The linear guide carries the payload and maintains directional straightness. Selecting the appropriate guidance system requires matching rolling-element contact geometry, block profile, and structural compliance to your specific load profiles and machine bed preparation.
A. Rolling Element Geometry: Point Contact (Balls) vs. Line Contact (Rollers)
Ball-Type Guides (HG / EG Series): Utilize recirculating steel balls contacting circular-arc raceways at a 45-degree angle. The resulting point contact provides low running friction, high velocity capability, and moderate elastic compliance, allowing these blocks to absorb minor mounting surface imperfections on welded or extruded frames without binding.
Recommended For: Standard CNC routers, automated pick-and-place systems, laser cutting machines, and packaging equipment.
Roller-Type Guides (RG Series): Replace spherical balls with precision-ground cylindrical rollers. Rollers create a line-contact interface that increases structural stiffness by up to 300% and distributes dynamic stress across a wider raceway area.
Recommended For: Heavy-duty CNC milling centers, horizontal boring mills, surface grinders, and metal-forming presses where deflection under load must be strictly minimized.
Mounting Requirement: Because roller guides exhibit minimal elastic compliance, they should be mounted to precision-ground, co-planar steel or cast-iron reference surfaces.
B. Carriage Architecture: Square vs. Flanged Profiles
Square Blocks (HGH / RGH / EGH): Feature a narrow lateral footprint with top-down tapped mounting holes. Optimal for compact columns, vertical Z-axis assemblies, or multi-rail clusters where horizontal envelope space is constrained.
Flanged Blocks (HGW / RGW / EGW): Feature wide lateral mounting flanges ("wings"). This broader bolt pattern significantly increases resistance to roll moment loads (MR). The flange incorporates through-tapped holes that support both top-down and bottom-up fastening, providing crucial accessibility when overhead tool clearance is restricted.
C. Low-Profile Architecture (EG Series)
When vertical overhead space is restricted, the EG Series reduces overall assembly stack-up height (e.g., EG15 assembly height is 24 mm versus 28 mm for standard HG15). A lower center of gravity reduces moment-arm leverage on high-acceleration, rapid-traverse axes.
D. Supported Round Rails (SBR / TBR Series)
When machine beds are fabricated from structural aluminum T-slot extrusions or non-machined steel tubing, rigid profile rails can bind. SBR and TBR Supported Round Rails utilize open-type linear ball bushings riding on a continuously supported round shaft. The cylindrical geometry provides rotational compliance, accommodating frame twist and surface variations while minimizing shaft deflection over extended travel lengths at a cost-effective price point.