How to use Chotest Flash Measuring Machine VX8300 Calibrate Steel Ruller

Rulers are widely used in schools and carpentry. There are many kinds of rulers in the market. There are plastic ruller and steel ruller, and printed scales and laser engraved scales. If you compare, you will find there are some difference between different rullers. Which ruller is more accurate?
Today we use Chotest Flash Measuring Machine VX8300 to test Xianfeng printed steel ruler and Deli laser-engraved steel ruler.
Measurement results:
Xianfeng Printed ruler:
1 cm error: Max +48 μm, Min +15.1 μm
9 cm (1cm-10cm section) error: +278.3 μm
19cm (1cm-20cm) error +554.4 μm
Deli ruler:
1 cm Error: Max -11.7 μm, Min ±0.4 μm
9 cm (1cm-10cm section) error: -4.2 μm
19 cm (1cm-20cm section) error -17 μm
Note: 1 mm = 1000 μm
Conclusion: Deli laser-engraved steel ruler is more accurate!