:\/\/shengenfab.com\/?p=22912"},"modified":"2025-11-23T19:46:56","modified_gmt":"2025-11-24T03:46:56","slug":"sheet-metal-fabrication-terms","status":"publish","type":"post","link":"https:\/\/shengenfab.com\/en_gb\/sheet-metal-fabrication-terms\/","title":{"rendered":"Sheet Metal Fabrication Terms Every Engineer Should Know"},"content":{"rendered":"
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Clear communication is one of the most potent tools in sheet metal fabrication. Even one misunderstood word can shift a bend by a millimeter, misalign a hinge, or cause a part to fail during assembly. Engineers may design with one definition in mind while the shop follows another. When this happens, quotes become inaccurate, samples need rework, and production slows down.<\/p>

Many teams encounter these issues without realizing the underlying cause. A buyer might request a \u201ctight tolerance,\u201d but the term means different things to different factories. An engineer might set a bend radius that appears fine on screen, but the material cracks during the forming process. These problems often resemble manufacturing errors, but the root cause is frequently found in unclear terminology used during the design stage.<\/p>

The goal of this guide is to prevent these gaps. The sections below explain the sheet metal terms that influence cost, accuracy, and long-term performance. Each term appears daily on shop floors, in design reviews, and in RFQs.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Design and DFM Terms<\/h2>

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Good designs depend on understanding how metal behaves when it bends or forms. The following terms help teams avoid cracking, warping, and dimensional drift during fabrication.<\/p>

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Bend Radius<\/h3>

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The bend radius<\/a> is the inner radius formed when metal bends. It affects cracking, stretch, and final strength. A radius that is too small forces the material to stretch beyond its limits, especially in stainless steel or aluminum.<\/p>

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Most projects start with a radius equal to 1\u00d7 material thickness. More complex alloys\u2014such as stainless steel or high-strength steel\u2014often need 1.5\u00d7 to 2\u00d7. A correct radius reduces springback and helps form cleaner, more precise angles.<\/p>

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Example:<\/em><\/p>

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A 1.0 mm stainless steel bracket with a 0.5 mm radius often cracks at the bend line. Increasing the radius to 1.0\u20131.5 mm usually removes the issue.<\/p>

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K-Factor<\/h3>

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The K-factor<\/a> determines the location of the neutral axis during bending. This axis does not stretch or compress. Its position determines how much the material elongates.<\/p>

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Air bending typically yields K-factors ranging from 0.3 to 0.5. Bottoming or coining compresses the metal more deeply, pushing the neutral axis inward. Using the correct K-factor ensures accurate flat pattern lengths and prevents holes from shifting after bending.<\/p>

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Real-world use:<\/em><\/p>

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Incorrect K-factors are one of the most common reasons flat patterns do not match finished parts.<\/p>

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Bend Allowance and Bend Deduction<\/h3>

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Bend allowance (BA)<\/a> measures the arc length created by the bend. Bend deduction (BD) compensates for how much flange length must change to achieve accurate dimensions.<\/p>

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Both values depend on thickness, radius, angle, and the K-factor. Incorrect BA or BD leads to mismatched edges, doors that do not close, or tabs that do not line up. Accurate values reduce the time needed for prototype tuning.<\/p>

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Why it matters:<\/em><\/p>

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A 0.2 mm error in BA on a single bend can multiply across multiple bends in an enclosure.<\/p>

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Flange Length<\/h3>

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Flange length is the straight section that extends from a bend. Press brakes require a minimum flange length for secure clamping. A standard guideline is:<\/p>

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Minimum flange = 4\u00d7 thickness + bend radius<\/strong><\/p>

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Shorter flanges can slip during bending or cause interference with tooling. Proper flange length ensures stable, repeatable forming.<\/p>

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Example:<\/em><\/p>

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A 1.5 mm steel part with a 3 mm flange is often impossible to form without special tooling.<\/p>

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Tolerance and Tolerance Stack-Up<\/h3>

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Tolerance defines acceptable variation for a dimension. Sheet metal forming often uses tolerances of \u00b10.1 mm to \u00b10.3 mm, depending on the geometry and process.<\/p>

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Tolerance stack-up refers to the accumulation of minor variations across multiple features. Even if each dimension stays within spec, the combined error can cause misalignment in hinges, mounting holes, or PCB locations.<\/p>

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Why stack-up matters:<\/em><\/p>

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In a large enclosure, a 0.2 mm variation in five locations can result in a 1.0 mm misalignment at the final assembly step.<\/p>

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Springback<\/h3>

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Springback<\/a> happens when metal relaxes after bending and returns slightly toward its original shape. Stainless steel, high-strength steel, and aluminum often show more springback than mild steel.<\/p>

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Values typically range from 1\u00b0 to 5\u00b0, depending on thickness, angle, tooling, and alloy. Designers compensate by over-bending or adjusting tooling. Planning for springback improves consistency across all batches.<\/p>

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Practical insight:<\/em><\/p>

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Ignoring springback is one of the most common causes of inconsistent angles between prototypes and mass-produced parts.<\/p>

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Material and Thickness Terms<\/h2>

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Material choice impacts strength, corrosion resistance, weight, and the ease with which the part forms. These terms help teams select the right sheet for both function and cost.<\/p>

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Gauge vs. Thickness<\/h3>

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Gauge<\/a> is a numbered system used to describe thickness, but gauge values change between materials.<\/p>

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Example:<\/strong><\/p>

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