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Advances in Cleaning Equipment
By Brendan Baker
You could argue that the dishwasher is one of the greatest inventions of the twentieth century. Up until its introduction in households, people had to wash each dish individually, by hand, and dishpan hands were common among women and children. But the dishwasher changed all of that for families, and on its arrival, children everywhere rejoiced.
Much as the dishwasher did for your household, the age of automated cleaning equipment has changed life for the engine builder. While cleaning has not become obsolete by any means, the time and hassle involved since more automated systems became available have been greatly reduced.
There are several types of cleaning systems on the market that may, depending on your shop's needs, have the same effect as the dishwasher does for your family.
According to our annual Machine Shop Market Profile (MSMP), the majority of shops have either a cleaning oven system or jet spray washer or, in many cases, both. The type of system you use depends mostly on what kind of metals you clean and what type of finish you require. Manufacturers and engine builders we spoke to agree that there is not one perfect system that does it all. Each system offers benefits that may be more desirable for a particular reman operation but not as desirable for another. Therefore, you must know the final result you wish to achieve before setting up your cleaning operations. Do you clean mostly cast iron, mostly aluminum or both?
Our most recent MSMP reveals that engine builders spend, on the average, 13 percent of their production time cleaning engine parts. This is one of the reasons engine builders are seeking more automated systems when they decide to upgrade cleaning equipment. Some experts say they estimate a typical shop will spend almost one-third of its overhead expenses on cleaning costs. That may seem high but when you factor in the cost of equipment, chemicals, labor, maintenance and disposal of hazardous waste, it makes more sense.
Aqueous cleaning systems offer many benefits to engine builders, and one the biggest benefits is that it's fast. The cycle times on typical aqueous systems can be as little as 10 to 15 minutes compared to hours of soaking in caustic tanks or solvents. When using an automated spray washer or flow through system it's as simple as pushing a button and moving on to the next task, which is hopefully a more profitable one. There are several types of aqueous systems including these common ones:
These systems utilize a large tank of alkaline cleaning chemical in which the component is immersed, allowing the solution to get into all the blind areas. An added lift platform and recirculation pump further agitates the chemical surrounding the component, forcing chemical cleaning solution into all of the tight areas of the engine part, creating additional scrubbing action. This system is not as labor intensive as a manual system but does not eliminate other cleaning steps including hand cleaning.
Jet spray washer cabinets
Much like that dishwasher in your home, a jet spray washer uses a pattern of nozzles that spray cleaning solution with higher pressure (typically 40-60 psi) onto components. With a combination of water pressure impinging against the surface of the parts and the detergent dispersing and rinsing away dirt and grime, this system is very effective on most engine components. There are disadvantages with spray washers as stand-alone cleaning systems because they cannot reach all areas of more complex components such as cylinder heads.
High-pressure spray cabinets
These machines require manual operation and work much like a bead blasting machine but with aqueous solution instead of glass bead. Typical high-pressure spray booths blast out 400-600 psi, which is a lot of blasting power for cleaning those blind, tight areas.
These machines were first used for cleaning drapes and repair smoke damage from fires. Later it was discovered that ultrasonic sound waves produced under water were an effective way to clean many automotive components, especially areas where it is difficult to reach with mechanical devices on complex parts such as automatic transmission parts. When sound wave vibrations rise above a frequency audible for humans (above 18 Kilohertz) in a chemical solution bath, the results are a high vacuum and high-pressure area at any given point in the solution as sound waves pass. The vacuum creates what is called cavitation, an air bubble that implodes, resulting in high-pressure shock waves that, in turn, do all the work of scrubbing the component free from contaminants. Ultrasonic cleaning systems work very well on baked-on carbons and oils and are particularly effective at cleaning blind holes and complex parts.
Oven Bake and Shot Blast
Since the 1970s, engine builders have been using ovens to effectively clean engine parts, particularly cast iron components but also aluminum in recent years. Engine builders who have used the thermal method generally prefer the advantages it offers for cleaning parts that have a lot of soil without having to do as much hand cleaning.
The results of this process creates a "like new" condition on the parts. One engine builder we spoke to said that if anyone ever tried to take his oven from him he would chain himself to it in protest.
The oven cleaning method involves more than simply heating a component in an oven. Thermal cleaning involves a two-step process. To effectively thermal clean you must combine the oven thermal step with an airless shot-blasting step. The oven will bake all of the oils and grit out of the piece and turn it to a dry ash state, but the airless shot blaster knocks all of the ash off and produces the "like new" look that has long been associated with this cleaning process.
One of the more effective methods for removing baked-on carbons and oils is with a soda blasting system. Soda media is a form of baking soda that has been developed for industrial use to remove stubborn contaminants. Makers of these systems say soda is much easier to use for removing hard carbons and baked on sludge since the media is water-soluble and there is no need to worry about it becoming trapped in hard to reach areas. However, soda is a "one pass" media, so engine builders will likely want limit their use of this product to the most heavily soiled areas.
Wet Slurry Blasting
Recently introduced to the automotive engine rebuilding industry, wet slurry blasting has been used successfully for many years in other high end remanufacturing industries and aerospace industries. A few companies have developed smaller machines for use in engine remanufacturing operations and have displayed them at industry trade shows.
Wet slurry systems typically mix water or chemical solution with an abrasive media and either send the slurry to a nozzle in manual systems or to a blast wheel in automated systems. Different than dry-blast systems which may only strike the component once, wet slurry systems scrub the part and wash it away all at once.
Peterson Machine Tool's Dave Cox says his company is coming out with a new high-pressure jet spray machine in August for the AERA RPM Show in Indianapolis. "It's going to be a little bit of a new approach to cleaning aluminum," says Cox. "It'll be a specialist's machine for doing aluminum cylinder heads, because aluminum heads have changed the way engine builders need to clean. It'll also work for blocks and bimetal parts, but it's specifically designed for getting the nasty parts of the cylinder head clean at a reasonable price."
Cox says, "The safest way to clean aluminum, I think, is to have a high-pressure system. We had a system set up but it was pretty expensive. At $40,000 not many shops are going to be able to afford that price just to clean aluminum. So we incorporated much of the same technology in a system that only costs about a quarter of that price so smaller shops can afford it."
Sunnen's Tim Meara says that his company's aqueous jet spray systems are very effective for cleaning both aluminum and cast iron components. Although Meara notes that, in an ideal world, it is better to have two separate systems for each type of metal so you can get the most out of the aqueous cleaning solution, that's not always possible.
"Always with cleaning, there's not just one good answer for everything," says Meara. "You need to have a mixed bag of tricks to clean. Some systems work really well on aluminum, and some work really well on cast iron. There's not a magical 'one thing fits all' type of system.
"For us, the jet spray washer is where the market is going, but we have a thermal cleaning system in our lab and I really like it for cleaning cast iron blocks and heads and a lot of other parts. But you still need a spray washer for cleaning aluminum and cleaning parts post-machining. And the jet spray washer is also good for cleaning performance blocks and such where you are basically doing a touch up and not a complete rebuild," Meara explains.
Meara says where the market has changed in recent years is there are a lot more shops building performance engines and aftermarket engines where they start out with a clean part and maybe do four or five machining operations on that new part. It is possible to get by just using an aqueous system. In the past, where an engine with over 100,000 miles on it had to be thoroughly cleaned and prepped for racing applications, now there are a lot more new castings that shops are working with.
Winona Van Norman
Winona's Ed Keibler says that for the most part, thermal cleaning equipment has not changed much in recent years. "I think thermal cleaning is alive and well, but the systems typically last 20 years so there are a lot of guys who are just now replacing their systems and, believe it or not, some who are purchasing systems for the first time."
Kiebler says he sells to shops using thermal systems for both cast iron and aluminum. "There are people who are adamantly opposed to thermal systems for aluminum and people who are adamantly in favor of them. But that's common of many things in this industry," he says.
"One of the reasons I think our thermal system is safe and effective at cleaning aluminum is because of our blast wheel," Kiebler explains. "Normally, a shot blaster throws the shot at a very high velocity to create the ricochet effect. Some other systems use small impellers spinning at high velocity to create a shot curtain and the ricochet effect. With our blaster, we have one impeller that stretches the entire length of the cabinet, so that produces a shot curtain across the entire length of the cabinet on a 36", 44" and 54" system. Therefore, we don't have to throw the shot at nearly as much velocity. And when you don't throw shot fast you don't find thread or surface deformation that you do in more conventional systems."
Kiebler says meeting customer needs and demands is important. "We try to make the whole package available to engine builders, from slow bake and rotisserie style ovens to jet spray washers. The only thing we are not manufacturing is ultrasonic machines."
Axe's Terry Erichsen says his company has made some advancements in the jet spray washers offered. Axe manufactures everything from agitating hot tanks and spray booths to tumblers and jet spray washers.
For convenience, says Erichsen, all of their washers are equipped with mechanical timers for automatic "on/off" operation to the heat source and the oil skimmer (an optional feature).
All of Axe's electric heated machines are tuned for optimum water temperature warm up and recovery time. With water temperatures reaching 190° F, water evaporation can occur quickly, and while you are busy doing other important tasks the electric heater is monitored by a low water conductor that will automatically turn the power off to the heater should the water level drop below the element. Erichsen says this standard feature will save you money and a lot of aggravation.