PRA January-February 2014 Feature-Hot Runners

Injection Moulding Asia Hot Runners

The importance of accurate temperature control for medical moulding

By Matthew Cummings, Product Manager, Altanium, Husky Injection Molding Systems

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he medical market is driven by complex applications that require reliable, repeatable moulding solutions. For medical moulders who must quickly and consistently manufacture high quality parts using difficultto-mould resins, as well as complex tooling that hold extreme tolerances, this leaves little room for error.

An ageing population and increasing demand for disposable medical devices present significant short and long-term opportunities for medical manufacturers of plastics components. But while medical moulding is a growing market, it is also a challenging industry characterised by lengthy product development processes, many clinical trials, demanding record keeping practices and greater regulatory oversight than other industries. These increased regulations are for the purpose of driving part quality, process stability and risk mitigation as a means to eliminate part failure and possible injury or death of patients. Maintaining the most accurate and repeatable temperature control in a moulding operation is key to producing high quality, highly complex medical parts consistently and reliably.

Husky Injection Molding System’s newly introduced Altanium Delta3 hot runner controller is specifically designed to provide solutions to help comply with the medical industry’s stringent requirements. Accurate and repeatable temperature control with minimised

cavity-to-cavity and shot-to-shot variability is a key aspect of part quality and process stability. Altanium Delta3 delivers on this through the deployment of Active Reasoning Technology, also known as ART. Requiring no intervention by the user, ART is able to generate a parameter set to precisely fit each zone’s unique thermal response characteristics.

Once the optimal control algorithm has been calculated, it utilises a modulation method that delivers a rapid, uniform flow of power, minimising the amount of time that energy is not being delivered to heaters.

Using a technique known as oversampling, the integrity of the temperature signal is preserved, allowing the algorithm to execute power changes based on It deploys repeatable the most accurate data. temperature control with Additionally, isolated minimised cavity-to-cavity and thermocouple inputs shot-to-shot variability using assure the reliability of Active Reasoning Technology incoming temperature measurement by providing a high degree of immunity to electrical noise. This eliminates the potential risk associated with electromagnetic interference emitted by the servo motor systems found on all electric moulding machines. The outcome is the industry’s most accurate and repeatable temperature control, regardless of the hot runner system or processing environment.

There are times when it is necessary for the controller to stop heating the mould or circumstances that require the machine to stop cycling. If this occurs, material could degrade, resulting in bad parts entering into the

Delta3 hot runner controller with 24 zones

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Hot Runners downstream process. Altanium Delta3 provides the following interlocks to mitigate this risk: • At-Temperature Output – Inhibits injection until the mould is at processing temperature • PCM Output – Stops the injection moulding machine from cycling if the controller stops heating the mould • Remote Standby Input – Brings the processing setpoint to a lower temperature if the machine stops cycling This connectivity enables the machine and controller to make informed decisions, based on the state of the other, which provides assurance against defective parts reaching end users.

Other aspects of medical manufacturing include rigid documentation of the process, including any changes or deviations from the original parameters used during the mould Users can access and monitor up to 50 controllers connected to a qualification. Altanium Delta3 ensures these network parameters are retained by permanently storing single view to better understand the effects of them in a set-up file that is available for recall the process and thermal relationship between at the press of a button. To further enhance zones. All of these variables are tracked through this capability, there is an optional remote load the process targets screen and compared against function that allows the corresponding mould specification limits tied to thresholds that, if set-up in the controller to be loaded from the violated, trigger an alarm and digital output injection moulding machine. The system also to alert operators to an issue while halting the supports a wide range of file types for storing molding operation or diverting the parts moulded and managing critical documentation right from during the last cycle. the controller’s screen. These can be imported or Finally, there is a stand-alone program exported over a network or using a thumb drive. available that allows Altanium Delta3 also a user to access and provides several process “….Delta3 also provides monitor up to 50 monitoring features, making it a powerful tool several process monitoring controllers connected to a network. This for analysing the system, features, making it a server based application optimising the moulding process, tracking errors, powerful tool for analysing provides a dashboard view of all connected and finding the source of a the system…..” systems with the ability recent error or predicting to drill down to the where future errors may details of individual zones. Since it is a browseroccur. Altanium Delta3’s event log contains based program, it is accessible from any weba complete record of all user interactions so enabled device that supports Internet Explorer that each step leading up to an issue can be 9, Chrome, Firefox or Safari. This allows all followed. Additionally, the process history controllers on the plant floor to be remotely screen provides a visual summary of a mould’s monitored locally and in real-time within the recorded operation to map the behaviour of the same factory or by off-site personnel anywhere system at the time of the error and search for around the world. potential causes. This data can be exported in For moulders who must produce the most a common file format and stored externally or precise, highly complex medical parts, Altanium used to create custom reports to further satisfy Delta3 provides the ideal platform for achieving documentation requirements. For issues related better part quality and process stability while to events occurring in real-time, the process mitigating the risk of bad parts entering the trend screen plots data as it occurs and provides supply chain. a graphical comparison of multiple zones in a 3 JANUARY / FEBRUARY 2014

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