MOTION SYSTEM APPLICATIONS
Shock-absorber technologies
for automated applications By Larry Cavalloro • ACE Control • www.acecontrols.com
A top objective for designers of industrial-automation machinery is to build and tune axes for minimal vibration (free or forced); gently and precisely slow axes’ moving masses; and render unavoidable machinery vibration either isolated or damped — in other words, fully dissipated. These techniques let machine axes settle back to equilibrium as quickly as possible — which is especially useful for those running high-speed reciprocating, positioning, or other precise automation tasks. The vast host of options for damping and vibration isolation include industrial and safety shock absorbers, profile dampers, rotary dampers, industrial gas springs, hydraulic dampers, vibration isolators, air springs and hydraulic feed controls. We put the technologies into four broad categories. Automation control with shock absorbers and dampers include miniature shock absorbers, industrial shock absorbers, heavy industrial shock absorbers, profile dampers, and damping pads. Options for motion control include push-type and pull-type industrial gas springs, hydraulic dampers, hydraulic feed controls, door dampers, and rotary dampers.
Variations classified as vibration control include rubbermetal isolators, vibration-isolating pads, and low-frequency pneumatic leveling mounts. Safety products include safety shock absorbers, safety dampers, and clamping elements. In this feature, we focus on one leading option from the first category — that of automation control with industrial shock absorbers.
INDUSTRIAL SHOCK AND DAMPING OPTIONS COMPARED
Hydraulic dashpots deliver a high stopping force at the stroke start. With only one metering orifice, moving loads under the control of a hydraulic dashpot sees abrupt slowdown at the start of the stroke. Braking force rises to a high peak at the start of the stroke (giving high shock loads) and then falls away rapidly. Springs and rubber buffers exhibit high stopping forces at end of stroke. At full compression, they also store energy rather than dissipating it … causing loads to rebound. Air buffers and pneumatic cylinder cushions output high stopping force at end of stroke. Due to the compressibility of air, these exhibit sharply rising force towards the stroke end … so most of the energy is absorbed near the end of the stroke. Industrial shock absorbers deliver uniform stopping force through the entire stroke. The moving load is smoothly and gently brought to rest by a constant resisting force throughout the entire shock absorber stroke. The load is decelerated with the lowest possible force in the shortest
Industrial shock absorbers from ACE Controls include MC33 to MC64 models for high energy absorption. Capacity is 155 to 5,100 Nm per cycle and impact velocity range is 0.15 to 5 m/sec and beyond for custom builds. The shock absorbers mount in any orientation and include an integrated positive stop. The damping medium is automatic transmission fluid (ATF) that circulates through the pressure chamber with metering orifices (colored here in red). Applications include linear slides, swivel units, turntables, and portal systems. Noise reduction of 3 to 7 dB is possible with the inclusion of a special impact button.
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DESIGN WORLD — MOTION
Shock Absorbers & Dampers - MC 11-19 V3.indd 78
11 • 2019
motioncontroltips.com | designworldonline.com
11/18/19 3:19 PM
