Stencil Printer Substrate Alignment with Ball Screw Drive
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Solution Overview
Problem
Existing stencil printers face challenges in accurately aligning and stabilizing substrates during the printing process, particularly in achieving precise movements in the x, y, and rotational directions, which affects the uniform deposition of viscous materials like solder paste on circuit boards.
Innovation Solution
The stencil printer incorporates a substrate support movement assembly with three movement mechanisms, including ball screw drive assemblies, to enable precise x, y, and rotational movements of the substrate support table, allowing for accurate alignment and stabilization of the substrate under the control of a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spring-loaded actuators are used to control substrate support movement, then the substrate can be aligned with the stencil, but the alignment precision and stability are insufficient
Solution Approach 1:
The patent replaces the spring-loaded actuator system with a ball screw drive mechanism. The ball screw converts rotational motion from motors into precise linear motion of the substrate support table, enabling accurate control of x, y, and rotational movements. This mechanical substitution provides both the precision needed for alignment and the stability required for reliable printing operations.
Solution Approach 2:
The patent implements a dynamic alignment system where the substrate support table can be precisely positioned and repositioned during operation. The ball screw mechanisms allow for controlled movement in multiple degrees of freedom, enabling the system to adapt to different substrate positions and maintain alignment stability throughout the printing process.
2Manufacturing precision
If the substrate support is fixed with respect to the stencil, then printing can proceed, but precise movement control in x, y, and rotational directions is lost
Solution Approach 1:
The patent creates a dynamically adjustable substrate support system using ball screw mechanisms. The table can be precisely moved in x and y directions and rotated, allowing operators to easily adjust substrate positioning before printing. Once positioned, the same mechanisms maintain the precise position during printing, thus providing both ease of operation and manufacturing precision.
Solution Approach 2:
The substrate support table serves multiple functions: it supports the substrate during printing, enables precise positioning through ball screw mechanisms, and allows rotational adjustment for alignment. This multi-functional design eliminates the need for separate adjustment mechanisms while maintaining both precision and operational ease.
3Manufacturing precision
If the substrate is not properly stabilized, then alignment can be adjusted, but uniform deposition of viscous material cannot be achieved
Solution Approach 1:
The patent implements a stabilized substrate support system where the ball screw mechanisms precisely position and hold the substrate table in place during printing. The ability to dynamically adjust and then firmly maintain position ensures that the substrate remains stable relative to the stencil, enabling uniform deposition of viscous solder paste material across the entire printing area.
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 ensures precise alignment and stabilization of substrates, leading to improved uniformity and viscosity of the solder paste deposition, enhancing the printing process efficiency and accuracy.
Implementation Method 1
Each of the first, second and third movement mechanisms may comprise a ball screw drive assembly having a threaded shaft and a ball screw member axially movable along a length of the threaded shaft
Implementation Method 2
The ball screw member of the substrate support movement assembly may include a linear bearing secured to the bottom surface of the table and to the movable frame assembly
Data Source
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AI summary
A stencil printer for printing viscous material on a substrate includes a frame (12), a stencil (16), and a print head (18) to deposit and print viscous material over the stencil. A substrate support (78) supports a substrate in a print position. A substrate support movement assembly (30) includes a first movement mechanism (100A) configured to move the substrate support in a first direction, a second movement mechanism (100B) configured to move the substrate support in a second direction, the second direction being generally perpendicular to the first direction, and a third movement mechanism (100A), spaced from a first movement mechanism, configured to move the substrate in the first direction. The stencil printer further includes a controller (14) coupled to the substrate support movement assembly to move the substrate support by the first, second and third movement mechanisms in an x-direction, a y-direction and a rotational direction to align the substrate.