1., the way of expansion should be combined, so as to save materials and workability.
2. reasonable choice of gap and wrapping method, T=2.0 below the gap 0.2, T=2-3 ask gap 0.5, the way of wrapping long edge package short edge (door type)
3. reasonably consider the tolerance dimension: the negative difference goes to the end, the positive error goes half; the hole size: the positive error goes to the end, the negative difference walks half.
4. burr direction
5. draw teeth, press riveting, tearing, bump bump (package), etc. position direction, draw sectional view.
6. check material, plate thickness, plate thickness tolerance
7. special angle, the radius of the bending angle (general R=0.5) should be measured and expanded.
8. where there is error prone (similar asymmetry), we should give priority to hints.
9. places with more size should be added to the big picture
10. the need for spraying protection must be expressed