How to choose the right type of linear rail actuator for your application

Your linear motion system is likely to be the kingpin of your processing plant – whether you’re using a linear rail actuator within your gantry robot system, in semiconductor manufacture or in your packaging process, we can guarantee that it’s a critical component in keeping your business running. Choosing the right linear motion system for the job is key to ensuring an efficient, cost-effective industrial plant. We take a look at some of the factors to consider when selecting your linear rail actuator.

uploads - MTB-exploded-view-min.jpgOrientation: the direction in which your actuator is mounted can affect which type of actuator to choose. Most linear rail actuators are suited to horizontal and inclined mounting orientations. However, if you are looking for a linear rail actuator to be mounted vertically, the answer may not be as straightforward. Whilst all linear motion systems would have built-in safety mechanisms for vertical loads, a linear ball screw actuator would usually be better suited to carrying a load vertically. This is because ball screws are unlikely to back drive if there is a brake failure and so ball screw linear actuators are often considered to be a failsafe option because of their inherent reluctance to free-fall.

Stroke length: the distance that you require your linear rail actuator to move a load in one direction is the stroke length. Linear ball screw actuators are usually designed at around 1000mm stroke length, however, larger diameter balls can be used and will allow a load to be moved 3000mm or more.

Speed: this can be a critical factor in selecting your linear motion system, with speed impacting output and efficiency rates. A ball screw linear actuator will usually perform at around 1.5 m/s at stroke lengths under a metre, but supports added to the assembly can allow the actuator to reach higher speeds and longer lengths.

Load: it is critical that the linear rail actuator is selected with load in mind, and there are several factors to consider in relation to load. Both the radial and axial load capacity need to be taken into account, as well as the moment capacity of the support carriage. Position of the load in terms of its size (including any overhang) as well as the orientation in which the load is being moved should also be considered.

Repeatability: Your choice in linear rail actuator will affect how accurate the movement is, therefore impacting both budget and assembly time, and in some cases the quality of the finished product. Linear ball screw actuators offer increased accuracy over other actuator types due to their design, providing tighter tolerances on achieving both the same position on each stroke and also the travel accuracy.

Maintenance: a lack of lubrication is the most common reason for failure in linear motion systems. The guide system must be regularly lubricated, and in ball screw linear actuators there are additional lubrication requirements. Some systems are pre-lubricated for a given lifespan, making maintenance less of a commitment.

Environment: it is critical that the environment in which a linear rail actuator is to be used is considered during the selection process. An actuator which is to be used in a cleanroom environment has very different demands placed on it to one working in a dusty space, or where it is to be submerged in chemical fog. Materials, lubrication and protection requirements will all be affected by a linear motion system’s intended environment.

There are many factors to be considered when selecting the right linear rail actuator for a processing plant, and here at Matara, we have many years of experience in identifying and selecting the right actuator for any given application. We will work with you to understand your needs, your budget and the demands that will be placed on your linear motion system to ensure that you end up with the best possible solution. If there is not a suitable linear rail actuator available from stock, we can build a custom solution to suit your business. Call us today to talk to one of our engineers about your linear motion system on 01684 850000.