Glass Vial Hot Forming Diameter Reduction
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Solution Overview
Problem
Conventional methods for producing pharmaceutical glass bottles result in high alkali release and delamination issues due to the volatilization of alkali borate components during the hot forming process, leading to suboptimal container quality for pharmaceutical use.
Innovation Solution
The method involves reducing the glass tube diameter by pressing a molded part onto the softened area before separation, allowing for lower temperatures and shorter processing times, thereby minimizing alkali borate evaporation and delamination risks, and using a rotating drive and tungsten alloy or electrographite shaped bodies to enhance diameter reduction and wetting behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass tube is heated to high temperature during hot forming, then the glass becomes deformable and can be shaped, but alkali borate components volatilize and deposit on the inner surface causing delamination and high alkali release
Solution Approach 1:
The patent applies preliminary action by reducing the diameter of the glass tube in the heated area before separation occurs. A molded part is pressed onto the softened glass tube to reduce its diameter, creating a constriction that facilitates cleaner separation. This preliminary diameter reduction allows the separation to happen at lower temperatures and shorter times, preventing alkali borate volatilization and delamination while still achieving successful bottle formation
Solution Approach 2:
The patent changes the physical parameters of the glass tube during processing. Specifically, the diameter of the glass tube in the heated area is reduced by pressing a molded part onto it, transforming the glass from its original state to a constricted state that enables cleaner separation. This parameter change (diameter reduction) allows the process to proceed at lower temperatures and shorter durations, resolving the contradiction between achieving glass deformability and preventing alkali release
2Manufacturing precision
If the glass tube is held at high temperature for extended period to ensure complete forming, then shaping is achieved, but alkali borate evaporation increases leading to higher alkali release
Solution Approach 1:
The diameter reduction is performed as a preliminary action before the final separation step. By pressing the molded part onto the softened glass tube to create a constriction first, the subsequent separation can occur more quickly and at lower temperatures. This preliminary constriction ensures that the glass has already begun to take the desired shape, allowing the process to be completed faster and with less alkali borate evaporation
Solution Approach 2:
The patent applies the 'rushing through' principle by significantly reducing the separation time. The molded part is pressed onto the glass tube to create a constriction that enables rapid separation. This rushed-through approach minimizes the time the glass spends at high temperature, thereby reducing alkali borate evaporation while still achieving complete forming through the combination of preliminary heating and快速 separation
3Ease of manufacture
If conventional hot forming process is used, then glass bottles can be produced, but delamination occurs due to deposited alkali components on the glass surface
Solution Approach 1:
The molded part is pressed onto the softened glass tube as a preliminary action to create a constriction and reduce the diameter in the heated area. This preliminary shaping action allows the subsequent separation to occur cleanly with minimal glass wall melting and alkali component deposition, thereby preventing delamination while maintaining ease of manufacture
Solution Approach 2:
The patent changes the diameter parameter of the glass tube in the heated area by pressing a molded part onto it. This parameter change creates a constricted geometry that facilitates cleaner separation with less glass wall melting. The diameter reduction transforms the separation process from one that causes delamination to one that maintains glass surface quality, while the overall process remains easy to manufacture
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 approach significantly reduces alkali release and delamination tendencies, resulting in glass bottles with improved uniformity and reduced sodium content, meeting stringent ISO 4802 standards for pharmaceutical applications.
Implementation Method 1
The rotating glass tube is heated in a certain area by one or two cutting burners to such an extent that it becomes deformable
Implementation Method 2
This causes the pipe to expand in the warm-up area while simultaneously narrowing its diameter
Implementation Method 3
The glass tube contracts further at the constriction area due to the flow pressure of the burner gases, so that the glass wall melts together in the heating area
Implementation Method 4
reducing the diameter by pressing at least one molded part onto the softened area
Data Source
Figure 1a~2h
Figure 3
Figure 4
AI summary
A method for producing glass vials, in particular pharmaceutical vials or pharmaceutical ampoules, from a glass tube is specified, said method having the following steps of: (a) rotating the glass tube (10) about the longitudinal axis (12) thereof; (b) locally heating the glass tube (10) from one side by means of at least one burner to at least the softening temperature (Ew) of the glass; (c) reducing the diameter by pressing at least one shaped part (28a) laterally against the heated region (16); and (d) separating the glass tube by means of a burner (14). A glass vial produced in such a way releases a reduced amount of alkali in accordance with ISO 4802 and has a decreased delamination tendency. Furthermore, in the hot-formed peripheral region, the alkali content is only slightly reduced compared with the alkali content in the glass interior.