In the last years, needle-free injection systems were created to solve problems related to the presence of a steel needle for inject a medical fluid. A needle-free syringe has, first of all, the advantage of generating painless injections due to the high speed of the thin fluidic needle produced by its orifice at the tip. The easiest way to provide the required thrust for inject is by means of a compression spring, but in the state of the art technology some drawbacks and room for improvements has been found: integrating the loading system inside a single device, have a pressure control on the patient skin to ensure a complete medical fluid injection without any leakage and a integrated lock system preventing any undesired injection without the user control. The ease of use had to be a main feature for this new device and least but not last, it had to be reasonably small and aesthetically pleasant. During the very first design step, problem solving techniques based on the Theory of Inventive Problem Solving (TRIZ) were applied to explore possible solutions and overcome technical problems. Patent search was performed to acquire inspiration from the state-of-the-art solutions and avoid any future patent infringement. During the nest design steps for the first prototype, Autodesk Inventor Professional wand used for the mechanical design and subsequently Design for X (DfX) techniques were used for simplify and drive the final assembly toward a manufacturable and workable product. Structural validations of the critical components were performed with a preliminary analytical approach, where possible, and with Finite Elements simulations using Abaqus CAE. The FEM validation was focused on maximum stress static assessment with convergence analysis, calculation of safety factor and fatigue assessment. After creating the components, the mechanical and electrical parts were assembled in the laboratory of Dondi Ingegneria S.r.l.; and finally the first prototype was tested. These tests showed that required effort for load the system was moderated and the device had the capability of exert the necessary thrust to create a fluidic needle and inject the fluid.
Negli ultimi anni, i sistemi d'iniezione senz'ago sono stati creati per risolvere problemi legati alla presenza di un ago d'acciaio per iniettare un fluido medico. Una siringa senz'ago ha, prima di tutto, il vantaggio di generare iniezioni indolori grazie all'alta velocità del sottile ago fluidico prodotto dal suo orifizio in punta. Il modo più semplice per fornire la spinta necessaria per iniettare è per mezzo di una molla di compressione, ma nello stato dell'arte della tecnologia sono stati trovati alcuni inconvenienti e spazio per miglio�ramenti: integrare il sistema di caricamento all'interno di un unico dispositivo, avere un controllo della pressione sulla pelle del paziente per garantire un'iniezione completa di fluido medico senza alcuna perdita e un sistema di blocco integrato che impedisca qualsiasi iniezione indesiderata senza il controllo dell'utente. La facilità d'uso doveva essere una caratteristica principale per questo nuovo dispositivo e, ultimo ma non meno importante, doveva essere ragionevolmente piccolo ed esteticamente piacevole. Durante la primissima fase di progettazione, sono state applicate tecniche di problem solving basate sulla Teoria della Soluzione dei Problemi Inventivi (TRIZ) per esplorare possibili soluzioni e superare i problemi tecnici. La ricerca dei brevetti è stata eseguita per acquisire ispirazione dalle soluzioni allo stato dell'arte ed evitare qualsiasi futura violazione brevettuale. Durante le fasi di progettazione del primo prototipo, Autodesk Inventor Professional è stato utilizzato per la progettazione meccanica e successivamente sono state utilizzate tecniche di Design for X (DfX) per semplificare e guidare l'assemblaggio finale verso un prodotto fabbricabile e funzionante. Le validazioni strutturali dei componenti critici sono state eseguite con un approccio analitico preliminare, dove possibile, e con simulazioni agli elementi finiti utilizzando Abaqus CAE. La validazione FEM si è concentrata sulla valutazione statica dello sforzo massimo con analisi di convergenza, calcolo del fattore di sicurezza e valutazione della fatica. Dopo aver creato i componenti, le parti meccaniche ed elettriche sono state assemblate nel laboratorio della Dondi Ingegneria S.r.l.; ed infine il primo prototipo è stato testato. Questi test hanno mostrato che lo sforzo richiesto per caricare il sistema era moderato e il dispositivo aveva la capacità di esercitare la spinta necessaria per creare un ago fluidico e iniettare il fluido.
Design and prototyping of a medical device for needle-less injections
Bondioli, Luca
2021/2022
Abstract
In the last years, needle-free injection systems were created to solve problems related to the presence of a steel needle for inject a medical fluid. A needle-free syringe has, first of all, the advantage of generating painless injections due to the high speed of the thin fluidic needle produced by its orifice at the tip. The easiest way to provide the required thrust for inject is by means of a compression spring, but in the state of the art technology some drawbacks and room for improvements has been found: integrating the loading system inside a single device, have a pressure control on the patient skin to ensure a complete medical fluid injection without any leakage and a integrated lock system preventing any undesired injection without the user control. The ease of use had to be a main feature for this new device and least but not last, it had to be reasonably small and aesthetically pleasant. During the very first design step, problem solving techniques based on the Theory of Inventive Problem Solving (TRIZ) were applied to explore possible solutions and overcome technical problems. Patent search was performed to acquire inspiration from the state-of-the-art solutions and avoid any future patent infringement. During the nest design steps for the first prototype, Autodesk Inventor Professional wand used for the mechanical design and subsequently Design for X (DfX) techniques were used for simplify and drive the final assembly toward a manufacturable and workable product. Structural validations of the critical components were performed with a preliminary analytical approach, where possible, and with Finite Elements simulations using Abaqus CAE. The FEM validation was focused on maximum stress static assessment with convergence analysis, calculation of safety factor and fatigue assessment. After creating the components, the mechanical and electrical parts were assembled in the laboratory of Dondi Ingegneria S.r.l.; and finally the first prototype was tested. These tests showed that required effort for load the system was moderated and the device had the capability of exert the necessary thrust to create a fluidic needle and inject the fluid.| File | Dimensione | Formato | |
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Design and prototyping of a medical device for needle-less injections_LUCA BONDIOLI.pdf
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https://hdl.handle.net/10589/186104