# SendCutSend Sheet Metal Manufacturing Package & DFM Specification

**System:** 6U 19-Inch Open-Source Tri-Mode Storage Array  
**Document ID:** MECH-SPEC-02  
**Supplier Compatibility:** SendCutSend / Xometry / Protocase  
**Material Specification:** 5052-H32 Aluminum (1.27mm / 0.050" or 1.60mm / 0.063") / 3.0mm for Rack Ears  
**Manufacturing Process:** CNC Fiber Laser Cut (Tolerance $\pm 0.1\,\text{mm}$ / $\pm 0.005"$), Deburred, Flat (Zero Bends)  

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## 1. Design-for-Manufacturing (DFM) Strategy

To achieve the sub-$65 chassis budget target and eliminate costly multi-axis sheet metal press brake tooling:
1. **100% Bend-Free Flat Pattern Topology:** Every panel is a 2D flat laser-cut plate. All structural stiffness, corner joints, and 3D volume are provided by the 2020 extrusion skeleton.
2. **Standardized Hole Sizing:** 
   - Panel mounting screw clearance holes are standardized to **Ø4.5mm** (for M4 button head screws into drop-in T-nuts).
   - Component standoff holes are **Ø3.5mm** (for M3 motherboard/PCB standoffs).
3. **Minimum Feature Spacing Rules (SendCutSend DFM Checked):**
   - Hole diameter $\ge \text{Material Thickness}$ ($4.5\,\text{mm} > 1.27\,\text{mm}$ $\checkmark$).
   - Hole-to-edge distance $\ge 2\times \text{Thickness}$ ($10.0\,\text{mm} > 2.54\,\text{mm}$ $\checkmark$).
   - Hole-to-hole web thickness $\ge 2\times \text{Thickness}$ ($20.0\,\text{mm} > 2.54\,\text{mm}$ $\checkmark$).

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## 2. Complete Sheet Metal Panel Schedule

| Panel ID | Panel Description | Dimensions (W x H / L) | Qty | Material & Thickness | Est. Cost / Unit (SendCutSend 100+ Vol) |
| :--- | :--- | :---: | :---: | :--- | :---: |
| **SMP-01** | Top Enclosure Cover Plate | $436.0\,\text{mm} \times 500.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 1.27mm | $5.20 |
| **SMP-02** | Bottom Base Plate | $436.0\,\text{mm} \times 500.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 1.27mm | $5.40 |
| **SMP-03** | Left Side Exterior Skin | $500.0\,\text{mm} \times 260.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 1.27mm | $3.10 |
| **SMP-04** | Right Side Exterior Skin | $500.0\,\text{mm} \times 260.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 1.27mm | $3.10 |
| **SMP-05** | Rear I/O & Exhaust Vent Plate | $396.0\,\text{mm} \times 220.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 1.27mm | $4.80 |
| **SMP-06L**| 6U Structural Rack Mount Ear (Left) | $40.0\,\text{mm} \times 260.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 3.00mm | $2.60 |
| **SMP-06R**| 6U Structural Rack Mount Ear (Right)| $40.0\,\text{mm} \times 260.0\,\text{mm}$ | 1 | 5052-H32 Aluminum 3.00mm | $2.60 |
| **TOTAL** | **Complete Sheet Metal Package** | — | **7 pcs**| — | **~$26.80** |

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## 3. Detailed CAD Dimensioning & Hole Coordinate Maps

### 3.1 SMP-01: Top Cover Plate ($436.0\,\text{mm} \times 500.0\,\text{mm}$)
- **Outer Bounds:** $X \in [0, 436.0]$, $Y \in [0, 500.0]$.
- **Mounting Hole Centers (Ø4.5mm Clearance for M4):**
  - **Left Edge ($X = 10.0\,\text{mm}$):** $Y = 25.0, 150.0, 275.0, 400.0, 475.0\,\text{mm}$ (5 holes).
  - **Right Edge ($X = 426.0\,\text{mm}$):** $Y = 25.0, 150.0, 275.0, 400.0, 475.0\,\text{mm}$ (5 holes).
  - **Front Edge ($Y = 10.0\,\text{mm}$):** $X = 109.0, 218.0, 327.0\,\text{mm}$ (3 holes).
  - **Rear Edge ($Y = 490.0\,\text{mm}$):** $X = 109.0, 218.0, 327.0\,\text{mm}$ (3 holes).
- **Total Holes:** 16x Ø4.5mm holes.

### 3.2 SMP-02: Bottom Base Plate ($436.0\,\text{mm} \times 500.0\,\text{mm}$)
- **Outer Bounds:** $X \in [0, 436.0]$, $Y \in [0, 500.0]$.
- **Perimeter Extrusion Holes (Ø4.5mm):** Identical 16-hole pattern to SMP-01.
- **Baseboard Mounting Grid (Ø3.5mm for M3 Standoffs):**
  - Radxa + Broadcom Carrier PCB footprint ($180.0\,\text{mm} \times 120.0\,\text{mm}$ at $X_{\text{offset}} = 30.0\,\text{mm}$, $Y_{\text{offset}} = 220.0\,\text{mm}$):
    - Hole 1: $(X=40.0, Y=230.0)$
    - Hole 2: $(X=200.0, Y=230.0)$
    - Hole 3: $(X=40.0, Y=330.0)$
    - Hole 4: $(X=200.0, Y=330.0)$
- **Mezzanine PCIe Anchor Grid:** 4x Ø3.5mm holes at $X = 280.0\,\text{mm}$ and $380.0\,\text{mm}$, $Y = 230.0\,\text{mm}$ and $430.0\,\text{mm}$.

### 3.3 SMP-03 & SMP-04: Left & Right Side Panels ($500.0\,\text{mm} \times 260.0\,\text{mm}$)
- **Outer Bounds:** $X \in [0, 500.0]$, $Y \in [0, 260.0]$.
- **Top Edge ($Y = 250.0\,\text{mm}$):** $X = 25.0, 150.0, 275.0, 400.0, 475.0\,\text{mm}$ (5 holes).
- **Bottom Edge ($Y = 10.0\,\text{mm}$):** $X = 25.0, 150.0, 275.0, 400.0, 475.0\,\text{mm}$ (5 holes).
- **Front Upright ($X = 10.0\,\text{mm}$):** $Y = 70.0, 130.0, 190.0\,\text{mm}$ (3 holes).
- **Rear Upright ($X = 490.0\,\text{mm}$):** $Y = 70.0, 130.0, 190.0\,\text{mm}$ (3 holes).
- **Total Holes per Side Panel:** 16x Ø4.5mm holes.

### 3.4 SMP-05: Rear I/O & Exhaust Vent Plate ($396.0\,\text{mm} \times 220.0\,\text{mm}$)
- **Outer Bounds:** $X \in [0, 396.0]$, $Y \in [0, 220.0]$.
- **Perimeter Frame Mounting (Ø4.5mm):**
  - Top & Bottom Edges ($Y=10.0, 210.0\,\text{mm}$): $X = 30.0, 130.0, 266.0, 366.0\,\text{mm}$.
  - Left & Right Edges ($X=10.0, 386.0\,\text{mm}$): $Y = 60.0, 110.0, 160.0\,\text{mm}$.
- **Exhaust Vent Honeycomb Array:**
  - Hexagonal perforation zone: $X \in [30.0, 220.0]$, $Y \in [30.0, 190.0]$ (190mm x 160mm active area).
  - Hexagon geometry: 6.0mm across flats, 1.2mm web, >68% open area to guarantee unimpeded exhaust airflow.
- **Vertical PCIe / GPU Expansion Slot Cutouts (Zone $X \in [250.0, 310.0]$, $Y \in [30.0, 190.0]$):**
  - Dual vertical full-height bracket openings ($120.0\,\text{mm} \times 21.6\,\text{mm}$) with top screw retention tabs.
- **Host & Power Cutouts (Zone $X \in [330.0, 380.0]$):**
  - Dual RJ45 Port Opening: $32.0\,\text{mm} \times 14.0\,\text{mm}$ at $(X=335.0, Y=40.0)$.
  - Dual USB 3.0 Opening: $16.0\,\text{mm} \times 15.0\,\text{mm}$ at $(X=335.0, Y=65.0)$.
  - 12V DC Barrel Jack Port: Ø11.5mm circular cutout at $(X=355.0, Y=110.0)$.
  - High-Current 8-pin Molex Power Cutout: $20.0\,\text{mm} \times 10.5\,\text{mm}$ at $(X=345.0, Y=140.0)$.

### 3.5 SMP-06L & SMP-06R: 6U Heavy-Duty Rack Ears ($40.0\,\text{mm} \times 260.0\,\text{mm}$, 3.0mm Thickness)
- **Outer Bounds:** $X \in [0, 40.0]$, $Y \in [0, 260.0]$.
- **Chassis Extrusion Attachment Holes (Ø5.5mm for M5 Bolts into Corner Upright EXT-01):**
  - Centers at $X = 15.0\,\text{mm}$: $Y = 20.0, 70.0, 130.0, 190.0, 240.0\,\text{mm}$ (5 holes).
- **EIA-310-D Standard 19" Rack Mounting Slots ($10.0\,\text{mm} \times 6.8\,\text{mm}$ Oblong Slots):**
  - Centers at $X = 30.0\,\text{mm}$ (aligned with 465.1mm standard rack hole spacing):
    - **1U (Base):** $Y = 12.7\,\text{mm}, 28.6\,\text{mm}, 44.5\,\text{mm}$
    - **2U:** $Y = 57.2\,\text{mm}, 73.0\,\text{mm}, 88.9\,\text{mm}$
    - **3U:** $Y = 101.6\,\text{mm}, 117.5\,\text{mm}, 133.4\,\text{mm}$
    - **4U:** $Y = 146.0\,\text{mm}, 161.9\,\text{mm}, 177.8\,\text{mm}$
    - **5U:** $Y = 190.5\,\text{mm}, 206.4\,\text{mm}, 222.2\,\text{mm}$
    - **6U:** $Y = 235.0\,\text{mm}, 250.8\,\text{mm}$