Continuous Injection Molding for Profile Length Control
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Solution Overview
Problem
Existing methods for producing elongated profiles or strips from solidifying molding compounds are limited in producing high-quality profiles of defined lengths, as they often result in restricted geometry and inconsistent quality due to the conventional injection molding process.
Innovation Solution
The method involves filling only the end section of the mold cavity initially, with a free melt front opposite the upper mold part, and using a temperature control element to maintain the melt front temperature, allowing continuous injection and expansion of the profile length while ensuring problem-free flow and high-quality formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection molding is used to fill the entire mold cavity at once, then the production cycle is short, but the profile geometry is restricted and quality is inconsistent
Solution Approach 1:
The mold cavity is divided into a closed end section and an open longitudinal section. The closed end section allows for controlled injection and defines the start of the profile, while the open longitudinal section allows the profile to extend freely. This segmentation enables better control over the injection process and profile formation, improving geometry and quality without requiring overly complex mold structures.
Solution Approach 2:
The mold design allows the profile to be continuously lengthened during injection by moving the profiled mold insert relative to the sprue insert. This dynamic approach enables the profile to grow in length continuously rather than being fixed, improving geometric flexibility and quality while maintaining manageable mold complexity.
2Manufacturing precision
If the entire mold cavity is filled simultaneously, then the injection process is simple, but the melt front temperature control is poor resulting in quality issues
Solution Approach 1:
Temperature control is applied locally at the melt front through the temperature control element positioned in the closed end section. This localized temperature management ensures the melt front remains at the optimal temperature for high-quality surface formation, while the rest of the injection process remains relatively simple. The local quality principle allows precise control where needed without complicating the entire process.
Solution Approach 2:
The closed end section is prepared in advance with temperature control elements and gating structures that pre-condition the molding compound before it enters the open longitudinal section. This preliminary action ensures the melt is properly prepared and temperature-controlled before the main injection, improving surface quality while keeping the overall process straightforward.
3Adaptability or versatility
If profiles are produced with restricted geometry in conventional molds, then the mold structure is simple, but the profile length and geometry flexibility are limited
Solution Approach 1:
The profiled mold insert is designed to move relative to the sprue insert in the longitudinal direction during injection. This dynamic configuration allows the profile to be continuously lengthened and produces profiles with enhanced geometric flexibility. The movable components enable adaptability in profile length and geometry while maintaining a relatively simple overall mold structure.
Solution Approach 2:
The invention transitions from traditional fixed cavity molds to a system where the profile extends in the longitudinal dimension with a distinct open section. This dimensional approach allows profiles of varying lengths to be produced by controlling the relative movement distance, providing geometry flexibility without requiring completely different mold structures for each profile size.
4Length of moving object
If continuous injection is used to lengthen profiles during transport, then profile length flexibility is improved, but temperature control of the melt front becomes critical
Solution Approach 1:
Temperature control is concentrated at the melt front through the temperature control element in the closed end section, rather than attempting to control temperature throughout the entire profile. This localized approach ensures the critical melt front region maintains stable temperature during continuous injection and profile lengthening, enabling profile length flexibility without compromising temperature stability.
Solution Approach 2:
The temperature control element is positioned to pre-heat or maintain the melt front temperature before the molding compound enters the open longitudinal section. This preliminary temperature management ensures the melt remains at the correct temperature during the continuous injection and profile extension process, allowing flexible profile length control while maintaining temperature stability.
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 enables the production of high-quality profiles or strips of defined lengths with improved geometry and surface quality by maintaining the melt front temperature and controlling the injection process, resulting in enhanced product quality and flexibility in profile length production.
Implementation Method 1
the front section behind the sprue point of the molding compound remains positioned as a free front portion opposite the upper mold part during the relative movement of the mold components by the process pressure
Data Source
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AI summary
The invention relates to a method for producing elongated profiles or strips (21) from hardened moulding compounds in a mould comprising at least one lower mould part and at least one upper mould part, with continuous injection of moulding compound (20) into a cavity (4), wherein, as the continuous lengthening of the profile or strip (21) that is formed progresses, injected moulding compound (20) is transported away from the feed point or points and out of the mould by a relative movement of the mould components, and wherein the moulding compound (20) is injected until the profile or the strip (21) has reached its intended length. To allow profiles and strips of a particularly high quality to be produced, at the beginning of injection the moulding compound (20) fills an end portion (4a) of the mould cavity (4) that is closed in the exiting direction of the profile or strip (21) to be formed, to behind the feed point (3), wherein, behind the feed point (3), the front portion of the moulding compound (20) remains positioned as a free front portion (20a) with respect to the upper mould part during the relative movement of mould components as a result of the process pressure, wherein the mould cavity (4) is filled while the moulding compound (20) is being transported away from the feed point (3) and out of the mould.