Chris Tudor, engineering manager at Aeroplas answers questions about the company’s recent installation of a Sumitomo El Exis SP injection moulding machine
Having recently installed a Sumitomo 350 El Exis SP fast cycling injection moulding machine, Aeroplas engineering manager Chris Tudor recommends the system to plastics manufacturers looking to purchase a fast cycling system. The company, a thermoplastic injection moulder of horticultural and plastic catering products, installed an El Exis SP in January 2012 at its Tipton facility in a bid to improve manufacturing efficiency, reduce cycles times and lower energy consumption, on over 100 plastics products.
In this Q&A, Chris gives a technical appraisal of the system, which uses a blend of drive technologies including a servo driven hydraulic clamp unit to achieve precise movements, a hydraulic accumulator delivering high injection rates, and an electric screw drive for parallel plasticising.
Q: How well does Sumitomo’s blend of drive technologies help achieve your commercial objectives?
A: “The clamping system, whose main function is to open and close the mould along with ejecting the parts, is particularly well engineered. The mechanical five point double toggle driving the clamping unit is powered dually by a servo motor and a hydraulic motor. This duplex power not only enables the clamping system to be very easily controlled, but most importantly ensures a balanced distribution of clamp force and even toggle wear. There is very little movement of the machine during the mould opening and closing, which in turn should increase the machine’s lifespan. Other benefits from the machine’s minimal vibrations include minimal wear and tear to the mould, reduced chance of damage to the components and consistent quality plastic products with no variations to the wall thickness.”
Q: Does the machine design enable engineers to easily access vital parts and components?
A: “The machine has a very solid feel and every component has its place. In our high pressure, 24/7 manufacturing environment every minute lost to unplanned stoppages eats into operational costs and if a component does fail, the last thing an engineer wants is a struggle to reach it. With the El Exis all electrical components are well laid out and accessible with ample space around all drives, contactors and power supplies, so should we require further electrical equipment to be retrofitted into the electrical cabinet at a later date, we know it’s possible.”
Q: How has your machine build quality criterion been met?
“From initially inspecting the El Exis, the build quality is the thing that stands out it is superb. It is testament to both the build quality and the excellent layout that no fans are employed within the electrical cabinet none are needed as the components are sensibly spaced out to allow for heat dissipation. The components are the perfect size to allow cool running.”
Q: How does the system meet your cycle and injection requirements?
“The dynamic balance of the machine is unbelievably smooth. Independent control loops operate in parallel for the clamping unit, the injection unit and the secondary movements, for example core and ejectors, which allows the El Exis SP to achieve fast, harmonic and consistent movements. Thanks to the servo valve with 24vdc failsafe, the hydraulic accumulator and high quality valves and pneumatics, a high speed of injection is achieved seamlessly.”
Q: Has the machine lived up to the promises that were made by Sumitomo?
“The El Exis has been in production with us for the last 9 months and has been inconspicuous, as it was installed with minimal disruption – to date it has been maintenance and trouble free with no downtime. All cycle times that were initially quoted by Sumitomo Demag have been met or reduced. We have nothing but praise for this machine and would wholeheartedly recommend it to other plastic manufacturers.”
Sumitomo (SHI) DEMAG