Cementitious 3D Printing Pump Segmentation for Overhang Stability
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Solution Overview
Problem
Existing 3D printing systems for cementitious materials face challenges in producing complex architectural structures with overhangs due to the material's rheological limitations, which restrict printing speed and complexity, requiring temporary reinforcements or slowing down the process.
Innovation Solution
A system with a print head that includes a mixing chamber, dynamic mixer, and pressure/flow-controlled booster pump to adjust the cementitious material's rheology by adding admixtures, allowing for continuous and uniform deposition of beads with controlled pressure and flow rate, enabling the creation of complex parts with overhangs without slowing down the printing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the cementitious material is supplied in a state close to its pumping limit to prevent sagging, then the material stability is improved, but the printing speed and flow rate are significantly reduced
Solution Approach 1:
The system segments the material flow control into two independent stages: a feed pump that supplies material at high flow rate and a booster pump that precisely controls pressure near the nozzle. This segmentation allows the feed pump to operate at high speed while the booster pump ensures material stability, resolving the contradiction between printing speed and material stability.
Solution Approach 2:
The booster pump acts as an intermediary device between the feed pump and the nozzle. It receives material at high flow rate from the feed pump and transforms it into a controlled, pressure-stabilized flow at the nozzle outlet. This intermediary component enables both high printing speed and material stability to coexist.
2Stability of the object's composition
If the printing operations are slowed down to prevent excessive overhangs, then the material stability is improved, but the construction time and productivity are significantly increased
Solution Approach 1:
By segmenting the pumping system into feed pump and booster pump with distinct functions, the system achieves both rapid deposition (reducing construction time) and material stability (preventing overhang issues). The feed pump maintains high speed while the booster pump ensures stability, eliminating the need to slow down operations.
Solution Approach 2:
The system independently controls flow rate and pressure parameters through separate pumps. The feed pump controls flow rate at high levels for speed, while the booster pump controls pressure at precise levels for stability. This parameter separation allows rapid printing without compromising material stability, reducing construction time.
3Stability of the object's composition
If temporary reinforcements are added to support overhangs, then the structural stability is improved, but the device complexity and manufacturing cost are significantly increased
Solution Approach 1:
The dual-pump system enables the material to support itself during extrusion by maintaining optimal pressure and flow rate. The booster pump ensures the material is deposited with sufficient pressure to maintain structural stability without requiring external temporary reinforcements, simplifying the overall system.
Solution Approach 2:
By precisely controlling pressure and flow rate parameters through the booster pump, the system achieves structural stability through material deposition alone, eliminating the need for additional reinforcement structures and reducing system complexity.
4Stability of the object's composition
If the flow rate is reduced to maintain material stability, then the material stability is improved, but the productivity and output per unit time are significantly reduced
Solution Approach 1:
The segmentation of pumping functions allows the feed pump to operate at high flow rate for productivity while the booster pump ensures material stability through precise pressure control. This eliminates the need to reduce flow rate, maintaining both high output and material stability.
Solution Approach 2:
The booster pump serves as an intermediary that decouples the relationship between flow rate and material stability. It receives high-flow material from the feed pump and stabilizes it through pressure control, enabling high productivity without sacrificing material stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of complex architectural parts with enhanced resistance and precision, maintaining the material's properties similar to traditional construction techniques without the need for molds or formwork, while ensuring stable and repeatable manufacturing at a lower cost.
Implementation Method 1
a dynamic mixer configured to be able to mix the cementitious material and the admixtures supplied by the admixture device in the mixing chamber
Implementation Method 2
an eccentric screw dosing pump configured to be able to convey the cementitious material from the inlet of the print head to the mixing chamber
Implementation Method 3
a pressure/flow sensor for the cementitious material circulating in the print head adapted to transmit pressure/flow measurements to the feed pump
Implementation Method 4
a feed pump for the cementitious material supply line from the storage tank configured to control the feeding of the supply line to the measurements transmitted by the sensor
Data Source
Figure 1~3
Figure 4a~5
AI summary
The invention relates to a system for extruding cementitious material beads for a robot used for the additive manufacturing of architectural structures, comprising: a head for depositing beads of cementitious material, referred to as printhead (30), comprising an inlet mouth (31) and an outlet nozzle (34) configured to form beads of cementitious material; a feed circuit (20) for said printhead (30), comprising a reservoir (10) for storing cementitious material, a feed conduit (21) connecting said storage reservoir (10) to said printhead (30), and a booster pump (22) for said feed conduit (21), characterised in that it further comprises a sensor (33) for sensing the presure/flow rate of the cementitious material flowing in said printhead (30), and suitable for transmitting pressure/flow rate measurements to said booster pump (22), and in that the booster pump (22) is configured to control the boosting of the feed conduit (21) on the basis of the measurements transmitted by the sensor (33).