Strain Wave Gear Dispensing Head for Precise PCB Corner Access
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Solution Overview
Problem
Existing dispensing systems struggle to accurately place viscous materials close to corners or hard-to-reach areas on electronic substrates, such as printed circuit boards, due to limitations in movement control and orientation of the dispensing unit.
Innovation Solution
A dispensing system incorporating a strain wave gear system that allows the dispensing unit to tilt and rotate up to 360 degrees, enabling precise placement of viscous materials on electronic substrates by combining a gantry system with a support bracket and a movable bracket, facilitated by a first and second strain wave gear system for enhanced rotational and tilting capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the dispensing unit is moved along x-axis and y-axis to reach desired locations, then the dispensing unit can cover the substrate area, but it cannot accurately place material close to corners or in hard-to-reach areas
Solution Approach 1:
The dispensing unit is made dynamically adjustable with two degrees of rotation freedom through strain wave gear systems. The movable bracket can rotate relative to the support bracket, and the dispensing unit can rotate relative to the movable bracket, enabling the nozzle to reach corners and hard-to-access areas while maintaining precise placement accuracy through controlled rotational movement.
Solution Approach 2:
The system adds rotational dimensions to the traditional linear x-y-z movement. By incorporating two strain wave gear systems that enable rotation about two different axes, the dispensing unit gains angular degrees of freedom, allowing it to approach the substrate from multiple angles and reach corner areas that are inaccessible with linear movement only.
2Adaptability or versatility
If a strain wave gear system is added to enable rotation and tilting, then the dispensing unit gains rotational capability, but the mass and compliance of the system increase
Solution Approach 1:
The strain wave gear system utilizes a flexible spline component that allows rotational movement without requiring heavy rigid gear teeth throughout the entire mechanism. The flexible spline enables the movable bracket and dispensing unit to rotate while maintaining structural integrity, reducing the overall mass compared to traditional rigid gear systems.
Solution Approach 2:
The patent replaces traditional mechanical gear systems with strain wave gear technology, which uses elastic deformation of the flexible spline instead of rigid tooth engagement. This substitution reduces the mass and inertia of the rotating components while maintaining the rotational capability needed for accessing hard-to-reach areas.
3Adaptability or versatility
If traditional gear systems are used for rotation, then rotational movement is achieved, but backlash reduces positioning precision
Solution Approach 1:
The flexible spline in the strain wave gear system eliminates backlash by using continuous elastic deformation rather than discrete tooth engagement. As the wave generator rotates the flexible spline, the material continuously deforms and returns without gaps or play, ensuring precise positioning during rotational movement to corners and hard-to-reach areas.
Solution Approach 2:
The strain wave gear system employs composite structural elements including the flexible spline made from materials with specific elastic properties. This composite approach combines rigidity where needed with flexibility in the spline portion, achieving both rotational freedom and backlash-free positioning precision simultaneously.
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
The system achieves precise and accurate dispensing of viscous materials on electronic substrates, including printed circuit boards, by allowing the dispensing unit to reach hard-to-reach areas with increased speed and precision, minimizing added mass and compliance, and providing zero backlash.
Implementation Method 1
a flexible spline having a spline portion disposed between the circular spline and the wave generator
Data Source
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AI summary
A dispensing system includes a dispensing unit assembly configured to dispense viscous material and a gantry coupled to the frame. The gantry is configured to support the dispensing unit assembly and to move the dispensing unit assembly in x-axis and y-axis directions. The dispensing unit assembly includes a support bracket secured to the gantry and a movable bracket rotatably coupled to the support bracket by a first strain wave gear system configured to enable the rotation of the movable bracket with respect to the support bracket about a first axis. The dispensing unit assembly further includes a dispensing unit rotatably coupled to the movable bracket by a second strain wave gear system configured to enable the rotation of the dispensing unit with respect to the movable bracket about a second axis generally perpendicular to the first axis.