Dispenser Calibration for Vision-Position Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dispensing systems face errors due to non-constant relative positions between dispensing units and vision systems, especially when these components are on separate gantries, leading to inaccuracies in dispensing viscous materials onto substrates like circuit boards.
Innovation Solution
A method involving 'wet dispensing' where a pattern of deposition features is created and then located using the vision system to map out errors, allowing for calibration and correction of relative distances between dispensing units and vision systems, which are stored for future use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vision system and dispensing unit are mounted on separate gantries, then the system can perform dispensing operations, but the relative distance between the vision system and dispensing unit is not constant, leading to positioning errors
Solution Approach 1:
The patent applies preliminary action by performing a calibration routine before actual dispensing operations. The system dispenses test material at multiple predetermined locations, captures images with the vision system, and calculates relative distance errors in advance. These calculated errors are then stored and used to correct positioning during normal operation, effectively compensating for the non-constant relative distance between separately mounted vision system and dispensing unit.
2Measurement precision
If a standard calibration routine is used to calibrate vision system positioning, then positioning errors are corrected, but the non-constant relative distance between vision system and dispensing unit is not sufficiently accounted for
Solution Approach 1:
The patent implements feedback by using the vision system to capture images of dispensed material at known locations, calculating the actual relative distance between vision system and dispensing unit at each location, and using this feedback information to correct positioning errors. The system continuously refines the error model by comparing expected positions with actual vision system measurements, thereby accounting for the non-constant relative distance that standard calibration routines miss.
3Reliability
If the relative distance between vision system and dispensing unit is not constant, then mechanical variance occurs, but implementing a comprehensive calibration method increases system complexity
Solution Approach 1:
The patent applies self-service by enabling the system to automatically perform its own calibration without requiring external intervention or complex manual procedures. The calibration routine autonomously dispenses test material, captures images, calculates relative distance errors at multiple locations, and generates correction values. This self-calibrating approach maintains high reliability while keeping the procedure manageable through automation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method is used to identify and compensate for errors created by changes in the relative positions of a deposition unit and a vision system of a dispenser. The method includes calibrating the vision system, dispensing a pattern of features over a working area, moving the vision system over a deposition location to locate a deposition, obtaining an image of the deposition, tagging data associated with the image, calculating a relative distance between the deposition unit and the vision system, storing correction data with spatial location in a file for later use, and using the stored data to make small corrections prior to dispensing additional material.