19 May 2022

OPC-UA interface optimises liquid silicone rubber processing

State-of-the-art elastomer injection moulding system with brand-new SAM-C robot


At Fakuma 2021 (October 2021), Sumitomo (SHI) Demag presented a fully optimised and automated elastomer injection moulding system and liquid silicone rubber (LSR) production cell developed for tight tolerance automotive applications.

The LSR package features a fully automated Nexus metering system on an all-electric IntElect 130/520-450. All is integrated seamlessly with the company’s new own-branded SAM-C kinematic robotic system and meeting the new 2021 OPC-UA 40082-3 standard for LSR dosing systems to optimise and control and processing stability on automotive applications.

The demonstration featured the production of a complex, freeform automotive axial seal, designed to be moulded using a ‘direct gate’ without material closure. Produced using a Nexus two-plate tool, a retainer keeps the seal component stable on the ejector side. A silicone rubber, Elastosil LR3003/50 from Wacker Chemie, has been selected. It has a temperature range of -55 to +210°C and a Shore A hardness of 50.

In addition to the automotive industry, freeform seals are also used for electronic components in consumer goods and electronic products. Silicone rubbers are heat-resistant, retain flexibility when cold and shouldn’t age when exposed to UV and air etc. They are easy to process and have good mechanics that remain stable over a wide temperature range. Additionally, they are tasteless and biologically inert.

“The sealing lip must be completely pronounced to offer full functionality,” explained Henrik Langwald, Director Automotive & Electronics. “We are setting a new benchmark to repeatably mould the tightest tolerances in 16 cavities, burr-free, with no conversion.”

The LSR exhibit demonstrates the importance of using robotics to eliminate component contamination and consequent product impairment. Developed in-house by Sumitomo (SHI) Demag, the newly launched SAM-C ‘handle & place’ Cartesian robot, then removes and stores the part. It is designed specifically for injection moulding machines with clamping force sizes between 50 and 500 tons, and for standard applications with cycle times of 10s and higher. This involves working with a cold runner needle closure system and direct injection. The tool concept includes interchangeable inserts.

As a result of the high precision processing, stability is maintained to deliver the optimal sealing requirements so critical for automotive safety.

An important component is the ServoMix Z200 metering system from Nexus. “The system is unsupported and the barrel can be swiftly and safely changed in less than 5min from an angle of up to 104°,” reports Langwald. “This provides easy and faster access for cleaning and maintenance, as well as helping to eliminate human errors.”

Additionally, the metering system features numerous interfaces, including the TrueFlow Nano colour control to ensure precise dosing of colour additives, and a calibration function.

The flowmeter design features a quick-change pump body with measuring cells located directly on the pump body. This is especially relevant in the medical sector. Another advantage of this design is faster cleaning of the injection moulding screw.

All new dosing devices now feature the newly-released OPC-UA interface, directly linking metering measurement data of with the IntElect 130/520-450 processing data, ensuring a fully traceable and stable production process. “The timeshot or balancing system in the mould can be mirrored by the injection moulding machine via VNC,” adds Langwald.

Compared to hydraulic systems, the newest ServoMix models report low energy consumption. They work more sustainably, and there is much less waste and material consumption. By regulating the flow rate according to actual requirements, users can save up to 70% of the energy consumption, while material losses due to residual quantities in the barrel amount to less than 0.3%.

The drive system of the IntElect is developed in-house. The frequency inverters and the entire servo motor control system make it one of the most efficient injection moulding machines. “Compared to conventional all-electric systems, the IntElect requires up to 20% less energy,” states Langwald.

The “myConnect” web-based software developed in-house by the Sumitomo (SHI) Demag team provides direct access to a wide range of fully networked support services, helping to better manage production inefficiencies, reduce costs and total cost of ownership, troubleshoot errors and minimise downtime.

Twitter: Sumitomo Demag UK (@demaghamilton)
LinkedIn: https://www.linkedin.com/company/sumitomo-corporation-europe-ltd/