Helical Rack Pinion 3D Printer Motion System
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Solution Overview
Problem
Current 3D printers using cartesian movement with belt-based kinematic chains suffer from non-constant transmission ratios due to belt elasticity, leading to inhomogeneous motion and reduced precision, whereas geared kinematic chains offer more precise but are not commonly used in 3D printing.
Innovation Solution
The use of geared kinematic chains with helical teeth for movement, where racks are fixed and pinions move, significantly reducing inertial masses and friction, allowing for more precise and efficient 3D printing by eliminating backlash and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If belt-based kinematic chains are used for movement, then the device complexity is reduced and ease of manufacture is improved, but manufacturing precision deteriorates due to non-constant transmission ratios from belt elasticity
Solution Approach 1:
The patent replaces belt-based mechanical transmission with a direct geared kinematic chain system where motors are directly coupled to drive pulleys, eliminating the intermediate belt transmission that causes elasticity-related precision losses. This substitution maintains mechanical simplicity while achieving constant transmission ratios through direct gear meshing between drive and driven pulleys.
2Manufacturing precision
If geared kinematic chains are used for movement, then manufacturing precision is improved with constant transmission ratios, but device complexity increases
Solution Approach 1:
The patent merges the motor and drive pulley into a single integrated unit, eliminating the need for separate belt tensioners, pulleys, and belts. The geared kinematic chain directly couples the motor shaft to the drive pulley, combining multiple components into one unified assembly that reduces overall system complexity while maintaining precision.
Solution Approach 2:
The patent extracts and eliminates the intermediate belt transmission components (belts, pulleys, tensioners) from the kinematic chain, retaining only the essential geared connection between motor and driven elements. This extraction simplifies the system by removing unnecessary components that contribute to complexity without providing functional benefit.
3Device complexity
If racks move along with the printing means, then the system structure is simplified, but the inertial masses to be displaced increase, reducing speed and increasing energy consumption
Solution Approach 1:
The patent inverts the conventional arrangement by making the rack stationary and the pinion movable. Instead of the rack moving with the printing means, the rack is fixed to the chassis and the pinion is attached to the moving carriage. This inversion dramatically reduces the inertial mass that must be accelerated and decelerated during motion, enabling higher speeds and lower energy consumption.
Solution Approach 2:
The patent effectively counteracts the inertial mass problem by fixing the heavy rack to the stationary chassis, creating a counterbalancing effect where the stationary mass does not need to be accelerated. Only the lighter pinion and carriage assembly need to be moved, significantly reducing the effective inertial mass and improving dynamic performance.
4Manufacturing precision
If helical teeth are used in racks and pinions, then manufacturing precision is improved with reduced friction and noise, but ease of manufacture decreases
Solution Approach 1:
The patent changes the geometric parameters of the gear teeth from straight to helical configuration. This parameter change improves manufacturing precision by providing more gradual tooth engagement, reducing friction and noise through smoother contact patterns. While helical teeth are slightly more complex to manufacture, modern machining capabilities make this change straightforward and worthwhile for the precision gains.
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 enhances the precision and speed of 3D printing, reducing the force and torque required for movement, leading to improved production times and energy efficiency, while maintaining high accuracy and reducing costs.
Implementation Method 1
the movement means comprises at least one motor (Mx, My) and a geared kinematic chain with helical teeth
Implementation Method 2
use of pinions and racks with helical teeth is envisaged
Implementation Method 3
The helical solution enables considerable limitation of the problems regarding friction and noise that are typical of gears with straight teeth
Implementation Method 4
moving a smaller inertial mass leads to considerable benefits, namely: less force to be applied to overcome the initial friction; possibility of increasing the speeds
Implementation Method 5
using for example two racks with helical teeth and corresponding pinions on the axis Y and one helical rack and pinion on the axis X, it is possible to reduce drastically the backlash that could arise during operation
Data Source
AI summary
Disclosed is a mechatronic movement system for three-dimensional printing for a rapid-prototyping machine, such as a 3D printer, of the type provided with at least one microprocessor electronic management board, in which the movement of the printing way of the 3D printer along the axes X and Y of the horizontal plane is obtained exclusively with geared kinematic chains.