Injection Mold Plasma Nozzle for Surface Activation

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Solution Overview

Problem

Current methods for plasma pretreatment of injection-molded plastic parts require separate process steps, leading to increased cycle times, energy consumption, and limitations in treating complex geometries due to the need for mold opening and robot movement, which hinders efficient and resource-effective production.

Innovation Solution

Integration of a plasma nozzle within the injection mold allows for plasma treatment of the molded part while the mold is still closed, utilizing the residual heat and negative pressure to enhance surface activation, reducing exposure time and energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plasma treatment is performed using a robot moving a plasma nozzle over the surface after the injection mold has been opened, then the surface of the injection molded part can be activated, but the cycle time increases due to the longer mold opening time and robot travel time

Engineering Contradiction:
Improvesurface activation qualityVSAvoidcycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The plasma treatment device is integrated directly into the injection mold structure, merging the molding process with the surface treatment process. This allows both processes to occur simultaneously within the closed mold, eliminating the need for separate robot movement and mold opening operations, thereby significantly reducing cycle time while maintaining surface activation quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plasma treatment is performed immediately after injection while the mold is still closed and the part is still hot, taking advantage of the residual heat and negative pressure conditions. This preliminary action eliminates the need for subsequent separate treatment steps and reduces overall processing time

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a robot is used to move the plasma nozzle over the surface, then plasma treatment can be applied, but the complexity of the device increases and the process requires additional space for robot movement

Engineering Contradiction:
Improvesurface treatment capabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The plasma treatment functionality is merged into the injection mold itself, eliminating the need for external robots and complex positioning systems. The mold structure now serves dual purposes: forming the part and delivering plasma treatment, thereby reducing device complexity and space requirements

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The injection mold is designed to perform multiple functions: it forms the plastic part through injection and simultaneously delivers plasma treatment through integrated nozzles. This multi-functionality eliminates the need for separate dedicated plasma treatment equipment and robots, simplifying the overall system

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the mold is opened for plasma treatment, then the plasma nozzle can access the surface, but the treatment of complex geometries with undercuts is not possible due to limited access angles

Engineering Contradiction:
Improveplasma jet accessibilityVSAvoidgeometry complexity capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By integrating plasma nozzles directly into the mold cavities and cores, the system achieves universal access to all surface geometries including undercuts and complex shapes. The plasma is delivered from within the mold itself, allowing treatment of any surface that contacts the mold, regardless of orientation or accessibility

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mold cavity and core structures serve as intermediaries that deliver plasma directly to all surfaces of the part, including those in undercuts and complex geometries. This intermediary delivery system overcomes the limitations of external robot-based approaches that cannot access certain angles

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If separate process steps are used for injection molding and plasma treatment, then each process can be optimized independently, but energy and resource efficiency decreases and production time increases

Engineering Contradiction:
Improveprocess optimization flexibilityVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The injection molding and plasma treatment processes are merged into a single integrated operation performed simultaneously within the closed mold. This eliminates the additive effect of separate process times and improves overall production efficiency while maintaining the ability to optimize plasma treatment parameters independently through controlled delivery

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces cycle time, enables treatment of more complex geometries, and improves adhesion properties by using the plasma jet within the closed mold, promoting energy and resource efficiency.

Implementation Method 1

During plasma treatment, the ions and free electrons in the plasma jet incorporate nitrogen and oxygen into the polymer surface

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

the ions and free electrons in the plasma jet incorporate nitrogen and oxygen into the polymer surface

Methodology Applied
Scientific EffectIon implantation: Ion Implantation

Implementation Method 3

the residual heat of the injection molded part can be used in this way to increase the affinity of the materials or the surface tension

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 4

the negative pressure that typically occurs in the injection mold promotes the plasma propagation and activation of the injection-molded part surface

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentEP3277475B1Injection-molding tool and method for producing an injection-molded part
Publication Date: 2018.12.19 PLASMATREAT GMBH
  • EP3277475B1 patent drawingFigure 1
  • EP3277475B1 patent drawingFigure 2
  • EP3277475B1 patent drawingFigure 3

AI summary

The invention relates to an injection-molding tool (2, 32, 72) for producing an injection-molded part (8, 38, 88), in particular from plastic, comprising an injection mold (4, 34, 74), which has a cavity (6, 36, 86) corresponding to the negative of the shape of the injection-molded part (8, 38, 88) to be produced, wherein a plasma nozzle (18, 52, 92, 130), which is designed to produce an atmospheric plasma jet (154), is connected to the injection mold (4, 34, 74) in such a way that, in the injection mold (4, 34, 74), a plasma jet (154) can be applied to an injection-molded part (8, 38, 88) produced in the injection mold (4, 34, 74). The invention further relates to a method for producing an injection-molded part (8, 38, 88) by means of an injection-molding tool (2, 32, 72), wherein the injection-molding material, in particular a plastic, is introduced into a cavity (6, 36, 86) of the injection mold (4, 34, 74) such that an injection-molded part (8, 38, 88) is formed, and wherein an atmospheric plasma jet (154) is applied to the injection-molded part (8, 38, 88) in the injection mold (4, 34, 74).