Technology / product information

Minimize CNC downtime by detecting signs before the P point on the P-F curve, using numbers instead of impressions.

■ Why factories must start monitoring now
CNC machine tools demand higher accuracy and surface quality than general equipment, which means vibration thresholds must be stricter than ISO 10816/20816 zones. In Thailand, challenges like humid rainy seasons, fine dust, and strict energy-management rules in the EEC make it critical to minimize both unplanned downtime and wasted energy.

bearing lubrication breakdown, followed by misalignment, unbalance, looseness, or belt wear. CNC machines are also affected by foundation stiffness, feed resonance, and servo/spindle dynamics. Relying only on listening and touch misses early signals. A shared numerical language ensures production, maintenance, and quality work on the same evidence.

■ Detecting problems with vibration data
The key metric is RMS vibration velocity (mm/s RMS), supported by frequency analysis:

‐ Unbalance: 1× signal increasing with speed
‐ Misalignment: Dominant 2×, strong axial
‐ Looseness: Wide spectrum with sidebands
‐ Bearing faults: High-frequency, found via Envelope Analysis

> Use site-specific baselines taken after installation/overhaul under real cutting conditions. Design two-tier thresholds with trend/action alarms and dwell time to avoid false alerts.

■ Two-tier threshold design
1. Quality threshold: Stricter than ISO, detects early signs of surface finish or dimensional drift, as well as tool wear.
2. Protection threshold: Aligned with ISO for safe shutdown and equipment protection.

Even small increases in RMS velocity can signal rising problems. Monitoring the rate of change (slope) is as important as the absolute values.

■ KPI examples for CNC maintenance
‐ % of machines exceeding quality thresholds (by line/team)
‐ Average recovery time from vibration alarm to corrective action (MTTR)
‐ Tool life improvement after vibration correction
‐ Energy efficiency: Material removal per kWh before/after vibration fixes

These KPIs help balance uptime, quality, and energy management.

■ Recommended equipment
‐ MODEL-1332B: Portable meter for baselines & spot checks (Free Download)
👉 https://prime.nc-net.com/105994/en/catalog/detail/7285
‐ MODEL-2502: 4–20 mA transmitter for PLC/SCADA (Free Download)
👉 https://prime.nc-net.com/105994/en/catalog/detail/7541
‐ MODEL-2590C: Panel display with relay alarms (Free Download)
👉 https://prime.nc-net.com/105994/en/catalog/detail/7540

■ Showa Sokki’s recommendation
Start by asking: “What do you want to protect—surface finish, accuracy, tool life, or throughput?” With clear goals, thresholds become shared values for quality and uptime.

Showa Sokki provides not only instruments but also advice on measurement points, sensor mounting, and setup suited to Thailand’s environment. We recommend starting with one optimal unit, verify results, and expand step by step to avoid over-measuring or over-investing.

For details, you can download the product PDF or contact us directly.

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【Glossary】
‐ P-F curve: Timeline from first detectable point (P) to functional failure (F)
‐ RMS velocity: Primary vibration metric (mm/s RMS)
‐ Two-level alarm: Trend vs. Action thresholds with delay
‐ Threshold: Based on site baseline, not generic ISO tables
‐ BPFO/BPFI: Bearing fault frequencies found by Envelope Analysis
‐ VSD (inverter): Variable-speed drives needing RPM-aware thresholds
‐ Resonance: Amplified vibration at natural frequency
‐ Electrical fluting: Bearing damage from stray current

【References】
‐ ISO 10816/20816 vibration guidelines
‐ CNC-specific threshold practices
‐ Thailand climate impact: humidity, dust, rainy season
‐ Energy-management rules for designated factories
‐ EEC production & investment outlook
‐ Bearing frequency & envelope analysis resources


#CNC #VibrationMonitoring #PredictiveMaintenance #ThaiFactory #ShowaSokki #DowntimePrevention

(Last update : 2025-09-10)