Self-check:

– Are there any areas on the part that have suddenly become thinner or thicker?
– What is the thinnest part in millimeters? Is the thickness of the aluminum material less than 0.8mm? And is the thickness of the steel material less than 1.5mm?
– Is it possible to use reinforcing ribs instead of increasing the overall wall thickness?

Improvement suggestions:

• For metal parts, the wall thickness should be at least 0.8mm (for stainless steel, at least 1.0mm).
• Try to keep the wall thickness uniform and avoid abrupt changes in the cross-section. If a change is necessary, design a smooth transition chamfer or arc.
• If certain parts require higher strength, it is preferable to increase the reinforcement positions rather than thickening the entire area – this way, the rigidity can be ensured without increasing the processing difficulty or material cost.

Self-check:

– Are all the internal angle positions marked with rounded corners?
– Is the radius of the rounded corners greater than or equal to the available standard tool radius?
– For sheet metal parts, have the internal rounded corners taken into account in the bending rebound?

Improvement suggestions:

• The recommended inner corner radius should be ≥ 0.5mm, and it is preferable to be equal to the radius of the commonly used cutting tools.
• For sheet metal bending parts, the inner corner usually needs to be ≥ 0.5 times the sheet thickness. Larger inner corners help reduce the risk of springback and cracking.
• If a certain inner corner really needs to be sharp, consider using electrical discharge machining to remove the corners after processing. However, this should be clearly stated on the drawing, and the higher cost should be accepted.

Self-check:

– Is the distance from the center of the hole to the nearest edge ≥ 1.5 times the hole diameter?
– Is the distance from the hole edge to the bending line ≥ 3 times the plate thickness?
– If the hole must be close to the bending line, can it be drilled after the bending process?

Improvement suggestions:

• For through holes, the minimum distance from the center of the hole to the edge is 1.5 times the hole diameter. It is recommended to be more than 2 times.
• The safety distance from the edge of the hole to the bending line should be at least 3 times the thickness of the plate. If the plate thickness is 2mm, then at least 6mm should be left.
• If the above distances cannot be met, the option could be to drill the hole after bending, or to change the round hole to a semi-circular groove to release the deformation stress.

Self-check:

– Is this dimension for the mating surface or the non-mating surface?
– If this dimension has a deviation of 0.1mm, will the product fail?
– Have I clearly marked on the drawing which dimensions are the Critical to Quality (CTQ) dimensions?

Improvement suggestions:

• Mark the parts that truly require strict control with special symbols on the drawing.
• For non-critical dimensions, use the general tolerance standard; typically, ±0.2 mm to ±0.5mm will suffice.
• If tight tolerances are necessary, make sure that this feature is truly required and consider using precision machining processes such as grinding or honing. However, be prepared to accept the corresponding time and cost.

Self-check:

• What is the maximum depth-to-diameter ratio of the deepest hole?
• Can it be changed to a through-hole?
• Can it be designed as a stepped hole to reduce the actual depth-to-diameter ratio?

Improvement suggestions:

When the depth-to-diameter ratio is ≤ 5:1, the economic performance is optimal; for 5 to 10:1, internal cooling drills should be used; for ratios> 10:1, it is strongly recommended to switch to through holes, stepped holes, or combine them into special-shaped slots. The depth of the threaded bottom hole for sheet metal should be ≤ 2 times the diameter.

Self-check:

– Are the diameters of all holes and the widths of all slots standard sizes?
– Can all processing features be completed in one setup? If not, what is the minimum number of setups required?
– Are the bending directions consistent? Can the parts be prevented from being flipped over?

Improvement suggestions:

Give priority to using standard tool sizes and avoid non-standard values. Arrange the features in the same direction, or complete multi-faceted processing in a single clamping with an Angle head. All the sheet metal bending is in the same direction and is positioned in one go.