Medical Handpiece Cooling Path via Stack Molding

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Solution Overview

Problem

Conventional dental handpieces face challenges in achieving high precision and effective cooling due to limitations in processing techniques, such as metal injection molding, which results in inadequate cooling efficiency and increased flow resistance in cooling paths.

Innovation Solution

The use of stack molding to create a medical handpiece with a medium passage that includes a bent portion for fluid flow, allowing for high precision and efficient cooling by using stereolithography composite processing, which forms complex shapes with low path resistance and high flow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If metal injection molding is used to form the handpiece, then manufacturing complexity is reduced, but manufacturing precision deteriorates to about several hundred microns

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidprocessing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical manufacturing methods (metal injection molding, drilling, cutting) with laser-based additive manufacturing (selective laser melting). This substitution enables direct formation of complex 3D cooling paths with high precision (tens of microns) without the limitations of traditional subtractive or molding processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the manufacturing approach from conventional molding to additive manufacturing, fundamentally altering the process parameters and capabilities. This enables precision improvement from several hundred microns to tens of microns while maintaining ease of manufacture through digital modeling and automated processing.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If linear holes are drilled to form cooling paths, then manufacturing is simplified, but flow resistance increases and cooling efficiency deteriorates

Engineering Contradiction:
Improvecooling path formation simplicityVSAvoidflow resistance
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent replaces linear, planar cooling paths with bent, three-dimensional cooling paths that follow curved trajectories. This curvature allows the cooling medium to flow more efficiently through the head structure, reducing flow resistance and improving cooling effectiveness while maintaining manufacturing simplicity through additive manufacturing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from two-dimensional planar cooling paths to three-dimensional bent cooling paths. This dimensional enhancement allows the cooling medium to navigate through the head structure more effectively, reducing flow resistance and improving heat dissipation while maintaining ease of manufacture via additive manufacturing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the cutting tool rotation rate is increased five times, then cutting performance is improved, but heat generation increases causing head warming

Engineering Contradiction:
Improvecutting performanceVSAvoidhead temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent creates a replicated cooling path structure that encloses the tool holding portion, effectively distributing heat away from critical areas. This cooling path copying approach enhances heat dissipation efficiency, allowing higher rotation rates without excessive head warming.

Inventive Principle:
Principle #26Copying

4Adaptability or versatility

If a complicated shape is required for the head, then functional performance is improved, but conventional processing cannot achieve desired precision

Engineering Contradiction:
Improvehead shape complexityVSAvoidprocessing precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent forms the head and cooling paths as an integrated structure through additive manufacturing, eliminating the need for separate assembly of multiple components. This segmentation-free approach achieves high precision complicated shapes that would be impossible to assemble from conventional processed parts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces conventional mechanical processing methods with laser-based additive manufacturing, enabling direct formation of complicated 3D shapes with high precision. This substitution removes the limitations of traditional machining and molding processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables the formation of medical handpieces with high precision and improved cooling efficiency, effectively addressing the limitations of traditional methods by reducing flow resistance and enhancing the cooling performance of the handpiece.

Implementation Method 1

a medium passage permitting a working medium to flow therein and including a bent portion at which a flow direction of the working medium is changed

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

stack molding including a medium passage permitting a working medium to flow therein, by use of stack molding... stereolithography composite processing

Methodology Applied
Scientific EffectStereolithography: Photopolymerisation

Data Source

PatentEP3108846B1Medical instrument element
Publication Date: 2021.06.23 J MORITA MANUFACTURING CORP
  • EP3108846B1 patent drawingFigure 1
  • EP3108846B1 patent drawingFigure 2(a)~2(b)
  • EP3108846B1 patent drawingFigure 3(a)~3(d)

AI summary

An object is to provide a medical instrument element, a medical instrument, a medical instrument component, and a medical handpiece processed in a complicated manner so as to provide a desired level of performance, and a method for producing the medical instrument element. A head housing (31) including a cooling path (50) permitting cooling water to flow therein and including a bent portion at which a flow direction of the cooling water is changed is formed by stack molding.