A cost-effective process chain for thermoplastic microneedle manufacture combining laser micro-machining and micro-injection moulding

Gülçür, Mert; Romano, Jean–Michel; Penchev, Pavel; Gough, Tim; Brown, Edward A.; Dimov, Stefan Simeonov; Whiteside, Ben

doi:10.1016/j.cirpj.2021.01.015

Cited by 38 publications

(30 citation statements)

References 25 publications

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“…The latest additive manufacturing and 3D printing processes manufacturing is a great breakthrough for plastic gears manufacturing, but it is mainly used in small batch production [ 8 ]. At present, plastic gears are mainly manufactured by injection molding [ 9 , 10 , 11 ] because of its low production cost and short production cycle. The injection molding technology for conventional gears is mature and can basically meet the use requirements.…”

Section: Introductionmentioning

confidence: 99%

A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

2021

Polymers

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This paper was aimed at finding out the solution to the problem of insufficient dimensional accuracy caused by non-linear shrinkage deformation during injection molding of small module plastic gears. A practical numerical approach was proposed to characterize the non-linear shrinkage and optimize the dimensional deviation of the small module plastic gears. Specifically, Moldflow analysis was applied to visually simulate the shrinkage process of small module plastic gears during injection molding. A 3D shrinkage gear model was obtained and exported to compare with the designed gear model. After analyzing the non-linear shrinkage characteristics, the dimensional deviation of the addendum circle diameter and root circle diameter was investigated by orthogonal experiments. In the end, a high-speed cooling concept for the mold plate and the gear cavity was proposed to optimize the dimensional deviation. It was confirmed that the cooling rate is the most influential factor on the non-linear shrinkage of the injection-molded small module plastic gears. The dimensional deviation of the addendum circle diameter and the root circle diameter can be reduced by 22.79% and 22.99% with the proposed high-speed cooling concept, respectively.

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Section: Introductionmentioning

confidence: 99%

A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

2021

Polymers

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“…[178] Thus, the pressure exerted by individual needle tips may be insufficient to penetrate the skin so that a higher applied force is required. [179] Moreover, the inter-needle skin topology prior to puncture results in pressure reductions at the tips which also reduces their effectiveness in puncturing the skin with consequently reduced APE. [28] It is noteworthy that the number of MNs also affected the pain score, where a tenfold increase in MN projections increased the pain score just over twofold, [41] and also may result in reduction in drug permeability due to bed of nails effects.…”

Section: Geometrical Effectsmentioning

confidence: 99%

Microneedle Arrays for Drug Delivery and Diagnostics: Toward an Optimized Design, Reliable Insertion, and Penetration

Ebrahiminejad

Prewett

Davies

et al. 2022

Adv Materials Inter

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DDS can also be in the form of rapid parenteral intravenous, intramuscular, or subcutaneous delivery, which is suitable for emergency situations and mostly accompanied with pain, and hence not preferred by patients. [2,3] Inhalation drug delivery is a painless DDS method received through the lungs that is mainly used for respiratory diseases with the risk of overdosing upon self-administrations. [4] Another method of drug delivery is transdermal drug delivery through skin layers via application of creams, hypodermic needles, ultrasound, electroporation, iontophoresis, or use of microneedles (MNs). [4][5][6] In therapeutic monitoring, early stage diagnostics, efficiency of biological samples, timely analysis, non-invasiveness, and potential for self-administration are all highly desirable. [7] Point-of-care (POC) medical tests using MNs have the potential to provide rapid, minimally invasive, and real time diagnostics, [7] sampling either capillary blood or interstitial fluid (ISF) in competition with venous blood, breath, stool, and sputum. ISF has been shown to contain 83% of serum proteins, only 50% of which are found in serum, indicting the significance of ISF biomarkers for monitoring and diagnostics. [8,9] Therefore, ongoing pathophysiological events such as chronic conditions can be rapidly and painlessly detected using POC MN diagnostic systems enabling collection of ISF samples with unique biomarkers using MN systems. [10] Single MNs can be used as a painless alternative to steel hypodermic needles but they are more likely to be used as arrays of multiple MNs incorporated into diagnostic or therapeutic patches. [11] Their painless, non-invasive, and selfadministrative capabilities have received increasing attention in recent years. [12] Conventional hypodermic needles can induce pain, are semi-invasive, create hazardous wastes, and require trained medical staff for administration. Instead, minimally invasive MNs can be administrated without discomfort to the patient by bypassing the stratum corneum (SC) barrier of skin, [12][13][14] while avoiding contact with nerve system and blood vessels. It can be self-administrated and create less waste in comparison to the traditional hypodermic needles. [15][16][17] MNs are potentially capable of delivering ionic, hydrophilic, and large molecular weight drugs more effectively than passive diffusion using needle-free patches or topical creams. [18,19] Thus, MNs are an attractive candidate for delivery of drugs including insulins, growth hormones, proteins, siRNA, immunobiological,

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“…The product used in the present study is based on a 0.5-mmthick circular disc shape with 17 mm diameter which accommodates an array of microneedle cavities in 6×6 configuration in a μIM tool as discussed in our previous study [2,22]. The quality proxy of the moulded products in this work has been defined as the microreplication efficiency of the microneedle features (M μ ) obtained from each part or manufacturing cycle.…”

Section: Part Design and Process Detailsmentioning

confidence: 99%

“…Pressure sustained during at any stage of μIM is of importance and can be a reliable process quality indicator [8,22,24]. Viscosity of a polymer can be considered as resistance to flow, and higher viscosities result in bigger pressure drops in polymer processing.…”

Section: Derived Process Fingerprints (Dpfs)mentioning

confidence: 99%

A study of micromanufacturing process fingerprints in micro-injection moulding for machine learning and Industry 4.0 applications

Gülçür

Whiteside

2021

Int J Adv Manuf Technol

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This paper discusses micromanufacturing process quality proxies called “process fingerprints” in micro-injection moulding for establishing in-line quality assurance and machine learning models for Industry 4.0 applications. Process fingerprints that we present in this study are purely physical proxies of the product quality and need tangible rationale regarding their selection criteria such as sensitivity, cost-effectiveness, and robustness. Proposed methods and selection reasons for process fingerprints are also justified by analysing the temporally collected data with respect to the microreplication efficiency. Extracted process fingerprints were also used in a multiple linear regression scenario where they bring actionable insights for creating traceable and cost-effective supervised machine learning models in challenging micro-injection moulding environments. Multiple linear regression model demonstrated %84 accuracy in predicting the quality of the process, which is significant as far as the extreme process conditions and product features are concerned.

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A cost-effective process chain for thermoplastic microneedle manufacture combining laser micro-machining and micro-injection moulding

Cited by 38 publications

References 25 publications

A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

Microneedle Arrays for Drug Delivery and Diagnostics: Toward an Optimized Design, Reliable Insertion, and Penetration

A study of micromanufacturing process fingerprints in micro-injection moulding for machine learning and Industry 4.0 applications

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