1. Minimize part count
2. Use standard components
3. Design for ease of fabrication
4. Design for ease of assembly
5. Design for ease of service
6. Consider process capabilities
7. Minimize secondary operations

Holes:
- Standard drill sizes preferred
- L/D ratio < 5 for drills
- Flat bottoms require end mill
- Provide drill point clearance

Pockets:
- Corner radius = tool radius
- Max depth < 4x tool diameter
- Provide tool access

Threads:
- Standard thread sizes
- Depth 1.5-2x diameter sufficient
- Provide thread relief

Wall thickness:
- Minimum 1-2 mm for steel
- Consider deflection during machining

Draft angles:
- External: 1-3 degrees minimum
- Internal: 2-5 degrees
- Deep pockets: increase draft

Wall thickness:
- Minimum: 3-5 mm (sand casting)
- Minimum: 2-3 mm (die casting)
- Uniform thickness preferred
- Gradual transitions

Radii:
- Internal corners: R > 3 mm
- External corners: R > 1 mm
- Avoid sharp transitions

Wall thickness:
- Uniform 1.5-4 mm
- Transitions < 25% thickness change
- Avoid thick sections (sink marks)

Draft:
- 0.5-1 degree per side minimum
- Textured surfaces: add 1 degree per 0.025 mm depth

Ribs:
- Thickness: 50-75% of wall
- Height: < 3x wall thickness
- Spacing: > 2x wall thickness

Bosses:
- Wall: 50-75% of base wall
- Height: < 2x diameter
- Add gussets for strength

Minimum bend radius:
- Soft materials: 0.5x thickness
- Hard materials: 1-2x thickness
- With grain: smaller radius OK
- Against grain: larger radius

Minimum flange:
- Flange > 4x thickness
- Flange > 3 mm practical minimum

Hole-to-bend:
- Distance > 2x thickness + bend radius
- Prevents hole distortion

Minimum hole size:
- Round: 1x material thickness
- Square/rectangle: 0.8x thickness

Minimum edge distance:
- 2x material thickness minimum
- Prevents edge deformation

Minimum hole spacing:
- 2x material thickness minimum

Manufacturing cost components:
1. Material cost
   - Raw material
   - Scrap/waste
   - Special materials

2. Labor cost
   - Setup time
   - Run time
   - Inspection time

3. Equipment cost
   - Machine time
   - Tooling amortization

4. Overhead
   - Facility
   - Support functions

Before specifying tight tolerances:
1. Verify functional requirement
2. Check assembly chain
3. Confirm process capability
4. Consider inspection cost
5. Evaluate statistical tolerance

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