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The company approached Wheelabrator Group for advice and assistance with a solution to meet the ever-demanding health and safety requirements of the medical products industry.

Paul Mitchell, Equipment Sales Manager (South) at Wheelabrator Group said: “As long standing customers of Wheelabrator Group, when the time came to upgrade the blast equipment at some of their sites in order to meet latest legislation, the company had no hesitation in approaching us for sound advice and reliable machine solutions. In particular, they were in search of a solution to contamination caused by excess dust around the working area – a problem complicated by the fact that parts were mainly cobalt chrome, which makes the dust potentially hazardous to machinery operators and end users.”

During consultation, Wheelabrator engineers discovered the contamination problem was being caused by a number of factors. Over time the dust collectors had collected dirt and become less effective. The media was also found to be escaping from the blast cabinet when the door was opened, causing it to circulate in the air and spill onto the floor. This was partly due to the machine operators prematurely opening the cabinet door before the dust had had chance to settle, and also because the blow off guns which separate the dust from the blasted parts were being used when the blast door was open.

These factors, combined with the blast machine being situated in a relatively confined area, resulted in potentially hazardous conditions for the machine operators and raised significant health and safety concerns for the organization.

Wheelabrator Group engineers introduced a number of simple devices to existing machinery in order to safeguard against the dust contamination threat.

These included a solenoid timed door interlock that ensures sufficient time is given for dust to be evacuated from the cabinet before operators can open the cabinet door.  A dust collector / foot pedal interlock was also installed which prohibits the use of the machinery unless the dust collector is switched on.

Automatic filter pulsing and Highly Efficient Particular Air (HEPA) filters were also installed, to give continuous cleaning of cartridge filters and reduce dust emissions from the exhaust vents to very low levels. A door / blow off gun interlock was also installed to inhibit the use of the air blow off guns while the cabinet door is open.

Mitchell comments: “By introducing new technologies, as well as upgrading and modifying their existing machinery we were able to resolve the contamination problem and increase the effectiveness of the existing machinery at the same time. This, coupled with the introduction of cleaner, leaner operational processes, has resulted in an increase in efficiency, with noticeable gains in both productivity and output quality.”

Wheelabrator Group engineers were also able to add value by installing an in-line sieve to the machine. Each time the media is blasted onto the components a portion of it breaks up, which can result in differences in component surface roughness between blasts. 

Previously, the media was replaced with almost every blast to ensure component consistency was maintained. Wheelabrator engineers spotted an opportunity to deliver greater savings by reducing the volumes of media used.

The in-line sieve is a size classification unit that sifts the media after each blast, removing the portion that has broken up which allows the majority to be used again. Not only has this simple addition saved considerable investment in media, it has also enabled operatives to realise savings in time too, having reduced the number of surface roughness measurements from each blast, to just twice a day.  

An acoustic panel was also built around the sieve, in order to reduce noise machinery levels for the operatives. This has brought the machine within the required health and safety sound regulations and enabled it to be moved out of its confined space and into the main factory area.

Paul Mitchell concludes, “We’re delighted with the benefits we’ve been able to deliver to the company in addition to resolving their initial contamination problems. Following the success of these installations and modifications we have been able to apply these benefits to numerous other medical and key aerospace customers.”