XLPE foam ducts boast several advantages compared to blow-molded, rigid PP ducts that are commonly used at present according to Illig. For example, ducts molded using XLPE foam (density of approximately 70 to 80 kg/m³ depending on the application) are not only substantially more lightweight than ducts made of solid PP (density of 900 kg/m³); among other properties they also possesses substantially lower heat conductivity and superior acoustic dampening behavior thanks to their foamed structure.

There are over 5,800 companies operating in the UK plastics industry, contributing £25 billion to our economy each year. As a key player in Britain’s manufacturing sector, injection mould shops must embrace technological advancements in injection moulding machinery and accompanying automation for improved profit, productivity and sustainability.

The injection moulding process is responsible for up to 90 per cent of the Global Warming Potential (GWP) in the entire mould lifecycle. Recognising this, TM Robotics has championed investment in all-electric injection mould machines to replace older, more energy-intensive models.

The most obvious application for robots in mould machine shops is for the loading and unloading of injection mould machines. However, many end users currently have relatively low robotic ability, having traditionally chosen Cartesian X-Y gantry style robots to unload injection moulding machines.

In the thermoforming process, XLPE sheet (thickness 3 to 4 mm) is supplied by two material roll stands and each material is heated up in the forming station to a surface temperature of up to 200 C. Subsequently the heater is rapidly removed from the forming station– in less than 3 seconds – in order to minimize cooling of the material prior to commencement of the forming process. Further, the servo drives for the upper and lower mold table are especially designed for rapid movement speeds of up to 500 mm/s, even for tools with a weight of up to 1 t per mold table.

Lightweight and moreover flexible automotive air ducts are molded in sophisticated 3D geometries using XLPE foam and the thermoforming process on this Illig unit.

Another area of debate in the injection moulding world is robot integration. The UK seriously lags behind other developed countries for its number of robot installations. That’s not just for the world of injection moulding, but in the UK manufacturing sphere more widely.  In fact, the International Federation of Robotics (IFR) reports that the UK has just 101 robots per 10,000 employees — rookie numbers compared to competitors in the US, China and Germany.

Injection moulding applications have long played a key part in the UK’s manufacturing industry, producing everything from medical components, automotive parts, food containers, packaging items and much more. Traditionally, our manufacturers have relied on hydraulic-powered injection moulding machines in their operations. However, the industry is now at a crossroads, faced with the imperative to embrace technological advancements for sustainability and cost-effectiveness.

Due to this lack of uptake, the UK industry is missing some of the potential benefits of industrial robots, including improved productivity, efficiency and throughput. As a primary distributor of Shibaura Machine robots in the UK, the TM Robotics team has spotted opportunities for the injection moulding sector to reap the rewards of robotic automation.

In this way the foam’s lower heat conductivity minimizes condensation of water in the air duct after switching off the air conditioning system. High elasticity and good resilience of the ducts reportedly provide further benefits, such as ease of assembly and reduction of squeaking and rattling sounds even within a compact installation space.

One notable observation is the prevalence of hydraulic legacy equipment that is still being used by UK manufacturers. The TM Robotics’ injection moulding servicing department has witnessed this first-hand and regularly visits manufacturing sites to service and maintain Shibaura Machine’s own hydraulic injection mould machines — some of which have been in action for up to three decades. On one hand, it is a testament to the resilience of these machines, but the industry must consider the environmental downsides of this ageing equipment.

A leading Spanish automotive supplier has put its third twin-sheet thermoforming line into operation for the manufacture of ducts for automobile air conditioning. The UAR 155g  machine was supplied by Illig of Germany.

In twin-sheet thermoforming of cross-linked polyethylene (XLPE) foam, two sheets heated up to processing temperature are formed into half shells in the mold, supported by vacuum, and at the same time they are welded together on the outer contour. With the system developed by Illig; the formed parts are punched directly in the mold after the end of the cooling time. The upper mold half is equipped with extendible serrated knives. The lower mold half is equipped with grooves in which the knives interlock during punching. The punched out parts are secured by “holding bridges” and removed from the forming station. Upon removal from the thermoforming machine, only the joint areas of the air ducts have to be cut – just like blow-molded rigid ducts.

A further benefit provided by thermoforming with twin-sheet technology versus extrusion blow molding is that multiple parts of differing dimensions and geometries can be manufactured simultaneously by utilizing a large-area tool (the UAR 155g features a forming area of up to 1450 x 1200 mm). This capability also has implication in terms of cycle time per air duct, which is naturally shorter. On these accounts, air ducts made of foam are cost competitive when compared with rigid PP blow-molded ducts– manufacturing costs per duct are in fact comparable.

The flagship all-electric range from TM Robotics is the SXIII all-electric series from Shibaura Machine. Shibaura Machine is the new name for Toshiba Machine — the Japanese manufacturer of industrial robots and injection mould machines. The SXIII range boasts faster injection speeds, enhanced sustainability and a streamlined design when compared to its hydraulic predecessors. What’s more, despite the perception of higher costs for all-electric machines, this range can improve cost efficiency by lowering the cost-per-part.

This was demonstrated by TM Robotics’ customer Lotan, a manufacturer of plastic containers based in Leicestershire, UK. Lotan’s production facility exclusively uses all-electric injection mould machines from Shibaura Machine. The SXIII provides significantly faster injection speeds than traditional moulding equipment, providing 35% faster cycle times than conventional hydraulic servo IMMs.

Nigel Smith, managing director of TM Robotics, the international distribution partner of Shibaura Machine and the UK and Ireland distributor of its injection mould machines, explores the changing landscape of plastic's injection moulding sector and argues the case for investment in new technologies, both for better operational efficiency and improved sustainability.