Lattice-Structured Metal 3D Printing for Eyewear

Comprehensive Technical Documentation for Manufacturing Implementation

Section 1: Lattice Physics & Mechanical Properties

1.1 Fundamental Lattice Structures

1.2 Mechanical Properties by Structure Type

Structure Type	Relative Density	Elastic Modulus	Yield Strength	Failure Mode
BCC	0.30-0.40	E* = 0.12Es(ρ*)¹	σ* = 0.09σs(ρ*)¹	Stretch-dominated
FCC	0.35-0.45	E* = 0.15Es(ρ*)¹	σ* = 0.11σs(ρ*)¹	Stretch-dominated
Gyroid	0.50	E* = 0.19Es(ρ*)²	σ* = 0.14σs(ρ*)¹·⁵	Progressive
Diamond	0.45	E* = 0.17Es(ρ*)²	σ* = 0.12σs(ρ*)¹·⁵	Progressive

1.3 Maxwell Criterion for Structural Efficiency

1.4 Critical Buckling Analysis

Section 2: CAD Design Specifications

2.1 Parametric Lattice Generation Code

class LatticeEyewearFrame:
    def __init__(self, scan_data):
        self.base_geometry = scan_data
        self.stress_field = None
        self.lattice_params = {
            'cell_size': 3.5,  # mm
            'min_thickness': 0.4,  # mm for Ti
            'max_thickness': 1.0,  # mm
            'min_density': 0.15,
            'max_density': 0.60
        }
    
    def generate_variable_lattice(self):
        # 1. FEA Analysis
        self.stress_field = FEA_solve(
            self.base_geometry,
            load_cases=['nose_pressure', 'temple_flex']
        )
        
        # 2. Density Mapping
        density_field = remap(
            self.stress_field,
            self.lattice_params['min_density'],
            self.lattice_params['max_density']
        )
        
        # 3. TPMS Generation
        if material == 'Ti64':
            thickness_field = interpolate(0.3, 0.8, density_field)
        elif material == 'PA12':
            thickness_field = interpolate(0.5, 1.2, density_field)
        
        # 4. Boolean Operations
        inner_offset = self.base_geometry.offset(-2.0)
        outer_offset = self.base_geometry.offset(0)
        lattice_volume = boolean_subtract(outer_offset, inner_offset)
        
        return apply_tpms(lattice_volume, thickness_field)
        

2.2 Design Rules for Printability

Parameter	Ti64	PA12	316L
Strut diameter	0.3mm	0.5mm	0.4mm
Wall thickness	0.4mm	0.7mm	0.5mm
Gap clearance	0.2mm	0.3mm	0.2mm
Cell size range	2-6mm	3-8mm	2-5mm
Escape holes	N/A	2.0mm	N/A

2.3 Temple with Gradient Lattice Design

Section 3: File Preparation & Standards

3.1 STL Export Settings

Parameter	Sculpteo (PA12)	Imaginarium (Ti64)
Format	STL ASCII	STL Binary
Chord Height	0.05mm	0.01mm
Angle Control	15°	5°
File Size Limit	100MB	200MB
Mesh Quality	Watertight	Watertight + Manifold

3.2 Build Preparation XML

<build_configuration>
  <material>Ti-6Al-4V</material>
  <machine>EOS_M290</machine>
  
  <orientation>
    <rotation_x>35</rotation_x>
    <rotation_y>0</rotation_y>
    <rotation_z>15</rotation_z>
    <rationale>Minimize supports on lattice</rationale>
  </orientation>
  
  <support_strategy>
    <type>tree_support</type>
    <contact_diameter>0.6</contact_diameter>
    <trunk_diameter>2.0</trunk_diameter>
    <z_gap>0.3</z_gap>
    <xy_gap>0.2</xy_gap>
  </support_strategy>
  
  <process_parameters>
    <layer_thickness units="μm">30</layer_thickness>
    <laser_power units="W">280</laser_power>
    <scan_speed units="mm/s">1200</scan_speed>
    <hatch_spacing units="mm">0.09</hatch_spacing>
    <contour_passes>2</contour_passes>
  </process_parameters>
</build_configuration>
        

Section 4: Manufacturing Parameters

4.1 LPBF Process Parameters by Material

Parameter	Ti-6Al-4V	316L SS	AlSi10Mg
Laser Power	200-400W	150-300W	200-370W
Scan Speed	800-1400 mm/s	600-1000 mm/s	1000-1650 mm/s
Layer Height	30-60 μm	20-40 μm	30-50 μm
Hatch Spacing	90-120 μm	80-100 μm	100-130 μm
Build Rate	5-20 cm³/hr	7-25 cm³/hr	10-35 cm³/hr

4.2 SLS Parameters for Polymers

Parameter	PA12	PA11	TPU
Laser Power	20-30W	25-35W	15-25W
Layer Height	100-120 μm	100-120 μm	120-150 μm
Chamber Temp	170°C	185°C	90°C
Refresh Rate	30-50%	30-50%	20-30%

4.3 Post-Processing Workflow

Section 5: Economic Analysis

5.1 Total Cost Comparison (10,000 frames/year)

5.2 Per-Unit Economics

Cost Element	Traditional	Metal AM	Polymer AM
Material	$15	$50-150	$1.27-5
Labor	$40	$18	$8
Equipment Amortization	$9	$20	$10
Overhead	$10	$8	$5
Total Cost	$74	$96-196	$24-28
Retail Price	$200	$350-600	$150-200
Margin	63%	65-73%	84-86%

Section 6: Partner-Specific Workflows

6.1 Sculpteo France Workflow

6.2 Imaginarium Mumbai Workflow

Section 7: Hinge Design Library

7.1 Print-in-Place Hinge Types

7.2 Verified Source Files

Source	File Type	Test Status	Access
GrabCAD	STL + CAD	Ti & PA tested	grabcad.com/library/eyeglasses-hinge-print-in-place-1
Printables	STL + SCAD	PA12 validated	printables.com/model/287634-parametric-eyeglass-hinge
MyMiniFactory	F360	Both materials	myminifactory.com/object/3d-print-184623

Section 8: Quick Reference Tables

8.1 Weight Achievements

Product	Material	Weight	Comparison
Monoqool Slider	PA	4g	Lightest ever
POC Elicit Ti	Ti64	22g	4 sheets paper
Hoet Couture	Ti64	25g	5 paperclips
MYKITA MYLON	PA11	15-20g	3-4 paperclips
Traditional	Acetate	45-60g	10-12 paperclips

8.2 Market Data

Metric	2024	2029 (Projected)
Market Size	$268M	$829M
CAGR	-	25.3%
Premium Segment	75%	60%
Mass Market	25%	40%

8.3 Critical Contacts

Organization	Contact	Specialty
Sculpteo	pro@sculpteo.com	Design optimization
Imaginarium	aditya.c@imaginarium.io	Ti production
Objectify Tech	design@objectify.co.in	Indian market files
Treatstock	design service portal	Hinge conversion
Materialise	eyewear@materialise.com	Complete solutions

8.4 Troubleshooting Guide

Issue	Cause	Solution
Lattice collapse during print	Insufficient support	Add tree supports at 45° angles
Warping in Ti frames	Residual stress	Heat treat at 800°C for 2 hrs
Powder trapped in lattice	Cell size too small	Increase to 3mm minimum
Surface roughness excessive	Wrong parameters	Reduce scan speed by 20%
Hinges binding	Insufficient clearance	Add 0.05mm to all gaps