As miniaturization trends drive the demand for more complex compact linear motion systems, the need for customization continues to grow. However, machine designers may not have to build an entirely new system from the ground up. Working closely with motion technology vendors, they can get an optimal solution from standard configurations with targeted customization. This avoids the higher cost and drawn-out development times of fully customized solutions without sacrificing performance.
Starting with Standards
Generally, starting with a standard compact linear system assembly is best. These systems typically incorporate the following motion control modules:
- A stepper motor with an integrated lead screw
- A load-bearing nut that rides across the lead screw threads
- Carriage blocks and linear bearings that travel with the nut to support the load
- Round or profile rails that provide additional guidance and support, anchored by end blocks and motor support blocks
Small systems like these are often available in one of three standard configurations. When the application needs a smaller footprint but has vertical space available, the designer might choose an assembly that stacks the lead screw vertically above a profile rail, as shown in Fig. 1 (left side). This slim configuration has a smaller footprint than comparable configurations but is taller, and thus requires more overhead space.
Where overhead space is limited, designers might arrange the screw and profile bearing horizontally, as shown in Fig. 1 (middle). This configuration flattens the configuration but demands a larger footprint.
A third standard popular configuration involves mounting round rails on each side of the lead screw, as shown in Fig. 1 (right). This version can span across gaps without requiring full support along its length. Dual rail configurations can also handle roll moment loads because two evenly spaced rails share the load.
One final example of a flexible design enables its use in dirty environments while providing positioning and movement using ball screws and linear bearings. The enclosed design provides greater application opportunities while keeping the design in a standard product family, as seen in Fig. 2.
These configuration examples represent a range of available possibilities using just standard components. They are typically offered in a wide set of standard sizes and have served most purposes. However, the demand for more complex configurations grows as modern industrial processes evolve.
Despite the complexity of future manufacturing, most emerging applications will not require total customization. As manufacturers continue to broaden but standardize their product offerings, designers will be able to create a solution using off-the-shelf modules that require minor adaptations. Systems might need shorter or wider support blocks, relocated mounting holes, different bolt patterns, reorientation of the guide rails to the lead screw, modified stroke lengths or resizing of the motor to accommodate load changes.
These minor modifications fall within the existing manufacturing process limitations for the product. Manufacturers are beginning to incorporate these minor modifications into their process to expedite delivery times while providing flexibility in their offerings.
Suppose the designer concerned with moment load handling chose the configuration with two round rails flanking the lead screw (Fig. 1). The application requirements changed during the design process, needing a higher moment load capacity. The engineer can adapt and accommodate the change starting with off-the-shelf round rails, lead screws and nuts. This may be achieved by widening the mount of the existing product or upsizing the bearings to maintain a specific envelope. Because mounting blocks are machined individually, changing support block designs can be done with little added expense and results from using standard product.
XY assemblies are yet another application that often benefits from adapting standard modules (Fig. 3). Like the previous examples, these units might require redrilling mounting holes or modifying mounting surfaces for customized gantries to accommodate cable management, limit switches or pneumatic hoses/accessories. These considerations are usually very specific to the application. But even then, much of the adaptation is made with standard mounting blocks.
Critical Success Factors
Targeting customization to only specific components can have tremendous value in cost-optimizing your motion control system for confined space operation. However, this approach’s success depends on three things: the breadth of the vendor’s product line; the expertise of the design team comprising the end-user, distributor and vendor; and the extent to which modern engineering collaboration tools can be leveraged. These could be as simple as drawings, sizing tools or even simulation software.
The product line breadth is essential because it compresses the supply chain, eliminating the cost and time needed to locate and bring in outsourced components. It also means that the vendor will have more capability to mass-produce the product efficiently.
The design team’s expertise is important for their experience with similar adaptations or additional insight into a manufacturer’s abilities within a product line. The combined knowledge of the end-user, distributor and manufacturer will always offer more information and views on tackling a difficult application.
Lastly, modern engineering collaboration tools are valuable for enabling real-time collaboration around the customer’s specific problem, shortening the time between customization and production (Fig. 4).
Moving Into the Future
If the automation industry trend-spotters are right, we are on the verge of Industry 5.0, where humans and machines interact more effectively to leverage the unique benefits of each. As part of expanded cyber-physical interaction or the Extended Internet of Things (XIoT), more axes of motion will benefit from automation. Standard linear motion technology will continue to drive the bulk of applications in this space. Targeted customization with a foundation of standard products will make the transition smooth and cost-effective.
Matt Palmer is the product line manager of systems for Thomson and manages the linear motion systems business, supporting product line growth initiatives and product development efforts. Chris Diak is the Southeast automation manager at Motion.com and has worked in the electrical/automation field for 28 years.