Mold inserts for injection molding prototype applications fabricated via material extrusion additive manufacturing

Gohn, Anne M.; Brown, Dylan; Mendis, Gamini P.; Forster, Seth; Rudd, Nathan D.; Giles, Morgan

doi:10.1016/j.addma.2022.102595

Cited by 22 publications

(25 citation statements)

References 27 publications

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“…However, this surface smoothing does not improve demoldability in consecutive cycles nor does it improve the quality of the demolded PUR foam surface. It must be noted that recent works concluded that PLA filaments allow obtaining flat surfaces with lower Ra values between 7 mm and 35 mm (Golhin et al, 2023;Heshmat et al, 2023), confirming that the values obtained in the present study, both for Ra and Sa, are of normal quality for this material when processed by FFF.…”

Section: Evaluation Of Superficial Affectionsupporting

confidence: 91%

Manufacture of thermoplastic molds by fused filament fabrication 3D printing for rapid prototyping of polyurethane foam molded products

Guerrero-Vacas,

Gómez-Castillo,

Rodríguez-Alabanda

2024

RPJ

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Purpose Polyurethane (PUR) foam parts are traditionally manufactured using metallic molds, an unsuitable approach for prototyping purposes. Thus, rapid tooling of disposable molds using fused filament fabrication (FFF) with polylactic acid (PLA) and glycol-modified polyethylene terephthalate (PETG) is proposed as an economical, simpler and faster solution compared to traditional metallic molds or three-dimensional (3D) printing with other difficult-to-print thermoplastics, which are prone to shrinkage and delamination (acrylonitrile butadiene styrene, polypropilene-PP) or high-cost due to both material and printing equipment expenses (PEEK, polyamides or polycarbonate-PC). The purpose of this study has been to evaluate the ease of release of PUR foam on these materials in combination with release agents to facilitate the mulding/demoulding process. Design/methodology/approach PETG, PLA and hardenable polylactic acid (PLA 3D870) have been evaluated as mold materials in combination with aqueous and solvent-based release agents within a full design of experiments by three consecutive molding/demolding cycles. Findings PLA 3D870 has shown the best demoldability. A mold expressly designed to manufacture a foam cushion has been printed and the prototyping has been successfully achieved. The demolding of the part has been easier using a solvent-based release agent, meanwhile the quality has been better when using a water-based one. Originality/value The combination of PLA 3D870 and FFF, along with solvent-free water-based release agents, presents a compelling low-cost and eco-friendly alternative to traditional metallic molds and other 3D printing thermoplastics. This innovative approach serves as a viable option for rapid tooling in PUR foam molding.

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Section: Evaluation Of Superficial Affectionsupporting

confidence: 91%

Manufacture of thermoplastic molds by fused filament fabrication 3D printing for rapid prototyping of polyurethane foam molded products

Guerrero-Vacas,

Gómez-Castillo,

Rodríguez-Alabanda

2024

RPJ

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“…The injection-molding process provided a faster cooling rate compared with extrusion, which reduced the time and hindered the kinetics to allow for crystallization. Neat EVA has been shown under similar conditions to crystallize to a higher degree in extrusion compared with injection molding [21]. Within each subgroup, there appeared to be little effect on absolute crystallinity from CaCO3 particle size or shape at 50% loading, as no trends were apparent.…”

Section: Discussionmentioning

confidence: 94%

“…For the injection molding process, a barrel and hot sprue temperature of 180 • C, shot size of 14.5 mm, and injection velocity of 20 mm/s were used. The part geometry was filled to 95% of the maximum volume by shot size alone, then a holding pressure of 850 psi was Pharmaceutics 2022, 14, 1139 3 of 10 applied for 3 s to compensate for shrinkage during melt solidification [21]. To compare dissolution characteristics as a function of the manufacturing conditions, samples were also fabricated via single-screw extrusion.…”

Section: Methodsmentioning

confidence: 99%

Dissolution from Ethylene Vinyl Acetate Copolymer Long-Acting Implants: Effect of Model Active Ingredient Size and Shape

et al. 2022

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In recent pharmaceutical applications, an active pharmaceutical ingredient (API) can be mixed with a polymer material to yield a composite long-acting drug-delivery device. These devices boast higher patient compliance, localized drug delivery, and lower dosage concentrations, which can increase patient safety. As a laboratory-safe option, calcium carbonate (CaCO3) was used as a drug surrogate to mimic the release kinetics of a low-solubility API. The release of CaCO3 from a poly(ethylene vinyl acetate) (EVA) polymer matrix was studied in ultra-high-purity water. The geometry of CaCO3, along with the manufacturing technique, was manipulated to study the implications on surrogate drug release. It was found that injection molding proved to yield higher burst release, due to higher pressures achievable during manufacturing. The extrusion process can affect the surface concentration of the pharmaceutical ingredient when extruded through a water bath, resulting in a lower initial burst concentration. Regarding CaCO3 geometry, the particle size was more critical than the surface area in terms of CaCO3 release. Larger particles showed a higher release rate, though they also displayed higher variability in release. These data can be used to engineer specific release profiles when designing composite formulations and manufacturing methods for pharmaceutical-drug-delivery applications.

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“…Even though a number of micro-components can be fabricated using soft tooling, their production cannot be reliably assured without process characterisation as shown herein. High-resolution AM of soft tools is challenging because of the minimum feature size that can be achieved and mould-feature deformation during micromoulding (Bagalkot et al , 2019; Gohn et al , 2022). Hence, characterisation and development of rapid, soft-tooled μ-IM processes are essential for delivery and development of high-added value products in significantly reduced time frames.…”

Section: Introductionmentioning

confidence: 99%

Rapid tooling: investigation of soft-tooled micro-injection moulding process characteristics using in-line measurements and surface metrology

Gülçür

Couling

Goodship

et al. 2023

RPJ

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Purpose The purpose of this study is to demonstrate and characterise a soft-tooled micro-injection moulding process through in-line measurements and surface metrology using a data-intensive approach. Design/methodology/approach A soft tool for a demonstrator product that mimics the main features of miniature components in medical devices and microsystem components has been designed and fabricated using material jetting technique. The soft tool was then integrated into a mould assembly on the micro-injection moulding machine, and mouldings were made. Sensor and data acquisition devices including thermal imaging and injection pressure sensing have been set up to collect data for each of the prototypes. Off-line dimensional characterisation of the parts and the soft tool have also been carried out to quantify the prototype quality and dimensional changes on the soft tool after the manufacturing cycles. Findings The data collection and analysis methods presented here enable the evaluation of the quality of the moulded parts in real-time from in-line measurements. Importantly, it is demonstrated that soft-tool surface temperature difference values can be used as reliable indicators for moulding quality. Reduction in the total volume of the soft-tool moulding cavity was detected and quantified up to 100 cycles. Data collected from in-line monitoring was also used for filling assessment of the soft-tool moulding cavity, providing about 90% accuracy in filling prediction with relatively modest sensors and monitoring technologies. Originality/value This work presents a data-intensive approach for the characterisation of soft-tooled micro-injection moulding processes for the first time. The overall results of this study show that the product-focussed data-rich approach presented here proved to be an essential and useful way of exploiting additive manufacturing technologies for soft-tooled rapid prototyping and new product introduction.

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Mold inserts for injection molding prototype applications fabricated via material extrusion additive manufacturing

Cited by 22 publications

References 27 publications

Manufacture of thermoplastic molds by fused filament fabrication 3D printing for rapid prototyping of polyurethane foam molded products

Manufacture of thermoplastic molds by fused filament fabrication 3D printing for rapid prototyping of polyurethane foam molded products

Dissolution from Ethylene Vinyl Acetate Copolymer Long-Acting Implants: Effect of Model Active Ingredient Size and Shape

Rapid tooling: investigation of soft-tooled micro-injection moulding process characteristics using in-line measurements and surface metrology

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