Pipette Tip Rib Design for Low Ejection Force
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Solution Overview
Problem
Conventional pipette tips require high forces for attachment and removal due to steep spring characteristics and high static friction, leading to user burden and increased power consumption in motor-driven systems, with dimensional tolerances affecting ejection forces.
Innovation Solution
A pipette tip design featuring axially extending ribs that undergo partial plastic deformation upon attachment, storing part of the insertion force as elastic deformation, reducing the ejection force needed and minimizing the influence of dimensional tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pipette tip uses a conventional conical attachment design, then the attachment is secure and reliable, but the attachment and removal forces become excessively high
Solution Approach 1:
The seating area is segmented into multiple functional zones: an insertion area with expanded diameter for easy engagement, a holding area with radially inwardly projecting ribs for secure attachment, and a sealing area for liquid-tight sealing. This segmentation allows each zone to perform its specific function optimally without requiring excessive forces throughout the entire structure.
Solution Approach 2:
Different regions of the pipette tip are given different mechanical properties and geometries tailored to their specific functions. The insertion area has increased diameter for low-force engagement, the holding area has rigid ribs for secure positioning, and the sealing area has compliant material for tight sealing. This local differentiation resolves the contradiction by allowing secure attachment through localized features rather than uniform high-force design.
2Reliability
If the spring characteristic is made steep to ensure secure attachment, then the attachment reliability improves, but the static friction and removal force increase significantly
Solution Approach 1:
The rib structure provides dynamic adaptation during attachment and removal. During attachment, the ribs deform elastically to accommodate the conical approach, creating secure holding. During removal, the elastic deformation allows the ribs to flex outward, reducing friction and enabling easy ejection. This dynamic behavior resolves the contradiction between secure attachment and easy removal.
Solution Approach 2:
The mechanical properties of the rib structure change depending on the operational phase. The ribs exhibit elastic deformation characteristics that provide high attachment force during engagement but reduce friction during removal. The geometric parameters of the seating area (expanded insertion area, rib projection depth) are optimized to create different force characteristics during attachment versus removal cycles.
3Reliability
If high attachment forces are applied to ensure secure fixing, then the pipette tip is firmly attached, but the power consumption of motor-driven systems increases
Solution Approach 1:
The rib structure performs self-adjustment during attachment. The radially inwardly projecting ribs automatically deform to accommodate dimensional variations in the conical approach, creating secure holding without requiring excessive attachment force. This self-adjusting mechanism reduces the energy required by motor-driven systems while maintaining reliable attachment.
Solution Approach 2:
The elastic properties of the rib structure allow it to adapt to dimensional tolerances through controlled deformation. This parameter adaptation enables secure attachment with lower forces, directly reducing the power consumption of motor-driven attachment mechanisms while maintaining fixing reliability.
4Device complexity
If the pipette tip design does not account for dimensional tolerances, then the design is simple, but the ejection force varies significantly with dimensional variations
Solution Approach 1:
The elastic rib structure acts as a cushioning element that compensates for dimensional tolerances before they affect attachment security or ejection force. The ribs deform elastically to absorb dimensional variations, ensuring consistent ejection force characteristics regardless of manufacturing tolerances in the conical approach dimensions.
Solution Approach 2:
The design incorporates dimensional parameters (rib projection depth, insertion area expansion, wall thickness) that are specifically optimized to compensate for standard dimensional tolerances. These parameter choices ensure that ejection force remains consistent across variations in conical approach dimensions, resolving the contradiction between design simplicity and operational consistency.
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 design allows for easy attachment and reduced ejection force, alleviating user effort and power consumption in motor-driven systems, while compensating for dimensional variations.
Implementation Method 1
the ribs are partially plastically deformed
Implementation Method 2
an elastic deformation occurs outside the ribs in the seating area
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 1e
AI summary
The tip (1) has a seat section provided next to an upper opening (6) at an inner periphery. The seat section includes a holding region with radial inward projecting part, axially extending ribs and a sealing region that is formed below the holding region. The sealing region is formed, so that the tip is held and sealed on a neck, during insertion of the tip with the seat section on the neck by fitting force. The ribs are plastically deformed, and an elastic deformation occurs on an outer side of the ribs in the seat section.