Dimensional Control of Sawn Lumber: from a Spreadsheet to a System

Documentation-only case study of a quality-control method and data-acquisition system for small and mid-sized sawmills, developed between 2017 and 2019 in technology-transfer work in Chile.
Problem: sawmills measured lumber with digital calipers, wrote readings on paper and typed them in later — control that arrived too late to control anything.
Method: four control points per piece, nominal vs. target size (after drying shrinkage and planing), context on every record, and four statistical outputs: standard deviation per machine and cut, histogram against tolerance, under/over-size hit rate per control point, box plot per machine.
Prototype (Nov 2017, joint INFOR-CETMA project): an Excel workbook with macros tested with real plants. Concept (Dec 2018, CETMA): caliper with data output -> Android app that attaches batch context -> web platform with alerts against NCh 2824 tolerances. The concept was the technical basis of a CORFO Technology Diffusion Project awarded to Universidad de Concepcion (2019) and of the module INFOR implemented on open, low-cost Bluetooth calipers; the author coordinated the developer's hiring and initial stage, and the workbook's calculation logic was ported into the system.
No spreadsheet, plant data, operator names, suppliers or source code are published. The resulting applications are owned and maintained by INFOR.

Technology Stack:

Statistical process control (control charts, tolerance histograms, hit rate, box plots), NCh 2824, Excel (formulas, advanced filters, named ranges, VBA macros), system concept: Bluetooth digital caliper -> Android app -> web platform, CORFO PDT formulation, technology transfer to SMEs

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