A comparison of predictive control strategies for a highly segmented injection mold tempering

Hopmann, Christian; Kahve, Cemi; Schmitz, Mauritius; Röbig, Malte

doi:10.1016/j.polymer.2021.123494

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…[ 49 ] Additionally, controlling the mold temperature and managing the pressure drop inside of the mold are also important factors affecting shrinkage. [ 50 ] Due to the secondary crystallization process occurring in P(3HB ‐co‐ 3HHx) during ageing, shrinkage of the specimens takes place during this period. For conditions 40–80, the observed shrinkage is 1.33%.…”

Section: Resultsmentioning

confidence: 99%

Commercial Grade of P(3HB‐co‐3HHX) Final Properties Adjustment by the Modification of Cooling Conditions in the Injection Molding and Ageing Process

Ivorra‐Martinez,

Gomez‐Caturla,

Peydro

et al. 2024

Macro Materials & Eng

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Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) is a polymer obtained by bacterial fermentation that emerges as an alternative to polymers of petrochemical origin. The complex crystallization kinetics that occurs over 15 days after melting, known as ageing, limits its industrial application. During the aging process, there is a change of the degree of crystallinity, which has an effect on the chemical structure of the material. Additionally, changes in the mechanical properties, colorimetry, and dimensional shrinkage are observed. Different material properties are observed depending on the cooling conditions employed. For the ageing process, two different conditions are considered: ageing at room temperature and annealing at high temperature (60 °C).

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Section: Resultsmentioning

confidence: 99%

Commercial Grade of P(3HB‐co‐3HHX) Final Properties Adjustment by the Modification of Cooling Conditions in the Injection Molding and Ageing Process

Ivorra‐Martinez,

Gomez‐Caturla,

Peydro

et al. 2024

Macro Materials & Eng

View full text Add to dashboard Cite

show abstract

“…To protect the ceramic heating element from large thermal stresses, a copper shield is built-in under the heating ceramic, Figure 1, right. In addition, liquid carbon dioxide with a temperature of about À 78 °C can be injected into the expansion chamber for cooling [14,15]. The ribbed surface of the copper shield enhances the heat transfer induced by the evaporation of liquid carbon dioxide in the expansion chamber, effectively increasing the surface area for thermal exchange.…”

Section: Mold Concept For Local Dynamic Controlmentioning

confidence: 99%

“…In addition, zones 2, 5, and 8 are equipped with a special combination of infrared and piezoelectric pressure sensors to measure the cavity pressure along the melt flow path. Furthermore, each sensor has a built-in thermocouple that measures the cavity wall temperature [14,15].…”

Section: Mold Concept For Local Dynamic Controlmentioning

confidence: 99%

“…This horizon is necessary for the control of the part properties, since approximately three seconds elapse until the temperature changes on the mold surface, due to the mold's large thermal mass. Together with the infrared and pressure measurements as well as semi‐empirical pvT‐models, the specific volume becomes calculable and controllable, which was subject to many previous works [14–16].…”

Section: Mold and Control Concept For Local Dynamic Temperature Controlmentioning

confidence: 99%

“…This work therefore aims modify local temperatures, such that melt properties can be homogenized to reduce stresses, eliminating part warpage for different materials. In our previous works, we demonstrated that a model predictive control yielded parts with significantly higher control accuracy and reproducible part warpage compared to a PID-controller [14,15]. Since the model predictive control is based on a self-developed simulation of the part temperature (based on Fourier's law in one dimension), the same input parameters always result in the same output parameters for the power to control the temperature (see discussion in Section 2.3).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of a self‐optimizing local mold temperature control for inline warpage reduction of injection molded parts

Hopmann,

Kahve,

Fritsche

et al. 2024

Materialwissenschaft Werkst

Self Cite

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Dimensional accuracy is a highly important quality criterion for injection molded parts and due to the decreasing tolerance criteria an ongoing issue for mold makers, part designers and manufacturers. Variations in the molding process regarding temperature, pressure and thus the specific volume are leading to inner stress distributions within the part, which ultimately cause warpage. To reduce warpage, a homogenization of the local melt properties, such as the temperature, cooling rate or specific volume is necessary. To be able to manipulate these melt properties locally, a mold with a highly segmented temperature control, consisting of 18 heating ceramics and carbon dioxide expansion chambers was designed. This work seeks to reduce warpage using a newly developed control loop that adjusts target values for the upcoming molding cycle while considering the control error of the previous cycle. The self‐optimizing control loop‐ aiming to homogenize the local mold temperatures over multiple cycles‐ was evaluated in experimental trials. Test specimens were produced, and measured for warpage. Compared to the reference (no control), the warpage of a plate‐shaped geometry was reduced by 10 % with the mold temperature homogenization approach.

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In-mold condition-centered and explainable artificial intelligence-based (IMC-XAI) process optimization for injection molding

Gim,

Lin,

Turng

2024

Journal of Manufacturing Systems

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A comparison of predictive control strategies for a highly segmented injection mold tempering

Cited by 5 publications

References 8 publications

Commercial Grade of P(3HB‐co‐3HHX) Final Properties Adjustment by the Modification of Cooling Conditions in the Injection Molding and Ageing Process

Commercial Grade of P(3HB‐co‐3HHX) Final Properties Adjustment by the Modification of Cooling Conditions in the Injection Molding and Ageing Process

Evaluation of a self‐optimizing local mold temperature control for inline warpage reduction of injection molded parts

In-mold condition-centered and explainable artificial intelligence-based (IMC-XAI) process optimization for injection molding

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