Five Key Steps for Selecting Lead Screw-Driven Motion Control Systems

Christopher Nook by Christopher Nook

Selecting the right motion control system can often mean the difference between success and failure. To optimize performance, reliability, maintenance requirements, and service life, design engineers should conduct a thorough evaluation of their options in conjunction with configuring the most suitable lead screw as a means to drive the specific application.

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Selecting the right motion control system can often mean the difference between success and failure. To optimize performance, reliability, maintenance requirements, and service life, design engineers should conduct a thorough evaluation of their options in conjunction with configuring the most suitable lead screw as a means to drive the specific application.

There are critical motion control factors that influence linear motion performance that you need to consider before you select or design a motion control system. Here are five things to consider during evaluation.

1.) Lead Screw Characterisitics

The first question to ask yourself is how large does the screw need to be? This will vary from application to application but key size considerations include the diameter and length of the lead screw, as well as the lead screw’s load capacity. You certainly don’t want to oversize or undersize your motion control system, so understanding space and load constraints as they apply to lead screw size represents the first step toward identifying the right motion control system.

2.) Precision, Timing, and Back Driving

The next important consideration is to assess the precision, timing, and reversibility requirements of your application. Select the best lead—the linear distance the screw travels in one revolution— for the load and timing of your application. Make sure to choose a lead that produces sufficient friction to maintain linear motion without slipping under load.

What pitch does your application warrant? Like the lead, the pitch—the distance between a point on one thread and a corresponding point on the next thread that is parallel to the axis—carries ramifications based on load, travel distance, and timing.

What amount of motor torque is required to drive your system? To evaluate motor torque requirements, you’ll need to consider inertial torque, drag torque, and torque-to-move, the last of which is the torque required to drive just the screw assembly. Additional torque to be considered includes that associated with driving frictional bearings, motor shafts, other moving components and drag related to general assembly misalignment. You’ll also need to assess the back driving torque required to reverse and return the system back to its original position.

3.) Power Control Options

What type of power source do you need to drive your system? Should you use a motor powered by AC or DC or configure your system for both to accommodate power outages? What kind of control signal is required? Some motion control systems may require a highly accurate control signal, such as that provided by the Nook Sensor System™, which features repeatability up to ± .004" (0.1mm).

4.) Cost Factors

Anticipating cost factors and evaluating the cost/benefit of your motion control system is critically important to maintaining a lean, well-functioning system. Investigate overall costs related to your system to maximize your cost/benefit ratio.

5.) Diagnostics, Maintenance, and IT

The last key step for selecting a motion control system is to evaluate the availability of diagnostics for maintaining and trouble-shooting the system, assessing overall maintenance requirements, and projecting the involvement of IT support. In other words, who will own the IP (intellectual property) of your motion control system? If your company will, then diagnostics, maintenance, and service will be the responsibility of your IT department or make sure that your motion control vendor provides a suitable alternative solution.

Contact Helix to Better Understand Motion Control Systems

Consult with Helix Linear Technologies for answers to questions regarding what motion control systems to use for your particular application. No matter the nature of your linear motion needs, Helix can help you through the process of determining the best solution for your particular application.

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