Sheet Metal Design
Tolerances
Sheet metal tolerances
should not be tighter than necessary to make the part
functional. Tight tolerances raise the cost of
manufacturing significantly. Practical tolerances
vary according to the design requirements. Tolerances
of +/- .010 should be considered minimum.
Linear tolerances should be held as loose as possible.
Recommend +/- .020 for general, and tolerance functional areas
as needed.
Flatness
Flatness specifications
are applied with perfect form not required at maximum material
condition. If there is a rule of thumb, a flatness
tolerance of .005" per inch is the best that can be achieved
without secondary individual checking and
straightening. In general the primary datum should have
some type of form specified. Defining the primary datum
by datum targets in a retrained condition is
preferred.
Minimum
Bend
Radii
The minimum bend radii
data contained within the given charts are measured to the
inside of the bend. The bend radii listed are standard
minimum for manufacturing for aerospace and space
applications. Commercial sheet metal radius are created
with less concern for stresses created during forming and
radii can approach zero (sharp internal corner) for many thin
sheet metal gages.
ALUMINUM (BARE &
CLAD) Minimum Bend Radii
Bend radius of
zero is achievable for .012 - .050 material thickness.
| MATERIAL |
SHEET
THICKNESS |
| -- |
.012 |
.016 |
.020 |
.025 |
.032 |
.040 |
.050 |
.063 |
.071 |
.080 |
.090 |
.100 |
.125 |
.160 |
.190 |
| 2024-0
& W |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
.22 |
.31 |
.36 |
| 2024-T3 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.16 |
.22 |
.25 |
.31 |
.38 |
.44 |
.62 |
.75 |
1.00 |
| 2024-T36 |
.06 |
.09 |
.09 |
.09 |
.12 |
.16 |
.19 |
.25 |
.31 |
.38 |
.44 |
.50 |
.75 |
1.00 |
1.25 |
| 3003-0 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
| 3003-H14 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
.22 |
.31 |
.38 |
.44 |
| 5052-0 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
.22 |
| 6061-0
& W |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
.22 |
| 6061-T4
& T6 |
.06 |
.06 |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.12 |
.16 |
.19 |
.22 |
.31 |
.38 |
| 7075-0
& W |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.16 |
.19 |
.22 |
.25 |
.31 |
.38 |
.50 |
.62 |
| 7075-T6 |
.06 |
.09 |
.12 |
.12 |
.16 |
.22 |
.25 |
.31 |
.41 |
.44 |
.50 |
.69 |
.87 |
1.00 |
1.25 |
| 7178-0
& W |
.06 |
.06 |
.06 |
.06 |
.09 |
.09 |
.12 |
.19 |
.22 |
.25 |
.31 |
.38 |
.50 |
.75 |
- |
| 7178-T6 |
.06 |
.09 |
.16 |
.19 |
.22 |
.31 |
.38 |
.50 |
.56 |
.62 |
.62 |
.75 |
1.00 |
1.25 |
- |