3D Plastic Impeller Molding for Seamless Twisted Blades
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Solution Overview
Problem
Existing manufacturing methods for 3-dimensional plastic impellers face challenges such as high material waste, high processing costs, structural weakness, and inefficiencies due to seams or structural discontinuities, making them unsuitable for high-efficiency and high-temperature/high-load applications.
Innovation Solution
A method involving a mold with a fixed die and a moving die forms the hub rim part and shroud rim part in a single piece with the impeller's twisted blade portions, allowing for seamless integration and efficient demolding, while using heat welding or melting rods for assembly, ensuring structural integrity and high-efficiency performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional 2-dimensional impeller manufacturing methods are used, then production cost is low and manufacturing is simple, but pump efficiency is low due to inadequate flow channel geometry
Solution Approach 1:
The patent transitions from conventional 2-dimensional impeller blades to 3-dimensional twisted blade geometry. The blade surface is defined by varying blade angles along the spanwise direction, creating a true 3-D flow channel that better matches the fluid flow patterns and improves pump efficiency while maintaining manufacturability through injection molding technology.
Solution Approach 2:
The patent varies the blade angle parameter along the spanwise direction from hub to shroud, creating an optimized 3-D blade geometry. The blade angle changes continuously to match the flow requirements at different radial positions, improving hydraulic efficiency while the injection molding process captures these complex geometric variations.
2Productivity
If 3-dimensional twisted blade portions are formed using existing methods, then pump efficiency improves, but material waste increases and processing costs rise
Solution Approach 1:
The patent combines the hub rim part, shroud rim part, and twisted blade portions into a single integrated component manufactured in one injection molding cycle. This eliminates the need for separate manufacturing of blade portions and their subsequent assembly, significantly reducing material waste and processing costs while maintaining the high-efficiency 3-D blade geometry.
Solution Approach 2:
The patent incorporates the twisted blade portions directly into the hub and shroud structures during the initial injection molding process, rather than adding them separately afterward. This preliminary formation of the complete 3-D geometry prevents material waste associated with secondary processing and assembly operations.
3Productivity
If 3-dimensional twisted blade portions are formed using existing methods, then pump efficiency improves, but structural strength decreases due to seams and structural discontinuities
Solution Approach 1:
The patent merges the hub rim part, shroud rim part, and twisted blade portions into a single monolithic structure manufactured by injection molding. This eliminates seams and structural discontinuities that would compromise strength, while the integrated 3-D blade geometry maintains high pump efficiency. The single-piece construction provides continuous material flow and uniform structural properties throughout.
4Productivity
If conventional molding methods are used, then manufacturing is simple, but demolding complexity increases for 3-dimensional twisted blade portions
Solution Approach 1:
The patent segments the mold into a movable die and fixed die, with the twisted blade portions formed between them. The movable die can be withdrawn axially from the hub hole, allowing easy demolding of the complex 3-D blade geometry without requiring complex side-actions or breaks in the blade surfaces. This segmentation simplifies the demolding process while maintaining geometric complexity.
Solution Approach 2:
Instead of forming the twisted blade portions on the outer surface and trying to remove the mold from the outside, the patent forms them by injecting material into the hub hole from the inside out. The movable die is inserted through the hub hole and forms the blades in reverse sequence, making demolding straightforward by simply withdrawing the die axially.
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
This approach reduces manufacturing costs, enables mass production of high-efficiency 3-dimensional plastic impellers capable of operating at high temperatures and loads, with improved structural strength and reduced demolding complexity.
Implementation Method 1
a mold with a fixed die and a moving die forms the hub rim part and shroud rim part in a single piece with the impeller's twisted blade portions
Implementation Method 2
using heat welding or melting rods for assembly, ensuring structural integrity and high-efficiency performance
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
The disclosure relates to a manufacturing method of a die-formed 3-dimensional plastic impeller of a centrifugal pump and the impeller manufactured thereby, including a mold for twisted blade and a mold for impeller outlet, the mold for twisted blade is configured to form a twisted blade portion of each blade of the impeller, the mold for impeller outlet is configured to form a rear portion of each blade, a hub rim part of the impeller, and a shroud rim part of the impeller so that the hub rim part, the shroud rim part, and the blades are formed in a single piece at the same molding process.