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How-to Guide: Selecting the Right Linear Axis Actuator for your Design

A comprehensive guide to selecting the right Vention linear axis actuator for your application.

Justin Mcleod Mechanical Engineer / Mar 10th, 2019

Linear Actuators

MO-LM-003-585/855/1530, MO-LM-016-XXXX



Introduction

This Vention Design Tip features a comprehesive guide on selecting the appropriate linear axis actuator for your application based on available lengths, linear speed and maximum force capacity.

Vention’s belt-driven and ball screw linear actuators have been designed to simplify the design of automated equipment. Components are readily available in Vention’s 3D MachineBuilder™ and can be added to any assembly to create simple linear motion for light-duty and medium-duty applications. All linear actuators can be coupled with Vention all-in-one MachineMotion™ controller and MachineApps™ publicly available.


Belt-Driven Linear Actuator Overview

Belt-driven linear actuators are used for light and medium duty applications that require high speed and high acceleration.

Design and Construction

The assembly consists of two concealed timing belt pulleys, bolted at the extremities of a 45 × 90mm extrusion. The end-supports allow motor mounting options for any of Vention’s Nema 34 stepper motors on both sides. All lengths and configurations include a zero backlash steel-reinforced polyurethane timing belt. The timing belt’s open ends can be joined and tensioned using Vention’s timing belt tensioner for installation under any gantry plate. Add plastic bumpers on each end to protect the equipment. Bumpers also have a feature to mount M18 sensors for end of travel detections.

Available Lengths

Timing belt drives are listed as MO-LM-016-XXXX, where the notation “XXXX” in the part numbers corresponds to the extrusion length, ranging from 585mm to 1530mm in increments of 45mm, as well as length of 1980mm and 2295mm.

Roller Wheel or Linear Bearing Configurations

Gantry loads can be supported by roller wheels or linear bearings, depending on the application. Roller wheels are made out of glass-filled nylon and use the extrusion’s V-shaped groove as guides. The linear bearings can be mounted to the same gantry plates and use 16mm hardened steel shafts directly mounted on the extrusion with support blocks. The shafts are available in the following lengths: 585, 855, 1530 and 2295mm.

Additional lengths available on request, contact support@vention.io for more info.

Exhibit 1. Vention belt-driven linear actuator (MO-LM-016-0585) Exhibit 2. MO-LM-016 series shown with small gantry, nylon wheels, stepper motor, and proximity sensors Exhibit 3. MO-LM-016 series shown with small gantry, linear bearings and shafts

Ball Screw Linear Actuator Overview

Ball screw driven linear actuators are used for medium-duty applications requiring higher load and resolution.

Design and Construction

The assembly consist of a ball screw supported on each end by two angular ball bearings and support plates. The ball screw is 16mm in diameter and has a 10mm pitch. A ball nut housing connects the ball nut to the gantry plate. The outer frame consists of 45 × 90mm Vention extrusions. At one extremity of the assembly, a coupling housing provides a connection for any of Vention’s NEMA 34 stepper motors. 45 x 90 mm Vention extrusions link the two subassemblies together. Proximity sensors can also be added using an M18 sensor mounting bracket.

Available Lengths

Ball screw driven linear actuators are available in three different lengths: MO-LM-003-0585, MO-LM-003-0855 and MO-LM-003-1530, where the last four digits correspond to the linking extrusion lengths in millimeters.

Roller Wheel or Linear Bearing Configurations

Gantry loads can be supported by roller wheels or linear bearings, depending on the application. Roller wheels are made out of glass-filled nylon and use the extrusion’s V-shaped groove as guides. The linear bearings can be mounted to the same gantry plates and use hardened steel shafts directly mounted on the extrusion with support blocks. The shafts are available in the following lengths: 585, 855, 1530 and 2295mm.

Additional lengths available on request, contact support@vention.io for more info.

Exhibit 4. Internal components Exhibit 5. MO-LM-003 series shown with medium gantry, nylon wheels, stepper motor, and proximity sensors Exhibit 6. MO-LM-003 series shown with medium gantry, linear bearings and shafts

Technical Characteristics


Belt Driven Linear Actuator

Ball Screw Linear Actuator

Characteristics
Typical Applications High-speed Applications
  • General linear robotic
  • High-speed vision systems
  • Robot's 7th axis (RTU)
  • Pick and place equipment
Precise, High-load Applications
  • General linear robotics
  • CNC routers
  • Handling systems
  • Automated gantries
Available Lengths 585mm to 1530mm in 45mm increments + 1980mm, 2295mm

Net displacement is equivalent to the extrusion length minus the gantry's longitudinal dimension
585mm, 855mm and 1530mm

Net displacements are equivalent to 405mm, 675mm and 1350mm respectively
Compatible Gantries
Compatible Guides Linear bearings (MO-LM-010-0001) on 16mm hardened steel shaft (MO-LM-014-XXXX)
  • Suitable for high duty cycle applications requiring minimum friction
  • Shaft available in lengths of 585mm, 855mm, 1530mm and 2295mm
  • Bearing capacity: 1kN each
Roller wheels, concentric (MO-LM-001-0028) and eccentric (MO-LM-001-0027)
  • Wheel material: fiber glass reinforced nylon
  • Mounted on 2× double-sealed deep-groove ball bearings
  • Roller radial and axial capacity: 280N each
Speed Ratio (mm/turn) 150 10
Linear Force / Torque Ratio (N/Nm) 42 565.5
Linear Force Capacity (N) 320 3,700
Repeatibility (mm) ±0.25 (with roller wheels)
±0.025 (with linear bearings & shafts)
±0.023 per 300mm length
Max Linear Speed (mm/s) 1,600 1,117
Back Drive Resistance Low High
Motor Compatibility NEMA 34, 14mm shaft
MO-SM-001-0001, MO-SM-002-0001, MO-SM-003-0001

Selecting the Right One


The figure below demonstrates a comparison of the linear force output in function of the linear speed of both the ball screw and belt-driven linear actuator.


Exhibit 7. Force in function of linear speed comparison between the ball screw and belt-driven linear actuators

Observing the ball screw actuator's behaviour from the graph and table above, its maximum force capacity starts at 3700 N but sharply decreases as linear velocity increases. In comparison, when observing the belt-driven actuator's behaviour, its maximum force capacity starts at 320 N and slowly declines as linear velocity increases, remaining relatively consistent at all speeds. Both actuators intersect at a linear speed of 435 mm/s, representing a maximum force capacity of 265 N.

Consequently, if your application requires higher force capacites, higher torque, and higher precision, we recommend the ball screw. If your application requires higher speeds with a large range of available lengths, we recommend the belt-driven actuator.



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