Wackersdorf, Germany - small scale plastic injection molding

With an assembled solution, the highest quality standards for materials, geometry and dimensions can be realised in the extrusion process. This approach offers far greater possibilities when post-processing extruded tubing to expand the assembly into customised soft cannulas. Thus, for many modern drug delivery systems, there is no viable alternative to a customised assembled version of a soft cannula.

Injection moulding might presently be responsible of up to 90% of the processes GWP. However, the performance of all-electric IMMs like Shibaura Machine’s SXIII and EC-SX show this trend can be reversed, with positive effects on sustainability and also manufacturers’ bottom line.

Here, Dervish Ibrahim, international sales manager at TM Robotics, explains why all-electric injection moulding machines are the way forward for reducing the process’s environmental impact — while also helping manufacturers achieve a lower cost-per-part.

The Journal of Clean Production’s findings are a wake-up call to manufacturers, particularly as demand for injection moulding processes continue to grow. For example, the market for injection moulded medical devices plastics is expected to see booming growth between 2023 and 2030.

Certain designs, e.g. long versions of a soft cannula, cannot be realised through an injection moulding process but require the usage of the existing process and extruded tubes. In addition, certain dimensions and materials are not suitable for a moulding process, although the limitations are constantly changing.

Injection moulding machines powered by a hydraulic motor can produce higher energy levels and higher injection pressures, and the initial cost of the machine is lower. But there are also disadvantages with hydraulic machines. They include the machine’s high consumption of electric energy, because its hydraulic power is connected to an electric power unit that works at maximum capacity during every phase of the moulding process.

The single-mould soft cannula on the other hand reduces the necessary process steps. All process steps prior to the overmoulding such as tube extrusion, length cutting and the head forming of the tube can be eliminated.

All-electric moulding machines also have the edge when it comes to maintenance. With PLC controllability, injection moulding operations can be tie-into the production facilities Internet of Things (IoT) things systems. Data on the IMM’s performance can be collected through sensors and relaid to the plant’s enterprise resource planning (ERP) or manufacturing execution systems (MES) to support preventive maintenance, traceability and quality management.

Besides eliminating costly and time-intensive production steps, there’s another striking benefit to the single-mould technique; due to its monolithic character, there’s no critical interface between the soft cannula and the housing. This is a major advantage as it further minimises the risk of adverse effects such as leakage.

Central to this revolution of drug delivery systems is the soft cannula, a critical component designed for subcutaneous (“beneath the skin”) injections. It serves as the critical final piece that connects the patient to the device. From an engineering standpoint, soft cannulas offer the upside of being versatile, catering to a wide range of drug delivery systems as an integral component of both patch pumps and belt pumps, enhancing patient comfort – and minimising the risk of complications.

But there’s a challenge to this approach; the assembly technique for connecting a soft cannula to a distributor system is currently costly.

In the evolving landscape of drug delivery, wearable injectors stand at the forefront, combining medication administration with a high degree of precision and patient comfort. Among these advancements, patch pumps and belt pumps for subcutaneous injections have emerged as game changers.

The company relies on Shibaura Machine’s all-electric injection moulding machines (IMM) supplied by TM Robotics. The machine is manufactured in-house by Shibaura Machine, formerly known as Toshiba Machine. Performance benefits of the IMM include a range of clamping force from 50 to 2,500 tons, which can be calibrated by a digital direct screw transfer (DST) control for added production flexibility.

More than 90% of the costs of injection moulding can be attributed to energy use. This mainly applies to the electricity used to power and operate the injection moulding machine. As a result, there has been some debate in industry about the cost and sustainability advantages of hydraulic injection moulding versus all-electric machines.

To address these challenges, RAUMEDIC has filed a patent for a soft cannula manufactured in one piece. This development is designed to not only streamline the manufacturing process by reducing the complexity and number of parts, but also to minimise the risk of leakage.

Aside from performance advantages, injection moulding machines must also be easy to use. This guarantees Lotan’s team can stay on-track to meet their key performance indicators (KPIs) by controlling the equipment and keeping it running sustainably. That’s why SXIII range of injection moulding machines are equipped with Shibaura Machine’s user-friendly controller that connects to Lotan’s programmable logic controller (PLC) for simple, repeatable operations.

The soft cannula market could experience a major disruption due to a manufacturing approach that could make production safer and more cost-effective: manufacturing soft cannulas as a single-piece injection moulded part.

Although all-electric machines are initially more expensive with lower injection pressures, they are shown to outperform hydraulic versions in a variety of other ways. Advantages include higher rates and speeds of injection because the all-electric machining relies on toggle clamping rather than direct pressure clamping, which is better for high-speed injection moulding.

In addition, the aspect of enhanced safety, which is always the paramount criterion for medical and pharmaceutical applications, the economic aspect of cost minimisation is an advantage not to be neglected. In a world of shifting demographics and economic uncertainty, public healthcare spending is under constant scrutiny, and the pressure on budgets is only set to grow. That’s one of the reasons why RAUMEDIC decided to develop a single-mould soft cannula - the unit price could be lowered in a meaningful and measurable way, compared to the classic approach.

As RAUMEDIC is one of the few partners worldwide working to offer multiple manufacturing approaches for a fundamental cannula component, it is time to ask the most important question: will novel injection moulded soft cannulas, moulded in one piece, soon replace assembled and more complex “classic” soft cannulas? Answering this question requires a detailed look at the components, the manufacturing process, and the pros and cons of different soft cannulas.

Classic soft cannulas typically consist of multiple components. In the case of RAUMEDIC’s needle insertion system: short pieces of an extruded tube, being formed to the soft cannula, thermoplastic overmoulded housing, an integrated septum, and a closing clip, bringing it to a total of four components.

With RAUMEDIC’s development, a soft cannula manufactured in a single mould, the number of parts can be lowered to three components: the cannula from a single mould, a septum, and a clip. Thus, this approach allows the combination of two components and saves several steps in the process.

Indeed, Shibaura Machine’s all-electric IMMs have been found to yield energy savings of 60% compared with European hydraulic servo IMMs. Other performance tests by Shibaura Machine measured its EC650SX-61B IMM, with a clamping force of 650 tons, against a hydraulic servo machine. It delivered a 51% energy reduction.

RAUMEDIC, a German company specialising in customised polymeric solutions for medical and pharmaceutical applications, can produce soft cannulas the “classic” way - as an extruded tube that is finished when forming the tip and flaring the tube end. Additionally, the connection to the insertion system and the pump mechanism is done via overmoulding with appropriate thermoplastic materials.

But, what about the energy efficiency of all-electric versions hydraulically-powered machines? By using Shibaura Machine’s all-electric IMMs, Lotan has experienced 20 to 40% lower running costs compared with older-fashioned hydraulic machine. Traditional hydraulic injection moulding machines are also less efficient because they consume energy even while idle, whereas all-electric injecting machines only use energy while in action.

These devices simplify the management of diseases such as diabetes, a growing ailment affecting more than half a billion people worldwide – a number that is expected to grow by 46% by 2045. In the case of diabetes, novel devices are delivering insulin directly beneath the skin, offering an efficient and less invasive alternative to traditional injections.

In another instance, another EC-SX model, the 1,800 ton EC1800SX-155B, was tested against a competing all-electric IMM. Although both machines had the same energy consumption, the Shibaura Machine IMM delivered a faster cycle time, which gave overall energy efficiency savings of 30%.

According to the Journal of Clean Production, injection moulding may be responsible of up to 90% of the Global Warming Potential (GWP) created by the entire mould lifecycle, mainly caused by energy consumption.

Further advantages include improved dry cycle times and the overall stability of the mould itself. Lotan has ordered several more Shibaura Machine IMMs from TM Robotics, specifically its newest SXIII range of injection moulding machines. The SXIII is an enhanced performance model that provides significantly faster injection speeds than traditional moulding equipment. As a result, the machine offers a 35% faster cycle time than conventional hydraulic servo IMMs. Lotan also achieved a lower cost-per-mould.

Although hydraulic injection moulding machines are less expensive initially, it’s important to consider the whole life cost when buying new machines. This was demonstrated by TM Robotics’ customer Lotan, a manufacturer of plastic containers based in Leicestershire, UK. All of the injection moulding machines in Lotan’s production facility are electric, rather than hydraulic.

Injection moulding is used to manufacture a huge variety of parts, and has several advantages. They include the ability to mould a wide variety of plastics, good repeatability, consistently high production with low waste and a low-cost-per-part — the latter is always a priority.

Considering all the benefits of the approach of producing soft cannulas, this begs the question: will “classic” soft cannulas slowly but certainly disappear from the market, and become a museum piece to be examined with bewilderment by future MedTech professionals in the near future? The answer is a clear NO.

Maintaining a low cost-per-part throughout the manufacturing process is vital for reducing costs and delivering a higher product value — from both the manufacturer’s and the customer’s perspective. While injection moulding can support this, manufacturers are also concerned about the energy costs of injection moulding, and how this effects sustainability and the bottom line.

The manufacturing process of classic a soft cannula involves cutting the tubing into short sections, forming a tip according customer requirements, and then tailoring the back end into various geometries for further processing. The method requires high precision to ensure a form fitting connection between the cannula head and the housing during the overmoulding process.