Mitutoyo 293-100-20 High-Accuracy Digital Micrometer

Technical Overview

Sub-micron digital outside micrometer with 0-25mm range, switchable 0.1µm/0.5µm resolution, ±0.5µm accuracy, ABS rotary sensor, and constant 7-9N force.

Key Features

The world's first 0.1 µm resolution handheld digital micrometer [1.1.6]
Highly rigid frame combined with a constant-force mechanism (7.0 - 9.0 N) for superior measurement stability
Removable heat shield blocks body temperature transfer to minimize frame expansion
ABSOLUTE electromagnetic induction type rotary sensor eliminates startup origin setting
Equipped with Digimatic SPC data output for effortless integration into quality systems
Switchable digital resolution steps (0.0001 mm / 0.0005 mm)
Carbide-tipped, micro-lap finished measuring faces reduce abrasive wear over time

Technical Specification Matrix

Parameter	Value
Measuring Range	0 - 25 mm
Digital Step / Resolution	0.1 µm / 0.5 µm (switchable)
Maximum Permissible Error (J MPE)	±0.5 µm
Flatness	0.3 µm
Parallelism	0.6 µm
Measuring Face Type	Carbide-tipped, micro-lap finish, ø3.2 mm
Measuring Spindle	With spindle lock, ø6.35 mm diameter, spindle pitch 0.5 mm
Measuring Force	7.0 to 9.0 N
Display Type	LCD, character height 7.5 mm
Sensor Type	Electromagnetic induction type ABS rotary sensor
Power Supply	1 x Lithium battery (CR2032)
Battery Life	Approx. 2 years
Auto Power Off	Yes, after 20 minutes of non-use
Data Output	Yes (Digimatic d2 format)
Physical Weight (kg)	0.4
Dimensions L x W x H (cm)	17.8 x 2.5 x 7.27

Industrial Applications

1. High-Precision Gauge Block Calibration

Calibrating reference grade 1 and grade 2 gauge blocks requires absolute measurements at the sub-micron scale. The 0.1 µm resolution and an instrumental error of just ±0.5 µm allow metrologists to verify minimal deviations under stable laboratory temperatures.

Problem Solved

Standard handheld micrometers lack the sub-micron resolution (typically 1 µm or more) and suffer from frame expansion due to thermal transfer. This micrometer's high accuracy and removable heat shield solve this, keeping thermal expansion errors to near-zero.

Gauge Block CalibrationSub-Micron ResolutionHeat ShieldABS Rotary SensorInstrumental Error

2. Statistical Process Control (SPC) in Automotive Valve Manufacturing

Automotive engine valves require extremely tight tolerances to maintain cylinder compression. Using the integrated Digimatic data output, operators can instantly transmit real-time 0.1 µm measurements of the valve stem diameter directly to an SPC software database.

Problem Solved

Manually recording sub-micron values is highly prone to human error and slows down inspection times on high-throughput assembly lines. The SPC output and switchable 0.0001mm resolution allow for error-free logging and instant quality trend analysis.

SPC Data OutputDigimatic InterfaceValve Stem InspectionQuality Trend ControlStatistical Process Control

3. Delicate Silicon Wafer Thickness Profiling

Inspecting the micro-lap thickness profile of silicon wafers directly in cleanrooms requires constant-force measurements to prevent wafer fracturing. The micrometer applies a constant measuring force of 7 to 9 N using its high-performance ratchet thimble, ensuring repeatable measurement on delicate materials.

Problem Solved

Varying operator hand forces can crush or damage delicate silicon wafers or yield inconsistent thickness readings. The constant-force ratchet mechanism standardizes the measuring pressure, while carbide-tipped micro-lap finished measuring faces prevent abrasive wear.

Constant-Force MechanismRatchet ThimbleCarbide-Tipped Measuring FaceSilicon Wafer InspectionMeasuring Force