A-sample to SOP collapses every assumption.
The drive unit that hit 8000 rpm on the bench at A-sample needs a 500,000-cycle stator winding by SOP. We design the housing + the PCB + the connector around the assumption set you’ll actually ship.
Automotive & EV
Three power systems. One drawing pack. One pallet.
Inverter housings, motor stators, battery pack hardware, drive-unit casings, and high-voltage PCBs for electric vehicle platforms. From A-sample drive unit to a 50,000-unit production cell — built to your three-power architecture, not ours.
What makes this hard
Three engineering realities every EV program eventually meets.
EV programs are a three-power problem — drive (motor + inverter), storage (pack + BMS), and charging (OBC + converters). The teams that win solve them together; the teams that don’t end up renegotiating their BoM 18 months after A-sample.
Cooling is structural — and the structural part doubles as cooling.
Modern e-axles run die-cast aluminum housings that ARE the coolant jacket. CNC + cast hybrid lets you proto with the production thermal profile instead of finding it 12 months in.
High-voltage hardware fails differently.
800 V is not 12 V × 67. Creepage, clearance, EMI gaskets, and the plating on the busbar contacts all change. We build to LV 215-2 + ISO 6469 + IEC 62133 ahead of formal qualification.
Capability map
Six factories, one PM, one BoM for the whole drive unit.
A modern EV drive unit pulls from die-cast, CNC, sheet, IM, PCBA, and specialist plating. You shouldn’t need six suppliers — every part below ships from a single FabDigit cell against a single drawing pack.
Inverter housings · bearing carriers
CNC machining
Aluminum HPDC blanks finish-machined to ±0.025 mm flatness on the sealing flange. Coolant-port back-bores and bearing-carrier seats run in the same op.
Learn more Pack trays · coversSheet metal
Pack trays in 5052 / 5754 aluminum, stamped or formed steel covers, pre-finished and welded. Powder-coat, anodise, cataphoretic dip in the same line.
Learn more HV connectors · coversInjection molding
High-voltage connector bodies in GF-PA66 / PPS, V-0 PC covers, co-moulded EMI inserts. Hardened steel tooling rated for 1 M-shot production runs.
Learn more Cooling jackets · jigs · A-samples3D printing
SLM AlSi10Mg for first-article coolant jackets when HPDC tooling is 12 weeks out. PA12 (SLS) for assembly fixtures and ESC strain reliefs.
Learn more Inverter · BMS · OBCPCB & PCBA
4 – 12 layer high-voltage power boards with 4-oz copper pours, heavy bus-tabs, conformal coat as standard. ENIG / hard-gold on busbar contacts.
Learn more Drive integration · qualificationEngineering consultancy
Embedded engineering on stator winding selection, inverter thermal modelling, and LV 215-2 / ISO 6469 hardware compliance. Co-locate for qualification.
Learn moreCapability envelope
What we typically ship — and where the EV moat sits.
Working ranges across recent EV programs. Coatings row carries the moat: plating and conversion lines restricted on US/EU sites that our partner plants still run.
Mechanical tolerance
Sealing flange flatness on die-cast inverter housings.
±0.05 → ±0.025 mm
A-sample lead time
CAD-frozen → first drive unit.
28 – 56 days
Prototype run size
A- / B-sample drive-unit cell.
10 – 300 units
Production cell size
Rolling per-week throughput, sustained.
1,000 – 3,000 drive units / wk
Coolant-loop leak rate
Helium-trace test on inverter housings.
1×10⁻⁶ → 1×10⁻⁵ mbar·L/s
Coatings & finishes
Plating, conversion, and seal finishes used routinely on EV hardware. Restricted-elsewhere lines marked with a flag.
Cataphoretic dip (e-coat)Chemical conversion (Alodine 1200)USHex chromate (touch-up)USHard anodize Type III (sealed)Black sulfuric anodize Type IITin plate (Sn) on busbar contactSilver plate, selectiveENIG on inverter PCBPowder coat — RAL matchDielectric parylene on HV PCB
A reference build
Anatomy of a 220 kW EV drive unit, decomposed.
Composite of recent passenger-EV drive units. 220 kW peak, 400 V or 800 V bus, single-speed reducer. Hover any callout to see the hand-off.
01 · Stator
02 · Inverter housing
03 · HV connectors
04 · Inverter PCB
05 · Cooling loop
06 · Bearing carrier
- 01
1 · Hairpin stator + rotor
Laminated steel stator with copper hairpin windings. We build the stator carrier + bearing housing in 7075-T6, machined-to-cast tolerance.
- 02
2 · Cast aluminum inverter housing
HPDC AlSi10Mg housing with integrated coolant jacket. CNC-finished sealing flange + bearing seats; flatness ±0.025 mm; helium-trace leak-tested before shipment.
- 03
3 · 3-pin HV connector receptacle
IM-moulded GF-PA66 connector bodies with co-moulded EMI gaskets and silver-plated busbar lug interfaces.
- 04
4 · Power-stage PCB
6-layer PCB with 4-oz copper pours, heavy-bus tabs, and selective parylene over the HV traces. ENIG on the busbar contact pads.
- 05
5 · Coolant manifold
Integrated into the cast housing as a labyrinth jacket. Coolant flow validated against the inverter thermal map at qualification.
- 06
6 · Front bearing carrier
Co-machined with the inverter sealing flange. Bore concentricity 0.01 mm TIR; sealed crossed-roller bearing pre-fit at the cell.
Parts we ship most
Six part archetypes that drive an EV bill of materials.
These six parts make up the majority of the spend on a typical EV drive unit. Spec ranges below are working envelopes — your drawing tightens them.
Inverter housing
HPDC AlSi10Mg housing, CNC-finished sealing flange, integrated coolant jacket. Helium-trace leak-tested.
- Material
- AlSi10Mg HPDC
- Process
- HPDC + 5-axis CNC
- Tolerance
- ±0.025 mm flange
- Run size
- 200 – 50,000 pcs
Motor stator carrier
Machined aluminum stator-housing carrier with co-machined bearing seat. Drop-in for hairpin or distributed-winding stators.
- Material
- 7075-T6
- Process
- 5-axis CNC
- Tolerance
- ±0.01 mm bore
- Run size
- 100 – 10,000 pcs
Battery pack tray
Stamped + welded aluminum pack tray with integrated cold-plate channels. Pre-finished with cataphoretic dip and EPDM seal groove.
- Material
- 5052 / 5754 / 6022
- Process
- Stamp + form + weld
- Tolerance
- ±0.2 mm
- Run size
- 200 – 20,000 pcs
Inverter PCB
High-voltage 6 – 12 layer power-stage PCB. 4-oz copper pours, heavy-bus tabs, selective parylene, hard-gold busbar contacts.
- Layers
- 6 – 12 layer
- Copper
- 4 oz heavy Cu
- Surface
- ENIG / Hard gold
- Run size
- 500 – 100,000 pcs
Drive-unit housing
Reducer-side housing co-machined with the inverter housing. Integrated mounting bosses, gasket grooves, breather seats.
- Material
- AlSi10Mg HPDC
- Process
- HPDC + CNC
- Tolerance
- ±0.05 mm
- Run size
- 200 – 50,000 pcs
HV connector body
IM-moulded GF-PA66 / PPS connector bodies with co-moulded EMI gaskets and silver-plated busbar interfaces.
- Material
- GF-PA66 / PPS
- Process
- IM + selective plate
- Tolerance
- ±0.1 mm
- Run size
- 5,000 – 1 M pcs
The decision treeFour vehicle classes.
Four vehicle classes.
Three power systems.
One drawing pack.
Every cell below is a real combination FabDigit ships. Click any intersection to see the exact parts that move from vehicle class to vehicle class — and which stay fixed. The tabs filter the matrix by vehicle. The big card on the right reveals the hand-off for the selected cell.
Passenger EV
Bus: 400 / 800 V · Power: 120 – 350 kW
B-, C-, and D-segment passenger vehicles. Highest unit volumes, tightest cost-walk, longest qualification chain — A-sample to PPAP to SOP in 24 – 36 months.
DriveMotor + inverter + reducer
StoragePack + module + BMS
ChargingOBC + DC-DC + HV junction
Passenger EV
Light commercial
Heavy commercial
2/3-wheel
Engineering data
Three questions EV teams eventually ask.
Industry-typical ranges from recent engagements. Specific commitments land in your quote.
Chart · Cost vs volume
Cost-per-inverter-housing by process and volume
At A-sample, SLM AlSi10Mg wins because the HPDC tool cost is irrelevant. By B-sample, soft HPDC takes over. By SOP, hard HPDC is the only game in town.
SLM AlSi10MgSoft HPDC + CNCHard HPDC + CNC
Chart · Material profile
Inverter housing material trade-offs
Three candidate materials. AlSi10Mg is the standard; AlSi9Cu3 is cheaper at the cost of finish; Mg AZ91 wins on mass for 2-wheeled platforms.
AlSi10MgAlSi9Cu3Mg AZ91
Chart · Build timeline
A 56-day A-sample drive-unit schedule
Freeze-to-A-sample-on-the-dyno for a fresh 220 kW drive-unit revision. SLM proto housings run in parallel with soft-tool HPDC.
Program lifecycle
How an EV drive-unit program moves through ASample → SOP.
Three years from CAD to SOP is the modern OEM cadence. The six phases below are how we keep one moving without dropping the qualification chain — A-sample to PPAP to SOP, with no silent overruns.
Phase 01
CAD intake & drive-architecture review
Drawings, STEP, stator winding spec, inverter topology land in our portal. An ME + a power engineer review them within 48 hours, flagging cast-feasibility, coolant routing, and PCB stack-up decisions ahead of quote.
Phase 02
A-sample tooling + first drive unit
Soft tooling for HPDC, SLM proto inverter jackets, first drive unit on the bench within 28 – 56 days of PO. Dyno test report ships with the parts.
Phase 03
B-sample qualification + PPAP prep
Hardened tooling cut, 30 – 100 pc B-sample run, full PPAP package compiled: CMM, FMEA, control plan, capability study, helium-trace leak data, dyno runs.
Phase 04
C-sample + design freeze
Field-rep C-sample fleet, real-condition validation, final ECN cycle. Drawing pack freezes at the end of this phase.
Phase 05
SOP ramp
1,000 – 3,000 drive units / wk inside a single cell, daily SPC, monthly cost-walk, named cell lead. Pricing curve committed on a 24-month rolling basis.
Phase 06
Field support + ECN
Field returns route into engineering. Cost-impacted, scheduled, no silent change orders. Production cell uses last-in-first-out BoM so the field never gets two rev levels at once.
Inside the cell
Where aluminum becomes a drive unit.
A dedicated HPDC cell for inverter and drive-unit housings. 900-tonne and 1,200-tonne machines, in-line vacuum degassing, and a robot tending hand-off straight to the 5-axis CNC for finish-machining. Helium leak-test station inside the cell.
In the field
A passenger-EV OEM cut A-sample by 11 weeks.
A composite of recent programs, anonymised to protect customer IP. Numbers are real ranges from the engagements they’re drawn from.
Inside a recent program · Tier-2 passenger-EV OEM, Asia
Compressed A-sample-to-PPAP from 38 weeks to 16 by parallelising hard tools and SLM proto coolant jackets.
The customer had a 220 kW drive unit on a 38-week A-sample-to-PPAP plan with three separate suppliers (HPDC, CNC finish, PCBA). HPDC tooling lead time was the long pole at 14 weeks.
We started with an SLM AlSi10Mg first-article inverter housing — qualification-grade thermal profile in two weeks, not fourteen. The soft HPDC tool was cut in parallel; the moment the first SLM jacket passed the helium trace, we kicked off the hard tool cycle.
A-sample landed in week 12 instead of week 26. PPAP package complete in week 16. The customer hit SOP eight months ahead of original plan; the next two drive-unit variants are already on our DFM queue.
The coatings moat
Six finishes US EV shops can no longer run.
Environmental rulings since 2018 have closed dozens of US-side conversion and plating lines. Our partner plants still run them daily. The short list below is what shows up most on EV drive-unit drawings.
Alodine 1200 (Cr⁶⁺ conversion)
Hex-chromium conversion on aluminum drive-unit housings and motor mounts where the bond to chassis ground must remain conductive.
Cataphoretic dip (e-coat)
Black e-coat over pack trays, brake hardware, and chassis brackets. Pinhole-free 25 µm uniform; ASTM B117 salt-spray 1,000 hr.
Selective silver plate, busbar
Silver-on-copper selective plating on busbar lugs and HV connector pins. Spec to 4 µm uniform; closed-loop process.
Tin plate (Sn) on contacts
Tin plating on HV connector busbar tabs for repeatable insertion force and contact resistance.
Hard anodize Type III sealed
Sealed Type III on stator-carrier bearing bores and motor end-caps. PTFE-impregnated options for self-lubricating service.
Powder coat — RAL match
In-house powder lines that can match RAL or OEM colour books, low-VOC formulations, rated for IEC 60068-2 salt-spray 500 hr.
Frequently asked
The questions EV teams keep asking us.
We build to PPAP Level 3 + 4 routinely; IATF 16949 certification is held by the partner plants we deploy through. Drawing pack, FAI, PFMEA, control plan, capability study, gauge-R&R — all standard deliverables for our drive-unit programs.
Yes. HPDC blanks are loaded directly into the 5-axis CNC cells without travel through a third-party finisher. Same drawing pack, same QC team, same cost-walk.
For programs over 200 A-sample units, we run a parallel SLM AlSi10Mg first-article cell while the hard tool is being cut. The SLM jackets are qualification-grade thermal-profile parts in 2 weeks instead of 12 – 14.
Yes. Silver-plated busbar lugs, tin-plated contacts, selective gold on PCB interfaces. Plating thickness audited per lot.
Drive-unit cells in Shenzhen, Suzhou, and a US Tier-1-partner cell in Michigan for export-controlled programs. NDA and site audit available with 14 days notice.
For hairpin stators, yes — we build the carrier + bearing housing and partner on the actual winding cell. For wound stators, we handle the carriers and integrate at final assembly.
Services this industry uses most
Adjacent industries we serve
Ship the drive unit, not the press release.
Send drawings, or send a stator winding spec + bus voltage. Either way you’ll have an ME reviewing within 48 hours and a real quote on a real schedule shortly after.