Contactless Sensor Print Bed Levelling for Additive Manufacturing

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Solution Overview

Problem

Existing print bed levelling systems in additive manufacturing are not robust against external factors such as temperature changes, humidity, and contamination, leading to inaccurate position calibration of nozzle bodies relative to the print bed.

Innovation Solution

A print bed levelling system with a contactless sensor member that uses capacitive, inductive, or ultrasonic displacement sensors to maintain accurate position calibration of nozzle bodies, minimizing the impact of external disturbances and ensuring reliable measurement, where the sensing surface is fixedly attached to the nozzle head assembly for synchronous displacement and improved measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact sensor is used for position calibration, then measurement accuracy is improved, but the system becomes sensitive to contamination and wear

Engineering Contradiction:
Improveposition calibration accuracyVSAvoidrobustness to contamination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical contact-based sensing with a capacitive sensor that measures distance through non-contact electrical field interaction. This substitution eliminates mechanical wear and contamination issues while maintaining measurement precision for position calibration of the print bed relative to the nozzle assembly.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If temperature and humidity control is implemented, then measurement stability is improved, but system complexity and cost increase

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidenvironmental control system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces environmental control mechanisms with an environmental-compensated measurement system. The capacitive sensor inherently compensates for temperature and humidity variations through its non-contact measurement principle, eliminating the need for complex thermal and humidity control systems while maintaining measurement stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the sensing surface is fixed to the nozzle head assembly, then synchronous displacement is achieved, but the sensor may be affected by nozzle movement

Engineering Contradiction:
Improveposition calibration accuracyVSAvoidmeasurement consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the measurement function from the nozzle function by placing the capacitive sensor on the stationary print bed while the nozzle assembly moves independently. This segmentation allows the sensor to measure the position of the nozzle assembly without being affected by nozzle movement, achieving both synchronous displacement measurement and measurement consistency.

Inventive Principle:
Principle #1Segmentation

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 provides cost-effective and accurate position calibration of nozzle bodies, maintaining high measurement resolution and reliability even under changing conditions, with the contactless sensor ensuring that the nozzle bodies remain calibrated and operational despite environmental and contamination factors.

Implementation Method 1

the contactless sensor member comprises a capacitive displacement sensor in capacitive sensing engagement with the print bed member

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

the contactless sensor member comprises an inductive displacement sensor in inductive sensing engagement with the print bed member

Methodology Applied
Scientific EffectInductive sensing: Electromagnetic Induction

Implementation Method 3

the contactless sensor member comprises an ultrasonic displacement sensor in ultrasonic sensing engagement with the print bed member

Methodology Applied
Scientific EffectUltrasonic sensing: Ultrasound

Data Source

PatentEP3135460B1Print bed levelling system and method for additive manufacturing
Publication Date: 2021.05.05 ULTIMAKER BV
  • EP3135460B1 patent drawingFigure 1
  • EP3135460B1 patent drawingFigure 2~3
  • EP3135460B1 patent drawingFigure 4~5

AI summary

Print bed levelling system for an additive manufacturing system, comprising a nozzle head assembly (2) movably arranged with respect to a substantially flat print bed member (4), wherein the nozzle head assembly (2) comprises one or more nozzle bodies (6, 7) each having a nozzle end (8, 9), and a contactless sensor member (10) disposed at a print bed engagement end (12) of the nozzle head assembly (2). The contactless sensor member (10) comprises a sensing surface (14) in sensing engagement with the print bed member (4) over a relative sensing distance range between a distal sensing position and a proximal sensing position.