Torque Testing: 7 Things you Need to Consider Before ...

Whether it is a fastener such as a nut, screw, or electrical equipment such as an electric motor, it needs a force to turn. However, if you fasten the nut too tight, this excessive Torque can lead to stretching and, consequently, breaking bolts. On the other hand, if you provide it with insufficient Torque, it will result in loose connections. To ensure quality in manufacturing or repairing, you need to perform torque testing.

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What is Torque Testing?

Torque testing is the measurement of the force you apply on particular machinery. This method tries to determine how the object under observation will react to turning it commonly and excessively.

Consider a typical scenario of tightening nuts of the tire while changing it for puncture. Here you have to apply a torque test to avoid loose bolts on the go. For testing the Torque, you will insert a torque transducer between the turning tool, i.e. the wrench, and the object on which you are applying force, i.e. the nut. If this force is sufficient, you are ready to continue your journey. Otherwise, you will fasten the bolts again.

When to test the Torque?

Testing the Torque is vital while dealing with machinery with rotating parts such as engines and motors. Some typical applications for torque testing are

To Check Fastening

In the assembly process of heavy and complex machinery, you will involve several screws and nuts. At this point, the manufacturer must ensure proper fastening. However, suppose there are loose fasteners. In that case, the integrity of the entire machinery will be at stake, which can cause severe danger to innocent lives.

Therefore, you have to tighten the bolts until it achieves its maximum Torque. Nevertheless, there may be many cases where the threaded fastener has malfunctioned. If so, your nut will reach the peak torque value, and in actuality, it has not completed its turns at all. Hence, to cater to such a situation, you need objective measures.

One proven method is to capture the Torque vs angle signature during the fastening process. By this, you will identify the number of full rotation angles that the object has moved when it gets to the maximum torque value. In addition, you can check whether the fastener is the root cause of the defect or any other issue is also present.

To Check Torque-to-Turn

Torque-to-turn is the force a system need when overcoming the inertia and friction it faces from its environment. Shaft and bearing assemblies undergo tests for these two types of torques

• Breakaway Torque used to initiate the rotation of a system
• Running Torque used to keep the system in its running state

Consider a simple motor that has to overcome the friction around it to get moving. For that, it may use fuel or electricity to produce enough energy for breaking away from inertia. This friction may be the result of insufficient lubricant, damaged parts, or debris inside bearings. Greater is the force of friction; more significant is the energy that it will use up.

Just like the fastening process, you can check for a predetermined value of Torque and use it to check whether the engine is assembled correctly. Yet you need to dive into the details for proper analysis of the machine. Record the Torque vs time signatures and you will get to know the performance at each second, thus unveiling the issue.

Likewise, in testing the running Torque, you can check for the predefined highest value, but this will result in no more profound analysis. In this case, you again can record Torque vs angle signatures. Observing it will lead you to identify whether your problem has to do with damaged gears or their geometric imperfections.

How to perform Torque Testing?

With experience, you may know the proper torque of equipment it needs for fixation. Even so, you need to conduct a periodic audit as time passes to maintain the system. General testing methods that you can opt for are

• First Movement Test: This technique calculates the tension or residual torque present in a joint after tightening it, using torque wrench testing.

For this method, use a wrench with a torque meter on it. Rotate the already fixed fastener in the direction you moved it while tightening. Upon a slight movement of the bolt, note the value on the meter. You will get the original Torque the joint needs for fastening. Note that do not move the nut further as it will cause damage.

• Loosening Test: This method works the same as above. Here, the main difference is that instead of tightening the nut, you will loosen it up with the help of a torque tester.

Here, you will note the torque reading as the fastening breaks lose. It will give you the value of the approximate Torque you need for the joint.

• Marking Test: For this method, you need to do machine screw torque testing. Mark up the surface until which you tighten up the nut completely. Now lose it and retighten until you reach the marked surface. Here you can check the original Torque you need for the fastening up of the joint.

Things to Consider Before Getting a Torque Tester

You need to measure the Torque at all stages of manufacturing and assembling. For that, you will need an appropriate torque measuring tool for proper torque values. Torque tester can be an investment of your business, which will not waste since it will benefit you in a project. By using a suitable torque tester, you can save yourself and your assembled machinery from various defects.

To choose from a range of torque testers, you need to understand your work type. So a little pre-purchase research will help you in making the right choice. In our opinion, there are 7 things you should consider before choosing a tester.

Understand the type of tools

For each of the different types of equipment, there are types of testers available in the market. When you purchase one, you need to see whether it has the complete functions that you need or not. Therefore, knowing the type of tools that you will be handling will narrow down the choices, and you will get your required tester.

Consider the type of measured Torque

There are two types of Torque, static or dynamic. With each class, different factors will play a role in the accuracy of data found. Hence, before selecting a tester, you must identify whether you are working with static Torque or dynamic Torque to minimize errors.

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Understand the type of Torque Test

Different tests require special testers with meters installed on them for the specific value like the above cases. Two approaches to test the Torque are

• Inline method where you determine the force used to turn a rotating part.
• Reaction method where you define the force used to prevent the rotating part from turning.

Each technique requires a unique type of sensors and thus special testers. That is why it is an essential factor to consider.

Check if you want the tool for Torque Verification

As shown above, torque testing involves three methods: the fastening, loosening, and marking test. So if you want to test the joint relaxation points from the following tests, you need to consider them before buying the tester.

Check if you want the tool for Torque Auditing Program

In auditing, you validate, inform and then confirm a specific thing. It is necessary to check the performance of a job, and it is a preventive measure on latent failures. To audit the Torque, you need to test

• The first movement in tightening direction
• The first movement in the loosening direction
• The angle of rotation.

Hence, your tester should be able to check for all these values if you want them for the auditing program of Torque.

Check the need of using external sensors

In many situations, you need an external sensor, as you have to enter the value into some software. If so, you have to a digital torque tester that is compatible. That way, it will convert the value into an electrical signal. The system will utilize it in the decision-making process.

Check the need for Pulse Tools

Similarly, your project may need some pulse tools to provide torque to your system in small increments. For that, you need a torque tester that measures the Torque and the pulse too. This type of tester could be very beneficial for the other projects because it gives you more information and accuracy. You can further use this data to schedule your maintenance schedule for the device.

Conclusion

Since insufficient amounts can cause joints to lose and disconnect the machine, you need to test it over the period. Over tightening of the nuts also give them no benefit as extra force can cause wear and tear of the fasteners. So, torque Testing is necessary.

By the way, to keep your motors safe, you need to assemble them with care and perfection. Here at Cloom, we offer custom wiring assembly with attention to each detail so that your devices are easy to maintain. Please fill the form and contact our team now.

The torque test can determine the breaking torque, and it is mainly suitable for bolts and screws that cannot be tested for tensile tests.

Note: Breaking torque is the torque at which the screw is sheared.

What is a Torque Testing Machine?

The torsion testing machine is used to measure the mechanical properties of metal or non-metal samples under torsion. This testing machine can apply torque to the sample and measure the magnitude of the torque. It is special equipment for torsion experiments.

There are various types of torsion testing machines, generally consisting of two basic parts: loading and force measurement.

What is the Difference Between Dynamic Torque and Static Torque?

The torque of fasteners is divided into dynamic torque and static torque.

What is Dynamic Torque?

Dynamic torque is the maximum peak value measured during the fastening process of the fastener, the torque displayed in real-time by tools or equipment during the assembly process, and the torque achieved by the bolt overcoming dynamic friction. Both wrenches and power tools can apply dynamic torque, which is measured during tightening.

What is Static Torque?

Static torque is the maximum torque achieved by overcoming static friction by continuing to rotate the fastener in the tightening direction after it has been tightened. Static torque is measured after tightening. The static torque standard is used to monitor the stability of the production process. Generally, the peak torque measured by the pointer manual wrench is the static torque.

Dynamic Torque and Static Torque Measurement Methods

Dynamic torque measurement method: 

The torque measurement method is divided into three categories: balance force method, energy conversion method and transfer method.

1. Measured by an additional sensor between the fastening tool and the fastened part.

2. Measured by the torque sensor attached to the tightening tool itself.

Static Torque Measurement Method:

Use a force measuring wrench (with dial type, digital display type, etc.). The value obtained by tightening an angle of <5° in the direction of tightening the fastener within 5 minutes after tightening.

This article will introduce the difference between dynamic torque and static torque, and the method of measuring torque. Through this article, you will learn the basics about torque experiments.

KENENG can produce fasteners that meet the requirements. You can provide drawings or specific usage requirements, and our professional designers and production personnel will recommend suitable products for you.

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