Energy costs are one of the biggest ongoing pressures for injection moulders, which is why suppliers' efficiency claims are increasingly being put to the test on the shop floor rather than taken from a spec sheet. A recent like-for-like comparison carried out by a UK-based plastics manufacturer has done exactly that, and the results give a clear picture of what switching hot runner systems can actually achieve.

The test

The manufacturer fitted a four-drop valve gate GÜNTHER BlueFlow® system to a mould with the same footprint as an existing tool that was running a competitor's hot runner system. Both tools were used to produce identical PP caps, with a wall thickness of approximately 1.6mm and a part volume of 9.46cm³, at cycle times of 14.8 seconds.

To keep the comparison fair, both tools ran on the same injection moulding machines and used independent temperature controllers from the same third-party manufacturer. Barrel temperatures on both tools were set between 225°C and 210°C, with hot runner temperatures set at 210°C. Each temperature controller was fitted with an energy monitor so consumption could be measured directly rather than estimated.

Over a one-hour measurement period, the competitor's system used 764Wh, compared with 576Wh for the GÜNTHER BlueFlow® system.

Why the difference

The BlueFlow® system uses GÜNTHER's thick-film heater technology, the much thinner design of the thick-film heater ensures better heat transfer and saves energy thanks to its ultra-fast thermal response. Paired with Gunthers patented bi-metallic titanium shaft technology these nozzles are designed to provide a more even temperature profile and reduce heat loss between the hot runner and the mould tool, while also supporting leak-free operation.

GÜNTHER's own figures put typical energy savings for its nozzles at up to 50% when measured in isolation. For this test, engineers at the moulding company wanted a more complete picture, so they measured total system energy consumption, including manifold consumption, under real-world production conditions.

What the team found

"We wanted to see if the energy savings from the GÜNTHER BlueFlow® nozzles stacked up against the other tools we were using with a different hot runner supplier, and the tests confirmed a 24.6% reduction in total hot runner energy consumption," said the Injection Moulding Chief of Development. "This was our first time using a GÜNTHER system, and we've found the valve gate design straightforward to maintain."

A brief training session was provided to the manufacturer's in-house toolroom team, who were shown how the shaft seals within the mould inserts, how valve pins can be easily adjusted or replaced and how worn or damaged gates can be replaced by exchanging PM inserts. This kind of practical handover matters as much as the energy figures themselves, since a system is only as efficient as the team's ability to maintain it.

The bigger picture

These results add to a small but growing body of comparative data on hot runner energy consumption. As energy costs continue to rise, more moulders are choosing to assess supplier options against measured performance on the shop floor, alongside the specifications suppliers provide.

About Gunther UK Limited

Gunther UK supplies hot runner systems to the plastics industry and has been the exclusive UK and Ireland agent for the Günther Hot Runner Technology group since 1988. The company provides technical support for injection moulding tooling projects across the UK.

Interested in how GÜNTHER BlueFlow® could perform on your own tooling? Get in touch with the Gunther UK team to discuss a comparison for your application.