Sludge and Varnish: The Hidden Productivity Killers of Injection Moulding Operations

For plastic injection moulding, productivity is a priority. Any unplanned downtime caused by equipment breakdown impacts directly on your bottom line, placing delivery deadlines at risk and incurring costs from maintenance and unused labour.

At the heart of these machines lies the hydraulic system, where hydraulic fluid plays a vital but often underestimated role, with between 50 and 70 per cent of mechanical failures related to ‘improper hydraulic fluid condition’, often as a result of sludge and varnish build-up¹.

Though most standard Oil Condition Monitoring (OCM) tests can help screen for problems such as ineffective corrosion protection, they cannot detect the build-up of sludge and varnish, because soft contaminants don’t typically impact the bulk chemistry of the hydraulic fluid, making them difficult to measure.

Equipment failures can then occur, with the resulting unplanned downtime and necessary oil change impacting finances greatly.

Additionally, short oil-drain intervals are expensive not only in terms of the oil cost but also oil waste costs.

Poor-quality hydraulic fluids are more susceptible to this problem as they readily oxidise in the presence of yellow metals, water and air contamination. They also contain additives that are not thermally stable and so decompose at elevated temperatures.

Avoiding unplanned downtime and unexpected costs

The best way to avoid this is to use a high-quality hydraulic fluid which has high oxidation resistance and excellent thermal stability, helping to mitigate the risk of sludge and varnish build-up while lowering the operator’s Total Cost of Ownership².

The Shell Tellus range of hydraulic fluids has been specifically formulated to meet the demands of modern hydraulic systems by:

• resisting thermal and chemical breakdown
• providing enhanced reliability and system cleanliness
• mitigating breakdown risk and its associated costs.

¹ _{Source: multiple surveys by industry bodies including additive companies, filter manufactures, hydraulic equipment manufacturers. One source includes Parker Hannifin GmbH Bulletin: HY30-3248/ UK: Hydraulic Fluids for Parker Axial Piston Pumps Series PV}

² _{Total Cost of Ownership (TCO) is defined by Shell Lubricants as the total amount spent on industrial equipment, including cost of acquisition and operation over its entire working life, including costs of lost production during equipment downtime}