Conard's Photo Etching Blog

Why use Photo Etching for Sensor Elements?

Posted by Kathleen Stillman on Jun 25, 2013 8:40:00 AM
Kathleen Stillman
Find me on:

Sensors are the physical links between the "real" world and the digital world.  Sensors can detect strain, load, acceleration, inclination, vibration, motion, mass, flow, pressure, temperature, proximity, position, torque, traffic, substances, and conditions, to name a few. Many types of sensors are made from metals, and many are new types of semiconductors.

Photo etching is used to make many varieties of metal sensor elements.  The advantages of etching include the alloys and thin metal gauges that can be used. Sensor elements with unusual shapes are not...unusual, and photo etching makes unusual shapes easily.

The ability to incorporate half-etched features such as channels and tiny cavities is a simple matter with photo etching and is done in the production flow without the need for secondary operations.

photo etched gas sampling disks with half-etched flow channels and through holes These stainless steel atmospheric sampling discs feature half etched flow channels and through holes at the junctions of the x-points.

 

Some sensor elements are used to detect motion.  These are often made of alloys that have some spring characteristics such as phosphor bronze, tempered beryllium copper, spring steel or other specialty spring materials such as Eligiloy or Havar.  In many cases, this class of sensor element has secondary forming, and often heat treating or plating.

 

Microswitch actuators combine etching and forming of high yield strength stainless steel in a highly reliable sensing device.  Spectroscopy sensors can have very delicate etched features.

etched and formed hugh yield stainless microswitch actuatoretched stainless steel spectroscopy sensors

 

 

 

 

 Many different kinds of industrial, scientific and medical instruments rely on the physical link of a sensor element to detect and convey a signal to the electronic system that interprets and analyzes the information.

Some sensor devices, often called burst disks or pressure membranes, are designed to activate rapidly when certain conditions are met.  They may be used to vent overpressure in valves or piping to prevent a large blowout by failing in a predicted way. In some cases, they are intended to be actuators that trigger an extremely fast but controlled release of energy.  Explosive bolts would be in this class of device, as well as the actuators that deploy vehicle airbags.  Pressure membranes are often used in certain types of fuzing devices for munitions.

photo etched steel burst disks

Stainless steel burst discs are used to protect valves and other control devices from dangerous over pressure conditions.  The depth and width of the half etched channels are designed to fail before the system sustains critical damage.

Some sensor elements are very small.  We've made parts as small as .020" diameter.  And, some are pretty large.  We etch stainless steel elements that are 24" x 60" but only .005" thick.

The versatility of photo etching with the wide variety of alloys at thicknesses down to .001", the ability to create unusual shapes at effectively no extra cost, and the range of sizes that can be made offers sensor element designers a very unconstrained design space for their applications. 

As the trends of miniaturization and ubiquitous data continue to exp

Topics: Photo chemical etching, FAQs