When purchasing non-standard assembly lines, first define requirements across six dimensions, then quantify the parameters (Source: Industry practice): Six Dimensions: Product/Takt Time/Workshop/Scalability/Automation/Budget (Source: Sohu); Core Elements: Production Capacity Table + Process Parameter Table + Site Interface Table (Source: Xuri Dong) — Principle: Specify parameters precisely to avoid divergent interpretations by suppliers (Source: Industry perspective).
I.
Product Characteristics
Weight: Weight of the heaviest workpiece plus fixture (Source: EVS); Dimensions: Maximum envelope dimensions (L×W×H) (Source: EVS); Material: Carbon steel/stainless steel/aluminum/coating (Source: EVS); Material Thickness: Thinnest and thickest specifications (Source: EVS); Special Requirements: Electrified/anti-static (Source: Sohu) — Product: Weight + Dimensions + Material (determines the load-bearing capacity of the line).
II.
Production Capacity and Takt Time
Annual Output: Annual target (Source: Styler); UPH: Units per hour (Source: Styler); Takt Time: Target takt time (Source: Styler); Shifts: Workdays + shifts (Source: Styler); Utilization Rate: Planned utilization rate + minimum batch size (Source: Xuri Dong) — Capacity: Annual volume + UPH + Takt time (determines the speed of the line).
III. Process Parameters
Process Takt Time: Duration of each process step (Source: Chenqi); Critical Dimensions: Tolerance ±0.01mm (Source: Chenqi); Quality Points: Control points + appearance standards (Source: Chenqi); In-line Inspection: Vision/gauge requirements (Source: Xuridong); Changeover: Frequency of changeovers (Source: Sohu)—Process: Takt time + tolerance + inspection (determines workstation configuration).
IV.
Site Interfaces
Factory Building: Area + ceiling height + column spacing (Source: Sohu); Load-bearing Capacity: Floor load capacity (Source: Xuridong); Power Supply: Voltage, phases, and frequency (Source: Sanypak); Air Supply: Air pressure and flow rate; Logistics: Logistics routes + upstream/downstream interfaces (Source: Xuridong)—Site: Ceiling height + load capacity + power supply (these are the key bottlenecks later on).
V.
Line Parameters
Length: Several meters to tens of meters (Source: Yazhi); Width: 200–1200mm (Source: Yazhi); Speed: Fixed speed/variable frequency calculated based on takt time (Source: Yazhi); Material: Aluminum profiles/powder-coated carbon steel/stainless steel (Source: Yazhi); Control: Push-button/VFD/PLC interlocking (Source: Yazhi)—Line: Length, width, height + speed + material (determined by process layout).
VI. Carrier Electrical Control
Carrier: Pallet/fixture/hanging rack; Turning: Turning radius + climbing angle; Cleanliness: Cleanliness class; Electrical Control: Modbus open architecture; Redundancy: 15% redundancy margin in cycle time—Carrier Electrical Control: Pallet + Cleanliness + Protocol (determines scalability).
VII.
Procurement Recommendations
First, six-dimensional requirements (define these first); second, production capacity schedule (annual volume + UPH); third, process specifications (cycle time + tolerances); fourth, site specifications (power supply + air supply);
fifth, quantified documentation (contractualizing the URS and SOW)—Parameters: Product + Capacity + Site (all three schedules required).
