Selecting between flanged (HGW) and square (HGH) carriages often comes down to installation access and spatial envelope constraints.
1. Installation Accessibility & Bottom-Up Mounting (HGW Flanged Series)
A primary mechanical reason to specify the HGW flanged block is assembly accessibility.
The HGH (Square) Limitation: Square blocks feature tapped blind holes on their top mounting surface. Fasteners must pass vertically downward through the carriage plate and thread into the top of the block. If the carriage assembly has pre-installed components covering the top surface (such as spindle motors, vacuum tables, or fluid reservoirs), installing or servicing the carriage bolts can require extensive teardown of the payload.
The HGW (Flange) Solution: Standard HGW blocks (such as the CC and HC types) incorporate threaded through-holes within their lateral flanges.
The Engineering Benefit: This design supports bottom-up mounting, allowing technicians to pass bolts upward through the flange and thread directly into tapped holes on the underside of the carriage plate. This makes the HGW block particularly advantageous for enclosed machine beds, optical tables, and dense gantry frames where top access is obstructed.
2. Spatial Constraints & Symmetric Loading (HGH Square Series)
While the HGW flanged block provides mounting versatility and roll-moment stability, the HGH square block is preferred in specific design scenarios:
Restricted Lateral Width: In narrow vertical Z-axis columns or assemblies where parallel rails must be nested closely side-by-side, the lateral wings of the HGW may exceed space limits. The narrow HGH profile provides a compact footprint for tight horizontal envelopes.
Standard Distributed Top-Mounting: When the payload is evenly supported across four blocks on twin parallel rails, roll moments (MR) are primarily absorbed by the rail span rather than individual block bodies. In these balanced, top-accessible configurations, the compact HGH square block provides an efficient, cost-effective solution.