Engineering Reference Case Profile · OEM Component Supply
OEM Component Supply · Impellers, Bare Motors, Shafts and Bearings to Drawing
The largest single segment in LONGWELL’s own correspondence is not a finished-fan application at all — it is component supply to manufacturers who build their own machines. A sweep of the mailbox archive found 257 distinct customer organisations buying impellers, bare motors, shafts, sleeves and bearings to their own drawings. What decides these programmes is not a performance curve; it is tolerance, rotation direction, fixing detail, material certification and documents that match the goods exactly.
About this case profile: This profile is compiled from real LONGWELL project correspondence in this segment. Customer names, commercial terms and pricing are withheld; company names and branding have been removed from the photographs. Model numbers, electrical ratings and dimensions are quoted from LONGWELL controlled datasheets, product nameplates and customer-approved drawings. Where a figure is a typical range rather than a measured project result it is labelled as such. Named references are available under NDA on project qualification (sales@longwellfans.com).
1 · Challenge
- Three details decide a cross-flow impeller order, and none of them is a dimension: where the fixing boss sits (inboard or outboard), what the fastener is (headed screw or headless grub screw, thread and drive), and rotation direction — with CW and CCW usually split in an exact ratio across the batch.
- Colour is a specification. On a fan-coil programme, more than twenty impeller sizes were supplied in blue, green, black and natural, with batch-to-batch colour consistency treated as a quality characteristic.
- Metal parts are bought on material and hardness, not size alone. One shaft programme specified SS 420 J2 at 50 HRC with knurling and precise groove cutting, against a debit-memo claim if a batch failed.
- Customs and banking scrutiny is heavier on components than on machines. Descriptions and HS codes for bearings, shafts and fasteners have to match the goods exactly on the bill of lading draft, or clearance and payment both stall.
- Component buyers run assembly lines. A missed batch stops their line, so lead time is agreed in phases across long factory shutdowns rather than as one date.
- Nothing goes to volume without a signed drawing — and neutral packaging, printed inner boxes and specified shipping marks are frequently part of the deliverable.
2 · Solution architecture
Component supply is run as a drawing-controlled programme, not a catalogue transaction. Every order starts from a customer drawing or a LONGWELL drawing signed by the customer; fixing position, fastener type, rotation, hub bore, material and finish are dimensioned on it. Material certificates and dimensional inspection reports ship with the goods, and the document set — description, HS code, packing list — is reconciled against the physical goods before the bill of lading is finalised.
Component types supplied to drawing
| Component | Typical specification | Controlled details | Segment served |
|---|---|---|---|
| Plastic cross-flow impellers | Ø87–Ø115 mm × 520–932 mm, 8 mm hub bore | Colour (blue / green / black / natural), fixing position, fastener type, CW/CCW | Fan coil units, HVAC terminals |
| Plastic & aluminium cross-flow impellers | 101.5×450, 101.5×640, 97×300, 97×450, 97×640 mm | Inboard vs outboard fixing boss; 5 mm headless hex grub screw; CW/CCW split 50:50 | Fan and ventilation component integrators |
| Aluminium cross-flow impellers | Ø80 mm × 175 / 355 / 495 mm | Rubber bearing sleeve fixed on shaft, zero axial float | Transformer cooling equipment |
| Backward-curved EC fans (bare) | e.g. LWBE3G190-072NS-13, 230 V 50/60 Hz, 0.65 A, 87 W, 3,300 rpm, Class B, IP55 | PA6+GF30 impeller, separate power and 4-core control leads, CE/EAC/UL marks | Machine builders and OEM integrators |
| Precision motor shafts | Semi-finished shaft Ø6 mm × 36 mm knurled; steel shaft 6×35, 6×41 | SS 420 J2, 50 HRC, groove cutting and knurling, TC report with each lot | Motor and fan component manufacturers |
| Shaft sleeves | 15.5 × 20 × 48-8 | Free sample against drawing before volume | Motor assembly |
| Bearings and fasteners | Bearing Ø6×13.8; M4×0.7×6.6 round-point; M4×0.7×6.8 hex screw | HS codes reconciled to goods (bearings 84821090, shafts 84831099, screws 73181900) | Motor and fan assembly |
3 · Verified figures
Fan performance figures are quoted from LONGWELL controlled datasheets and product nameplates and are tested per AMCA 210/211 methods; third-party reports available on request. EC versus AC energy saving is approximately 30%, higher under strongly varying load — confirm against your own load profile. Final selection must be confirmed against the actual duty point (airflow, static pressure, ambient temperature, certification scope) of your machine.
Distinct customer organisations
257
Counted across the full mailbox archive sweep of this segment
Documented project threads
431
Real two-way correspondence with our reply on file
Impeller sizes on one programme
20+ sizes, 4 colours
8 mm hub bore, colour consistency treated as a quality characteristic
Shaft material and hardness
SS 420 J2 · 50 HRC
With knurling and groove cutting; TC report standard with each lot
Rotation split
CW / CCW 50:50
Agreed and counted per batch, not assumed
Fastener standardised
5 mm headless hex grub screw
Replaced a headed screw after assembly-space review
Batch example on one pallet
250 pcs · 277.5 kg net
LWBE3G190-072NS-13, crate 1,090×1,090×990 mm, CE and EAC marked
Release condition
Customer-signed drawing
No volume production before sign-off
4 · How these programmes run
Drawing received or issuedEither the customer sends their drawing or LONGWELL issues one. Fixing position, fastener, rotation, hub bore, material and finish are all dimensioned before any price discussion.
Assembly-space reviewWhere the fixing boss sits is checked against the customer’s own assembly clearance — this is the detail that most often forces a change after first samples.
Sample and sign-offSamples are supplied free against the drawing where useful. Volume starts only after the customer signs and stamps the final drawing.
Material and inspection evidenceFor metal parts, material grade and hardness are confirmed and a TC report plus dimensional inspection ships with each lot.
Document reconciliationDescription and HS code for every line are checked against the physical goods on the bill of lading draft before it is finalised.
Phased deliveryAround long shutdowns, delivery is split into phases with forecast agreed 60–90 days ahead so the customer’s assembly line does not stop.
5 · Engineering lessons carried forward
- On cross-flow impellers, settle three things at drawing stage every time: fixing boss position (inboard or outboard), fastener type and thread, and rotation direction with the CW/CCW split for the batch. Getting these right up front removes most later drawing revisions and assembly interference.
- Treat colour as a controlled characteristic, not a preference. On a multi-size, multi-colour impeller programme, batch-to-batch colour consistency has to be written into the production and inspection instruction or it will drift.
- For metal parts, confirm material grade and hardness before quoting, and make the material certificate a standard part of every lot. On a 50 HRC stainless shaft programme, a failed batch would have triggered a direct debit-memo claim.
- Component shipments face heavier customs and banking scrutiny than machines. Reconcile description and HS code line by line against the goods on the bill of lading draft — for shafts, bearings and fasteners this is where clearance and payment actually stall.
- Plan around long factory shutdowns 60–90 days ahead with the customer’s forecast, and build a safety-stock buffer. Late recovery by air freight turns into a commercial dispute that costs more than the buffer would have.
- Component customers are the quietest route to volume. They rarely need a performance presentation — they need a drawing you honour, a certificate that matches, and documents that clear.
6 · Project evidence
Every item below is a real project thread from LONGWELL’s own correspondence. Each carries an anonymised case reference, the counterparty described by industry and buying role only, an evidence grade, the actual dates from first contact to close, the length of the email thread and, where an invoice is on file, the order value band. Customer names, domains, brand artwork, prices and commercial terms are withheld — including from the photographs. Evidence grade A means controlled documents or test reports are on file for that thread; grade B means a structured enquiry and specification are on file. Order value bands are read from the proforma or commercial invoice held on file for that thread and are rounded to a band; the invoice currency is shown as invoiced. A band is only given where the invoice currency is unambiguous — 20 of the threads on these pages carry one. Unit prices are never published.
Fan-coil impellers — 20+ sizes, four colours, printed customer packaging
- More than twenty plastic cross-flow impeller sizes on an 8 mm hub bore — 95×611, 97×622, 107×522.7, 107×799, 95×580, 93×540, 97×707, 97×758, 91×792, 109×932, 115×895 mm and others — moulded in blue, green, black and natural.
- Colour consistency across injection batches, fastener type per drawing, colour-printed inner boxes carrying the customer’s own model numbers and their specified shipping marks on the outer cartons.
- The programme ran alongside a negotiated regional distribution framework with annual volume commitments.
Cross-flow impellers — fixing position, grub screw and CW/CCW split
- Plastic (ABS) and aluminium cross-flow impellers in 101.5×450, 101.5×640, 97×300, 97×450 and 97×640 mm.
- Engineering issued side-by-side ABS and aluminium structural drawings; the hub fixing was moved inboard or outboard to suit the customer’s assembly clearance, and the fastener standardised to a 5 mm headless hex grub screw.
- CW and CCW impellers were delivered in an exact 50:50 split, counted per batch.
Precision stainless shafts at 50 HRC, with phased delivery through the shutdown
- Semi-finished shaft Ø6 mm × 36 mm with knurling, and steel shaft 6×35, in SS 420 J2 at 50 HRC with precise groove cutting; shaft sleeve 15.5×20×48-8; bearing Ø6×13.8 and matched fasteners.
- Sleeve samples were supplied free of charge for drawing sign-off before volume. TC and dimensional inspection reports shipped with each lot — a failed batch would have triggered a direct debit-memo claim.
- Delivery was phased by sea and air around the Chinese New Year shutdown, prioritising the models the customer’s line needed first.
Shafts, screws and bearings — document and HS-code compliance as the deliverable
- Steel shaft 6×36-02 and 6×41-02, M4×0.7×6.6 round-point and M4×0.7×6.8 hex screws, bearing Ø6×13.8, machined to the customer’s assembly tolerances.
- Multiple rounds of document checking against Indian customs and banking requirements: description and HS code reconciled on every house bill draft (bearings 84821090, shafts 84831099, screws 73181900).
- Delivered in phases on EXW / FOB Ningbo to match the customer’s production rhythm.
Trench convector fan modules — grille and no-grille variants coded correctly
- Ø30 mm impeller, 24 V EC with 0–10 V control alongside 230 V AC, with noise and aerodynamic performance measured rather than quoted.
- Superseded models were mapped onto the current range with drawings issued for each: LWCD-30290MG-02 → LWCD-30290MN-07 plus grille; LWCD-30610MG-06 → LWCD-30610MN-06 plus grille; LWCA-30290SG-07 → LWCA-30290SN-07 plus grille.
- The MG/SG (with grille) versus MN/SN (without grille) suffix rule was written out explicitly — it is a recurring source of drawing mismatches in this segment.
Fan performance figures are quoted from LONGWELL controlled datasheets and product nameplates and are tested per AMCA 210/211 methods; third-party reports available on request. EC versus AC energy saving is approximately 30%, higher under strongly varying load — confirm against your own load profile. Final selection must be confirmed against the actual duty point (airflow, static pressure, ambient temperature, certification scope) of your machine.
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