Episode 105 ~2:00 3D CAD

SolidWorks: sheet metal

Flat pattern → bend table → DXF → CNC. The four-step chain that gets a luminaire body off the screen, onto the brake, and out of the shop without three trial parts.

Animated explainer, press play to watch the concepts now; the filmed cut publishes once production wraps.

What you'll walk away with

01

Sheet-metal mode tracks the K-factor.

Model the part as 3D folded; SolidWorks tracks bend allowance per the K-factor in your bend table. Flat pattern is auto-generated, not redrawn from scratch.

02

Forming tools = embosses, louvres, lances.

Library of stamped features that drop into the flat. They show on both the 3D model and the DXF. Manual lofts cost hours per part, forming tools cost seconds.

03

Mitre flange for boxes, edge flange for tabs.

Two flange tools, two jobs. Mitre flange wraps a perimeter (an enclosure rim). Edge flange adds a single bend. Mixing them up models parts that won't fold.

04

Export DXF in flat pattern only.

Configurations let you save a flat-only DXF for the laser, a folded STEP for the assembly, and an isometric PDF for QA. One model, three deliverables.

Sheet metal × K-factor × bend allowance

Numbers that decide whether the cut blank folds to size.

MaterialK-factor (typical)Min bend radius
DKP cold-rolled steel0.42 - 0.441× thickness
Galvanised steel (HDG)0.40 - 0.431× thickness
304 stainless0.41 - 0.451.5× thickness
316 stainless0.41 - 0.451.5× thickness
6063-T5 aluminium0.33 - 0.401× thickness
5052 aluminium0.33 - 0.401× thickness
5083 marine ALU0.33 - 0.402× thickness

Five decisions that ride on the K-factor

The model unfolds the same way every time. The shop tool dictates K-factor, calibrate to it.

K-factor lives in the bend table, not the part file.

Calibrate K-factor by material and thickness on your specific press brake, then save it in a SolidWorks bend table. Every new part references the table; a tool change updates one number, not 200 parts.

Inside vs outside dimension is a project standard.

Spec inside dimensions for enclosures where fit matters internally (cards, modules). Spec outside for fit against external surfaces. Write the choice into the title-block standard, mixing on one drawing causes 5 mm errors at assembly.

Hem allowances eat tolerance.

A closed hem adds ~1 sheet thickness back; an open hem adds ~2×. These add up across 4-edge boxes. Spec the hem clearly in the flatten dimensions, not just the formed view.

Flat-pattern bounding box drives nesting cost.

Optimize the flat for material yield: rotate parts so longest dimension aligns with sheet direction, allow common-edge cuts where geometry permits. Saves 8-15% on raw stock per job.

Forming features need the form tool, not extrudes.

SolidWorks form tools deform the material; extrudes remove it. Get this wrong and the flat pattern shows a hole instead of a louver. Form tools come in the design library, use them.

Next Episode

SolidWorks: Weldments

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