Vibration isolation of equipment: machine tools, presses, compressors

Why equipment needs vibration isolation

Almost every machine in a shop vibrates: a crank press strikes on every stroke, a reciprocating compressor rocks from its reciprocating masses, fans and pumps vibrate from residual imbalance. Through the concrete floor this vibration reaches neighbouring equipment and the building structure.

The consequences are not immediate, but they add up:

• Accuracy and surface finish: bed vibration turns into relative motion between tool and workpiece - waviness, lobing and size scatter appear on the part.
• Tool life: shocks and micro-vibration speed up chipping of cutting edges, especially carbide inserts and grinding wheels.
• Neighbouring machines: a grinding or jig-boring machine next to a press performs worse than the same machine in a separate room.
• Building and people: vibration travels through floor slabs to adjacent rooms, structure-borne noise rises, screeds and anchor fixings crack.

Passive vs active vibration isolation: the difference

The data sheets of OV mounts state that they are intended for passive and active vibration isolation. These terms describe the direction of protection, not the design of the mount.

Passive isolation protects the machine itself from external vibration. Example: a high-precision lathe or grinder stands in a shop with presses and an overhead crane, and the mounts keep that vibration away from the bed.

Active isolation protects the surroundings from a source machine. Example: a crank press or a compressor is set on mounts so that vibration does not go into the floor and to neighbouring machines. The same rubber-metal mount works in both modes because the resilient element reduces transmission in both directions.

An important note: some literature uses the word active for systems with sensors and actuators that cancel vibration in antiphase. Rubber-metal mounts are passive, unpowered elements; active in their data sheet only means isolating a vibration source.

How a vibration mount works: natural frequency and damping

A machine on rubber mounts is a mass on a spring. Such a system has a natural frequency: push the machine and it oscillates at that frequency. For OV, IV and hinged OV-30sh mounts the data sheet gives an average vertical natural frequency of 20 Hz, about 1200 oscillations per minute.

Isolation works when the disturbing frequency is clearly above the natural frequency of the system: by classical theory more than √2 times, i.e. roughly 1.4 times. The larger this margin, the less vibration reaches the floor. Near the natural frequency resonance occurs, and a resilient mount can even amplify vibration.

That is why the rubber in a mount is not only elastic but also damping: it absorbs part of the energy and limits the amplitude when the machine passes through resonance during start-up and run-down. OV mounts are equal-frequency mounts - designed so that the natural frequency changes little with load across the working range.

The practical conclusion: a mount reduces vibration at frequencies above its natural frequency well, while low-frequency, high-amplitude sources such as forging hammers need a vibration isolation design and a foundation per the manufacturer's documentation.

What equipment goes on anti-vibration mounts

According to the OV data sheet, they are used to install most metal-cutting machines without a foundation - lathes, milling, drilling and grinding machines - as well as crank presses, pumps, compressors and fans. The condition is a medium-size machine with a rigid bed that keeps its geometry on its own and does not rely on a foundation for stiffness.

The table below helps you orient. The load per mount is the machine mass divided by the number of support points, allowing for uneven distribution (heavy headstock, overhung motor).

Mounts are often ordered together with a machine: for new medium-size lathes and grinding machines, where passive isolation matters, and for presses, where the main task is active isolation and protection against creeping. For a press, a vibration mount fixator is added to each OV-31M. All mounts are in the machine tool components section.

How to choose vibration mounts for the load

The main rule: each mount must work within its range - not below the minimum and not above the maximum load. An overloaded mount bottoms out and loses its isolating properties; an underloaded one acts almost like a rigid block.

An example for orientation: a 2000 kg machine on four points gives about 500 kg per mount - the range of the OV-31M vibration mount. A 400 kg unit on four points gives about 100 kg per mount - the OV M12 vibration mount fits. Take the real mass distribution from the machine manual; a detailed calculation for uneven loads is in the article how many vibration mounts you need.

If the machine mass is unknown, estimate it from the main parts with the metal weight calculator or ask us via the quote form - we will match mounts by model or photo. The general selection procedure by mass, accuracy and floor condition is in how to choose vibration mounts for machine tools.

• OV-31M: 140 mm pad, M16 stud, 250-4500 kg, 12 mm height adjustment, from ~1,085 UAH excl. VAT.
• OV M12: 80 mm pad, M12 stud, 40-250 kg, no height adjustment, from ~684 UAH excl. VAT.
• IV M12 and hinged OV-30sh: hinged M12 stud, 55 mm pad, 40-250 kg, from ~620 UAH excl. VAT.
• Fixator for OV-31M: keeps the mount from shifting in operation, from ~345 UAH excl. VAT.

When vibration mounts are not the answer

A mount does not replace a foundation in every case. Options are compared in vibration mounts or a foundation; below, briefly, the cases where mounts alone will not help.

• The equipment maker does not recommend installation on mounts or requires anchoring to a foundation - the machine manual rules.
• Heavy long machines whose bed gets its stiffness only together with the foundation: on separate mounts it may deform.
• Forging hammers and other equipment with powerful low-frequency impacts - they need a dedicated vibration isolation design.
• Cutting vibration (chatter) caused by tool overhang, wear or cutting data: a mount does not make the machine stiffer and does not remove it.
• A faulty source - spindle runout, unbalanced pulley, play, worn press units. Repair first: press spare parts and machine units, then isolation.

Common vibration isolation mistakes

Most problems with vibration mounts come not from the mounts but from installation and selection. Step by step - in how to install a machine on vibration mounts.

• Identical mounts under every point although the mass is uneven - some mounts are overloaded, others barely work.
• Different mount types under one machine: different stiffness causes tilt and rocking.
• Rigid pipes, ducts and cable trays to a compressor or pump on mounts - they carry vibration around the isolation and can crack.
• A press without fixators: repeated impacts make the mounts creep, and the levelling goes with them.
• No check after run-in: mounts settle, so the level must be checked and readjusted per the machine manual.