Senstech AG is launching two new products at this year's SENSOR+TEST in Nuremberg: the compact KB-011-1600 force sensor bracket and the SA-011-1500 mini signal amplifier.

The force sensor bracket is a further development of the KB-011-0500 with a size of 9×14 mm. Initially, it is available for a force range of 20 N; however, with different sheet thicknesses, measuring ranges from approx. 3 to 100 N can be covered. The miniature sensor is mounted with an M2 screw and a dowel pin in a twist-proof manner. The force is applied to the bracket via a round-head rivet; alternatively,

two screw holes are available for usage-specific force application.

The SA-011-1500 mini signal amplifier is suitable for amplifying the output signal of a sensor directly in the supply line. This allows it to be transmitted without interference and digitized with simple means. The module is available in four variants covering operating voltages from 2.2 to 25 V and different input signal ranges. It is compatible with development platforms such as Arduino as well as with 0-10 V analog inputs.

Senstech is introducing the PicoBlade connector system for all its own products with stranded wires, which enables wire-to-wire and wire-to-board connections.

This means that in future our sensors can be connected to amplifier modules or to customers' circuits without soldering.

> Mini Signal Amplifier SA-011-1500 Data Sheet
> Force Sensor Bracket KB-011-1600 Brochure

Used in Medical Devices

This principle of pressure measurement without changing or interrupting the hose path is used by many of our customers in medical devices. Peristaltic pumps, for example, can detect blockages in the infusion flow by the increase in pressure and trigger an alarm. In ophthalmic surgery devices, the irrigation fluid pressure is measured in a similar way.

Connected Directly to the Arduino

Technically, the demonstrator is very simple. The sensor used is of type KB-011-0300 and has an integrated signal amplifier. It is directly connected to a "Seeeduino Lotus" development board, which linearly transforms the signal and displays it on a bar graph. Power is supplied by a USB power bank.

Many Applications Possible

The measuring principle shown can be used wherever pressures in the millibar range are to be measured, but hygiene requirements prohibit the use of classic pressure sensors. For example, it could also be applied in the food industry or in household appliances such as coffee machines.

Measurements on Loaded Components

Strain gauges are used whenever the deformation or movement of a loaded component is to be measured. Thin-film-based sensors made of spring steel are a robust alternative to the common foil strain gauges attached with glue. These sensors are Laser welded to the substrate and achieve a particularly high sensitivity, since the deformation is concentrated on a weakened central zone of about 1×1 mm, on which the strain gauge elements are placed. This allows for deformations in the micrometer range to be measured.

Suitable for Industrial Use

Since a Wheatstone full bridge can be placed on a very small surface, which is thermally coupled to the underlying metal part, the measured signal is insensitive to temperature fluctuations. In contrast to glued-on sensors, creeping layers, which can impair long-term stability, are avoided. The welded-on sensors thus represent a measurement solution suitable for industrial use, not only for individual measurements, but also for permanent monitoring applications. Wear effects can be made visible over months or years.

Versatile Applications

Accordingly, such sensors are used e.g. in metal processing, where they monitor the load on tools, or in the automotive industry as part of a load measurement system. The measuring arrangement and the dimensions of the sensors can be adapted to the respective application from as little as approx. 100 pieces. Shear forces or multi-dimensional forces can also be measured. The smallest specimens are only 5×5 mm in size. One disadvantage is the additional Laser welding step; however, this is offered as a service by Senstech.

Several Processing Methods in One Setup

Thanks to interchangeable processing heads, various machining processes such as laser cutting, laser drilling, laser welding, laser soldering, laser marking, laser structuring and laser ablation can be combined. It is even possible to operate two lasers in parallel within the system, such as a fiber laser for cutting and a nanosecond laser for ablation/engraving. This allows two different machining processes to be carried out on a part with a single clamping setup.

Accelerated Series Production of Sensor Panels

Due to the higher dynamics of the machine, we can produce the substrate panels for our series products about 10% faster than with our existing cutting laser.

In addition to all the process-related advantages, this investment enables us to also carry out laser welding on customer-specific parts in larger quantities, as well as to offer our own products with laser-welded housings in the future.

Excerpt of Specifications

• 2 independent zero-point clamping systems
• Axis stroke: X axis 700 mm, Y axis 400 mm, Z axis 330 mm
• Feed rate in rapid traverse: 54'000 mm/min
• Repeatability: ±0.002mm
• Fanuc B1i-B5 controller

Additional information on the Askias Precision is available in the manufacturer's video.

The roof of our company building had to be renovated. Due to changes in local building regulations, we were able to add new office space to the top floor of the building in the course of this renovation. Work was carried out in accordance with the Minergie standard for energy-efficient construction.

Linked Heating and Cooling Systems

In parallel with this expansion, we replaced all the heating, cooling and ventilation systems in the building. The cooling circuit of the production facilities was made more flexible and equipped with additional control and monitoring systems. The oil tank with a volume of 20,000 liters is now used as a central cold water reservoir. A second tank with 3000 liters stores hot water. Heating and cooling is now provided exclusively by heat pumps. Fossil fuels are no longer used.

During the cold season, the excess heat from the production facilities can be used to heat the premises. This minimizes the necessary heat exchange with the ambient air and thus the energy consumption of the building. The system is ready to accommodate a possible expansion of the production machinery.

The existing apartment on the 2nd floor of the building was also completely renovated. It is to be rented out again in the future, but also serves as a long-term reserve of space for the company.

Potent Solar System With Intelligent Control

A photovoltaic system was installed on the roof and on the terrace railing. With an expected annual yield of 60 MWh, it will cover more than half of the electricity needs of our production.

Thanks to intelligent control and generous storage capacities for hot and cold water, the power consumption of the building services can be flexibly distributed throughout the day. This allows for the system to be optimized so that a large part of the solar power is used internally.

These conversions make Senstech AG more climate-friendly and open up additional space reserves for future growth. The investment volume for the overall project amounted to approx. 2 million Swiss francs.

Increasing Importance of Laser Ablation

For several years, Senstech AG has been using laser technology in the production of its thin-film strain gauges. By now, almost all of our sensor elements are structured and trimmed with laser ablation. This eliminates labor-intensive photolithography processes. Instead, the thin layers are sputtered over the entire surface. Ultra-short pulse lasers are then used to cut linear structures into them, while leaving the underlying insulation layer intact. Only the gold layers used for solder pads and low-impedance tracks continue to be structured using photolithographic methods.

Securing the Ability to Deliver

For us as a component manufacturer and medical technology supplier, the ability to deliver products on time is of utmost importance, even if one of our production facilities should fail. For certain process steps, we can rely on certified third-party suppliers who perform these steps on our behalf if required. However, this is not the case for the laser ablation and trimming processes, since no company in our region has comparable equipment available. With the gradual phase-out of photolithography and the development of new sensors that require the use of laser technology, the acquisition of a second system was therefore an urgent necessity.

More Space for Process and Product Development

The increased capacity for laser ablation and trimming processes has advantages for production, but also for our development department. Additional machine time is now available that can be used for process development, such as to further optimize the productivity of ablation processes or to automate recurring measurement tasks using computer vision. It will also be easier to coordinate series production and prototype manufacturing. This creates added value for both existing and new customers.