TECHNOLOGY | MEDICAL
Automated overmoulding of syringe needles
US injection moulder Moldworx has devel- oped a process for the production of hypo- dermic needles using the overmoulding process to reduce costs and improve produc- tivity. The company says that it can design and build moulds to inject medical grade plastic around stainless steel needles as small as 0.012 in (0.305 mm), as well as the automation for this project. Moldworx was asked by a medical OEM to develop a single cavity injection mould to overmould a needle that is currently being glued in place. The first stage involved designing and developing an A-Series, single cavity injection mould with slides, with the needle being hand-loaded into the mould by an operator then moulded to a finished assembly to test the design. The next stage was designing a production mould and automation that would robotically feed the needles into the mould cavity, thus eliminating the operator. One challenge that Moldworx had to overcome was singulating
thousands of tiny needles that are bulk- packed. To do this, it designed and developed a ‘singulator’ with a ‘hopper’ that would introduce one needle at a time in the cell. Each needle is picked up by a robot and indexed in front of a set of high resolution inspection cameras. The needle is then placed into the mould, and the mould closes for the injection cycle. The robot removes the moulded assembly and the process repeated with all actions undrgoing inspection and verification. After successfully completing the single- cavity mould and automation, with customer testing and approving the parts, Moldworx built a multi-cavity mould with the required integrat- ed automation cells. The 4-cavity production mould will quadruple the automation cell production to keep up with required demand.
Moldworx developed the
automated process to reduce costs and improve productivity
precise injection control, together with smoother mould and ejector movements. The lifecycle of equipment and total cost of ownership are also big considerations.” At K2019, Sumitomo (SHI) Demag will unveil its
latest IntElect S medical machine, which has been specifically built to handle extremely narrow tolerance medical applications produced in high volumes, without having to invest in a larger machine to accommodate larger multi-cavity tool sizes. The 180-tonne IntElect S has an extended tie bar distance in order to fit larger multi-cavity moulds and matched to the smaller injection unit. Flowers says this is especially beneficial for preci- sion medical moulders. The 180-tonne IntElect S is GMP-compliant, with the layout of the mould space featuring special stainless steel covers to ensure it is clear of contaminants, particles and lubricants. In order to enhance patient safety, there is a drive towards using new and more innovative regulated materials with a better flow and high impact strength to mould components. “This is in order to meet future EU regulations, including the EU Medical Device regulations that come into effect 26 May 2020, as well as the In Vitro Diagnostic
62 INJECTION WORLD | September 2019
medical device regulations (known as IVDR) that are effective 26 May 2022,” adds Flowers. “The demon- stration at K2019 will showcase the moulding of pipette tips on a 64 cavity mould tool in partnership with Borealis. Bormed BJ868MO is a PP copolymer that was developed for the express purpose of enabling healthcare customers to achieve full compliance with MDR and IVDR when an antistatic agent is not required. The stiffness of the material delivers improved cycle time optimisation.” Flowers notes the suitability of the IntElect machines for medical micro-moulding thanks to the ability to install small screws, matched with a large mould space which improves the dosing and injection performance. This is made possible by the IntElect’s highly dynamic direct drive technology, which enables the acceleration of the injection speed to fill 64 cavities with precision. Another driver in medical injection moulding is item-level traceability, with new directives just around the corner, according to Flowers. “As a high liability market, authentication of individual components requires a fingerprint style approach to traceability,” he says. “Real-time traceability is about being able to call up data and verify the
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PHOTO: MOLDWORX
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