Vacuum cleaners for metalworking – what works best for different jobs?
Comments Off December 21, 2012 at 11:46 am by Canadian Metalworking
As the metalworking industry becomes more specialized so does the cleaning equipment.
Metalworking is a diverse industry, so it should come as no surprise that no one vacuum is suitable for tackling every different job.
Even when separating applications into wet and dry, there is no one vacuum that can handle all the wet, or all the dry. Whether for fluid management, protecting equipment from dust, or in finishing operations, employing the right metalworking vacuum can increase uptime, preserve product quality, enhance plant safety, and extend the lifespan of expensive equipment and materials.
In metalworking facilities it is not uncommon to see general purpose vacuums, like the shop-type wet/dry vacuums found on the shelves at hardware stores, however, those vacuums tend to be utilized in more of a janitorial sense for picking up small puddles or small debris.
When looking to clean a machining centre, machine tool or water jet cutter, it is necessary to look at solutions that are more specialized because vacuums are used day in and day out. Often users know they want something industrial but they don’t know what that is.
To better understand the diversity in metalworking applications and thus vacuum cleaning solutions, it’s beneficial to examine some of the common vacuum types used in the metals industry and regularly encountered debris.
Continuous Duty: Designed to withstand 24/7 operation and handle tough materials, continuous duty vacuums are including heavy steel shot or mounds of fine powders. Powerful enough to pick up a bowling ball, portable continuous duty vacuums are available with motors ranging from 5 hp to 30 hp with add-on intercept vessels to expand collection capacity and improve material handling.
Combustible Dust Vacuums: There are a variety of combustible dusts in a metalworking environment, including powder coatings, aluminum, and magnesium dust and so combustible dust vacuums must be completely grounded and bonded to meet the NFPA 70 requirements. These vacuums also meet the definition of an “intrinsically-safe system”. Although some combustible dust vacuums are available with electric motors, air-powered vacuums do not use electricity and do not generate any heat from operation.
Stationary Vacuums: These cleaning systems eliminate the need for chip carts and manual emptying, allowing operators to clean workpiece holders, parts carriers and T-slots quickly. One common stationary system consists of a vacuum pump and specialized receiver to collect chips and discharge them into a floor-level or below-grade chip conveyor for disposal, which eliminates the need to empty a collection drum or hopper which enables operators to focus on making more parts. Another type of stationary vacuum system automatically collects chips from individual machine tools delivers the chips to a central location eliminating the need for chip carts and manual emptying.
Metalworking liquid recovery vacuums: Sometimes called “pump-in, pump-out vacuums”, metalworking liquid recovery vacuums pick up liquids at 1-2 gallons (or approximately 4-8 litres) per second. In addition to the ability to pick up 100 per cent liquids, these vacuums also recover liquids with solid particles, such as chips, and are equipped with a lever that converts the unit from vacuum mode to pump-out mode to discharge filtered liquids from the drum at a controlled rate.
Industrial wet/dry vacuum: Intended more for one way vacuuming of metalworking liquids and debris, both wet and dry, these multi-purpose vacuums out-perform vacuums found at home improvement stores and janitorial catalogs.
Tank kit vacuums: These are air-powered liquid recovery vacuums designed to handle materials that are more viscous and can be used with closed top drums. Placement of the vacuum mechanism outside the drum, allows the drum to fill to 99 per cent its volume. Tank kits are well suited to clean out parts washers.
The range of industrial vacuums available for specific metalworking applications and debris, coupled with tools and accessories tailored to application needs, have advanced the equipment beyond general housekeeping and safety uses, and into production tools that increase uptime and improve product quality. Following is a list of common debris encountered in the metalworking industry and industrial vacuums types suited to tackling them:
Coolants: For vacuuming coolants and chips away from a machining centre, specialized liquid recovery vacuums, equipped with chip baskets and liners, preserve the integrity of the coolant and permit recovered fluids to be pumped back into the system. Use of these vacuums reduces the amount of accumulation of chips and fines in the sump reducing bacterial and fungal growth keeping workers safer.
These systems are also ideal for larger metalworking jobs, such as high speed milling of aircraft wings, where fluid must be removed from cavities in order to take precision measurements.
Sludge and swarf: Removal of sludge from sump pits and water jet cutting tables is another common application for vacuums in the metalworking industry.
This sand-like semi-solid material forms when residual particulates and chips settle in the bottom of a sump. This sludge is an ideal breeding ground for harmful bacteria and fungus that endangers workers’ health, shortens the life of metalworking fluids, interferes with machine function and can eventually plug fluid lines. According to tool manufacturers, dirty machine coolant can cause a loss of as much as 10 per cent of the cost of tools each year.
Using a continuous duty vacuum that facilitates high volume recovery of up to five tonnes per hour, not only reduces the downtime necessary to remove sludge, but also protects workers from ergonomic issues associated with shoveling masses of sludge.
Metallic filings or shavings removed by cutting or grinding tools should be cleaned with an industrial wet/dry vacuum. In addition, vacuums are utilized to suck swarf from trays and dump it into briquetting machines.
Chips: In wet cutting, chip baskets in liquid recovery vacuums capture and separate chips from metalworking fluids. In dry cutting, dry vacuums are used to remove debris from machine centres. Abrasion-resistant hoses are important when vacuuming chips. In the case of turnings, the longer byproducts of lathe machines, they are not ideal for industrial vacuuming because they can clog hoses easily.
Punch-outs, mill scale and grinding debris: Waste metal formed by punching holes in sheets can be collected with dry vacuums and nozzles or with high volume continuous duty vacuum systems that suck the punches from trays or pick up points on a continuous basis and dump them into collection containers.
For mill scale, the flaky surface of hot rolled steel when scattered about, is easily picked up with a dry vacuum, but when in piles, a heavy duty continuous duty vacuum is better equipped for the job.
The debris from manual grinding metals is difficult to capture and becomes a fugitive dust problem. Depending on the material, dry vacuums are sufficient to clean up grindings at the end of the shift. However, as materials dictate, a combustible dust vacuum may be necessary to remove grindings.
Slag and flux: These granular or irregular shaped abrasive chunks, a byproduct of submerged arc welding, generally need a heavy-duty continuous duty solution. It is fairly common to automate the process of removing slag with a vacuum cleaner.
Flux is a fine powder that is a source for fugitive dust and comes from large scale automated welding processes, which needs a dry vacuum for fine powders. With specialized vacuum accessories, flux powder can be recovered and reused.
Shot-blast media: Shot peening and abrasive blasting are slip hazards and ergonomic issues. If machines leak or the media lodges in parts and falls out in the plant, it is like walking on ice, and because the material is heavy, manual cleaning methods carry the risk of back injury. Continuous duty heavy-duty vacuums, capable of generating 12”Hg, are necessary for cleaning this media. VAC-U-MAX actually produces a vacuum cleaning solution to suck the media into a collection vessel and then deposits the media back in the blast machine for reuse, without operator handling.
Abrasive media (dry): Non destructive abrasive media like corn starch, walnut shell products and plastic grit are combustible dust hazards and require vacuums designed for use in Class 2 Div II areas. The dust may also contain hazardous materials such as cadmium or silica requiring the use of a Hepa-filtered vacuum.
Abrasive media (wet): Abrasive Flow Machining (AFM) media has viscoelastic or rubber-like properties. A heavy-duty vacuum eliminates the need to shovel the media as well as collecting the media for reuse.
David Kennedy is an expert in industrial vacuum cleaning technology with over 20 years of design and engineering experience. He is also the General Manager of VAC-U-MAX’s vacuum cleaning division.
For more information about industrial metalworking vacuums visit their website: www.vac-u-max.com.
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