Production Plan of Steel Tube Frame Wheelbarrows
Semi-Automatic Production of 10,000 Steel Tube Frame Wheelbarrows per Year
Executive Summary
This proposal outlines a semi-automatic production plan for manufacturing 5,000–20,000 units per year of metal wheelbarrows, featuring a steel tube frame and stamped steel tub.
The recommended production system combines CNC tube bending, modular welding fixtures, and automated powder coating with efficient manual operations, ensuring cost competitiveness, product consistency, and scalability.
Key investment highlights:
Annual production capacity: 10,000 units (expandable to 20,000)
Capital expenditure (CapEx): ~RMB 1.8 million
Operating expenditure (OpEx): ~RMB 1.44 million/year (labor) + ~RMB 1.2 million/year (materials)
Unit manufacturing cost: ~RMB 220/unit (excluding tax)
Payback period: 2.5–3 years
1. Manufacturing Process Flow
Steel tube cutting → CNC tube bending → Punching/flattening → Tub sheet metal forming → Welding assembly → Surface treatment (powder coating) → Assembly & packaging.
2. Facility Layout (I-shaped Flow)
|
Processing Steps |
Equipment Selection (Recommended) |
Process Parameters/Key Points |
Quality Inspection |
|
Fully automatic circular sawing machine / 3kW servo pipe cutting machine |
Cut burr ≤0.2mm; End face perpendicularity ≤0.5° |
First article + patrol inspection length ±0.5mm |
|
|
38CNC left-right rotation pipe bending machine (with push-bend function) |
Bending radius R=2.5D, Feeding accuracy ±0.1° |
Profile gauge + radius gauge |
|
|
63t Open-Die Press + Combination Dies |
Hole position ±0.2mm; Flattening thickness 2.4±0.1mm |
Gauge + vernier caliper |
|
|
Bucket Blanking |
Hydraulic Swing-Arm Shear 6×2500 |
Shear straightness ≤0.15mm/m |
Pattern |
|
Bucket Stretching |
200t Four-Column Hydraulic Stretching Machine |
Single draw depth 80mm, Flanging force 0.8MPa |
Surface free of drag marks |
|
Bucket Punching |
25t High-Speed Press + Progressive Dies |
Four-hole positional accuracy Φ0.3mm |
Gauge |
|
Welding Assembly |
1.5kW Pulse MIG Welder + Welding Positioner |
Current 90–130A, gas flow 20L·min⁻¹ (Ar + 20% CO₂) |
Weld height 2–3mm, no undercut |
|
Surface Treatment |
Manual Sandblasting + Powder Coating Line |
Film thickness 60–80μm, adhesion ≥ Grade 1 |
Grid test |
|
Assembly |
Pneumatic Wrench + Torque Wrench |
Wheel axle bolt torque 18N·m |
Torque sampling 10% |
3. Production Capacity & Cycle Time
Tube cutting: 15 s/pc
CNC bending: 45 s/pc (3D frame, single-pass)
Tub deep drawing: 60 s/pc
Welding: 6 min/unit (4 fixtures parallel)
Powder coating & curing: 30 min/rack (4 units per rack)
Output per 8-hour shift: ≥ 20 units
Annual output (single-shift, 250 days): ~5,000 units
Annual output (double-shift): 10,000–20,000 units
4. Fixtures & Quality Control
Modular welding jigs: quick-change (≤3 min), pneumatic clamping, copper inserts for deformation control.
Inspection gauges: frame contour gauge, tub hole-position gauge, folding-angle gauge.
QC checkpoints: dimensional accuracy, weld integrity, coating thickness, assembly fit.
5. Safety & Environmental Standards
Welding: 8 mobile fume extractors (dust ≤ 4 mg/m³)
Powder coating: cyclone + cartridge filter VOC recovery (emissions ≤ 30 mg/m³)
Equipment safety: two-hand control buttons, light curtains, bending machine safety fencing with interlocks
6. Optional Automation Upgrades
|
Control points |
Inspection Frequency |
Recording Method |
|
Pipe cutting length |
First piece + every 50 pieces |
SPC Chart |
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Bend angle |
First piece + every 20 pieces |
Gauge + Protractor |
|
Punching position accuracy |
First piece + every 100 pieces |
Gauge |
|
Weld appearance |
100% visual inspection |
Non-conforming Item Red Ticket |
|
Coating thickness |
One piece per batch |
Film Thickness Gauge |
|
Vehicle assembly |
One unit per batch |
Road Simulation 20 kg × 50 m |
7. Financial Analysis
Capital Expenditure (CapEx)
CNC tube bender, punching press, welding machines, powder coating line: ≈ RMB 1.8 million
Operating Expenditure (OpEx)
Labor: 18 operators × RMB 80,000/year = RMB 1.44 million
Materials: steel tubes, sheets, wheels ≈ RMB 120/unit → RMB 1.2 million/year (for 10,000 units)
Utilities & maintenance: ~RMB 0.3 million/year
Total OpEx: ~RMB 2.94 million/year
Unit Cost Estimate
Materials: RMB 120
Labor & overheads: RMB 100
Total manufacturing cost: ~RMB 220/unit (excl. tax)
8. ROI Estimation
Revenue assumption: average sales price RMB 350/unit
Gross margin per unit: ≈ RMB 130
Annual gross margin (10,000 units): RMB 1.3 million
Payback period: ~2.5–3 years (based on CapEx recovery through gross margin)
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