NMX‑DBM‑30 / Rev 00 / rotating machinery & overhaul / hard-bearing · vertical · high-speed 2026 · Product Page

NMX-DBM-30 · ENGINEERED TO ORDER — DYNAMIC BALANCING MACHINES

Every rotor lies until it spins. Make it tell the truth.

Name: Dynamic Balancing Machine
Brand: Neometrix

A rotor can sit perfectly level on knife edges and still shake a machine apart at speed — couple unbalance leaves no resting tilt at all. So the balancing machine spins it, reads amplitude and phase per correction plane, corrects the mass, and verifies the residual against an agreed ISO 21940 grade — because at speed the force is U × ω²: gram-millimetres become kilonewtons, turning with the shaft. Hard-bearing beds for production and overhaul, vertical machines for disc rotors, and the high-speed class — flexible rotors balanced at service speed, in vacuum, multi-plane against their modes. Machines of this class have been quoted across high-speed and general-purpose dynamic-balancing machine requirements; no delivered balancing machine is claimed — the class is engineered to order.

Enquire — balancing machines Capability sheet (PDF)

Illustrative of the class — a horizontal dynamic balancing machine in a working workshop: a long heavy cast bed in fresh machine-grey paint with bright precision ways, a headstock gripping one end of a plain stepped steel rotor with several smooth solid discs, the rotor's free journal cradled on a pedestal carriage with a pair of polished support rollers, an overhead twin-belt drive reaching down from a frame arm above, a small control pedestal standing apart with its panel angled away, benches and machines of the shop soft-focus behind, clean light floor with yellow lines, no people and no readable markings

Fig · 01 The hard-bearing machine — stiff pedestals, polished rollers, and a readout that is metrology, not opinion

Unbalance

gram·mma vector per correction plane

Grade

ISO 21940G6.3 · G2.5 · G1 by agreement

Speed

to service speedvacuum where windage rules

Verdict

residual verifiedUmar known · URR proven

Status

engineered to orderhigh-speed + general-purpose

ISO 9001 / 14001 Engineered to order ISO 21940 balance grades Dynamics test franchise Noida · India

Overview

The heavy spot, found and removed.

Every made rotor carries residual unbalance — casting porosity, machining runout, assembly stack-up, keys and fitted parts. At speed the force is unbalance times speed squared, and it turns with the shaft: bearings hammer, seals work, windings and structures fatigue. The balancing machine exists to measure that lie and correct it.

Illustrative of the class — a high-speed rotor balancing facility in a clean tall hall: a massive horizontal cylindrical steel vacuum chamber in fresh light-grey paint with heavy external ring stiffeners, its thick circular end door swung open showing a slender plain polished rotor on two pedestal bearings inside, large pipework dropping to floor-mounted pumps behind, a chain hoist above and fresh yellow safety railing to one side, clean light floor, no people and no readable markings

Fig · 02 The high-speed facility — a rotor balanced at service speed, in vacuum, behind engineered containment

The measurement is classical and honest. Spin the rotor — belt, end drive or air — and read amplitude and phase at each pedestal against a once-per-revolution reference; resolve the readings into unbalance vectors at the correction planes; correct — drill, mill, grind or add mass — and spin again to verify the residual. The hard-bearing machine measures force on stiff pedestals: permanently calibrated, direct readout in one run, the production and overhaul workhorse. The soft-bearing machine measures displacement on swinging pedestals: trial-mass calibrated, exquisitely sensitive for small and light rotors. We engineer both — and vertical machines for the disc-shaped world of impellers, fans and clutches.

The grade is the contract. ISO 21940 — the successor of ISO 1940 — sets balance quality as G = e × ω: G6.3 for general machinery, G2.5 for machine tools and turbomachinery, G1 and finer where the duty demands. Permissible residual follows from rotor mass, service speed and grade — so “smooth” stops being an opinion and becomes a number the certificate carries.

And the serious end is high-speed. Below roughly 70% of its first bending critical a rotor behaves rigid — two planes at low speed suffice. A flexible rotor — long turbine and compressor spools, high-speed spindles — bends as it approaches its criticals, so it is balanced at or near service speed, multi-plane against its mode shapes, inside a facility: vacuum against windage, engineered containment, precise drive control, telemetry. That facility class is exactly what the recent high-speed requirement asked for.

Machines of this class have been quoted across high-speed and general-purpose dynamic-balancing machine requirements — for an aircraft builder and an air force repair depot. No delivered balancing machine is claimed: the class is engineered to order, and the record is stated as it stands.

Vectorial

A vector, not a guess

Amplitude and phase, per correction plane, against a once-per-rev reference — resolved, corrected, verified.

Contractual

The grade is the contract

ISO 21940 agreed up front — permissible residual from mass, speed and grade, printed on the certificate.

Provable

The machine proves itself

Umar and URR demonstrated on calibration rotors, on schedule — so nobody chases corrections below the machine's own noise.

Architecture

Spin, read, correct, verify.

The schematic follows the measurement — the rotor spun to speed, the vector read per plane, the mass corrected, the residual verified against the grade — and the machine underneath: bed and pedestals, drive and speed control, sensors and electronics, tooling and records.

FIG · 03BALANCING MACHINE ARCHITECTURE · BED + PEDESTALS / DRIVE + SPEED CONTROL / SENSORS + PHASE / TOOLING + RECORDS

Fig · 03 The grade is the contract — smooth stops being an opinion

Arc · 01

Bed & Pedestals

Stiff ways and roller carriages set to the rotor's length — journals cradled on polished rollers, any rotor in the envelope.

Arc · 02

Drive & Speed Control

Belt, end drive or air — controlled and low-influence, because drive forces read as unbalance if the machine lets them.

Arc · 03

Sensors & Electronics

Force or displacement, phase-resolved per pedestal — the measurement chain that turns vibration into a correction vector.

Arc · 04

Tooling, Calibration & Records

Mandrels managed as calibration assets, Umar and URR proven, certificates with vectors — the audit trail of every rotor.

Balancing rotors — or equipping a whole overhaul line? Send the rotor envelope, masses, service speeds and grades — a clause-by-clause compliance matrix within two working days · [email protected]

Send tender spec

Specifications

Reference machines, built to the rotor book.

The parameters below describe reference machines. Bed length, pedestal capacity, drive power, measuring range and facility class all follow from three givens: the rotor envelope and masses, the service speeds, and the grades the shop must sign.

Illustrative of the class — close view of one pedestal of a dynamic balancing machine in a clean workshop: two polished hardened support rollers cradling the bright machined journal of a steel rotor, a thin black sensor cable clipped along the pedestal casting, a small plain silver reflective strip on the shaft, a smooth rotor disc behind whose face carries a neat shallow arc of small drilled correction holes, polished cylindrical mandrels and adapters racked soft-focus in the background, no people and no readable markings

Fig · 04 The tooling is part of the article — mandrels managed like calibration assets, corrections drilled in the planes

Where balancing goes wrong

The tooling's error balanced into every rotor — mandrel runout and adapter unbalance masquerading as the rotor's own. Key conventions mixed — armature and pulley each balanced to a different convention, assembled into a shake. A low-speed balance on a flexible rotor — passes on the machine, bends at service speed. Corrections chased below the machine's Umar — drilling noise, hole by hole. No agreed grade — “smooth” argued as an opinion after delivery. Drive influence uncontrolled — belt tension and joint moments read as unbalance. Thermal state ignored — a rotor balanced cold that bows warm. The residual never verified — corrected, assumed, shipped. And certificates that say “OK” — no vectors, no planes, no speed, no convention — worthless the day the overhaul is questioned.

So the discipline runs the other way. Tooling is balanced, runout-controlled and tracked like the calibration asset it is; the key convention is stated on every certificate. Rotor class decides the method — rigid rotors in two planes, flexible rotors at speed against their modes. The machine's Umar and URR are demonstrated with calibration rotors on a schedule, so corrections stop where the metrology stops. Drive influence is engineered out, thermal state is stated, and every rotor leaves with its vectors, planes, speed, grade and convention on the certificate — which is what lets an overhaul shop sign it, and defend it years later.

Full specification — expand

System	Dynamic balancing machines — horizontal hard-bearing & soft-bearing, vertical, and high-speed facility class; tooling, calibration regime & records
Governing Idea	Every rotor lies until it spins — couple unbalance shows no resting tilt; unbalance is a vector per plane, revealed only by rotation
The Physics	F = U × ω² — gram-millimetres become kilonewtons at speed, and the force turns with the shaft
The Measurement	Spin → amplitude + phase per pedestal against a once-per-rev reference → vectors at the correction planes → correct → verify residual
The Grade	ISO 21940 (ex ISO 1940): G = e × ω — G6.3 general machinery · G2.5 machine tools & turbomachinery · G1 and finer by agreement — the grade is the contract
Hard-Bearing	Stiff pedestals, force measurement, permanently calibrated, direct readout in one run — the production & overhaul workhorse
Soft-Bearing	Swinging pedestals, displacement measurement, trial-mass calibrated per rotor type — sensitivity for small & light rotors
Vertical	Disc-shaped rotors — impellers, fans, discs, clutches — on a tooling plate spindle, single-plane or two-plane
High-Speed Class	Flexible rotors balanced at service speed, multi-plane against mode shapes — vacuum chamber against windage, engineered containment, precise drive, telemetry; rigid-rotor rules end near 70% of the first bending critical
The Tooling	Mandrels, adapters & drive dogs balanced, runout-controlled, managed as calibration assets; key convention stated on every certificate
Machine Proof	Umar (minimum achievable residual unbalance) & URR (unbalance reduction ratio) demonstrated with calibration rotors on schedule
The Record	Per-serial certificates — initial & residual vectors, planes, speed, grade, convention — the audit evidence of every overhaul
The Split	The site's vibration & shock test system qualifies equipment against vibration; the balancing machine removes the rotating cause at its source. The chassis dynamometer's own rolls are balanced to ISO 1940 G2.5 — the grade this machine certifies
Scope Boundary	Ours: beds, pedestals & roller carriages, drives & speed control, measuring-electronics integration, high-speed facilities with vacuum & containment, tooling & mandrels, calibration-rotor regime, correction stations, retrofit of modern measurement chains onto existing beds, installation, commissioning, documentation, training, spares & AMC — including build to the customer's specification. Bought-in certified: transducers, measuring electronics, vacuum pumps, drive motors & VFDs. The customer's: the rotors and their acceptance grades
Status	Engineered to order — machines of this class quoted across high-speed and general-purpose dynamic-balancing machine requirements; no delivered balancing machine is claimed

PDF · 1 page

Dynamic Balancing Machine — Capability Sheet

Tender Response

Send rotor envelope, speeds & grades — compliance matrix in two working days

Variants

One discipline, four machines.

What changes is the rotor — its shape, its mass, and whether it stays rigid or bends at the speed it must live at.

Var · 01

Horizontal Hard-Bearing Machines

The universal workhorse — roller pedestals on stiff ways, belt or end drive, one-run readout, rotors from armatures to line shafts.

Var · 02

Vertical Balancing Machines

For the disc-shaped world — impellers, fans, discs and clutches on a tooling-plate spindle, corrected in one or two planes.

Var · 03

High-Speed & Facility Class

Flexible rotors at service speed — vacuum chambers, containment, multi-plane modal balancing, telemetry and drive control.

Var · 04

Retrofits, Tooling & AMC

Modern measurement chains on existing beds — the bed is iron, the honesty is electronics — plus mandrels, calibration rotors, training and support.

Applications

Wherever anything spins for a living.

The shops that make rotors, and the shops that bring them back.

A · 01Aeroengine & turbomachinery overhaul

A · 02Air force & defence repair depots

A · 03Pump, fan & motor manufacturers

A · 04Turbocharger & high-speed spindle rotors

A · 05Machine-tool & grinding-wheel balancing

A · 06Power-sector turbine overhaul

FAQ

Common questions.

Plain-language answers from the engineering team.

Q · 01 Why does a gram matter on a rotor?

Because the force grows with the square of speed, and it never stops turning. Unbalance is measured in gram-millimetres — mass times its radius from the spin axis — and the force it produces is U × ω². Run the arithmetic once and the fuss makes sense: a single gram sitting at 100 mm radius produces about 10 newtons at 3,000 rpm — noticeable. Take the same gram to 30,000 rpm and it produces about a kilonewton — a hundred kilograms of rotating force, from one gram, sweeping around the bearing five hundred times every second. And unlike a static load, this force rotates: every bearing element, every weld, every winding sees a full stress reversal every revolution — which is why unbalance shows up as hammered bearings, worked-loose fasteners, leaking seals and fatigue cracks rather than as anything dramatic on day one. The machine exists to find that gram and remove it — and the ISO 21940 grades exist so that “how much residual is acceptable” is decided by rotor mass and service speed, not by whoever argues loudest at handover.

Q · 02 Why must it spin — what does static balancing miss?

It misses half the problem — sometimes all of it. Static unbalance is the simple case: the centre of mass sits off the spin axis, so the rotor rolls to its heavy spot on knife edges and a level check finds it. But picture a rotor with two equal heavy spots at opposite ends, 180 degrees apart. Its centre of mass is exactly on the axis; on knife edges it sits level and looks perfect. Spin it, and each end throws its force in an opposite direction — a rocking couple that hammers both bearings and reverses every revolution. That is couple unbalance, and no static test can ever see it, because it produces no resting tilt at all — only rotation reveals it. Real rotors carry both kinds at once — dynamic unbalance — which is why the machine measures at two pedestals with phase and resolves the readings into two correction-plane vectors: the mathematical minimum needed to make a rigid rotor run true. It is also why the machine reads phase against a once-per-revolution reference: without knowing where in the revolution the heavy spot passes, amplitude alone says “something is wrong” but never where to drill. Every rotor lies until it spins — the machine's whole job is making it tell the truth in a form a correction drill can act on.

Q · 03 Hard-bearing or soft-bearing — which, and why?

They answer the same question through opposite mechanics. A hard-bearing machine holds the rotor on pedestals far stiffer than anything the unbalance can move, and measures the force the spinning heavy spot presses into them. Because force scales predictably with geometry and speed, the machine is permanently calibrated: enter the rotor's dimensions, spin at a modest fixed speed, and the readout is gram-millimetres per plane in a single run — no trial masses, no per-rotor setup beyond dimensions. That directness makes it the production and overhaul workhorse, and it is our reference architecture. A soft-bearing machine does the opposite: pedestals swing freely on flexures, the rotor runs above the suspension's natural frequency, and the machine measures displacement — how far the unbalance actually shakes the cradle. Sensitivity is superb, especially for small and light rotors whose unbalance forces are tiny, but calibration is per rotor type, established with trial masses. The honest selection rule: hard-bearing for throughput, mixed rotor populations and depot work; soft-bearing where grams are few and the residuals chased are finest. Both end the same way — a residual verified against the agreed ISO 21940 grade, on a certificate with vectors.

Q · 04 What makes high-speed balancing a different machine entirely?

The rotor stops being a rigid body. Every rotor has bending criticals — speeds where it resonates like a beam — and below roughly 70% of the first one it behaves rigid: correct in two planes at low speed and it stays balanced at any speed it reaches. The rotors at the serious end of aviation and power — long turbine and compressor spools, slender high-speed spindles — live near or beyond their criticals, and as they approach them they bend: the distributed unbalance excites the mode shapes, the rotor bows, and the bow itself creates new unbalance. A low-speed two-plane balance on such a rotor passes on the machine and shakes at service speed — the classic, expensive lie. The cure is to balance at or near service speed, in multiple planes, against the modes — and that turns the machine into a facility. Blade and disc windage at full speed is megawatts of air churn, so the rotor runs in a vacuum chamber. The honest possibility of a failure at speed demands engineered containment. The drive must hold speed precisely through resonances; pedestals must survive the criticals on the way up; instrumentation runs on telemetry. This facility class — chamber, containment, drive, pedestals, tooling and procedure as one engineered system — is precisely what the recent high-speed dynamic balancing machine requirement we quoted describes, and it is engineered to order around the rotor book it must serve.

Q · 05 How does this relate to the vibration system — and the dynamometer — you already build?

They stand on opposite sides of the same physics. The vibration & shock test system asks: can this equipment survive the vibration environment it will live in? It plays programmed spectra through an electrodynamic shaker and qualifies the article against the world's shaking. The balancing machine asks the upstream question: why is the world shaking? — and for rotating machinery the overwhelming answer is unbalance. One machine proves survival of the symptom; the other removes the cause at its source. A plant that balances well needs less of its equipment to survive; a laboratory that qualifies well knows which vibration is environment and which is a rotor asking for this machine. The chassis dynamometer makes the relationship concrete: its own rolls — tonnes of machined steel spinning under vehicles — are specified dynamically balanced to ISO 1940 G2.5, which is exactly the grade family this machine exists to certify. Every serious machine we build assumes balanced rotation somewhere inside it; this is the machine that makes the assumption true. And the gearbox load rig completes the family picture: it proves assemblies under load and torque, where the balancing machine proves the rotor itself as a manufacturing and overhaul operation — different altitude of the same dynamics discipline.

Q · 06 What do you build, what is bought in — and what is claimed?

Divided honestly. What Neometrix provides: the machines — horizontal hard-bearing and soft-bearing beds with their pedestals and roller carriages, vertical tooling-plate machines, and the high-speed facility class with vacuum chambers, containment, drives and telemetry; the measuring-electronics integration and its calibration regime; the tooling — mandrels, adapters, drive systems — balanced and managed as calibration assets; the calibration-rotor regime that demonstrates Umar and URR on schedule; correction stations; and retrofit of modern measurement chains onto existing mechanically sound beds — a recognised requirement class, because the bed is iron and the honesty is electronics. With all of it: installation, commissioning, documentation, method training, spares and AMC, including build to the customer's own specification. What is bought-in certified: force and vibration transducers, measuring electronics and instrumentation cores, vacuum pumps, drive motors and VFDs — proprietary instruments of established makers, integrated rather than imitated. What is the customer's: the rotors and their acceptance grades. And the record, stated plainly: machines of this class have been quoted across high-speed and general-purpose dynamic-balancing machine requirements — for an aircraft builder and an air force repair depot. No delivered balancing machine is claimed; the class is engineered to order, machine by machine, around the rotor book it must serve.

↗

The dynamics family from Neometrix.

The environment, the assembly, and the rolls that must run true — engineered at our Noida facility.

↗ Dynamics

Vibration & Shock Test System

Qualifying equipment against vibration — the symptom this machine removes at source.

↗ Vehicle Test

Chassis Dynamometer

Its rolls are balanced to ISO 1940 G2.5 — the grade this machine certifies.

↗ Powertrain

Helicopter Main Gearbox Load Test Rig

Assemblies proven under load — where this machine proves the rotor itself.

Browse all Neometrix product lines.

Get a quotation

Send the rotor book
and the grades.

The projects desk replies within two working days with a clause-by-clause compliance matrix and a budgetary quotation. Write to [email protected] or use the form.

Enquire — balancing machines Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED TO ORDER — DYNAMIC BALANCING MACHINES EVERY ROTOR LIES UNTIL IT SPINS · THE GRADE IS THE CONTRACT · RESIDUAL VERIFIED ENGINEERED IN NOIDA · INDIA

Every rotor lies until it spins. Make it tell the truth.

The heavy spot, found and removed.

A vector, not a guess

The grade is the contract

The machine proves itself

Spin, read, correct, verify.

Bed & Pedestals

Drive & Speed Control

Sensors & Electronics

Tooling, Calibration & Records

Reference machines, built to the rotor book.

Where balancing goes wrong

One discipline, four machines.

Horizontal Hard-Bearing Machines

Vertical Balancing Machines

High-Speed & Facility Class

Retrofits, Tooling & AMC

Wherever anything spins for a living.

Common questions.

The dynamics family from Neometrix.

Vibration & Shock Test System

Chassis Dynamometer

Helicopter Main Gearbox Load Test Rig

Send the rotor book
and the grades.

Similar Products

Share This Page

Every rotor lies until it spins. Make it tell the truth.

The heavy spot, found and removed.

A vector, not a guess

The grade is the contract

The machine proves itself

Spin, read, correct, verify.

Bed & Pedestals

Drive & Speed Control

Sensors & Electronics

Tooling, Calibration & Records

Reference machines, built to the rotor book.

Where balancing goes wrong

One discipline, four machines.

Horizontal Hard-Bearing Machines

Vertical Balancing Machines

High-Speed & Facility Class

Retrofits, Tooling & AMC

Wherever anything spins for a living.

Common questions.

The dynamics family from Neometrix.

Vibration & Shock Test System

Chassis Dynamometer

Helicopter Main Gearbox Load Test Rig

Send the rotor bookand the grades.

Similar Products

Share This Page

Send the rotor book
and the grades.