Doctor Blade Unit Segmentation for Coating Maintenance

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Solution Overview

Problem

Squeegee devices for coating applications are prone to wear and require frequent cleaning and component replacement, leading to inefficiencies in maintenance and reduced productivity.

Innovation Solution

The clamping tube is integrated into the foot part of the squeegee unit, allowing for easier removal and cleaning, and the pressing element is external, enabling faster replacement without downtime, along with the use of sealing hoses to reduce contamination and facilitate quicker service.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the clamping hose is integrated into the squeegee unit, then the squeegee unit can be removed as a complete assembly for easier cleaning, but the clamping hose is exposed to contamination from the application medium

Engineering Contradiction:
Improveease of cleaningVSAvoidcontamination
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The squeegee unit is divided into separable components: the head part with the squeegee rod, and the foot part with the clamping hose. This segmentation allows the head part to be removed for cleaning while leaving the clamping hose in place, avoiding contamination of the hose while enabling easy access to the coating surface for maintenance.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the pressing element is integrated into the head part, then the structure is simpler, but the pressing element must be replaced every time the squeegee unit is changed, increasing downtime

Engineering Contradiction:
Improvestructural simplicityVSAvoiddowntime
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The pressing element is extracted from the head part and positioned on the supporting squeegee bar independently. This allows the pressing element to remain in place when the head part is replaced, enabling faster squeegee unit changes and reducing machine downtime while maintaining structural simplicity through external positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the squeegee unit is designed as a modular system, then handling and configuration are easier, but accessibility to the squeegee unit for cleaning and maintenance is still not optimal

Engineering Contradiction:
ImprovemodularityVSAvoidaccessibility
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The modular squeegee unit is segmented into a head part and foot part that can be easily separated. The head part containing the squeegee rod can be quickly removed from the foot part, providing optimal accessibility for cleaning the coating surface while maintaining the modularity benefits for handling and configuration flexibility.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2103358B1Doctoring device
Publication Date: 2015.03.25 VOITH PATENT GMBH
  • EP2103358B1 patent drawingFigure 1~2
  • EP2103358B1 patent drawingFigure 3

AI summary

The doctor blade device comprises a doctor blade unit (3) comprising a head part, which forms a doctor blade holder for a cylindrical doctor bar (8) accommodated in a groove (9) as dosage and/or equalizing element and a tail part (5), which carries the head part and/or the blade holder. The tail part is present in a support girder (10) by a tubular clamp (6). The head part is pressed with a pressing element with respect to a substrate (2) to be coated. The tubular clamp is an integral component of the tail part. The pressing element is non-integral component of the head part. The doctor blade device comprises a doctor blade unit (3) comprising a head part, which forms a doctor blade holder for a cylindrical doctor bar (8) accommodated in a groove (9) as dosage and/or equalizing element and a tail part (5), which carries the head part and/or the blade holder. The tail part is present in a support girder (10) by a tubular clamp (6). The head part is pressed with a pressing element with respect to a substrate (2) to be coated. The tubular clamp is an integral component of the tail part. The pressing element is non-integral component of the head part and is accommodated in an external pressing device and influences the rear side of the head part and/or the blade holder from outside, where the rear side is opposite to the groove. A sealing tube is intended for the head part and/or the blade holder. The pressing element is a pressing tube. The sealing hose is accommodated in a recess of the blade holder. The sealing tube is arranged above the pressing element at the rear side of the head part and/or the blade holder and is present in the external pressing device, in which the pressing tube is accommodated. The tail part is positioned at a contact surface of the support girder. The head part and the tail part are formed as separate components or formed with one another in a single-piece. The head part and/or blade holder are polygonal shaped and the tail part is ring shaped. The head part and/or blade holder and the tail part are decoupled from each other with respect to their thermal expansion, and are positively connected. The head part and/or blade holder comprise another groove, in which the tail part intervenes with a bulge. The pressing tube, the tubular clamp and the sealing tube is formed as round or profile tube e.g. commercial nose hose. The head part and/or blade holder and the tail part are producible from the same material or different hard and/or different thermal materials. The tail part is suitable to carry the head part and/or blade holder in different sizes and shapes dependent on the size of the selected blade bar. A flexible section is present between the head part and/or blade holder and the tail part. The tail part comprises bending points as flexible section. The bending point is implemented as a notch or as a constriction or in form of a leaf spring. The blade bar is produced with a diameter of 8-40 mm with smooth or corrugated surface. An independent claim is included for a coating machine for applying a fluid or pasty application medium e.g. coating colors, on a substrate.