DLY Linear Guideway Types: HD, ED, MD and RD Series Guide

In precision motion systems, the right linear guideway series directly affects load capacity, rigidity, installation space, running accuracy and long-term machine stability. A guide rail that works well for compact automation may not be suitable for heavy CNC machining, and a high-rigidity roller guideway may be unnecessary for a light-duty positioning axis.

DLY supplies multiple linear guideway series for different industrial requirements, including HD Series heavy-duty linear guideways, ED Series low-profile linear guideways, MD Series miniature linear guides and RD Series roller linear guideways. Each series has its own structure, load characteristics and application range.

This guide explains the main DLY linear guideway types, compares their key features, and helps engineers choose the right series according to load, space, rigidity, speed and application requirements.

DLY Linear Guideway Series at a Glance

DLY linear guideways can be selected according to the actual working condition. The table below gives a quick comparison of the four main series.

HD Series – Heavy Duty Linear Guideway

The DLY HD Series is designed for strength, reliability and stable motion under industrial loads. With a four-row circular-arc groove structure, it provides high load capacity, high rigidity and equal load capacity in four directions. The self-aligning capability helps compensate for minor mounting surface errors, which improves installation tolerance and motion stability.

This series is a practical choice for machine tools and automation equipment that need strong support, repeatable movement and long service life. It is commonly used in machining centers, CNC tools, grinding machines, injection molding machines, automation lines and measuring instruments.

Model classification:

• HDW Series – flange type heavy-duty linear guide block, including HDW-CA, HDW-CB, HDW-HA and HDW-HB.
• HDH Series – square type heavy-duty linear guide block, including HDH-CA and HDH-HA.

View HD Series Heavy Load Linear Guide →

ED Series – Low Profile Linear Guideway

The DLY ED Series is a low-profile linear guideway designed for compact automation systems where installation height and block length matter. It keeps the advantage of a four-row ball structure while using a lower assembly height and shorter block design, making it suitable for equipment that needs both rigidity and space efficiency.

The ED Series also supports smooth motion, high-speed operation and convenient installation. Its self-aligning function and ball retainer help improve maintenance convenience and reduce installation difficulty in compact equipment structures.

Model classification:

• EDW Series – flange type low-profile guide block, including EDW-SA, EDW-SB, EDW-CA and EDW-CB.
• EDH Series – square type low-profile guide block, including EDH-SA and EDH-CA.

Typical applications include automation machines, transport systems, measuring devices and semiconductor equipment, especially where installation space is limited.

View ED Series Low Profile Linear Guide →

MD Series – Miniature Linear Guide

The DLY MD Series is designed for micro and precision equipment where compact size, light weight and smooth movement are important. Its Gothic-arch contact design supports loads from multiple directions while maintaining high rigidity and stable motion in a small footprint.

The built-in ball retainer helps prevent ball drop during installation, improving installation convenience and interchangeability within specified tolerance ranges. This makes the MD Series suitable for small equipment that requires stable motion but cannot use a larger standard guideway.

Model classification:

• MDN Series – standard miniature guide type, including MDN-C and MDN-H.
• MDW Series – wide miniature guide type, including MDW-C and MDW-H.

Typical applications include semiconductor equipment, PCB assembly machines, precision measuring instruments, office automation systems, robotics and medical devices.

View MD Series Miniature Linear Guide →

RD Series – Roller Linear Guideway

When high rigidity and heavy load capacity are required, the DLY RD Series roller linear guideway is the stronger choice. Instead of using steel balls, this series adopts cylindrical rollers. The line contact structure provides higher rigidity and reduces deformation under heavy load compared with standard ball-type guideways.

The RD Series maintains a 45° contact angle to provide equal load capacity in four directions, making it suitable for demanding machine tools and high-rigidity motion platforms. It is especially useful when the application has heavy load, high moment load, impact load or strict accuracy requirements.

Model classification:

• RDH Series – square type roller linear guideway, including RDH-CA and RDH-HA.
• Custom roller guideway series include RDL, RDS, RDW and RDF for different height, mounting and load requirements.

Typical applications include heavy-duty automation machinery, large CNC equipment, EDM machines, gantry machines, injection molding equipment and other precision motion platforms.

View RD Series Roller Guideway →

How to Choose the Right DLY Linear Guideway Series

Choosing a linear guideway should not be based only on rail size. The correct series depends on the load direction, moment load, machine rigidity, installation space, speed, accuracy requirement and working environment.

For most standard automation equipment, the HD Series or ED Series can meet common requirements. For compact equipment, the ED Series and MD Series are usually more suitable. For heavy-duty machine tools, large gantry structures or high-rigidity platforms, the RD Series should be considered early in the design stage.

DLY Linear Guideway Accuracy Grades

DLY linear guideways are available in multiple precision grades to match different machine accuracy requirements. For standard linear guideway series, common grades include C, H, P, SP and UP. For miniature guide series, common grades include C, H and P.

The accuracy grade should be selected together with preload, rail size, block type, mounting accuracy and machine rigidity. A high-accuracy rail cannot deliver stable performance if the mounting surface, rail parallelism or lubrication condition is not controlled properly.

For more technical information, you can also read DLY guides on linear guide preload selection, accurate linear guide installation and linear guide parallelism measurement.

What Information Should You Provide Before Selection?

To select the right linear guideway series and block type, it is helpful to confirm the working condition as clearly as possible. This allows the guide rail to be matched to the real application instead of only choosing by rail width.

• Required rail size or existing model number, such as 15, 20, 25, 30, 35 or 45mm.
• Block type, such as flange type, square type, standard block or long block.
• Load direction, load weight and whether there is moment load or impact load.
• Required stroke, rail length and number of blocks per rail.
• Machine speed, duty cycle and accuracy requirement.
• Working environment, including dust, coolant, chips, humidity or temperature changes.
• Drawing, photo or replacement sample if the guideway is used for maintenance or retrofit.

Summary

DLY linear guideways cover different application requirements through four main series. The HD Series is suitable for heavy-duty and general industrial equipment. The ED Series is designed for compact and low-profile structures. The MD Series supports miniature precision motion systems. The RD Series provides higher rigidity and load capacity for demanding machine tools and heavy-duty platforms.

The best choice depends on load, rigidity, installation space, precision requirement and working environment. Instead of selecting only by rail width, engineers should compare the guideway series, block type, preload, accuracy grade and application condition together to achieve smoother motion, longer service life and more stable machine performance.

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