Gantry Assembly Pivoting Reduction in 3D Printing
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Solution Overview
Problem
Existing additive manufacturing systems face challenges in accurately positioning a tool head in a two-dimensional plane due to unwanted pivoting of the carriage and tool-head mount, which affects deposition accuracy during the building of 3D parts and support structures.
Innovation Solution
A gantry assembly utilizing a single drive belt and multiple motors operating independently to move the tool-head mount in a two-dimensional plane, with features to reduce pivoting by using biased bearings and strategically designed bearing sleeves and pulleys, allowing precise control over the tool head's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional single-motor drive system is used to move the tool head along a linear path, then the system is simpler in structure, but the tool head cannot accurately reach arbitrary coordinate locations in a two-dimensional plane without unwanted pivoting
Solution Approach 1:
The gantry assembly is segmented into two independent motion systems: a first motor moves the carriage along the x-axis, and a second motor moves the tool-head mount along the y-axis relative to the carriage. This segmentation allows independent control of each axis, enabling precise positioning at arbitrary coordinate locations while eliminating unwanted pivoting motion.
Solution Approach 2:
The system transitions from one-dimensional linear motion to two-dimensional planar motion by adding a second independent motor and bearing shaft arrangement. The first bearing shafts extend along a first axis and the second bearing shafts extend along a second axis that defines a plane with the first axis, enabling the tool head to reach any coordinate location within the plane.
2Manufacturing precision
If bearing clearance is present in the bearing shafts, then the assembly is easier to manufacture, but the tool head positioning accuracy deteriorates due to increased play and pivoting
Solution Approach 1:
Spring elements are introduced to apply pre-load forces on the bearing shafts, counteracting the effects of bearing clearance and gravitational forces. The springs bias the bearing shafts to maintain continuous contact between the bearing surfaces, eliminating play and preventing unwanted pivoting motion while maintaining reasonable manufacturing tolerances.
3Manufacturing precision
If the carriage is allowed to pivot freely during movement, then the mechanism has greater flexibility and ease of operation, but the deposition accuracy deteriorates due to unwanted pivoting motion
Solution Approach 1:
The unwanted pivoting degree of freedom is extracted and eliminated from the system by using precision bearing shafts with minimal clearance and spring pre-loading. This constrains the carriage to move only along the intended linear path, removing the harmful pivoting motion while maintaining smooth operation through proper bearing selection and lubrication.
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 solution enables accurate positioning of the tool head with high resolution and reduced pivoting, enhancing the deposition accuracy of 3D parts and support structures by allowing the tool head to be moved to any coordinate location within the x-y plane with improved positional repeatability.
Implementation Method 1
a drive belt secured to the tool-head mount, a first motor having a first drive shaft engaged with the drive belt, and a second motor having a second drive shaft engaged with the drive belt
Implementation Method 2
a first bearing shaft extending along a first axis, a carriage slidably engaged with the first bearing shaft, and a second bearing shaft operably supported by the carriage
Data Source
AI summary
A gantry assembly for use in an additive manufacturing system, the gantry assembly comprising a first bearing shaft, a carriage slidably engaged with the first bearing shaft, and a second bearing shaft operably supported by the carriage, the second linear bearing extending along a second axis. The gantry assembly also comprises a tool-head mount slidably engaged with the second linear bearing, a drive belt secured to the tool-head mount, a first motor having a first drive shaft engaged with the drive belt, and a second motor having a second drive shaft engaged with the drive belt.