Tolerance Analysis
Tolerance analysis – detect tolerances and ISO fits from PDF drawings
This tool analyses technical PDF drawings and automatically detects tolerance data, ISO fits, limit dimensions and other manufacturing-relevant information.
The PDF file is processed server-side and automatically deleted after analysis.
What is tolerance analysis used for?
Tolerances and fits are central parts of technical drawings and are essential for manufacturing, quality assurance and assembly.
Typical applications:
- review of manufacturing drawings
- digitisation of technical documents
- quality control of supplier drawings
- preparation for CAM, CAQ and QM systems
- automatic capture of tolerance data
- analysis of archive drawings
Which tolerance types are recognised?
The tool detects various standard-compliant tolerance and fit specifications.
- ISO holes (e.g. H7)
- ISO shafts (e.g. g6)
- ISO fit pairs (e.g. H7/g6)
- symmetrical tolerances (±0.01)
- limit dimensions (+0.02 / -0.01)
- IT tolerance grades
- dimension and tolerance data in drawings
How does tolerance analysis work?
- Upload a PDF file
- Extract texts and drawing information
- Analyse OCR and vector text
- Detect tolerance specifications
- Classify fits
- Generate a structured analysis report
Depending on the document type, both embedded texts and scanned content are evaluated.
Which information can be evaluated?
- fit specifications
- tolerance zones
- dimension values
- limit dimensions
- hole and shaft systems
- manufacturing-relevant drawing data
Technologies used
The analysis uses modern open-source technologies and OCR methods.
- OCR text recognition
- PDF text analysis
- regex-based tolerance detection
- Python-based document analysis
Current limitations
- Current maximum file size is 80 MB per PDF file
- By default the first pages are analysed
- OCR quality depends on scan quality and contrast
- Individual letter–number combinations can be misinterpreted
- Very complex documents can take longer to analyse