One mil equals 0.001 inch or 25.4 microns. In a common flexible-film convention, 100 gauge equals 1 mil, so one gauge equals 0.254 micron. Never use the gauge conversion until both parties confirm that convention.
Use the base equations
- micron = mil × 25.4
- mil = micron ÷ 25.4
- micron = gauge × 0.254, only when 100 gauge = 1 mil is agreed
| Original | Reference conversion | Controlling entry |
|---|---|---|
| 8 micron | 0.31496 mil | 8 micron |
| 10 micron | 0.39370 mil | 10 micron |
| 12 micron | 0.47244 mil | 12 micron |
| 40 gauge* | 0.4 mil = 10.16 micron | 40 gauge under the stated convention |
Do not round into a new specification
Turning 40 gauge into “10 micron” changes 10.16 to 10.00. That may be acceptable, but it requires agreement. Keep extra precision during calculation and round once for display.
Add an original-unit clause
Example: “Nominal thickness 10.0 micron (0.3937 mil for reference); micron controls. Tolerance and measurement follow CF-THK-02.” Then use the thickness inspection method. YIYUAN's listed range uses micron, so a gauge-based RFQ should always include the agreed conversion.
