Two-Stage Viscosity Pump for Extrusion Response Time
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Solution Overview
Problem
Extrusion-based layered manufacturing systems face challenges with varying response times and flow rates due to the proportional relationship between the volume of flowable material and extrusion rate in standard liquefier pumps, which affects the consistency and speed of 3D object fabrication.
Innovation Solution
A two-stage pump system incorporating a screw pump with a liquefier and impeller, which maintains a low volume of flowable material and uses a dual drive motor system to achieve high flow rates and consistent response times by minimizing the volume of material in the barrel and optimizing the extrusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard liquefier pump is used with a larger volume of flowable material, then the extrusion system can maintain material flow during speed variations, but the response time becomes slower and less predictable
Solution Approach 1:
The pump system is divided into two distinct functional stages: a liquefaction stage that melts solid material and a pumping stage that transports the melted material. This segmentation allows each stage to be optimized independently - the liquefier can maintain adequate material volume for consistent feeding while the pump chamber maintains minimal volume for fast response times.
Solution Approach 2:
The invention introduces an intermediary chamber between the liquefier and the pump barrel. This intermediary serves as a buffer that receives melted material from the liquefier and feeds it to the pump, decoupling the volume requirements of the two stages. The intermediary allows the pump to operate with minimal material volume while ensuring continuous supply from the liquefier.
2Stability of the object's composition
If the volume of flowable material in the pump is increased, then extrusion continuity is improved, but the response time and flow rate consistency deteriorate
Solution Approach 1:
The system separates the material reservoir function (in the liquefier with larger volume) from the active pumping function (in the barrel with minimal volume). This ensures extrusion continuity is maintained by the liquefier while flow rate consistency is optimized by the minimal-volume pump chamber.
Solution Approach 2:
The drive motor controlling the impeller provides responsive control of material transport based on system demands. This active feedback control allows the pump to maintain consistent flow rates by adjusting impeller speed in response to pressure and flow conditions, compensating for the minimal material volume in the pump chamber.
3Loss of time
If a dual drive motor system with screw pump is used, then response time and flow rate consistency are improved, but device complexity increases
Solution Approach 1:
The pump system is divided into two distinct functional stages: a liquefaction stage that melts solid material and a pumping stage that transports the melted material. This segmentation allows each stage to be optimized independently - the liquefier can maintain adequate material volume for consistent feeding while the pump chamber maintains minimal volume for fast response times.
Solution Approach 2:
The invention introduces an intermediary chamber between the liquefier and the pump barrel. This intermediary serves as a buffer that receives melted material from the liquefier and feeds it to the pump, decoupling the volume requirements of the two stages. The intermediary allows the pump to operate with minimal material volume while ensuring continuous supply from the liquefier.
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
The system achieves faster and more predictable response times, enabling consistent high flow rates and improved fabrication of 3D objects with varied geometries by maintaining a low volume of flowable material and optimizing the extrusion process.
Implementation Method 1
The liquefier is configured to receive the solid material fed from the delivery assembly, to at least partially melt the received solid material
Implementation Method 2
The impeller is configured to drive the at least partially melted material that is directed to the barrel toward the extrusion tip under operational power of the second drive motor
Data Source
AI summary
A pump system comprising a delivery assembly configured to feed a solid material under operational power of a first drive motor, and a screw pump comprising a housing that at least partially defines a barrel of the screw pump, an extrusion tip secured to the housing at a first end of the barrel, a liquefier secured to the housing and intersecting with the barrel, and an impeller extending at least partially through the barrel. The liquefier is configured to receive the solid material fed from the delivery assembly, to at least partially melt the received solid material, and to direct the at least partially melted material to the barrel, and the impeller is configured to drive the at least partially melted material that is directed to the barrel toward the extrusion tip under operational power of a second drive motor.