Depending on the function, load and service location of a linear actuator, the functional parts of a linear actuator may be housed in one of two types of housing; plastic or aluminum.
The plastic housing is suitable for actuators that are either not exposed to a harsh environment, chemicals, or highly fluctuating external temperatures and its internal temperature does not rise significantly due to load and other strenuous work to affect the housing. Normally it is used for actuators that neither have the exposure to the harsh environment nor do they have esthetic reasons to finish the actuator housing in anything other than plastic for its application.
The increased fluctuations in temperature around the actuator may relax and contract the plastic actuator housing exposing the internal functioning mechanism.
The aluminum housing, depending on the application, is usually meant for linear actuators that operate in harsh environments with chemicals or highly fluctuating external temperatures. They are also highly suitable if the internal temperature of the linear actuator rises significantly due to load or other strenuous work requirements that create heat, like the repetitive movement of the actuator.
The aluminum body can also be found where it is needed for aesthetic reasons, such as the lifting columns that carry the standing desk upwards and downwards.
The slim body made out of aluminum for lifting columns in a standing desk also helps with stabilizing the desk and the rectangular housing prevents the columns from buckling when the standing desk has an unequal load on top of the desk.
To assure compliance with the rigidity of the actuator housing it is frequently tested by performing a dunk test on the actuator housing.
What is the Dunk Test?
To ensure that the housing of the actuator remains intact despite fluctuating temperatures an actuator’s housing is put through high temperatures both on the high and low end of the scale. During the dunk test, an actuator housing is heated to 85°C for several hours and then rapidly cooled down to 0°C by dunking the housing in cold water. This process is repeated 5 times during a dunk test to ensure that the rapidly increasing and dropping temperatures can be withstood by the actuator housing.
The aluminum housing can be designed with an aluminum housing integrated with steel back fixture or with a hole for the steel back fixture that operates independently of the housing. Actuator housing with an integrated back fixture limits its functioning to about 1000 Newtons or pull or push force and actuators with a standard hole for steel back fixture can operate above that range.
This is done to minimize the damage to aluminum housing in actuators that operate above the 1000 Newton limit due to rough vibration and push and pull of the parts. This protects the housing from suffering the vibrations due to extreme loads pushed or pulled by the actuator.
Another consideration for designing housing for a linear actuator is the protection of integrated electronics within the body of the actuator. Integrated electronics within an actuator’s housing is especially vulnerable to moisture created when the inner or the surrounding temperature of the actuator rapidly fluctuate. There are a number of precautions that are taken in order to protect integrated electronics within the body of the actuator. Things such as coated PCBs, polished inner tubes, cork sealing, and corrosion treatment are few of the ways the integrated electronics within the linear actuator body are protected.
For applications where an absorbent sealing like cork is not suitable, such as actuators located in a kitchen, silicone sealing is used to ensure both the safety of integrated circuits as well as hygiene requirements of the surroundings.
In conclusion, these are the technical details of how the housing of linear actuators is designed with every detail of application and aesthetics in mind. Well designed and compact linear actuators and lifting columns ensure both safety and performance and make LoctekMotion the global leader in linear actuators, and lifting columns for applications in standing desks, conference tables, storage racks or kitchen cabinets.