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Coolant control
CNC Coolant Concentration Chart
Check concentration ranges, refractometer practice, and sump condition before treating coolant as a cutting problem.
Direct answer: coolant concentration should be checked with a refractometer and adjusted by material, operation, and sump condition. Follow the coolant supplier data sheet and site EHS procedure.
Coolant control
CNC Coolant Concentration Chart
Coolant concentration planning ranges by operation and material, with refractometer and sump-condition checks.
Source: Created from the 2026-06-24 GSC maintenance and coolant support expansion; follow the coolant supplier data sheet and site EHS procedure.Updated: 2026-06-24
| Use case | Planning range | Check method | Adjustment note |
|---|---|---|---|
| General milling and turning | 5% - 8% | Refractometer with correction factor | Use as a daily baseline for stable mixed coolant. |
| Aluminum machining | 6% - 10% | Check pH, concentration, and tramp oil | Raise only when lubricity or staining risk supports it. |
| Stainless and tough alloys | 8% - 12% | Confirm supplier limit and foaming behavior | Higher concentration can help lubricity and tool life. |
| Grinding or light finishing | 3% - 6% | Check residue and wheel loading | Avoid over-concentration when cooling is the main goal. |
| Tapping / reaming support | 8% - 12% or spot lubricant | Review thread quality and tool wear | Use operation-specific lubricant when needed. |
| Sump out of control | Do not adjust blindly | Check concentration, pH, bacteria, odor, and tramp oil | Clean or service sump before chasing concentration. |
Coolant type
Compare soluble oil, semi-synthetic, synthetic, and straight-oil choices.
Maintenance cadence
Tie daily coolant checks to PM schedules, sump service, and recurring alarms.
Cost handoff
Estimate service, downtime, and maintenance cost when coolant issues repeat.
Download chart
Use the PDF at the machine or in the maintenance log binder.