Cables and energy supply systems prove themselves in high-speed injection moulding machine

Fast - faster - Hekuma: Hekuma stands for the high and high-performance automation of complete systems for plastics processing, which are used, for example, in medical technology, the automotive industry or in the production of consumer goods. The manufacturer automates not only the removal process in its injection moulding machines, but also upstream and downstream processes such as the punching of contacts or the insertion of punched parts into the injection mould. They work at extreme speeds. Typical cycle times are four to six seconds, with removal times of less than one second being achieved in some cases. This is also the case, for example, with a system from Hekuma with a 64-cavity mould for the production of laboratory sample containers, which is clocked with a cycle time of 5.5 seconds.
However, due to the high production speed, a failure of just a few minutes would quickly lead to tens of thousands of faulty parts. As a result, the mechanical system often reaches its limits, as do the electronics. Hekuma is therefore operating at the (speed) limits of mechanical engineering - and the question arises as to which cables and which energy chains the grippers are equipped with. With the typical cycle times, several million double strokes can be achieved within a few months, and this at very high accelerations of up to 10 g. A conventional cable would fail after just a few days under this load.

The cable solution chosen by Hekuma lasts for years. And has therefore been an integral part of the injection moulding machines for over ten years. Specifically, the company relies on the control cable from the CF9 series with a cross section of 0.25 to 0.34 mm2 as an INI cable. The cables from our chainflex® programme have been specially developed for use in energy chains. Only optimised stranded wire is used in the individual cores, the wire thickness of which is not too thin and not too thick. The individual cores are stranded in such a way that no "corkscrew" can occur. Bundle stranding helps here, in which the core is first stranded with a short pitch length and the resulting bundle is then stranded again to form an overall structure. This build-up takes place around a high tensile strength centre element. This ensures that the stranding remains stable even under the highest bending stress and high dynamics. The jacket made of special abrasion-resistant TPE ensures very good abrasion properties and the small bend radius of 5xd is also perfectly adequate. The small bend radius is crucial, as space for tool and workpiece handling is often extremely limited.
While some of the moving cables are exposed, they run in chain guides on the main axes. Hekuma has selected the E6-series plastic-energy chain as the standard system here. The requirements here are similarly high as for the cables: Due to the very short stroke, constant vibrations occur in the cable system, which act like short impacts. This causes very high stress on the chain and cable, in contrast to constant rolling movements.
The heavy injection moulding tool is only fully open for 0.8 seconds. The gripper must enter the mould in this short time and remove the finished plastic parts with a movement in the second axis before the mould closes for the next shot.