One-Piece Injection Mold for Machined Product Holding

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Solution Overview

Problem

Existing injection molding methods require additional holding or fixation devices for machining, as products formed in two-part molds are not securely held within the mold, necessitating additional processing steps and equipment.

Innovation Solution

A method involving the creation of a one-piece injection mold by layer-by-layer deposition, where the mold is machined to expose the product, allowing it to be firmly held via sprues for machining without additional devices, using techniques like direct additive laser manufacturing and incorporating metallic structures for enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a two-part mold is used for injection molding, then the mold can be easily assembled and disassembled, but the molded product cannot be firmly held in the mold for further machining without additional holding or fixation devices

Engineering Contradiction:

Improveease of mold assemblyVSAvoidcomplexity of holding devices

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the holding function with the mold structure itself by designing the mold cavity to retain the product during machining operations. The product is held firmly in the mold through the cavity geometry and cooling channels, eliminating the need for separate holding or fixation devices that would otherwise be required with traditional two-part molds.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If additional holding or fixation devices are used for machining, then the product can be securely held, but the process complexity and number of required devices increase

Engineering Contradiction:

Improveproduct holding stabilityVSAvoidnumber of holding devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The holding function is integrated into the mold cavity structure itself. The cavity geometry and cooling channel design provide inherent holding stability for the product during machining, eliminating the need for separate holding or fixation devices while maintaining reliable product positioning.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a one-piece mold block is used with layer-by-layer building, then the product can be firmly held via sprues for machining, but the mold production time increases

Engineering Contradiction:

Improveproduct holding stabilityVSAvoidmold production time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the production method from traditional machining to layer-by-layer additive manufacturing. This enables the creation of complex internal structures including cooling channels and sprue systems that provide firm product holding, while the incremental layer-by-layer construction allows for efficient production despite the complex geometry.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If the mold is machined to expose the product, then the product can be accessed for machining, but material is removed from the mold block

Engineering Contradiction:

Improveproduct accessibilityVSAvoidmold block material

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The mold design incorporates cooling channels and sprue systems that are built during the layer-by-layer construction process itself, rather than requiring subsequent machining operations. This preliminary integration of functional features reduces the need for material removal after mold production, as the product exposure and holding features are already optimized during additive manufacturing.

Inventive Principle:

Principle #10Preliminary action

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

Enables efficient production of individual products, such as medical implants, with smooth surfaces and complex structures, reducing the need for two-part molds and additional processing, and allowing for direct interfacing with various machines for further processing.

Implementation Method 1

depositing a laser melted metallic powder

Methodology Applied

Scientific EffectLaser melting: Laser

Implementation Method 2

cooling off the injected molten material so that an injection molded product is formed

Methodology Applied

Scientific EffectCooling: Cooling

Data Source

PatentUS8852478B2Injection molding method including machining of both injection mold and molded product

Publication Date: 2014.10.07 DEPUY SYNTHES PROD INC

AI summary

A method for manufacturing an injection molded product includes producing an injection mold by building a one-piece mold block including a mold cavity sized and shaped to correspond to a desired shape of the injection molded product and a first feeder duct extending from the mold cavity and injecting a molten material into the mold cavity via the feeder duct to form an injection molded product and a sprue extending therefrom into the first feeder duct in combination with machining a portion of the injection block to expose the injection molded product and machining the injection molded product while the sprue firmly holds the product in a remaining portion of the injection mold. The product is then cut from the sprue.