Microfluidic Device Ultrasonic Welding Channel Design

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Solution Overview

Problem

Existing microfluidic devices face challenges in maintaining accurate geometry and high tolerances during ultrasonic welding, which can lead to structural weaknesses and inefficiencies, especially when dealing with reagents or coatings that may interfere with the welding process, causing unwanted gaps or internal pressures.

Innovation Solution

The introduction of a microfluidic device design featuring elongated central welding portions with adjacent welding channels and draining channels that prevent reagents or liquids from interfering with the welding process, allowing for precise control of the welding material flow and maintaining vertical geometry, and optionally using an array of smaller energy directors with corresponding draining channels to enhance tolerance and prevent fluid entry into welding channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ultrasonic welding is used to assemble microfluidic devices, then manufacturing efficiency is improved, but welding precision and geometric accuracy deteriorate due to material flow and tolerance issues

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidwelding precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the welding region by introducing separate welding channels that are distinct from the microfluidic channels. The welding channel is divided into a first portion (for material flow) and a second portion (for sealing), allowing independent control of welding material flow and final seal quality, thus resolving the conflict between efficient welding and precision geometry maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a welding channel as an intermediary structure between the energy director and the microfluidic channel. This welding channel acts as a mediator that captures and directs the welding material flow, preventing it from directly entering the microfluidic channel and compromising its geometric precision, while still allowing efficient welding to occur.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If reagents or coatings are applied before welding, then device functionality is improved, but welding quality deteriorates due to interference and unwanted gaps

Engineering Contradiction:
Improvedevice functionalityVSAvoidwelding quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the welding material flow from the microfluidic channel by providing a dedicated welding channel. This allows reagents or coatings to be applied to the microfluidic channel without interfering with the welding process, as the welding material will flow into the separate welding channel instead of creating gaps in the microfluidic channel seal.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent allows reagents or coatings to be applied to the microfluidic channel before the welding step. The welding channel is designed to capture any welding material that might otherwise interfere with the reagents or coatings, ensuring that the preliminary application of functional materials is not compromised by the subsequent welding process.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If welding material flows freely, then welding speed is improved, but geometric accuracy deteriorates due to extra thickness and positioning errors

Engineering Contradiction:
Improvewelding speedVSAvoidgeometric accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by providing different functions in different portions of the welding channel. The first portion of the welding channel is designed to receive and accommodate welding material flow (prioritizing welding speed), while the second portion is designed to maintain proper sealing geometry (prioritizing geometric accuracy). This localized functional differentiation resolves the contradiction between welding speed and geometric precision.

Inventive Principle:
Principle #3Local quality

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 design ensures precise and strong welding with high tolerance, preventing structural weaknesses and fluid loss, and allows for the use of different fluid types and volumes, enhancing the device's universality and analysis capabilities.

Implementation Method 1

ultrasonic welding is used to assembly a top element to a bottom element

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Implementation Method 2

the energy directors are melt for welding purpose by applying simultaneously ultrasonic energy and mechanical pressure

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3544790B1Ultrasonic welding of a microfluidic device
Publication Date: 2023.12.27 SIEMENS HEALTHINEERS NEDERLAND BV
  • EP3544790B1 patent drawingFigure 1~2
  • EP3544790B1 patent drawingFigure 3~4
  • EP3544790B1 patent drawingFigure 5~6

AI summary

The invention is about an ultrasonic welding-based microfluidic device. It is mainly made of a first element and a second element welded one to the other via at least one structure (10, 10'). The structure (10, 10') comprises an elongated welded portion for said welding, a welding channel (12, 12') extending between the first and second elements and along one side of the welded portion, and a draining channel (13) communicating with the welding channel (12, 12') and the microfluidic path (20, 20') of the device. The invention is further about a method of manufacturing such a device.