Mask Template for Selective Lubricant Coating on Sheet Metal Blanks

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Solution Overview

Problem

In superplastic forming, existing lubricant technologies like boron nitride and graphite slurries lead to buildup in dies, causing maintenance issues and defects such as skid lines or slip lines due to friction and adhesion between the metal sheet and forming tool.

Innovation Solution

A system and method for applying a lubricant coating to a sheet metal blank using a mask template with an overspray fence and contact elements to protect specific regions from the coating, ensuring a uniform thickness on exposed areas while minimizing lubricant deposition on areas that need to remain uncoated, thereby reducing friction and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If solid lubricant (boron nitride) is used to reduce friction and adhesion, then material flow over forming surfaces is improved, but lubricant builds up quickly in the die causing maintenance downtime and defects

Engineering Contradiction:
Improvematerial flowVSAvoidmaintenance downtime
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent uses a disposable mask template that is discarded after a single use. This eliminates the need to clean and maintain reusable masking systems, as the mask is thrown away after one application cycle, directly addressing the maintenance downtime issue while allowing optimal lubricant application patterns.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the masking function from a complex reusable system and implements it through a simple single-use mask template. This extraction simplifies the overall system and eliminates the maintenance burden associated with reusable masking mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If solid lubricant is applied to the metal sheet, then adhesion to tool surfaces is prevented, but skid lines or slip lines appear due to metal sheet slipping over sharp features

Engineering Contradiction:
Improverelease aid performanceVSAvoidsurface defect free
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies lubricant selectively to specific regions of the metal sheet using a mask template with openings in predetermined patterns. This local quality approach ensures lubricant is applied only where release aid is needed, while leaving other areas free of lubricant to prevent skid lines and slip lines on visible surfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The mask template divides the metal sheet surface into coated and uncoated regions through its pattern of openings. This segmentation allows different surface treatments in different areas, enabling release aid performance where needed while maintaining surface quality where visible.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If mask template contacts the sheet metal surface directly, then precise positioning is achieved, but lubricant coating uniformity is compromised due to contact interference

Engineering Contradiction:
Improvemask positioningVSAvoidcoating uniformity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent resolves the positioning-coating conflict by moving the contact function to a different dimension. Contact elements engage the sheet in the vertical dimension for positioning, while the mask body extends in the horizontal dimension to define coating boundaries, allowing both functions to coexist without interference.

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

Solution Approach 2:

The mask template is segmented into contact elements for positioning and a mask body for defining coating boundaries. This segmentation allows the contact elements to provide precise positioning while the spaced-away mask body maintains coating uniformity by not interfering with the spray pattern.

Inventive Principle:
Principle #1Segmentation

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 solution effectively prevents lubricant buildup in dies and reduces defects like skid or slip lines by maintaining a uniform coating thickness on exposed regions and minimizing lubricant on protected areas, enhancing the superplastic forming process.

Implementation Method 1

a sprayer assembly for spraying the lubricant material toward the surface of the sheet metal blank

Methodology Applied
Scientific EffectSpray deposition: Aerosol

Implementation Method 2

at least one contact element extending to a second distance that is greater than the first distance away from the surface of the mask template, the at least one contact element for engaging the surface of the sheet metal blank and for releasably securing the mask template to the surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2651571B1Mask template, system and method for applying a coating of a lubricant material to a surface of a sheet metal blank
Publication Date: 2021.06.02 MAGNA INTERNATIONAL INC
  • EP2651571B1 patent drawingFigure 1
  • EP2651571B1 patent drawingFigure 2
  • EP2651571B1 patent drawingFigure 3

AI summary

The invention is directed to a system and method of applying a coating of lubricant material to the surface of a sheet metal blank in a controlled manner such that some areas of the blank have a uniform thickness of lubricant while other areas have no lubricant at all or have a variable amount (progressively increasing or decreasing) of lubricant. This is achieved through the use of a mask template that comprises an overspray fence and at least one contact element. The lubricated coated sheet metal blank is utile for superplastic forming to produce specialized complex shaped parts. The invention advantageously lessens the possibility of skid or slip lines appearing in the finished product as well as lessens the likely build-up of lubricant in forming dies - easing maintenance requirements.