NIPPON LINIAX CO., LTD., an affiliate of NICHICON CORPORATION, has successfully commercialized a thin-film strain-gauge-type 3-axial force sensor with built-in amp. The product is one of the smallest in the industry and offers high sensitivity and high reliability. Nippon Liniax develops, produces, and markets measuring systems in a range of fields with a focus on strain-gauge-type pressure sensors and transducers. The product uses Nichicon’s proprietary thin-film processing technology, in which sputtering* is used to form a film of a high-sensitivity special metallic oxidized strain resistive element directly onto a metallic elastic body, thus forming a bridge circuit. The sensor directly detects the metallic elastic body’s strain and outputs a signal that is proportionate to the change in strength.

Background to Development

With the increasing number of unmanned factories in recent years, assembly equipment is performing a greater range of functions, and more and more facilities are switching from people to machinery such as industrial robots to perform complex assembly work. Since these machines must perform with finely tuned force control, they require force sensors. Early on, Nichicon sought to meet these needs by seeking partners in related industries. The company teamed up with Nitta Corporation to commercialize the world’s first (as of April 2007; according to Nichicon) ultra-compact thin-film strain-gauge-type 6-axial force sensor. It has now successfully developed a 3-axial force sensor with built-in amp that is among the smallest in the industry and that meets customers’ needs for ease of use, low cost, high sensitivity, and high reliability. This product makes the most of Nichicon’s basic technology for manufacturing metal diaphragm integrated pressure sensors. Sputtering is used for an integrated formation process in which a high-sensitivity strain thin-film and a thin-film insulation are formed as one on to an elastic body. This results in superb performance with high sensitivity and reliability. The product is expected to find various force control applications, such as in precision-processing robotic hands, micro tension controllers, and precision medical equipment. 
This new sensor comes in two ratings, which Nichicon will use to tap new markets in which it can offer customers superior operability for their products.

Main Features

• Because the amp is built into this small, high-performance 3-axial force sensor, there’s no space needed to install an amp base. This helps make the product one of the industry’s smallest 3-axial force sensors with a built-in amp (as of March 2013; according to Nichicon). And because the amp is built in, the sensor output can be directly connected to the A/D transducer.
• Has a built-in function for resetting the standard signal deviation of the three axial caused by mounting.
• On the metallic diaphragm is a pattern formation of a special strain resistive film whose temperature coefficient is essentially zero. This makes it highly resistant to temperature change and means that only the change in force needs to be measured. Furthermore, because change in force is measured directly via the integrated insulation substance and elastic body, measurement is highly accurate with extremely high sensitivity and low noise.
• Thanks to Nichicon’s proprietary thin-film technology, the product can handle a wide range of temperatures.
• Compactness, light weight, and low cost make it available for a wide range of applications. 
  Example applications: force control for industrial robots, tactile measurement, joysticks, tension measurement, small precision medical equipment, etc.

Specifications

• Force detection method: Metallic elastic body thin-film strain-gauge-type force sensor (direct measurement method)
• Rating: MFS20-010: X, Y axis = 10N・cm, Z axis = 20N 
  MFS20-025: X, Y axis = 25N・cm, Z axis = 50N
• External dimensions: 
  20 × 20 × 18mm (W × D × H) (without connecting adapter)20 × 20 × 23mm (W × D × H) (with connecting adapter)
• Main unit weight: Approx. 26g/30g (with adapter/with cable)
• Static load bearing capacity: 200% of rating
• Usable temperature range: 0 to 50°C
• Cross-axis interference: No more than 10%FS (without interference cancellation)
• Linearity error: No more than 0.5% of rating
• Hysteresis error: No more than 0.5% of rating
• Response frequency: 5 kHz
• Temperature characteristics: No more than 0.5%/°C of rating
• Sample: In progress
• Mass-production start: May 2013
• Sales targets: 200 units in 2013, 500 units in 2014
• Manufacturing and marketing:
  NIPPON LINIAX CO., LTD. (ISO9001 certified)
  3-2 Sugahara-cho, Kita-ku, Osaka-shi
  Company division: FS Group
  Phone: 81-6-6362-6470
  Email: fs-information@liniax.co.jp

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