The house-building system “Ecocube"

The customer's idea to modify the basic technology for mass manufacturing was completely carried out by our engineers.

The preparation for automated production was done in 2 directions:

1. Optimizing the block design components by reducing the thickness of the plywood grid’s ribs of the inter storey slab. Strength calculations and tests on a physical prototype made it possible to find the optimal thickness of the ribs. The decreased thickness resulted in faster technological advancement and a shorter processing time for the ribs. The inter storey slab’s plywood grid was also optimized in this way.
   The materials used for the blocks' edges were also changed for thinner ones, which helped save the time it took to prepare the blocks for assembly thanks to faster technological processes.
2. Optimization of the block design involved moving away from the 'puzzle concept.' The original 'puzzle concept' included three types of blocks:
   1. blocks with fasteners only;
   2. blocks with fasteners and openings for fasteners;
   3. blocks with openings for fasteners only. Instead, the engineers proposed designing units with only openings, connected by independent fasteners.
      

This modification made it possible to replace a longer and more expensive milling procedure with a standard furniture machine, which saved 45% of the time to produce a single block.

The original block’s fastener system significantly constrained the team’s ability to develop the technology for mass manufacturing. However, EnCata’s engineers employed a distinct approach to the fastening mechanism and created “standard locks” (see pic.3) linking the blocks as independent pieces as opposed to being a component of each block. This made it feasible not only to accelerate the production, but also to simplify the installation of the house box on the construction site.

The developed fastener system made it possible to produce 1180 blocks in an 8-hour work shift in just one production line. Two issues were resolved at once by minimizing milling and substituting it with machinery for furniture production:

• it was possible to produce 83 blocks every hour, which was the required amount;
• the procedure became less expensive as a result of using less complex and costly machinery, and there were less operations required to prepare the fundamental block for combining with other blocks.

The automatic weighing of natural components supplied into the Ecocub was used to implement automatic density control. The density of the natural components has an impact on the thermal insulation. Our engineers approached this issue from a distinct perspective and asked a different question: “What amount of straw inside the block will offer the necessary thermal insulation?”

Computer simulations revealed a weight fluctuation of the fiber components of 60(-/+ 10kg). The range of allowable variances in 10kg made it possible to balance out different densities of the components while also offering the right amount of thermal insulation. In practice, loading of blocks with biomass was carried out in the following method: biomass fed into the intermediate block (which served as the weight batcher) from the storage block, after reaching the desired volume and mass, the components were transferred into the fundamental block.

Decisions were made all throughout the design phase based on mathematical calculations. Both the strength of the Ecocube elements and the capacity of the slab to support them were calculated. The use of the finite element method decreased the risk level during the design and assembly phases of the prototype, which allowed the development team to spend its resources more effectively.