Before selecting and buying a load pin, load cell or other force sensor, Strainsert recommends identifying and defining what specific tasks it will be used for by your company.
First, make sure you have answers to fundamental questions about the application:
Will one or multiple sensors be required?
Do you need to measure dynamic forces, static forces, or both?
For how many axes do you want to measure force?
Where will the sensor be fixed?
What aspects of the force data are most important to your applications?
What is the smallest force change the sensor should be able to measure?
Second, answer questions on the operating environment where the force sensor will be used:
Will there be a lot of electrical or other noise?
Are there any extremes of temperature, humidity, pressure, etc?
Will the environment itself be subject to movement (e.g. vibrations)?
Will the environment be clean, or will there be a large amount of dust?
Third, make sure to define and assess your resources. For example, space restrictions will determine the maximum size of the sensor. Time restrictions will determine whether you require a more “plug and play” type sensor. Distance or wiring specifications will prompt you to consider wireless force sensor solutions.
Fourth, be cognizant of the number of resources you'll need to or can devote to integrating the sensor into your existing systems and what related equipment you would need to operate the sensor and collect the data efficiently.
How much of a budget do you have available for the sensor(s)?
What electrical interface options can you already support?
Do you need a force sensor with integrated electronics?
How much time and work can you devote to the integration of the sensor?
What are the limits for the mechanical interface and size of the sensor?
Fifth, define what are absolute requirements for the application you need the force sensor for and what other aspects can be more flexibly applied or excluded if cost, time, or resource issues make them unrealistic.
As with many engineering decisions, choosing between different products is a balancing act. Products with better technical specifications usually cost more. Sensors with high performance in one specification might have low performance in another.
Do you really need the best sensor, or can you sacrifice a bit of performance?
Which specifications are vital to your application?
Which can you live without?
List each specification in order of preference. Below are some standard specifications that could be relevant for your application.
Force Measuring Range:
This is the range of force and torque that the sensor can measure. They are often listed separately on manufacturer datasheets. To choose this value, calculate the highest force which you will want to measure in all directions. Don’t forget dynamic forces! These are higher than static forces and dependent on the velocity of impact.
Maximum Overload Capacity:
This value represents the force that will provide permanent damage to the sensor. You really don’t want to be applying forces that are even close to this value.
Frequency/Maximum Data Output Rate:
The Maximum Data Output Rate defines the maximum sampling frequency of the sensor. This determines how often the sensor can provide new force data. Work out which frequency you require for your application and choose a force sensor that can supply at least this frequency.
There are three different specifications for precision that can be applied to force sensors: resolution, accuracy and repeatability. The most common to see on datasheets is resolution, which is the minimal change in force that the sensor can measure.
There are many technologies used for measuring force, including piezoelectric, resistive and hydraulic. Some technologies are more suited to particular applications and environments than others. Traditionally, most multi-axis force sensors use strain gauge technology.
In conclusion, the more preparation and definition work done before selecting your force sensor, the better the results are likely to be for your work and your company. Please contact us for any of your force sensor application, specification and product needs.