What to consider when specifying a linear slide

What to consider when specifying a linear slide


When a design engineer has fully defined a linear-motion application’s requirements regarding travel length, speed, force, and accuracy as well as repeatability, the next question to answer is this:Get more news about linear sliding table suppliers,you can vist our website!

Does an off-the-shelf linear slide (or a stock linear slide from a catalog) fully satisfy the application?

Off-the-shelf linear slides are advantageous for their quick delivery and lower cost than that of custom components. No wonder most linear-motion designs do in fact employ off-the-shelf linear slides from various component and system suppliers.But what about those designs for which there are no suitable off-the-shelf linear slides? Such designs may have parameters that might necessitate unacceptable compromises if reliant on stock product … these parameters can include nontraditional drive methods, unusually long lengths of travel, exposure to overturning loads and torques, and high force, load, and speed requirements. Elsewhere, the retrofitting of existing machine designs may significantly complicate the integration of the linear slide. Any such parameters that necessitate modifications to off-the-shelf linear slides will cause actual cost to escalate — sometimes to an unacceptable degree.

Where no stock catalog linear slides satisfy all of a machine design’s requirements, a custom-engineered linear slide may be the most cost-effective solution. Such linear slides are often machined and assembled by the manufacturer to include the base material, rail and bearing system, stage or table, and drive system.

Mounting-base material: The base material may be made of steel, stainless steel, aluminum, anodized aluminum, aluminum tooling plate, or granite. As this is the foundation it has to be rigid to support the load — and securely anchor the linear components.Drive system: The drive for the type of linear axis we discuss here may be driven by a servo motor or stepper motor coupled to a lead screw, ball screw, or belt. The linear system can also be powered by a hydraulic or pneumatic cylinder. The selection of the drive system is dictated by accuracy, repeatability, acceleration, speed, load, and environmental requirements.

Shafting (round rails) and linear bearings: Shafting and linear bearings offer the greatest flexibility in design for linear slides for high speeds and light to medium loads. Shafting or round-rail iterations include ceramic-coated aluminum shafting (having a Rockwell hardness of 60 Rc) and 440C, 303, or 316 stainless-steel shafting. Shafting is available without support and with support for heavier loads.

Linear bearings for use with round rails include stainless steel variations and PTFE-composite-lined linear bearings — as well as ceramic-coated and solid-ceramic linear bearings. Ceramic-coated PTFE-composite lined linear bearings feature a low coefficient of friction (0.09 to 0.12) and are available in closed or open configurations. They can deliver speeds to 400 ft/min. — plus can handle 10 times the load of linear ball bearings. They’re also smooth and quiet and suitable for applications requiring washdown or submersion … and can operate in contaminated environments.

In contrast, ceramic-coated linear bearings have coefficients of friction of 0.04 to 0.08 for smooth and efficient travel at a lower cost than bearings — with essentially unlimited travel speeds and acceleration. That makes them particularly suitable for long strokes and oscillating applications. Other benefits include their self-lubricating and inert nature — even when exposed to caustic chemicals.