(Choosing the appropriate linear guide and ball screw)
A linear guide from the company Tuli is a system that is intended to support the linear motion. It consists of two distinguished parts, the linear block, and linear rail.
The block moves forward and backward along the linear rail. To provide motion of a specific component, blocks need to be connected to the moving parts or mounted.
In this way, motion is created through recirculating ball bearings inside the mounting block on the rail.
There are different types of linear guides, but the two most basic ones are sliding contact and rolling element linear motion guides. These two types mostly differentiate on the type of motion of the linear block alongside the rail.
Sliding contact is the oldest type of linear guide, which tells us that is also the simplest way and has low manufacturing costs. The downside of a sliding linear guide is high friction in comparison to the other types. In addition, these guides don’t provide high-precision results.
Rolling element bearing for linear motion is most commonly used for the majority of applications. Rollers, in this case also known as ball bearings, are elements used to create the rolling motion of the block. The rolling motion is the key to avoiding unnecessary friction. Not only that these types of blocks ensure precise results, but also accurate and very fast. Another selling point is that the block of this type can be additionally customized, which gives much better results than the sliding ones
How to choose an appropriate linear guide?
Deciding on the appropriate tools can help you avoid mistakes in mounting, installation, and final linear motion results.
First, you need to decide if you need a radial ball bearing or a recirculating ball linear guide. The main difference between the two is that radial bearings use a cage to separate the balls. In this way, the balls inside a bearing are easier to control.
To simplify, when the balls are free to move (roll or slide), without any guidance from a separator or a ball chain, they will produce noise and cause friction. The metal sound of them hitting each other.
But, the ball chain prevents this type of contact amongst the balls, which will in return provide less heat, which in the end means longer life of the bearing.
So, it wasn’t long before producers of rail bearings started introducing ball chains or ball separators, their version of a ball cage. This move has proven to improve bearing life, noise, and running characteristics.
Ball separators were placed in ball screw nuts a couple of years later when the manufacturers solved the problem of unique design and specified the materials to make them.
Ball screw or a linear motor?
Both of the tools will help the linear guide run smoothly and achieve desired end results. However, there are significant differences between a linear motor and a ball screw.
Linear motors have been used in the electronic industry and applications for a long time because they provide excellent results. The downside of using linear motors is that they are predicted for a single application, which means they are a more expensive solution.
But, not only cost should be taken under consideration when choosing the ball bearing, but also performance requirements.
More and more industries opt-in for a less expensive option, and tend to use ball screws in packaging, loading applications, and assembly process.
Further developments in motion trends have helped improve the performance of a ball screw, making them more resilient to heavier loads and being made of much more stable material.
Electromechanical linear actuator systems already have high-load ball screws as an integrated part, helping it achieve better performance results and endure ever-changing environmental conditions. In this way, it is easier to resist extreme temperatures, chemical exposure, shock and vibration, and other problems.
Here are the points that need to be specified before buying any type of ball bearing.
Determine the load weight and required speed. These details will more than likely be changed in the process, but are the two most dependent characteristics.
The second is determining the life expectancy of the application. Calculate the time the ball screw will be operational. How many hours a day, days a week, and weeks yearly.
Accuracy requirements. Ball screw accuracy can be measured by lead accuracy. It can also show how far can a non-rotating ball nut travel while the ball screw makes one 360 degrees circle.
Establishing a repeatability component is the next key component. As opposed to accuracy, where we can see how closely a system will approach a set position, repeatability measures the ability of the system to be put back in place, while operating.
Resolve mounting issues. Mounting flexibility is a significant part of the ball screw. This can also impact the load and speed limitations a ball screw might have.
Decide if the ball nut needs to be tense or compressed. The ball screw can be stretched axially when enduring tensile loads. However, in tension, ball screws can handle loads up to the capacity of the ball nut.
Avoid friction, excess noise, and harmonic challenges. Ball screws are limited by the velocity, which allows vibration while working.
Handling and maintenance. This part is vital not only for the duration of the system but also for performance. The significant part of maintaining ball screws is having them properly lubricated. Oils help maintain low friction by minimizing the rolling resistance between balls and groves.
The last piece of advice is taking the advantage of finding the proper tools online.
In Tuli.hr, the best-equipped webshop, you can find all tools to improve linear motion needs and achieve better results, at affordable prices.