Quality Optimization of CLT-Element Milling by Controlled Digital Workflow

Cross-laminated timber, digital design, and digitally driven fabrication tools allow a novel collaborative cyclic design method and higher pre-fabrication rate. However, conventional linear and laborious manner of design,... [ view full abstract ]

Cross-laminated timber, digital design, and digitally driven fabrication tools allow a novel collaborative cyclic design method and higher pre-fabrication rate. However, conventional linear and laborious manner of design, fabrication, and construction is favored today. A recent study suggests that building industry has a long history of cost-based tendering (price as the main criteria) in construction. Companies resist unconventional approaches and lack the commercial vision, opportunism, and motivation rather than capability. (Jones et al., 2016) CLT-factories typically operate 5-axis CNC-routers, which have the capacity to cut with high precision and complexity in shape. However, the full capacity of these machines is not properly in use.

With the combination of design and fabrication teams, complex geometries such as highly optimized mechanical joineries could be manufactured directly into CLT-elements. Digital design and manufacturing tools enable transdisciplinary collaboration and a faster feedback loop from design to production.

The research teams consist of architects, fine carpenters, and CLT-factories. The goal is to

1. eliminate duplicated efforts by streamlining the workflow from CAD to CAM, and to achieve higher pre-fabrication rate,
2. create a design to production -workflow and a guideline for modeling instruction (which file format to use, how the shape is 3d-modeled, how certain details such as corners are dealt with to avoid damage to the  material, etc) and shared a visual language of how different fabrication options affect the result (chosen blades, fibre directions, blade speed, corner rounding). Virtually design and fabrication tools are already compatible.

The research consists of three parts:

1. interviews explicating the challenges faced by each discipline through the process
2. design research where a CLT-installation and numerous test pieces are designed, routed and assembled
3. systems design of an agile digital workflow based on the findings of the research.

A high level of prefabrication and lightness of the material advances construction stage in crane times, transportation and lighter construction. (Van De Kuilen et al., 2011) Moreover, highly developed mechanical wooden joinery systems would enable healthier, faster and more beautiful construction with less building parts and building phases.