Tech-dat/tech-dat.md
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- [[effects-dat]]
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-- [[fab-dat]] - [[fab-PCB-dat]] - [[fab-PCBA-dat]] - [[fab-stencil-dat]] - [[fab-workspace-dat]] - [[fab-3d-print-dat]]
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+- [[fab-dat]] - [[fab-PCB-dat]] - [[fab-PCBA-dat]] - [[fab-stencil-dat]] - [[fab-workspace-dat]] - [[fab-3d-print-dat]] - [[fab-soldering-dat]]
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- [[PCB-dat]] - [[PCB-design-dat]] - [[PCB-soldering-dat]] - [[footprint-dat]]
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fab-dat/fab-PCBA-dat/fab-PCBA-dat.md
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# PCBA-dat
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+- [[fab-PCBA-dat]] - [[fab-soldering-dat]]
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+
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+- [[fab-PCB-dat]] - [[fab-PCB-tools-dat]]
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- [[PCB-soldering-dat]] - [[desoldering-dat]]
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fab-dat/fab-PCBA-dat/fab-reflow-dat/fab-reflow-dat.md
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### 🔧 1. Basic Alloy Differences
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-| Property | Sn63/Pb37 | Sn42/Bi58 |
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-|-----------|------------|-----------|
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-| **Type** | Tin–Lead eutectic | Low-temp bismuth-based |
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-| **Melting Point** | **183 °C** | **138 °C** |
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-| **RoHS** | ❌ Not compliant | ✅ RoHS compliant |
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-| **Mechanical Strength** | High | Lower (more brittle) |
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-| **Thermal Fatigue Resistance** | Good | Moderate to poor |
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-| **Cost** | Low | Medium–high |
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+| Property | Sn63/Pb37 | Sn42/Bi58 |
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+| ------------------------------ | ----------------- | ---------------------- |
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+| **Type** | Tin–Lead eutectic | Low-temp bismuth-based |
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+| **Melting Point** | **183 °C** | **138 °C** |
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+| **RoHS** | ❌ Not compliant | ✅ RoHS compliant |
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+| **Mechanical Strength** | High | Lower (more brittle) |
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+| **Thermal Fatigue Resistance** | Good | Moderate to poor |
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+| **Cost** | Low | Medium–high |
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---
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### 🌡️ 2. Typical Reflow Profile Comparison
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-| Stage | Sn63/Pb37 (183 °C) | Sn42/Bi58 (138 °C) | Key Difference |
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-|--------|--------------------|--------------------|----------------|
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-| **Preheat** | 100–150 °C for 60–120 s | 80–110 °C for 60–120 s | Lower ramp to avoid flux burnout |
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-| **Ramp Rate** | 1–3 °C/s | 0.5–2 °C/s | Gentler ramp for Bi alloy |
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-| **Soak (Flux Activation)** | 150–170 °C for 60–120 s | 110–130 °C for 60–120 s | Lower soak temperature |
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-| **Peak (Reflow)** | 210–225 °C | 160–170 °C | ~50 °C lower peak |
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-| **Time Above Liquidus (TAL)** | 30–90 s | 30–90 s | Similar duration |
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-| **Cooling Rate** | 2–4 °C/s | 2–4 °C/s | Avoid fast cooling to prevent cracks |
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+| Stage | Sn63/Pb37 (183 °C) | Sn42/Bi58 (138 °C) | Key Difference |
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+| ----------------------------- | ----------------------- | ----------------------- | ------------------------------------ |
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+| **Preheat** | 100–150 °C for 60–120 s | 80–110 °C for 60–120 s | Lower ramp to avoid flux burnout |
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+| **Ramp Rate** | 1–3 °C/s | 0.5–2 °C/s | Gentler ramp for Bi alloy |
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+| **Soak (Flux Activation)** | 150–170 °C for 60–120 s | 110–130 °C for 60–120 s | Lower soak temperature |
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+| **Peak (Reflow)** | 210–225 °C | 160–170 °C | ~50 °C lower peak |
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+| **Time Above Liquidus (TAL)** | 30–90 s | 30–90 s | Similar duration |
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+| **Cooling Rate** | 2–4 °C/s | 2–4 °C/s | Avoid fast cooling to prevent cracks |
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+Sn63/Pb37
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+- preheat = 130C / 90s
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+- soak = 160C / 60s
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+- peak = 220C
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+
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+### Optimized Reflow Profile (Lead-Free) == Sn63/Pb37 (183 °C)
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+
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+To ensure high-quality solder joints and minimize "dross" or solder beads, your profile should follow these specific timing and rate constraints:
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+
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+| Phase | Temperature / Rate | Duration | Purpose |
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+| :--- | :--- | :--- | :--- |
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+| **Preheat** | 130°C | 90s | Evaporates solvents; prevents thermal shock. |
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+| **Soak** | 160°C | 60s | Activates flux; stabilizes board temperature. |
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+| **Ramp-to-Peak** | **1.5°C – 3°C / sec** | ~30s | Rapidly moves from soak to liquidus. |
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+| **Peak (TAL)** | **220°C - 235°C** | **30s – 60s** | Time Above Liquidus (TAL); ensures full wetting. |
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+| **Cooling** | **-3°C – -4°C / sec** | Until < 100°C | Rapid cooling creates a fine grain structure. |
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+### Critical Adjustments for your Profile:
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+
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+1. **Time Above Liquidus (TAL):**
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+ For most lead-free pastes, the melting point is around **217°C**. Since your peak is **220°C**, you have a very narrow "window."
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+ * **Advice:** Ensure the board actually stays above 217°C for at least **30 seconds**. If your oven has cold spots, you might want to bump the peak to **225°C** to ensure every joint melts fully.
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+
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+2. **The Ramp-to-Peak Rate:**
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+ Once you leave the 160°C soak, you must heat up quickly. If you go too slow, the flux will "burn out" before the solder melts, leading to grainy joints or oxidation (dross).
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+
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+3. **Cooling is Often Forgotten:**
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+ Do not just leave the board in a closed oven to cool slowly.
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+ * **Action:** Once the timer hits zero at peak, crack the oven door open slightly (if using a DIY toaster) to achieve a faster cooling rate. Fast cooling makes the solder joints **shiny and strong**; slow cooling makes them **dull and brittle**.
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+
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+
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### ⚙️ 3. Process Considerations
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-| Factor | Sn63/Pb37 | Sn42/Bi58 |
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-|--------|------------|------------|
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-| **Heat Sensitivity** | Suitable for most PCBs | Safer for heat-sensitive components (e.g. LEDs, flexible PCBs) |
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-| **Joint Reliability** | Ductile, strong | Brittle — not ideal for high vibration or stress |
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-| **Storage Stability** | Good | Can age faster; store below 10 °C |
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-| **Rework Temp** | ~250 °C | ~180 °C | Easier to rework Bi-based solder |
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+| Factor | Sn63/Pb37 | Sn42/Bi58 |
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+| --------------------- | ---------------------- | -------------------------------------------------------------- |
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+| **Heat Sensitivity** | Suitable for most PCBs | Safer for heat-sensitive components (e.g. LEDs, flexible PCBs) |
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+| **Joint Reliability** | Ductile, strong | Brittle — not ideal for high vibration or stress |
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+| **Storage Stability** | Good | Can age faster; store below 10 °C |
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+| **Rework Temp** | ~250 °C | ~180 °C | Easier to rework Bi-based solder |
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---
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