Positioning System Guide to Choosing the Correct Linear Actuator in 12 Steps – Part IV

1. Traverse Speed

The ball screws and bearings used in the linear actuator are the primary determinants of traverse speed and time. Typically, belt-driven linear actuators are faster than their ball screw, and linear bearing counterparts.

2. Acceleration & Deceleration Rate

In multi-positioning systems, acceleration by itself is not a crucial problem. The effect of acceleration on the load is what needs to be taken into consideration. In any automated system where linear motion systems are used, one also needs to consider the implications of deceleration on the load. For start-stop, or pick up and drop systems, acceleration, and deceleration needs to be factored in when choosing the right linear actuator.

3. Cycle Time & Fatigue Life

The fatigue life of a component will determine the life of a system. In addition, the fatigue life is dependent on the cycle time. Higher the frequency of the cycle, more will be the wear and tear; therefore, the fatigue will be higher. Hence, the actuator will have to be chosen depending on your expectations of the life of the actuating system. For example, if you consider two systems that need to function for the next 12 years, but the cycle time of one is double than the other. We can understand that the same linear actuator will not be able to provide the same results in the same budget. Two different actuator systems will need to be employed for both the test scenarios.

4. External Forces

When designing a system, we need to factor in accidents, extreme cases, emergencies, and the human factor. In case of an emergency, a load might need to be stopped or moved to another position abruptly. To incorporate this functionality into your actuator system, the components will have to be altered accordingly.

5. Environmental Factors

The linear system will have to be chosen according to the environmental factors. You need to consider the natural atmosphere of the location, as well as the application environment. The external atmosphere includes moisture, dust, and temperature. The application environment will include the ruggedness of the application, internal temperature, chemical exposure, abrasion, corrosive environment, physical cleaning, etc. You will also have to consider the level of vibration experienced within the application. For example, the actuators used in military applications are very different compared to those used in factories, or laboratories. In medical facilities, noise levels could be a problem, so the linear actuator will have to be chosen accordingly. Depending on the environment, you will have to choose the actuator, as well as the various seals, coatings, and casings that can be used to protect the equipment from damage.

When choosing a linear actuator, it is also important to consider the different electrical drives and systems that come into play. Most automated machines utilize complex components and electrical systems. Hence, it is important to choose a linear actuator that is compatible with the various electrical systems, and components.

Information and knowledge about linear actuators will assist you in choosing the other support components as well. It will also help you in incorporating the correct mounting methods, mounting arrangements, stacking of linear actuators, integrated drives, and affixation methods.