Helical Geared Motor Manufacturer – Gearbox Checklist

Gearbox Supplier Screening Checklist

Helical Geared Motor Manufacturer – Gearbox Checklist

Gearbox Supplier Screening Checklist

A shortlist of three suppliers usually lands on one desk with one question attached: which of them is a genuine helical geared motor manufacturer, and which one simply buys finished gearing and bolts it into a housing? The six markers below are the ones a parallel shaft geared motor manufacturer cannot answer cheaply — alloy grade, heat treatment, grinding, published torque, documentation and configuration — and each one can be checked against the FC series sheet before a purchase order is raised.

6markers to verify before a vendor is approved
FC37–FC157frame range to hold a supplier against
3input forms that change footprint and weight
FC series parallel shaft helical geared motor,SL-Transmission China geared motor,FC Series Helical Geared Motor - Helical Geared Motor Supplier

Six markers that separate a manufacturer from an assembler

Work down the list with every shortlisted vendor. Each marker has one question worth asking, one answer that should make you cautious, and one reason it changes your decision.

1

Material traceability

AskWhich alloy grade are the gears cut from, and can you show the mill certificate for the heat lot?
Weak answer"High-quality alloy steel" with no grade named.
Why it mattersLoad capacity starts at the alloy, not at the paint. The FC series names 20CrMnTi on its own sheet.
2

Heat-treatment proof

AskWhat hardness results from carburizing and quenching, and what case depth is specified?
Weak answer"Hardened gears" with no range and no record.
Why it mattersA hardness band without a measurement is a brochure line, not a specification.
3

Grinding precision

AskAre the teeth ground after heat treatment, and to which grade?
Weak answer"Precision ground" with no grade figure.
Why it mattersTeeth distort in quenching; the flank you buy is the flank that was corrected after it.
4

Spec-sheet transparency

AskShow the frame-by-frame permitted torque table, not the headline maximum.
Weak answerA single peak torque figure with no frame attached to it.
Why it mattersYou size a gearbox on the frame you are actually ordering, not on the largest number on the page.
5

Documentation pack

AskWhat physically ships with the unit — drawings, inspection records, nameplate data?
Weak answer"Certificate available on request."
Why it mattersYour end customer's auditor will ask for the same file set you accept now.
6

Configuration fit

AskWhich input forms and mounting positions exist for this specific frame size?
Weak answer"We can do anything" without a drawing.
Why it mattersInput style changes shaft alignment, footprint and shipping weight.

What 20CrMnTi and HRC58–62 actually prove

Most geared motor sheets stop at "hardened and ground gears". The FC series goes further and names the steel and the hardness band, which makes it checkable. That is the first point where a shortlist separates.

What the statement proves: the vendor has committed publicly to a named alloy and a hardness window, so you can demand a measurement against both and refuse a unit that misses them.

What it does not prove: core toughness, effective case depth, retained austenite, or consistency from one heat lot to the next. Surface hardness on its own tells you very little about how a tooth behaves under shock load, because a hard case over a soft core still deforms.

Stated on the FC series product page

"Gears in 20CrMnTi alloy steel; after tempering, carburizing, quenching and other heat treatment, the hardness can reach HRC58–62."

Grinding is then applied to the finished teeth, with precision stated as grade 6–5.

Ask the supplier for

  • A mill certificate naming 20CrMnTi for the heat lot used on your order.
  • Hardness readings inside the HRC58–62 band, with test locations marked on the tooth.
  • Effective case depth at the pitch line, plus the measuring method used.
  • Heat-treat batch records that tie those readings back to your serial numbers.

Ground to grade 6–5 versus unground teeth

The FC series states that all gears are processed by accurate grinding, with precision reaching grade 6–5. That sentence is worth more than it looks, and it is the easiest marker to test across a shortlist — put the same question to every vendor and compare the answers, not the adjectives.

Point of comparisonTeeth ground to grade 6–5Unground, as-cut teeth
Flank after hardeningQuench distortion is removed in a finishing pass after heat treatmentQuench distortion stays on the working flank
Contact across the facePredictable contact pattern; load is spread across the toothHigh spots concentrate load on a narrow band
Noise at operating speedFinely ground teeth support low noise and smooth meshingWhine that becomes more obvious as speed rises
Surface durabilityFiner finish resists pitting across continuous duty cyclesRougher finish starts pitting earlier in the same duty
Fit for continuous heavy dutyMatches the durability claim made for the FC series gear setReasonable for intermittent, low-speed, light duty only
How to verify itRequest the gear inspection report stating the grade achievedAsk the same question — a vague reply is the answer

Comparison is qualitative. Confirm the grade actually achieved for your order in the inspection report rather than in the sales brochure.

Read the torque table, not the headline

The FC series sheet carries two different torque figures. The product introduction describes output torque up to 50,000 Nm. The body copy and the frame table top out at 18,000 Nm on the largest standard frame, FC157. Both numbers appear on the same page.

That gap is not unusual — oversized frames and specially engineered builds sit outside a standard frame table — but closing it is your job, not the vendor's. Before you compare prices, ask which frame and which build the headline figure belongs to, and require the permitted torque for the exact frame you are ordering in writing.

A gearbox is sized on permitted torque at the driven shaft, for the duty cycle you actually run. Two suppliers quoting the same headline number can still be quoting two different frames.

FC series parallel shaft helical gearmotor housing and output shaft configuration
Model Solid shaft dia. (mm) Centre height (mm) Output flange dia. (mm) Power (kW) Ratio Permitted torque (Nm) Weight (kg)
FC3725k63070h130.12–34–13818013
FC4735k63580h130.12–5.54–17536016.5
FC5735k640100h130.18–7.54–19742027
FC6740k640100h130.37–7.54–19770031
FC7750k650120h130.75–114–197135055
FC8760m660155h131.5–224–1932500100
FC9770m670180h132.2–304–2033700170
FC10790m690200h133–454–2056500260
FC127100m6100240h135.5–904–20210000400
FC157120m6120270h1311–1604–19018000700

Selection data as published on the FC series sheet. Weights are without oil and without motor; shaft and flange input add 10%. The sheet also lists a hollow-shaft column that is blank for every frame, so it is omitted here. Confirm the figures for your build on the quotation drawing.

The documentation pack to demand before dispatch

Ask for this file set with the quotation, not after the goods arrive. A supplier who can send the list in a day is telling you something; one who "will check with the workshop" is telling you something else.

  • Gear inspection reportStating the grade actually achieved on the tooth flanks against the 6–5 target.
  • Material certificateNaming 20CrMnTi and referencing the heat lot used for your gears.
  • Hardness and case-depth recordReadings inside HRC58–62, with test positions marked.
  • Assembly run-test recordNo-load and load running notes, including noise and vibration observations.
  • Configuration drawingThe exact build you ordered: input form, mounting position, shaft and flange dimensions.
  • Commissioning dataNameplate data plus the oil grade and fill quantity for the mounting orientation.

Input form, mounting and shipping weight

Two units with identical gear data can differ in footprint, alignment and freight cost. The FC series offers three input forms and four mounting arrangements, and the sheet's own weight note is where freight budgets usually slip.

Directly connected with motor

Buyer decisionShortest overall length and one supplier accountable for alignment. Confirm the motor frame interface on the drawing.

Flange input

Buyer decisionLets you mount your own motor or existing drive. Check pilot diameter and bolt pattern, not just the flange size.

Shaft input

Buyer decisionFor belt or separate drive arrangements. Note the sheet's 10% weight adder for shaft and flange input.

Horizontal and vertical mounting

Buyer decisionVertical installation changes oil level and lubrication behaviour. Ask for the fill instruction for that orientation.

Small flange and torque arm

Buyer decisionReaction point and anchor detail must be on the drawing before fabrication starts at your plant.

Weight and oil at dispatch

Buyer decisionPublished weights exclude oil and motor. Confirm whether the unit ships dry and who fills it on arrival.

Match the application to a frame before you ask for price

The FC series is listed for cranes, conveyors and ceramic machinery. Each of those duties interrogates a different column of the table.

Crane travel and hoisting duty

Spec to interrogatePermitted torque against peak starting load, not average running load — for example FC97 at 3,700 Nm or FC107 at 6,500 Nm.
Buyer decisionSpecify the duty class and the shock factor in the enquiry. Choose the frame whose permitted torque clears the peak, and treat the next frame down as a false economy.

Continuous conveyor drive

Spec to interrogateOutput speed 0.15–270 rpm and the ratio band for the frame — mid frames run ratios from 4 to about 197.
Buyer decisionFix the required output speed first, read off the ratio, then confirm the frame's permitted torque at that ratio. Never select on ratio alone.

Ceramic machinery and dusty plant

Spec to interrogateGrinding grade and sealing in a continuous, abrasive environment where noise and pitting announce themselves early.
Buyer decisionAsk for the inspection report and the lubrication instruction together; in this duty the maintenance regime decides service life as much as the gear set does.

Retrofit and replacement

Spec to interrogateCentre height and solid shaft diameter: FC87 runs a 60m6 shaft at 60 mm centre height, FC97 a 70m6 shaft at 70 mm.
Buyer decisionMeasure the existing shaft, flange and bolt pattern before the enquiry. A frame that fits the torque but not the foundation is not a replacement.

Send duty data, not a model number

An enquiry that arrives with the numbers below is answered with a frame, a ratio and a permitted torque. An enquiry that says "quote me an FC series" is answered with a brochure.

  • Required output speed in rpm
  • Required torque at the driven shaft, including starting and shock load
  • Motor power available, in kW
  • Duty cycle: hours per day, starts per hour, duty class
  • Input form: direct motor, flange input or shaft input
  • Mounting: horizontal, vertical, small flange or torque arm
  • Ambient conditions: temperature, dust, washdown, indoor or outdoor
  • For replacements: existing shaft diameter, centre height and bolt pattern
  • Quantity, destination port and required delivery window
  • Whether the unit should ship dry or filled with oil

Get a quotation against the FC series table

Send the duty data and the mounting sketch. Ask for the permitted torque of the proposed frame, the grinding grade in the inspection report, and the weight with your input configuration included.

Related Reading

Three notes to help clarify product requirements before contacting the supplier.

Industrial Gearbox Replacement for Ceramic Machinery Retrofits

A ceramic machinery drive upgrade succeeds when the replacement gearbox matches the existing frame, seals against abrasive dust, and arrives with maintenance details the plant crew can use from the…

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What Is a Parallel Shaft Helical Geared Motor?

This guide explains what a parallel shaft helical geared motor is, how its parallel input and output shafts are arranged, and how that layout fits around the driven shaft.

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20CrMnTi Gear Steel in Heavy-Duty Helical Gear Motors

Gear teeth in heavy-duty helical gear motors last or fail because of what happens at the surface and just beneath it.

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Frequently Asked Questions

what should a supplier prove about the gear material?

The page works from 20CrMnTi carburised and hardened to HRC58–62; ask for the gear inspection report stating the grade actually achieved.

what is the difference between ground and unground teeth?

Ground teeth remove quench distortion in a finishing pass, give a predictable contact pattern and resist pitting, while unground teeth suit intermittent low-speed light duty only.

how should i read the torque table?

Match permitted torque in Nm, at the ratio you need, to the duty you run — the headline power figure alone does not tell you whether the gear set survives continuous heavy duty.

what documentation should arrive before dispatch?

The page asks for the gear inspection report, material certificate, hardness verification, run-out or noise check and a packing list showing the quantity and carton plan.

which input forms and mounting positions are available?

Directly connected, flange input and shaft input forms are listed, with horizontal or vertical mounting and the shipping weight given per frame size.

what should i send with the selection request?

Duty data rather than a model number: power, output speed or ratio, load type, duty cycle, mounting position and the acceptable noise level.

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