Actuator applications

Bimba now sells fully electric IntelliPress benchtop presses to expand the possibilities of factory automation. This press complements Bimba’s existing hydraulic and pneumatic press families by offering the benefits of electric motion (including energy savings, dynamic force and speed control, an infinitely variable stroke, reduction in oil and associated hydraulic mess) at an affordable price. The IntelliPress delivers force ranges to 3,000, 6,000, or 12,000 lb … and comes in configurations with varying degrees of electronic control integration for off-the-shelf operation and configurability.

Electric actuators are integratedmotion designs that include an electric motorand rotary-to-linear device for repeatablemotion to given positions.

Many linear actuators deliver multiple outputs with programmable controls that adapt to changing conditions. Applications with similar dynamics often make use of the same actuator types — those that pair motors with ballscrews or leadscrews; incorporate brushless dc motors and belt-and-pulley setups; take a rodstyle morphology; use motors with planetary roller screws; or integrate built-in guides. Consider four representative application examples from PBC Linear for leadscrewbased actuators.

Case study — High-precision Z axis: A manufacturer of a highly precise SLA style 3D printer needed to hold layer resolutions to an exacting level of 10 µm. The mechanical accuracy of the constant-force anti-backlash nut and leadscrew coupled with the high performance of a smart step-servo motor made for a system well within the specification at lower overall system cost — as this assembly needed no linear encoder for feedback from the point of interest.

Case study — X-Y contouring and dispensing: A fused deposition modeling (FDM) 3D printer tends to produce a part that shows ridges or the beads from each layer as it is placed on the printed part. Working with an FDM machine builder and using the consistent performance of the constant-force anti-backlash nut features, engineers were able to decrease the surface finish and layer resolution of prints while using the control commutation capabilities of a smart step-servo motor to improve performance resulting in twice the process output of a typical FDM printer.

Case study — Medical syringe pump: A leading manufacturer of syringe pumps for medical applications needed the highest levels of fluidic control with minimal flow variance over time. This was critical to their lifesaving equipment. Specific life tests were conducted with a constant-force zero-backlash nut and screws operating side-by-side with competitive screwand-nut assemblies using a conventional coil spring and collet. In the end, all the conventional designs failed to complete the test due to loss of preload, but the final results showed the leadscrew assembly with the constant-force nut to be 200% better for fluidic accuracy over the full 1.5 million cycles targeted.

Case study — Metals additivemanufacturing platform: Ballscrews are proven to be the product of choice for heavy load and high duty-cycle applications, and ground ballscrews offer extremely high precision. Even so, there are a growing range of applications for which the choice between rolled ballscrews and leadscrews isn’t as clear.

One leader in metal additivemanufacturing machines tested leadscrew and motor assemblies head-to-head with a similar rolled ballscrew unit. A leadscrew assembly with superior thread rolling, a polymer nut, and a motor optimized for linear performance exhibited less backlash and higher accuracy than a comparable ballscrewbased actuator. What’s more, the polymer nut’s self-lubricating nature eliminated the need for added lubricants … making the machine process cleaner and safe from printed-part contamination. Secondly, metalto-metal contact was eliminated between the nut and screw. This reduced noise for much quieter operation. In the end, the integrated leadscrew delivered superior cost advantages and print quality.

Tolomatic’s RSX096P electric linear actuator increases the force range of the RSX product family to 40,000 lbf. Optimized for force in the extend direction, the RSX press-model electric actuator excels in metal-forming and assembly — including pressing, punching, stamping, riveting, fastening, and joining.