Glass Container Bottom Forming for Tight Tolerances and Surface Quality
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Solution Overview
Problem
Existing glass container manufacturing processes face challenges in achieving low dimensional tolerances and mechanical stability, particularly in the glass bottom region, leading to issues in optical inspection and mechanical integrity.
Innovation Solution
A process involving a glass processing machine that heats a glass tube to a temperature above its transition point, separates portions, and uses a mold matrix to form the glass bottom while gradually reducing the distance between the mold matrix and clamping chuck, allowing for direct contact and precise shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If molding tools are pressed against the molten glass mass to form the glass bottom, then dimensional tolerances are reduced and shape precision is improved, but grooves and irregularities appear on the glass bottom surface due to direct contact
Solution Approach 1:
An air cushion is introduced as an intermediary between the molding tool and the molten glass mass. The air cushion is generated by a blowing device that directs compressed air onto the glass bottom surface during the molding process. This allows the molding tool to maintain contact with the glass through the air medium, achieving precise shaping without direct mechanical contact that would cause grooves and surface irregularities.
2Object-affected harmful factors
If the glass bottom is formed in a contact-free manner, then surface quality is improved and grooves are avoided, but dimensional tolerances increase and shape precision deteriorates
Solution Approach 1:
The air cushion serves as a mediator that combines the benefits of both contact and contact-free methods. It provides enough support and pressure transmission to enable precise dimensional control while maintaining a gap between the molding tool and glass surface to prevent mechanical contact defects. The compressed air delivers controlled force distribution for accurate shaping without the drawbacks of direct mechanical contact.
3Manufacturing precision
If the distance between the mold matrix and clamping chuck is reduced for precise shaping, then manufacturing precision is improved, but the risk of mechanical contact and surface defects increases
Solution Approach 1:
The air cushion is introduced between the mold matrix and the glass bottom surface, allowing the mold matrix to be positioned close to the glass for precise shaping while preventing direct mechanical contact. The compressed air layer transmits the necessary forming pressure while eliminating the risk of surface defects caused by mechanical contact with the mold matrix or clamping chuck.
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 process achieves glass containers with reduced manufacturing tolerances, high mechanical stability, and improved optical inspection compatibility, minimizing defects and ejections in automated inspection.
Implementation Method 1
the tube in a certain region is heated by one or two separating gas burners until the heated mass of glass becomes deformable
Implementation Method 2
the final shape of the glass bottom is formed using molding tools, for example in the form of a stamp, that are pressed against the molten mass of glass
Implementation Method 3
the tube—under continuing rotation and heating by means of the burner—is extended in axial direction by means of a linear downwards movement of the lower chuck
Data Source
AI summary
A process for the preparation of a glass container from a glass tube in a glass processing machine includes the steps of: I) heating the glass tube at a defined position between a first portion and a second portion to a temperature above a glass transition temperature of the glass tube while the glass tube is rotating around its longitudinal axis Ltube and pulling apart the first portion and the second portion thereby separating the first portion from the second portion and forming a closed bottom at one end of the first portion; and II) moving a mold matrix of the glass processing machine towards the closed bottom and bringing the mold matrix into contact with the closed bottom. While bringing the mold matrix into contact with the closed bottom, a distance Ym between the mold matrix and a first clamping chuck of the glass processing machine is decreased stepwise.