MATERIALS | LIQUID SILICONE RUBBER
Right: Elmet’s products at K2022
included its Smartmix 7000 Pro and Smartshot E cold runner system
linear handling device from Sumitomo (SHI) Demag removes the parts from the mould and transfers them to a weighing cell manufactured by Mettler Toledo. The Smartmix Top 7000 Pro from Elmet is its newest and most compact dosing system suitable for 200-litre drums. Compared to its predecessor the new Smartmix Top 5000 P, introduced in 2021, has a reduced footprint of 1,150 by 790 mm. It also has a completely new, simplified pump system in which the number of components is minimised. The unit handles approximately one-third the volume of liquid silicone as the prior model, which increases process reliability and reduces purging time. The smaller volume also facilitates cleaning and maintenance, which is important when the unit is used in medical and pharmaceutical applica- tions, where the pump unit is typically dismantled and cleaned each time the material changes, to prevent the mixing of different types of liquid silicone. Despite its compactness, the unit can operate at pressures up to 210 bar. The Smartmix 7000 Pro features an optimised
and recently patented follower plate geometry that helps reduce the amount of residual material and enables material utilisation levels of up to 99.6%. Drums holding each component of the LSR are changed fully automatically to increase ease of use. The incorporation of special seals made of FDA- compliant materials makes the Smartmix 7000 Pro suitable for medical applications. Fully automated detection of the follower plates and plate position eliminates operating errors during drum changes. Instead of side rails, full-surface slide plates facilitate drum changing, which can be carried out on three sides, the company says. A fixed and more readily accessible positioning
of the material outlet, which is decoupled from the pump unit, minimises the load on the hoses leading to the injection unit, further increasing process reliability. A new interface plate allows for many options to be retrofitted to the unit without having to rewire the system. Elmet’s all-electric Smartshot E cold runner system features servomotor driven movement of the needle that can control positioning in incre- ments as little as two thousandths of a millimetre. The innovative arrangement of the mini servomo- tors enables nozzle spacings of 44 mm. Moulding with up to 16 cavities can be balanced with greater needle precision than was possible with previous versions, which incorporated pneumatic or stepper motor actuation. Settings for operation and control of the cold runner are entered on an 18.5 in. display of the
42 INJECTION WORLD | July/August 2023
external Smartcontrol unit. The cold runner system is also designed with wear-free miniature industrial connectors and an optimised cable duct that can be removed as a single assembly without the need for a qualified electrician.
Fluid handling equipment manufacturer Graco developed an electric variable ratio (EVR) metering system for 2K materials that allows manufacturers to change ratios as they mix, meter, and dispense two-component materials, all with the same equipment. It can be used with silicone, epoxy, urethane, acrylic or any two-component material. Graco worked with material suppliers in research- ing the different ratios and ranges of material viscosities in developing the product. The high flow EVR unit can move up to 6,400 ofmaterial per minute, while flexingdispense
cm3
ratios anywhere between 1:1 to 5:1 or 2:1 to 10:1. When it is time to use a different material, the EVR’s base purge feature conserves the amount of solvent used to clean out the system by indepen- dently driving either material side. It also keeps old material from curing so that there is no need to replace a static or dynamic mixer because of fast curing materials or intermittent production runs.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.wacker.com �
www.elmet.com �
www.dow.com �
www.momentive.com �
www.elkem.com �
www.shinetsu.co.jp �
www.elmet.com �
www.sumitomo-shi-demag.eu �
www.graco.com
www.injectionworld.com
IMAGE: ELMET
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