Author Archives: Steve Parker

Brass and Aluminum Cold Forming Problems

August 1, 2014

High speed cupping and cold forming operations have traditionally used magnetic filters and/or bag type and pleated paper filters to remove the metal particulate from the lubricating or hydraulic oil streams. This works reasonably well for machines forming ferrous metals, but types of filters are not effective on non-magnetic metals or on very small particulate. The current manufacturing climate has placed new emphasis on high speed forming of non-ferrous metals such as brass and aluminum on larger scale presses, and in addition, has created some new fluid cleanliness problems. Not only are non-ferrous metal fines and chips more difficult to capture, but they also tend to react more quickly with any moisture to form acids and sludge in the oil. This leads to oil film break down, increased varnish accumulation, depleted oil protection and eventually manufacturing errors.

A customer with an aluminum cupping operation was experiencing constant die release contamination on their hydraulic cupping press and came to us for help. Our examination of the equipment and maintenance records showed rapid seal deterioration due to metal fines making their way into the hydraulic oil and reduced lubricity due to the die release contamination of the hydraulic fluid.

An 810-051.3.1 Hydra-Supreme Cupping Press filter was installed and the existing fluid was replaced. The system has now been running for several months with the fluid showing no signs of coolant/die release accumulation and the press has been running error free.

Most modern coil fed presses use a combination of hydraulic power and controls that respond well to effective off-line filtration. Keeping the hydraulic fluid clear of particulate and moisture contamination not only extends seal life and enhances the control function, but also allows uninterrupted production when the filter needs to be changed out. Clean valves are accurate valves, and it all starts with keeping the oil feeding them clean.

Sticking Servo Valves

July 10, 2014

You will read a lot of advertisements and technical articles about the particulate efficiency of many types of hydraulic filters being marketed today. Very few address the “hidden” killer of hydraulic system efficiency and accuracy – oxidized oil.

HTI recently received a call from a major furniture manufacturer who told us that their hydraulic fabricating machine has recently turned into a scrap metal making machine. They had resorted to hand cleaning each servo valve every weekend to try to maintain the accuracy of their punching programs! A quick analysis of the valves and oil revealed the presence of varnish in the spool landings and in their oil.

Oxidized oil, commonly known as varnish, typically occurs when oil is heated and the resulting goo adheres to whatever surface is available as it cools and congeals. The ensuing dark, resinous material then proceeds to create friction, flow resistance, and obstruction as it accumulates. In precision operations involving hydrostatic bearings and servo valves, this leads to placement and alignment errors that can range from annoying to catastrophic.

Removing varnish is one of the unsung attributes of the Hydra-Supreme filter element. In addition to removing very fine particulate and water, this filter also removes varnish from the oil, leaving the oil even cleaner than when it left the factory and greatly retarding the build-up of varnish inside the fluid system. It is important to note that even our filters cannot remove varnish that has already built up in an unprotected system. Once varnish has settled into place, it needs to be chemically or physically removed when it begins interfering with the function of the hydraulic or lubricating oil system.

HTI installed a Hydra-Supreme filter on the furniture manufacturer’s reservoir. We had them run the system as normal for a week without any other changes. The end of the week showed no valve failures, and the oil was noticeably clearer. They have now been producing furniture parts instead of scrap metal for 6 weeks and have had no valve or accuracy issues since. Everyone is happy, except the scrap metal dealer!