Neometrix / Hydraulic Cylinder Test Benches / Hydraulic Cylinder Test Bench / NMX-HCB-56

NMX-HCB-56 · ENGINEERED-TO-ORDER CLASS — SPECIFY · MOUNT · PROOF · MOVE · HOLD · PROVE

Hydraulic Cylinder Test Bench. Where it starts, where it leaks.

Name: Hydraulic Cylinder Test Bench
SKU: NMX-HCB-56

A proof test shows only that a cylinder does not burst. It says little about how the cylinder starts, how it slides, or what leaks past the piston.

So the bench is built around three things: a rigid, aligned mount, slow strokes at low pressure, and a hold at each end of the stroke.

Discuss a cylinder test bench Capability note (PDF)

A single hydraulic cylinder test bench: a long, low frame of grey painted steel with a heavy end block at each end, one double-acting hydraulic cylinder with a polished chrome piston rod held horizontally between the end blocks, two plain black hoses running to a brushed stainless steel valve manifold on the side of the frame and a slim position transducer rod alongside, and no people

Fig · 01 — A hydraulic cylinder test bench: one cylinder held between heavy end blocks, with its two hoses, a valve manifold and a position transducer — illustrative render.

The mount

rigid and alignedno side load on the rod

The moves

slow, at low pressurebreakaway, slide, cushion

The hold

pressure held at each enddecay shows a leak

The proof

both chambersheld at test pressure

Status

engineered to orderno bench yet delivered

ISO 9001ISO 14001ISO 10100 cylinder acceptance test referenceSAE J1335 no-load friction reference

Overview

Why a cylinder is judged by where it starts, and where it leaks.

Because proof pressure is the easy part. A cylinder can hold its test pressure and still stick, crawl or leak across the piston once it is in service.

Fig · 02 — The bench in one picture: the cylinder is mounted, driven through proof and slow strokes, and its pressure and position are read.

Proof pressure is the easy part.

What the bench is for

It tests hydraulic cylinders and actuators before they go into service. The cylinder is held in a rigid frame, driven from a pressure source through valves, and read with pressure and position sensors. It suits double-acting, single-acting and telescopic cylinders.

Why proof pressure is the easy part

A proof test takes both chambers to a test pressure above the working pressure, holds it, and checks for external leaks. It shows that the cylinder is strong. It does not show whether the piston seal leaks, or whether the cylinder moves smoothly.

Why low pressure tells the truth

At low pressure the cylinder has little force to spare, so friction shows. The pressure to start, the breakaway, is higher than the pressure to keep it sliding. A seal that sticks and slips makes the pressure saw up and down, and the rod crawls. The acceptance-test standard looks for a cylinder that moves at low pressure without vibration or crawling.

Why friction is measured with no load

With no load on the rod, the pressure needed to move it is the friction. A no-load friction test reads that pressure, static and dynamic, and so separates the cylinder's own friction from the work it will do.

Why the ends of the stroke are held

With the piston at the end of its stroke, one port is pressurised and held while the other is open. A tight piston seal keeps the pressure, and a leaking one lets it decay. Leakage across the piston shows as falling pressure, which a look at the rod never will.

Why the cushion is run

A cushion slows the piston over the last part of its stroke. The bench runs the cylinder into the cushion and checks that the adjusting throttle acts, because a cushion that does not act lets the piston hit the end cap.

The method

Specify, mount, proof, move, hold, and prove.

Six steps in a fixed order. The two shaded steps are the ones a quick order skips.

FIG · 02HYDRAULIC CYLINDER TEST BENCH · SPECIFY / MOUNT / PROOF / MOVE / HOLD / PROVE — WHERE IT STARTS, WHERE IT LEAKS

The step people underrate is the hold. A cylinder that survives its proof pressure and has never been held at the end of its stroke has not been tested for the leak that matters.

Fig · 03 — Three ways a cylinder lets you down: it sticks and slips, it leaks past the piston, and it has no cushion — a drawing of the idea, with no values.

1 · Specify

The bore, the stroke, the ports and the duty are stated by the customer, and the bench is set up to suit them.

2 · Mount

The cylinder is held rigid and aligned in the frame, so that no side load reaches the rod and adds friction that is not the cylinder's own.

3 · Proof

Both chambers are taken to the test pressure in turn, held, and checked for external leaks and for any permanent distortion.

4 · Move

The cylinder is stroked slowly at low pressure with no load. The breakaway, the sliding pressure and the cushion are read, and any crawl is seen.

5 · Hold

With the piston at each end of its stroke, pressure is held on one port with the other open, and the decay is read.

6 · Prove

The stroke is measured, and the record is handed over with the cylinder.

Work content

What the bench contains, element by element.

Read it as a checklist: a bench missing a row will pass a cylinder that fails in service.

A single double-acting hydraulic cylinder lying on a plain grey steel bench: a grey painted steel barrel with a heavy end cap, a polished chrome piston rod extended from the gland end, and two brushed stainless steel ports on the side of the barrel each with a plain black hose curving away, and no people

Fig · 04 — The cylinder under test: a double-acting cylinder with a polished rod and two ports, each with its hose — illustrative render.

Element	What it does	What matters
Rigid frame	holds the cylinder	heavy end blocks and a stiff base that take the reaction and keep the cylinder aligned
Mounting fixtures	fit the cylinder	adjustable clevis, flange and foot fixtures that put no side load on the rod
Pressure source	drives the cylinder	a pump unit with a relief valve, able to give test pressure to either chamber
Valves	direct and meter the oil	proportional or servo valves for slow, steady speeds, and isolating valves for the holds
Pressure transducers	read each chamber	one on each port, with a range fine enough to see the breakaway as well as the test pressure
Position transducer	reads the stroke	a transducer along the whole stroke, so that pressure is read against position
Load frame	adds load where the duty needs it	a reaction frame and a load cell for loaded tests, where the customer's duty calls for them
Test oil	carries the pressure	a clean hydraulic oil compatible with the cylinder's seals, held at a stated temperature
Cushion check	proves the cushion	a run into the cushion, with the adjusting throttle checked
Control & logging	run and record	PLC control of the strokes and holds, and a logger that keeps pressure and position for every one
Guarding	keeps people clear	a guard around the frame, relief valves on both ports and a safe way to release trapped pressure
Procedure	fixes the sequence	specify, mount, proof, move, hold and prove, the same for every cylinder
Testing & documentation	prove the bench first	a leak test, a transducer check and a record the customer can inspect

The element that decides whether the test is true is the pressure transducer range, because a transducer chosen only for the test pressure cannot see a breakaway.

Fig · 05 — One bench, three kinds of cylinder: double-acting, single-acting and telescopic, each read the same way.

Full specification — expand

System	A rigid frame with heavy end blocks and adjustable mounting fixtures that put no side load on the rod; a pressure source with a relief valve able to give test pressure to either chamber; proportional or servo valves for slow, steady speeds and isolating valves for the holds; a pressure transducer on each port, with a range fine enough to see the breakaway as well as the test pressure; a position transducer along the whole stroke; a reaction frame and load cell for loaded tests where the duty calls for them; a clean test oil compatible with the seals; a guard, relief valves and a safe release of trapped pressure; a PLC control with a logger; a written test plan; and testing and documentation before handover
The One Idea	A hydraulic cylinder is judged by where it starts and where it leaks.
Why Proof Pressure Is The Easy Part	A proof test takes both chambers to a test pressure above the working pressure, holds it and checks for external leaks, which shows that the cylinder is strong but not whether the piston seal leaks or whether the cylinder moves smoothly
Why Low Pressure Tells The Truth	At low pressure the cylinder has little force to spare, so friction shows: the pressure to start is higher than the pressure to keep it sliding, and a seal that sticks and slips makes the pressure saw up and down and the rod crawl
Why Friction Is Measured With No Load	With no load on the rod the pressure needed to move it is the cylinder's own friction, static and dynamic, which separates it from the work the cylinder will do
Why The Ends Are Held	With the piston at the end of its stroke one port is pressurised and held while the other is open, so a tight piston seal keeps the pressure and a leaking one lets it decay
Why The Cushion Is Run	A cushion slows the piston over the last part of its stroke, so the bench runs the cylinder into the cushion and checks that the adjusting throttle acts, because a cushion that does not act lets the piston hit the end cap
Standards	ISO 10100 is the public reference for the acceptance tests of hydraulic cylinders, and SAE J1335 is the public recommended practice for the no-load friction test of a hydraulic cylinder. This page prints none of their test pressures or limits, and no edition year: those come from the standard the customer names and from the customer's duty. Approval of a cylinder for use rests with the customer and the authority they name; none is claimed here
Configurations	A manual bench for one cylinder at a time with the valves set by hand, a programmed bench whose strokes and holds are run and logged by a PLC, and a multi-size bench with a frame that takes a range of cylinder sizes
Scope Boundary	This page is the bench for the hydraulic cylinder itself. It is not a multi-station rig that tests pumps, valves and motors as well (see universal hydraulic test rig), not a bench for servo actuators with frequency response (see servo hydraulic actuator test bench) and not a proof bench for compressed gas cylinders, which are pressure vessels and not actuators (see hydrostatic test bench). No certification is claimed here
Status	Neometrix has quoted against successive hydraulic cylinder and actuator test requirements, and no delivered hydraulic cylinder test bench is claimed.

Configurations

One method, three ways to build the bench.

The method, the record and the hold at each end are shared. What changes is how much of the bench is automated, and how many cylinder sizes it takes.

Manual bench

Frame, drive and hand-set valves

One cylinder at a time on a rigid frame, with the valves set by hand and the readings taken from the transducers.

Programmed bench

Frame, drive and PLC with logger

The strokes and holds run from a stored sequence, and pressure and position are logged for every one of them.

Multi-size bench

Frame, range kit and logger

A frame and fixtures that take a range of cylinder sizes, with a kit of adaptors and a logger that keeps one record per cylinder.

Fig · 06 — Three ways to build the bench, one method: a manual bench, a programmed bench, or a multi-size bench.

And the part that is not equipment at all, yet decides all three: the test plan. It fixes the mounting, the stroke speed, the points at which pressure is held and the date of the next check, and it is written from the cylinder's duty, not from the bench.

Where it is used

Wherever a cylinder is built, repaired or accepted, and has to move.

The common thread is a cylinder that will be asked to move under pressure, and a seal that has to hold when it stops.

Manufacture

Where each new cylinder is proved before it leaves the shop, and the record goes with it.

Repair and overhaul

Where a cylinder with new seals is tested again, so that a good-looking rod is not mistaken for a sound seal.

Incoming inspection

Where a bought-in cylinder is checked against the order before it is fitted to the machine.

Development and trials

Where a new cylinder design is tried for friction, leakage and cushion before it is released.

Watch

See it in motion.

A short walkthrough video of the hydraulic cylinder test bench.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 What does a hydraulic cylinder test bench actually do?

It holds a cylinder rigid and aligned, drives it with oil through valves, and reads pressure at each port and the position of the rod. With those it can take both chambers to a test pressure, move the rod slowly at low pressure to see how it starts and slides, run it into its cushion, and hold pressure at each end of the stroke to see whether the piston seal leaks. The bench does not mend a cylinder. It tells you what the cylinder will do.

Q · 02 Why is proof pressure called the easy part?

Because it asks the least of the cylinder. A proof test takes both chambers to a pressure above the working pressure and holds it, checking for external leaks and permanent distortion. A cylinder that passes is strong. But a cylinder that is strong can still stick, crawl, leak across the piston or hit its end cap, and none of those is found by pressure alone. A bench that only proves pressure answers the question that was least likely to be the problem.

Q · 03 What is breakaway, and why measure it with no load?

Breakaway is the pressure at which a stationary piston first starts to move. It is higher than the pressure needed to keep it sliding, because a seal at rest grips harder than a seal in motion. With no load on the rod, that pressure is the cylinder's own friction and nothing else, which is why the no-load friction test reads it, static and dynamic. A seal that grips and then lets go in turn makes the pressure saw up and down and the rod crawl. Only a pressure transducer with a range fine enough to see these small pressures will show it.

Q · 04 How does a hold at the end of the stroke show leakage?

Run the piston to the end of its stroke, so that it rests against the end cap. Pressurise one port and hold it, with the other port open to return. If the piston seal is tight, the pressure on the held port stays where it was set. If the seal leaks, oil passes the piston and the pressure falls, and the rate at which it falls is the leakage. This is done at each end, because a seal can be worn in one part of the bore and sound in another. Looking at the rod would never show it.

Q · 05 Is this the same as the universal rig, servo actuator or hydrostatic bench pages?

No, and the differences are worth stating precisely. The universal hydraulic test rig page is a multi-station rig that tests pumps, valves, cylinders and motors together, so the cylinder is one station among several. The servo hydraulic actuator test bench page is for servo actuators, with frequency response and dynamic load. The hydrostatic test bench page is a proof bench for compressed gas cylinders, which are pressure vessels and not actuators: the word cylinder means two things, and this page means the one with a piston and a rod. This page is the dedicated bench for that one. It does not replace the other three, and it does not claim what they claim a second time.

Q · 06 Has Neometrix built one of these?

We would rather answer this plainly than let a page imply otherwise. Neometrix has quoted against successive hydraulic cylinder and actuator test requirements, and no delivered hydraulic cylinder test bench is claimed. What stands behind the offer is adjacent: Neometrix engineers hydraulic test equipment of the multi-station kind (see the universal hydraulic test rig page), benches that test servo actuators (see the servo hydraulic actuator test bench page) and proof-pressure benches for gas cylinders (see the hydrostatic test bench page). The pump, valves, transducers, load cell and logger are catalogue items, bought in, not invented. What Neometrix engineers is the bench around them: the rigid frame and fixtures, the valve and hold circuit, the transducer ranges, the control and logging, the procedure and the record. So the honest position is that the bench is engineered to order, the neighbouring disciplines are in the building, and the first bench of this exact kind will be built around the customer's own cylinders rather than taken off a shelf.

Q · 07 Which standards apply, and what can the bench not do?

ISO 10100 is the public reference for the acceptance tests of hydraulic cylinders, and SAE J1335 is the public recommended practice for the no-load friction test of a hydraulic cylinder. This page prints none of their test pressures or limits, and no edition year: those come from the standard the customer names and from the customer's duty. The bench tests the cylinder alone, on a rigid mount, and says little about how the cylinder behaves when the machine bends the mounting or loads the rod from the side. It does not certify a cylinder or anything else: this page claims no certification or accreditation. No pressure, force or leakage figure is printed here, and approval of a cylinder for use rests with the customer and the authority they name; none is claimed here.

Q · 08 What do you need from us to quote?

Six things, and most of them describe your cylinders rather than the bench. First, the cylinders: the kinds, the bores, the strokes and the mountings. Second, the pressures, stated by the customer: working and test. Third, the tests: proof, friction, leakage and cushion, and the standard you work to. Fourth, the oil: the type and the temperature. Fifth, the record: what you want kept with each cylinder. Sixth, the space and services available for the frame and the drive. From that we come back with a bench concept, a written test plan you can check, and a budgetary price.

The neighbouring hydraulic test pages, and how they differ from this one.

Three neighbours: one tests several kinds of component, one tests servo actuators, one proves gas cylinders.

↗ A multi-station rig

Universal Hydraulic Test Rig

A rig that tests pumps, valves, cylinders and motors together - the cylinder is one station there, not the subject.

↗ A servo actuator bench

Servo Hydraulic Actuator Test Bench

A bench for servo actuators, with frequency response and dynamic load - a different test of a different part.

↗ A gas cylinder proof bench

Hydrostatic Test Bench

A proof-pressure and leak bench for compressed gas cylinders - pressure vessels, not hydraulic actuators.

Browse all Neometrix product lines.

Get a quotation

Tell us the cylinders, the tests,
and the pressures.

The projects desk replies within two working days with a bench concept, a written test plan you can check, and a budgetary quotation. Write to [email protected] or use the form.

Enquire — hydraulic cylinder test bench Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — HYDRAULIC CYLINDER TEST BENCH SPECIFY · MOUNT · PROOF · MOVE · HOLD · PROVE — WHERE IT STARTS, WHERE IT LEAKS ENGINEERED IN NOIDA · INDIA