The THK FBL35D Series represents a high-performance double slide rail system engineered for medium-load applications demanding exceptional rigidity, precision, and long-term operational reliability. This robust linear motion solution integrates two parallel FBL35-type slide rails with a compatible carriage block, creating a stable, balanced support structure ideal for handling significant moments and complex loads. The FBL35D is characterized by its 35mm rail width, offering an optimal balance between load capacity and compact design, making it suitable for integration into machinery where space constraints and performance are critical.

Technically, the FBL35D Series incorporates THK’s patented Caged Ball technology, where the recirculating steel balls are securely held within a polymer cage. This design fundamentally eliminates ball-to-ball contact, drastically reducing friction, heat generation, and wear. The result is a dramatic extension of service life, consistent smooth motion at high speeds, and a significant reduction in lubrication requirements compared to conventional linear guide systems. The rails and blocks are manufactured from high-carbon chromium bearing steel, heat-treated to achieve a surface hardness of HRC 58-64, ensuring superior resistance to indentation and abrasive wear. Precision grinding of all raceway surfaces guarantees high running accuracy and low noise levels, even under demanding cyclical operations. The inclusion of effective sealing systems, comprising scrapers and end seals, protects the critical ball recirculation pathways from industrial contaminants like dust, chips, and moisture, thereby maintaining the system’s integrity and precision in harsh environments.

The performance advantages of the FBL35D are substantial. Its double-rail configuration provides outstanding resistance to overturning moments, torsional forces, and complex load combinations, ensuring unparalleled motion stability. This inherent rigidity minimizes deflection under load, which is crucial for maintaining positional accuracy in precision applications. The low-friction Caged Ball design enables higher maximum speeds and accelerations while consuming less drive power, contributing to overall energy efficiency. Furthermore, the reduced maintenance needs and extended lubrication intervals translate to lower total cost of ownership and increased machine uptime.

Typical applications for the THK FBL35D Series are found across industries where reliability under medium loads is paramount. In industrial machinery, it is extensively used in the vertical columns and traverse mechanisms of heavy-duty machining centers, high-speed gantry-style CNC routers, and automated pallet changers. Within the automotive manufacturing sector, these slide rails are integral to the robust framing stations of robotic welding lines, precise positioning units in engine assembly systems, and heavy-load transfer conveyors. In the realm of precision equipment, the FBL35D provides the stable, high-accuracy linear motion required in semiconductor wafer handling robots, large-format coordinate measuring machines (CMMs), and the stages of advanced inspection and testing apparatus. Its combination of strength, precision, and durability makes it a cornerstone component for engineers designing machinery that must perform reliably in continuous, high-cycle production environments.