In international furniture procurement, up to 35% of delivery delays and quality disputes are caused by the lack of standardization of technical drawings.

Ⅰ. Core standard framework: a globally common drawing language

1. View and projection specifications

ISO 128-30: mandatory requirement to include at least a front view, a top view, a side view and a section view;

Third angle projection method: must be used for procurement projects in the United States and Japan, and first angle projection is accepted in Europe.

2. The golden rule of dimension marking

Unified datum: use the installation contact surface as the datum surface to avoid cumulative tolerances;

Tolerance grade:

3. Material and process marking

ISO 2553 standard: welding symbols must indicate the type, length and surface treatment of the weld;

EN 13986: wooden parts must indicate the formaldehyde grade and moisture content.

Ⅱ. Buyer's drawing review list: 5 high-risk areas

1. View integrity audit

Must-check items:

Whether the hidden line marks the movement trajectory of the active parts;

Whether the exploded view marks the assembly sequence of accessories.

2. Tolerance conflict detection

Typical errors:

Multiple reference surfaces lead to tolerance stacking;

Failure to distinguish between functional tolerance and appearance tolerance leads to over-processing.

3. Material process traceability

Mandatory marking:

Metal parts plating thickness;

Plastic parts recycled material ratio.

4. Digital compatibility verification

Format standard:

2D drawings: PDF/A-1 (non-editable archive version) + DWG (AutoCAD editable version);

3D model: STEP (AP214) format, facet accuracy ≤0.1mm.

5. Multi-version control

Naming rules:

Version number: TD-XXXX-EN-V2.1 (TD=technical drawing, XXXX=project number, EN=English version);

Revision record: must include modification content, date, and reviewer signature.

Ⅲ. Supplier Capacity Assessment: Drawing Implementation Test

1. Reverse Engineering Verification

Operational Process:

Provide drawings to suppliers without informing them of product usage;

Evaluate whether the DFM sent back by them identifies key functions;

Qualification Standard: Key function recognition rate ≥ 95%.

2. First Sample Comparison Tool

3D Scanning: Use GOM Atos and other devices to generate point cloud data, and compare the deviation chromatogram with the original CAD model;

Allowable deviation: Appearance surface ≤ 0.3mm, structural surface ≤ 0.8mm.

Ⅳ. Common Dispute Cases: How Drawing Errors Lead to Millions of Losses

Case 1: Confusion in Projection Method Leads to Structural Interference

Background: A US company purchased Chinese lockers without specifying the projection standard, and the supplier drew the drawings according to the first angle projection;

Consequences: During mass production, it was found that the back panel opening direction was wrong, 500 sets of products were scrapped, and the loss was $187,000;

Solution: It is mandatory to indicate "Third Angle Projection" in the title bar of the drawing.

Case 2: Tolerance stacking leads to installation failure

Background: The hole spacing of the desk bracket is not uniform, and the cumulative tolerance is ±2.5mm;

Consequences: The screws cannot pass through the holes, the entire batch is reworked, and the delivery is delayed by 45 days;

Solution: Use GD&T annotation to control the position accuracy to ±0.6mm.

V. Standardization upgrade path: from drawings to smart factories

1. AI drawing review system

Function: Automatically identify missing views, tolerance conflicts, and non-standard annotations, with an error detection rate of 98.3%;

Tools: AOYASI developed the TD-Check plug-in, which is integrated into AutoCAD/SolidWorks.

2. MBOM linkage

Data flow: Technical drawings are automatically associated with the bill of materials, and the version number is updated in real time;

Benefits: Reduce the response time of engineering change notifications from 72 hours to 4 hours.