New Weighing Technology: Surface Acoustic Wave

new weighing technology- surface acoustic waveIf you’ve been exposed to weighing technology, you’ve likely heard of the strain gage load cell.  This is the most common type of technology used by scale manufacturers around the world.  Just because it’s the most common technology used in our industry, it doesn’t necessarily mean it’s the best fit for your needs.

 

If you’ve never had a reason to utilize a scale to weigh fine resolutions as well as precise measurements, you may not be familiar with the limitations of strain gage load cells.  Companies requiring precise measurements such as laboratories, paint mixing companies, semiconductor manufacturers and others often have to keep track of an inventory of extremely lightweight parts. As a result, a scale that can accurately weigh these materials is necessary.

Strain Gage Limitations

 

The most common type of load cell, the strain gage, works by measuring strain or stress of the spring element of the load cell itself.  When an object is placed on a scale’s platform, this metal spring element bends in proportion to the total load weight.  To measure the amount of bend, strain gages are attached to the flexors of the spring element.

To put it more simply, when an object is placed on the platform, the spring element and flexors bend, the strain gages register the resistance and the voltage output changes.  The voltage then passes through an Analog to Digital Converter and the signal that has been digitized is sent to the scale’s display indicator where you’re able to read the weight as numeric digits.

One of the primary disadvantages of strain gages is that they’re not able to detect small changes in weight and most often only offer a readability of 1:5000 pieces.  A scale’s readability is integral to its performance.  While strain gage scales may meet the needs of many businesses, they typically do not work well for high resolution measurements required by certain industries.

Other strain gage disadvantages include:

  • Accuracy drops during changes in temperature.
  • Different types of adhesives are used to affix the spring element within the scale, which can result in loss of flexibility.
  • A direct relationship between resolution and capacity resulting in reduced resolution as capacity increases.
  • The Analog to Digital Conversion that is required reduces the scale’s accuracy.
  • Susceptible to shock loading damage (where a load is dropped onto the scale from a height) and overloading (where a load is placed on the scale that outweighs its maximum capacity).

Arlyn Scales Surface Acoustic Wave Technology

 

After decades of experience in the weight industry, Arlyn Scales has released an internationally patented Surface Acoustic Wave (SAW) technology that helps businesses that aren’t able to find reliable and affordable high precision scales that offer resolutions that meet their unique needs.

How Are SAW Load Cells Different from Strain Gage Load Cells?

 

As mentioned above, strain gage load cells measure strain or stress, whereas our SAW scales measure displacement.  By measuring displacement, our scales are able to reduce strain levels to less than 10% of what is found in most strain gage load cells.

This makes our ultra precision SAW scales far more reliable and better suited for most industrial applications because they feature a higher load capacity that is not subject to damage from shock or overloading.  These scales were designed to be used in the most taxing industrial environments and can accept up to 2.5 times their rated loads without damage, under certain circumstances.

SAW load cells also feature a higher resolution, even at higher capacities, as compared to standard strain gage load cells. Compared to 1:5,000 for most strain gage scales, our SAW scales offer 20 times enhanced readability (1:100,000).

For example, while a strain gage scale with a 50 lb. capacity could have a resolution of .01 lb., a SAW scale with the same capacity constraints would have a resolution of .0005 lb.

The chart below highlights the resolution differences at the same maximum capacities:

 

Capacity SAW Scale Resolution Strain Gage Resolution
10 0.0001 0.002
25 0.0002 0.005
50 0.0005 0.01
100 0.001 0.02
500 0.005 0.1

 

Another major advantage to our scale technology is that our SAW scale measurements are taken digitally, which ensures their accuracy and also increases the detection of small weight changes.  The spring element in a SAW load cell utilizes two attached transducers.

One transducer acts as the receiver and the other as a transmitter. The transmitter creates a bulk wave that is passed to the receiver where it is then passed back to the receiver, over and over.  Next when an object is placed on the scale platform, the spring element bends and changes the frequency of this wave.  Our SAW scales measure this frequency change to determine the weight of the object placed on the platform.

Finally, while changes in temperature can affect weight readings in all scales, our ultra precision SAW scales can reduce this problem significantly.  Typically, our scale readings may change less than 3:1,000,000 for each change of 1°C, which is far superior compared to strain gage scales.

Factory Direct Approach to Scale Manufacturing

 

Another benefit of our scales is the fact that Arlyn Scales is both a direct manufacturer and distributor of all of our products.  Each of our scales is designed and manufactured in our New York factory, where we ship our products directly to our customers.

This helps our team reduce our costs and pass on the savings directly to you.  It also allows us to invest in the latest research and design technologies (including SAW load cells) that allow you to receive a higher quality product at a price that is comparable to strain gage scales.

Contact Arlyn Scales Today

 

Another benefit of working with the manufacturer is that we can provide custom solutions based on your unique needs. With our decades of experience in the scale industry, we’re ready and willing to assist you in any way that we can. Contact us today to learn more about our SAW scales and find out if they may be right for you.