Segmented Squeegee Head for Flexible Screen Printing
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Solution Overview
Problem
Existing screen printing systems, particularly those using Rakel systems, face limitations in flexibility and pressure quality, making them unsuitable for soft or flexible surfaces like plastic bottles, and require lengthy setup times due to the need for precise preload adjustments and risk of ink or fluid contamination.
Innovation Solution
A specially designed Rakel rubber with a rectangular cross-section and grooves for increased flexibility, combined with a squeegee head featuring bolts with adjustable preloads and a two-part clamping system for secure and variable pressure application, allowing for slip-free absorption and improved guidance of the Rakel rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If bolts are guided in a guide block with springs and adjusting screws for preload adjustment, then pressure control is improved, but setup time increases and contamination risk increases
Solution Approach 1:
The guide block is divided into multiple individual guide elements, each capable of independent adjustment and replacement. This segmentation allows for quicker setup by pre-adjusting individual guides and enables selective replacement of only contaminated guides rather than the entire assembly.
Solution Approach 2:
The spring preload mechanism is designed with adjustable parameters that can be modified without disassembling the entire guide block. This allows for rapid pressure control adjustments during setup by simply changing spring parameters or guide positions.
2Stress or pressure
If bolts are guided in a guide block with springs and adjusting screws for preload adjustment, then pressure control is improved, but device complexity increases
Solution Approach 1:
The guide block is segmented into multiple independent guide elements that can function autonomously. Each segment contains its own spring and adjustment mechanism, simplifying the overall structure by eliminating the need for a single complex integrated system.
Solution Approach 2:
The guide elements are designed to be dynamically adjustable during operation, allowing preload changes without fixed complex mechanisms. This dynamic capability reduces the need for overly engineered static adjustment systems.
3Force
If the inner coating of the housing ensures sliding properties of the bolt, then friction is reduced, but contamination resistance decreases
Solution Approach 1:
The guide elements with their inner coatings are designed as replaceable components. When the coating becomes contaminated or degraded, individual guides can be quickly replaced without replacing the entire squeegee head, treating the coatinged surfaces as short-living protective layers.
Solution Approach 2:
Contaminated guide elements can be discarded or removed from service while the squeegee head remains functional. The coating on these guides serves its purpose until contamination occurs, at which point the guides are replaced rather than cleaned or repaired.
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
Enables higher pressure qualities to be achieved with shorter setup times, expanding the applicability to soft and flexible surfaces while maintaining precise control and preventing ink contamination, thus enhancing the quality and versatility of screen printing.
Implementation Method 1
A spring in each mounting bracket exerts a contact pressure between the squeegee rubber and the screen
Implementation Method 2
recesses (101) of length b1 and depth t1 in the longitudinal direction of the squeegee rubber (1) on the side opposite the squeegee edge (105) for slip-free reception of the squeegee rubber (1) in an engagement device (303)
Implementation Method 3
grooves (103) of length b2 and depth t2 in the longitudinal direction of the squeegee rubber (1) for increasing the flexibility of the squeegee rubber (1) in the longitudinal direction
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The present invention relates first to a squeegee rubber (1) with a squeegee edge (105), comprising in the longitudinal direction of the squeegee rubber (1) on the side opposite the squeegee edge (105) recesses (101) of length b1 and depth t1 for slip-free reception of the squeegee rubber (1) into an engagement device (303) on a squeegee head (3).Furthermore, the present invention relates to a doctor blade head (3) comprising: - at least one bolt (301) having at its first end (301a) an engagement device (303) for receiving a doctor blade rubber (1); - a base body (305) with at least one bolt guide (307), wherein each bolt guide (307) receives and guides the shank (301s) of a bolt (301); - at least one element (309) for receiving at least one spring (311) for generating a contact pressure of the at least one bolt (301), wherein the element (309) is arranged above the bolt guide (307) in the base body (305) and the spring (311) is in operative connection with the second end (301b) of the bolt (301); - at least one device (313) for generating a preload in the spring (311), which is received in a two-part clamping system (315a, 315b). is, wherein the device (313) can be reversibly secured by a terminal block (315b).Finally, a squeegee system (5) is the subject of the present invention.