Flexographic Print Deck Bearing Preload for Bounce Control

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Solution Overview

Problem

Flexographic printing presses face issues with print bounce and banding due to mandrel movement and torque spikes, which are not fully mitigated by stiffening mandrel roll bodies with composite materials, and are exacerbated by internal clearances in bearing arrangements.

Innovation Solution

Implementing two adjacent mandrel bearings with radial loading in opposite directions to increase stiffness, and a torque feed-forward control system to minimize disturbances, with adjustable radial loading for maximum stability and error reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single front bearing or two front bearings are used with internal clearances to allow mandrel side shifting and bearing removal, then ease of operation is improved, but manufacturing precision deteriorates due to magnified print bounce and banding

Engineering Contradiction:

Improvemandrel side shifting and bearing removalVSAvoidprint quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The bearing assembly is segmented into a stationary bearing support and a movable bearing support that can be independently positioned. This allows the movable support to be retracted during changeover operations while maintaining precise positioning during printing, thus resolving the contradiction between ease of operation and manufacturing precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bearing support system transitions from a static configuration to a dynamic one where the movable bearing support can be positioned in different states (engaged for printing, disengaged for changeover). This dynamic capability allows the system to optimize for precision during operation and for ease of maintenance during changeover, resolving the contradiction.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If mandrel roll bodies are stiffened with composite materials, then stability is improved, but print bounce and banding are not completely eliminated

Engineering Contradiction:

Improvemandrel stabilityVSAvoidprint quality

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs composite material construction for the bearing supports, combining rigid materials (such as aluminum or steel) with damping materials (such as rubber or polymer layers). This composite structure provides both the stiffness needed to minimize mandrel movement and the damping capability to suppress vibrations and shocks, thereby completely eliminating print bounce and banding while maintaining mandrel stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the physical parameters of the bearing support system by introducing damping coefficients and stiffness values through composite materials. This allows optimization of the system's dynamic response to minimize both mandrel movement and vibration transmission, resolving the contradiction between stability and print quality.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If internal clearances are provided in bearing arrangements for side shifting and bearing removal, then adaptability is improved, but reliability deteriorates due to magnified mandrel movement

Engineering Contradiction:

Improvebearing removal capabilityVSAvoidmandrel positioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The bearing system is segmented into fixed and movable components, allowing the movable bearing support to be independently removed or repositioned. This segmentation enables bearing removal for maintenance while maintaining precise positioning accuracy during operation, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The movable bearing support acts as an intermediary element that can be selectively engaged or disengaged. When engaged, it provides precise positioning; when disengaged, it allows bearing removal. This intermediary mechanism resolves the contradiction between maintaining reliability during operation and providing adaptability for maintenance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11230093B2Anti-bounce print deck for flexographic printing press

Publication Date: 2022.01.25 BW CONVERTING INC

AI summary

A device and a method is disclosed to maintain plate and anilox mandrel position stability in print decks of a flexographic printing press. In one aspect, the mandrel bearings associated with at least one of the plate roll and the anilox roll are preloaded for the purpose of eliminating backlash and increasing the positional stiffness of the bearings, and thus the mandrel. In another aspect, the roll drive motor control system is enabled to provide a torque additive command the torque profile to maintain rotational consistency and otherwise overcome torque transients experienced by the motor during print bounce. Accordingly, the problem commonly referred to as print bounce and or print banding is alleviated.