Many types of contact switches are used in our everyday lives. From the doorbell that signals your arrival to the elevator that stops at the right floor.
With these examples in mind, one would understandably be frustrated with a doorbell taking a few minutes to ring because it was too hot outside or even missing your floor completely because someone was tapping their foot.
Whether you are in machine building, automation, or robotics, choosing the right contact switch can make a significant difference in your operation’s performance.
Here are some key factors to consider when a high level of precision is necessary.
Application Requirements for Contact Switches
From environment conditions to angle of contact, the first thing to consider is the application’s requirements.
Environmental Conditions
Industrial environments vary widely, from machinery reaching temperatures of over 40°C, to high levels of vibration over a period of runtime.
When micron-level accuracy is necessary, it is important to understand how the conditions of your application could impact a measurement. The benefits of a quality position switch will stop any expansion or contraction due to temperature change, as well as prevent any false trigger due to vibration and shock.
Workpiece Shape
The type of contact, flat-type or ball-type, is dependent on whether the contact surface of your workpiece is curved or flat. In order to keep accuracy from fluctuating, remember to keep flat-type to curved surfaces and ball-type to flat surfaces.
Angle of Contact
The angle a workpiece will be measured at will have an impact on the type of bearing, plain or ball, that is selected. For applications using a straight-on approach, both plain bushing and ball bushing bearings can be used. If using an angled approach, or the potential of the workpiece tilting is a concern, ball bushing bearings should be used.
Waterproof Construction
Some machinery may have liquids, such as water or coolant, that can splash all over. When working in conditions like these, the potential for water damage causing a failure could result in damaged machinery and extended downtime.
A method of accounting for this would be to consider the IP Rating of the switch. For example, Metrol offers high-precision position switches that include an IP Rating of up to IP67, allowing it to perform at a high repeatability of half a micron without being water-damaged or affected by harsh environments.
Contact Switch Installation Considerations
Before choosing a contact switch, keep in mind the installation process, such as compatibility and how much space is available.
Compatibility
There is a wide range of cylindrical and rectangular switches to choose from when selecting a position switch. Depending on the space available, the right switch will make building, testing, and maintenance on a machine significantly easier.
Output Signal
With both options of Normally Open (NO) and Normally Closed (NC) available in a contact switch, it’s necessary to communicate with your controls team to see what your system will require. The previously mentioned doorbell is an example of a NO output, while an emergency stop is an example of a NC output.
The Difference Between Mechanical vs. Electrical Switches
Mechanical switches are lower cost and simpler builds, consisting of only mechanical components, and are less likely to be affected by environmental conditions. Due to the physical nature of a mechanical switch’s sensing, it can potentially deform the workpiece if not used correctly.
Electrical switches can offer greater precision and detect a workpiece without the chance of deforming it but could result in large signal variations if placed in an environment not suitable for it.
MISUMI is a great source of position switches, with access to brands like Metrol, Omron, and Halder. Click here to explore a catalog of precision contact switches.
