Gauge Eｍbedding/ Calibration Service for Bolts

The bolt fastening is used in a wide range of fields in modern society and is an indispensable element. Through the measurement of axial force applied to the bolts of machine structures, automobiles, aircraft, highways, bridges, segment fasteners, and other structures, it is possible to check and control the state of fastening (checking for looseness, overtightening, and the specified fastening force). This is also utilized for the measurement of bolt strength and the bolt fastening designs. We accept gauge installation for measuring the axial force of bolts. We will machine a hole in your supplied bolts, install the strain gauges for bolts, and perform load calibration. The installation on the existing bolts enables axial force control.

Strain gauge installation service

 

Construction with any of embedded bolt gauges or surface-adhering gauges. We can also handle special-shaped bolts upon consultation. Usable in a wide range of temperatures from low to high temperatures.

 

Installation method	Embedding type				Surface bonding type
Sensor	Embedding strain gauge				Strain gauge
Operating temperature	-30 to +100°C	-40 to +150°C	-10 to +80°C	-40 to +150°C	-269 to +80°C	40 to +80°C	-40 to +300°C
Machining	Machining hole diameter Ø0.8		Machining hole diameter Ø1.6, Ø2.0		Surface processing
Applicable bolt	M3 or more		M6 or more		M3 or more
others			Available with temperature measurement function		Axial force measurement, bending measurement, torque measurement

Processing method

There are two methods in strain gauge installation service. One is embedding, and the other is bonding. Choose between them according to the conditions of use.

Embedding: BTM series

A hole of 1.6mm or 2mm in diameter is drilled in the center of the bolt. The strain gauge is inserted into the hole and embedded with an exclusive adhesive. This method has the advantage of avoiding the gauge being damage by a washer, etc. while fastening the bolt.

Bonding: F, QF, ZF, CF series

Two strain gauges are bonded on both sides of the bolt shaft in axially symmetric positions to cancel the influence of bending. It is required to slightly scrape off the surface of the bolt shaft where the strain gauges are bonded, for the purpose of avoiding strain gauges being damaged while fastening the bolt or by contact of a washer. Choose strain gauges according to the usage conditions including temperature.

Calibration service

In order to achieve accurate measurement, we offer calibration service in which the bolt is calibrated with specified load. Instruments and calibration machines used for the calibration service are periodically calibrated and inspected by public institutions complying with the national standards.

Application example

 

Wind turbine generator facilities are aimed at enlargement in the scale. Management of axial force is indispensable for the bolts used in joint parts of the structures, both in assembling process and in actual working condition. It is possible to continuously monitor the axial force by installing bolt strain gauges in some of the bolts used in the joint part.

Channel Unit FSW-10L (for TDS-150)

This is a 10-channel unit allowing multiple measurements designed for exclusive use with portable data logger TDS-150. Up to five units (50 channels) can be connected. Allows measurement by strain gauge, strain gauge-type transducer, DC voltage, thermocouple, and Pt-RTD.

• Specifications

  Type	FSW-10L
  Measuring object	Strain, DC voltage, Thermocouple, PtRTD
  Number of measuring channels	10 channels
  Power supply	Supplied from data logger

Channel Unit FSW-10 (for TDS-150)

This is a 10-channel unit designed for exclusive use with portable data logger TDS-150. Five numbers of this unit (50 channels) at the maximum can be connected to one TDS-150. Measurement of strain, DC voltage, thermocouple and Pt-RTD are possible. It also accepts measurement of 1-gauge 4-wire method using modular plug for connection.

• Specifications

  Type	FSW-10
  Measuring object	Strain, DC voltage, Thermocouple, PtRTD
  Number of measuring channels	10 channels
  Power supply	Supplied from data logger

Switching Box SSW-50D

The SSW-50D switching box is used in combination with TML Data Loggers to expand the measuring channels. The number of measuring channel is 50 per unit, and in addition to measurements of strain in ordinary bridge configurations, DC voltage and thermocouple, and a new strain measurement method with a 1-gauge 4-wire is provided.
 Since modular connector plugs are available for the 1-gauge 4-wire measurement, wire connection can be speedy finished.

• Specifications

  Type	SSW-50D
  Measuring object	Strain, DC voltage, Thermocouple
  Number of measuring channels	50 channels
  Dimensions	SSW-50D : 298(W) x 100(H) x 500(D) mm SSW-50D-05 : 298(W) x 100(H) x 600(D) mm
  Weight	SSW-50D : Approx. 7 kg SSW-50D-05 : Approx. 8 kg (connector type)
  Power supply	Supplied from data logger. When the power booster is used, AC power is required. AC85-250V 50/60Hz 10 VA MAX

Switching Box ISW-50G

This is a switching box with a built-in A/D converter (ADC) developed to expand the number of measuring channels combined with a data logger TDS-540, TDS-630, or TDS-530.
Combined use with a data logger TDS-540 and 20 switching boxes ISW-50G allows high-speed scanning of 1000 channels in 3 seconds.

• Specifications

  Type	ISW-50G
  Number of measuring channels	50 channels
  Scanning time	50 channels in 2 seconds 1000 channels in 2 seconds
  Dimensions	ISW-50G : 298(W) x 100(H) x 500(D) mm ISW-50G-05 : 298(W) x 100(H) x 600(D) mm
  Weight	ISW-50G : Approx. 8 kg ISW-50G-05 : Approx. 8 kg (also serving as connector)
  Power supply	AC85-250 V 50/60 Hz 37 VA MAX DC10-16 V 0.8 A MAX

ZF series
High temperature use strain gauge

• Single-element / two-element / three-element

  Gauge pattern	Type	Gauge length (mm)	Gauge width (mm)	Backing length (mm)	Backing width (mm)	Resistance (Ω)
  Single-element (G.F. 2.1 approx.)	ZFLK-2-11	2	0.5	5.4	1.4	120
  	ZFLA-1-11	1	1.8	7	3	120
  	ZFLA-3-11	3	1.8	10.5	3.5	120
  	ZFLA-6-11	6	2.5	15.5	4.5	120
  	ZFLA-3-60-11	3	0.7	7.7	2.6	60
  	ZFLA-1-350-11	1	1.7	6.6	3.2	350
  	ZFLA-3-350-11	3	3.1	10.2	5.2	350
  	ZFLA-6-350-11	6	2.8	16	5.3	350
  90°2-element Rosette Plane type (G.F. 2.1 approx.)	ZFCA-1-350-11	1	1.7	8.5	8.5	350
  	ZFCA-3-350-11	3	1.4	10.5	10.5	350
  90°2-element Rosette Stacked type (G.F. 2.1 approx.)	ZFCAL-1-11	1	1.1	Φ5.4		120
  45°/90°3-element Rosette Plane type (G.F. 2.1 approx.)	ZFRA-1-350-11	1	1.7	8.5	8.5	350
  	ZFRA-3-350-11	3	1.4	10.5	10.5	350
  45°/90°3-element Rosette Stacked type (G.F. 2.1 approx.)	ZFRAL-1-11	1	1.1	Φ5.4		120

  Each package contains 10 gauges.
  *We can also make self temperature compensated strain gauges suited to materials where the coefficient of thermal expansion is other than 11×10^-6/℃ (made-to-order).
  Example material: stainless steel, aluminum alloy

• Leadwire-integrated ZF series (made-to-order)

  Application	Product name	Lead wire code	Operating temperature (℃)	Leadwire code exampled
  General measurement (no temperature change)	2-wire parallel vinyl wire	LJC	-20 to +80	ZFLA-3-350-11-3LJC
  General measurement	3-wire parallel vinyl wire	LJCT	-20 to +80	ZFLA-3-350-11-3LJCT
  Waterproof	3-strand twisted cross-linked vinyl wire	LJRTA	-20 to +100	ZFLA-3-350-11-3LJRTA
  High temperature	3-strand twisted FEP wire	6FA♦LT	+269 to +200	ZFLA-3-350-11-6FA3LT
  	3-strand twisted FEP single-core wire	6FB♦LT		ZFLA-3-350-11-6FB3LT
  	3-strand twisted PTFE wire	4FA♦LT	-269 to +260 (if only short time, up to 300°C)	ZFLA-3-350-11-4FA3LT
  	3-strand twisted PTFE single-core wire	4FB♦LT		ZFLA-3-350-11-4FB3LT

  * "♦" indicates lead wire length