Electric tricycle pickup truck assembly line

Electric three-wheel mini-trucks are built from nine modules: frame, cargo box, axle/suspension, e-power-train, steering, brakes, wheels, body panels and electrical auxiliaries.
Production follows blanking, welding, cathodic e-coat + powder painting, and final assembly with two sub-lines for cargo-box pre-assembly and battery quick-swap.
A 60 m slat conveyor running 150–180 s takt delivers 60 k units/year with 48 % automation; MES+ANDON trace every VIN, while robots handle welding, body flip and critical nut-runners.
Key quality gates: weld penetration ≥2 mm, coating 30–40 µm, motor hi-pot 1.5 kV, vehicle insulation ≥20 MΩ, 40 km/h roll-test power deviation ≤5 %.
Modular fixtures allow 1.5–1.8 m wheelbases and multi-body variants on one line.

1. Vehicle Structure (Modular Breakdown)

Electric three-wheel mini-truck = “3 + 3 + 3” nine modules; can be 60 %+ in-house or fully outsourced.

No.	Module	Key Sub-Parts	Material / Spec.	Remarks
1	Frame	Main rails, head tube, rear-axle brackets, battery tray	Q235 rectangular tube 50×30×2.5, e-coat after pickling	Weld in front-center-rear sections
2	Cargo box	Floor (2.0 checker plate), side boards, tail-gate, headboard	08Al cold-rolled sheet + rectangular tube frame	Corrugated roll-formed floor saves 8 % mass
3	Suspension / Axle	Unitized diff axle (with shift), 6/7 leaf springs, dampers	Axle tube φ80×8, ratio 8:39	800–1 500 kg three platforms
4	E-power-train	Motor 800–2 000 W, controller 18–36 MOSFET, Li 60/72 V 80–150 Ah	Air or liquid cooling	Slide-rail quick-swap battery box
5	Steering	Handlebar post, top bridge, ball bearing, 31 mm forks	Al die-cast + welded tube	Upgrade to automotive steering wheel optional
6	Brake	Front 180 drum / 220 disc, rear 220 drum, mechanical park, foot rod	Cable or hydraulic	Auto-adjusters included
7	Wheels	3.75-12 6PR load tyre, one-piece rim 3.0 B	8–10 km/h speed grade	Front 2.5 t, rear 3.0 t load
8	Body panels	Windshield, seat bucket, foot mat, side trim, lamps	ABS / PP injection	Quick clips ≤15 s
9	Electrical aux.	LCD meter, harness, lamps, horn, USB, GPS	IP67 sealed connectors	OTA port reserved

2. Assembly Process Flow (In-house frame + outsourced e-power-train)

Industry-standard “four main processes”: blanking → welding → painting → final assembly; plus “cargo-box pre-assembly” and “battery quick-swap” sub-lines.

2.1 Welding shop (92 % robot ratio)

Station	Equipment	Takt	Key QC
1.1 Blanking	3 kW laser + band saw	55 s / bar	Burr ≤0.2 mm
1.2 Bending	5-axis CNC bender	35 s / U-rail	Spring-back ≤0.5°
1.3 Sub-assy spot	6-axis robot 350 A	28 s / battery frame	Nugget φ6-8 mm
1.4 Main fixture	Pneumatic + servo	70 s / frame	Rail diagonal ±1 mm
1.5 Touch-up / grind	Manual + dedust booth	120 s	Weld Ra ≤12.5 µm

2.2 Paint shop (two-coat: cathodic e-coat + powder)
Degrease → rinse → condition → phosphate → e-coat (180 V 3 min) → bake (180 °C 25 min) → powder → bake (200 °C 15 min); salt-spray ≥500 h.

2.3 Final assembly (60 m slat conveyor, 1–3 m/min VFD)
“Upside-down → right-side-up” two-section layout, typical takt 180 s (60 k units/year).

Pos.	Task	Key Operation	Tool / Fixture	Torque / Spec.
0	Upside-down load	Frame on pallet, scan VIN	500 kg hoist	—
1	Axle install	Rear axle + leaf springs, pin press-in	5 t servo press	98 N·m
2	Brake rods & park	Rivet brake rod ball, cable preload 10 mm	4 kN riveter	Vernier check
3	Motor mount	800 W hub motor, 4-M10 self-tap	Torque wrench	38 N·m
4	Battery slide rail	Grease rail, latch 2-cycle test	Slide gauge	≤30 N hand force
5	Main harness	48/72 V clips, colour-coded anti-mis-plug	—	Withdraw ≥60 N
6	Controller fix	36-MOSFET Al housing, 0.2 mm paste	1.5 N·m	ΔT ≤30 K
7	Body flip	180° in 15 s	Servo flip	±0.3° repeat
8	Front fork & wheel	Bearing preload 0.05-0.15 mm	Dial torque	15 N·m
9	Cargo-box pre-line	Floor + sides 6 quick-pins, 4 headboard bolts	Air wrench	55 N·m
10	Meter & lamps	LCD CAN self-test 2 s	Scanner	DTC = 0
11	Vacuum fill	Brake pipe −0.08 MPa 30 s	Vac. pump	ΔP ≤0.005 MPa
12	End-of-line rain	15 m tunnel 8 min, 12 mm/min	Recycle tank	Zero leak
13	Dyno roll	40 km/h loaded 5 min	Motor dyno	Power ±5 %
14	Decals / nameplate	3C, EPA, VIN one-shot jig	Pneumatic press	Offset ≤1 mm
15	Wrap & warehouse	Stretch film + wooden front frame, 4 straps	Auto wrapper	30 s / truck

3. Continuous Assembly Line Design Notes

3.1 Conveyor type

• Slat + pallet: 1.2 t payload, 200 mm pitch, stackable fixtures.
• Overhead power-and-free: delivers cargo-box & large panels, frees floor space.

3.2 Takt & capacity

Item	Value	Remarks
Design takt	180 s / unit	Can shrink to 150 s (two-shift 10 h)
Yearly output	60 000	300 d × 2 shifts × 8 h × 85 % up-time
Head-count	36 / line	incl. 3 QC, 2 rework
Automation	48 %	6 robots, 8 auto flip / tighten cells

3.3 IT layer

• MES + barcode: critical torque & electrical data uploaded; missing bolt / mis-plug auto-stop.
• ANDON rope + e-board: reaction ≤5 min.

3.4 Flexibility

• Pallet locators fit 1.5 m, 1.6 m, 1.8 m wheelbases.
• Fixture swap ≤10 min for “mini-truck / flatbed / stake” mixed flow.

4. Key Quality Gates (with Test Limits)

Gate	Check	Equipment	Limit	Owner
Frame weld	Penetration	UT phased-array	≥2 mm	Weld shop
E-coat film	Thickness	Eddy-current	outer 30-40 µm, inner 20-30 µm	Paint
Motor safety	Hi-pot	1 500 V / 1 mA	No breakdown	Final
Vehicle isolation	Insulation	500 V megger	≥20 MΩ	EOL
Road test	Slide distance	40 km/h unladen	≤9 m	QC

5. Take-aways

1. Four-main-process + battery-quick-swap is now mainstream; higher in-house ratio demands tighter weld & paint consistency.
2. 150–180 s slat conveyor, 60 m long, is the economic sweet-spot for 60 k units/year; MES+ANDON baseline, robots focus on weld, flip, tighten.
3. Modular cargo box, slide-rail battery swap, two-layer anti-corrosion (e-coat + powder) are common upgrades in recent green-field lines and can be copied directly.