Hole Diameter
The minimum hole diameter should be at least equal to the material thickness.
Edge-to-Hole Spacing
Maintain a minimum distance of at least 2 times the material thickness between the edge and any hole.
Forming Bends Near Holes
Place bends at least 2 times the material thickness away from any hole to prevent deformation.
Notches and Tabs
The minimum width for notches and tabs should be at least 1.5 times the material thickness, and the minimum length of tabs should be twice the material thickness.
Bend Height
The minimum bend height should be at least 3 times the material thickness (e.g., for 1mm thick material, the bend height should be at least 3mm).
Hole to Form
Prevent deformation by ensuring the spacing is the bend radius plus 2.5 times the material thickness. If the hole diameter is less than 2.5mm, this distance should be twice the material thickness plus the bend radius. For larger holes, use the bend radius plus 2.5 times the material thickness.
Slot to Form
When bending near long slots, maintain a spacing of the bend radius plus a minimum of 4 times the material thickness.
Corners
The radius of the punch and die should be at least 4 times the material thickness. For materials 1.5mm or less, corners can be very sharp.
Squareness
Forming a square (90° angle) should allow for a variation of plus or minus 1 degree.
Flatness
Avoid over-specifying flatness requirements to prevent costly secondary operations. A flatness requirement of fewer than .003 inches may increase costs.
L-Shaped Parts
Include a bend relief notch to avoid fractures and cracks.
Grain Direction
For hard materials, avoid aligning the bend line of sharp V-bends parallel to the grain direction to prevent cracking.
Burrs
Burrs can reach up to 10% of the material thickness. Avoid complex cutouts and sharp corners to minimize burr severity, and note the burr direction in the design.
Shapes
Round shapes are the simplest to draw, followed by squares with sufficient corner radii. Irregular shapes or combinations of basic shapes may increase difficulty and cost.
Feature Distortion
Prevent distortion by ensuring holes and slots are not too close to a form, edge, or each other. Drawn parts are more prone to deformation than formed parts.
