Printing Mandrel Locking Rings for Precise Sleeve Mounting
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Solution Overview
Problem
The existing mandrels with deformable printing sleeves suffer from precision issues due to radial compressible layers, leading to increased TIR-values and reduced print quality, and the previous solutions, such as polyurethane expansion rings, face issues with temperature-induced unintended clamping, making it difficult to remove the printing sleeve.
Innovation Solution
A mandrel with a locking assembly featuring deformable rings having a cross-sectional profile with integrally connected arms that change shape to achieve radial expansion and contraction, allowing for a reliable press fit connection while considering thermal expansion coefficients, preventing unintended clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a radially compressible layer is used in the printing sleeve to enable mounting on the air mandrel, then the ease of operation is improved, but the manufacturing precision deteriorates due to surface displacement and increased TIR-value
Solution Approach 1:
The patent removes the radially compressible layer from the printing sleeve structure. Instead of using a deformable layer that causes precision issues, the invention uses a rigid printing sleeve that is mounted on the mandrel through a different mechanism (locking assembly with deformable rings), thereby eliminating the source of surface displacement and TIR-value increase while maintaining ease of mounting.
Solution Approach 2:
The patent applies local deformability only to the locking mechanism (deformable rings) rather than to the entire printing sleeve. The printing sleeve itself remains rigid to maintain precision, while the locking rings provide the necessary compliance for mounting and securing operations.
2Ease of operation
If polyurethane expansion rings are used to achieve radial expansion for clamping, then the ease of operation is improved, but the reliability deteriorates due to temperature-induced unintended clamping
Solution Approach 1:
The patent changes the material parameter of the expansion rings from polyurethane to a material with a low thermal expansion coefficient. This parameter change ensures that thermal expansion does not cause unintended clamping, thereby maintaining reliability while preserving the ease of operation through controlled radial expansion via the locking mechanism.
Solution Approach 2:
The patent addresses the harmful effect of thermal expansion by selecting a material where this effect is minimized. The potential harm of temperature-induced clamping is converted into a benefit by using a material whose dimensional stability under temperature changes ensures reliable, unintended clamping-free operation.
3Manufacturing precision
If a rigid printing sleeve is used to improve manufacturing precision, then the manufacturing precision is improved, but the ease of operation deteriorates due to difficulty in mounting and removal
Solution Approach 1:
The patent divides the mounting system into two separate components: a rigid printing sleeve for precision and a separate locking assembly with deformable rings for ease of mounting. The printing sleeve remains rigid to maintain precision, while the locking mechanism provides the necessary compliance for mounting and removal operations.
Solution Approach 2:
The patent introduces a locking assembly with deformable rings as an intermediary mechanism between the rigid printing sleeve and the mandrel. This intermediary provides the compliance needed for easy mounting and removal while allowing the printing sleeve itself to remain rigid for precision.
4Ease of manufacture
If the deformable rings have a rectangular cross-sectional profile, then the ease of manufacture is improved, but the reliability deteriorates due to temperature-induced radial expansion
Solution Approach 1:
The patent changes the cross-sectional profile parameter of the deformable rings from rectangular to a profile with reduced thermal expansion characteristics. This parameter change reduces the harmful effects of thermal expansion while maintaining manufacturability through standard forming processes.
Solution Approach 2:
The patent specifies using a material with a thermal expansion coefficient equal to or smaller than steel or aluminum. This material selection creates a composite effect where the deformable rings exhibit both the necessary mechanical compliance for mounting and thermal stability to prevent unintended clamping.
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 solution maintains the advantages of previous mandrels by providing a stable and precise connection while addressing temperature-induced issues, ensuring the printing sleeve can be reliably fixed and removed, enhancing print quality and longevity.
Implementation Method 1
deformable rings having a cross-sectional profile with integrally connected arms that change shape to achieve radial expansion and contraction
Implementation Method 2
addressing temperature-induced issues, ensuring the printing sleeve can be reliably fixed and removed
Data Source
AI summary
A mandrel for use in a printing apparatus includes a substantially cylindrical mandrel shaft and a locking assembly including a stop ring, a locking ring, and a plurality of deformable rings which are slidably and coaxially mounted on the mandrel shaft. Each deformable ring has a cross-sectional profile in a cross-sectional plane in which the mandrel shaft axis extends, which profile includes a first arm and a second arm which are integrally connected to each other at a first connection point. The first arm and the second arms include an angle which is sharper in the unlocked position than in the locked position of the locking assembly. The first arm has a first-arm-end remote from the first connection point, which defines the outer diameter of the deformable ring. The second arm has a second-arm-end remote from the first connection point, which second-arm-end defines the inner diameter of the deformable ring.