There are many reasons for processing deformation of aluminum parts, which are related to material, part shape, production conditions and so on. It mainly includes the following aspects: deformation caused by internal stress of blank, deformation caused by cutting force and cutting heat, and deformation caused by clamping force.


1 Process measures to reduce machining deformation 1. Reduce the internal stress of the blank. Natural or artificial aging and vibration treatment can partially eliminate the internal stress of the blank. Pre processing is also an effective process method. For the blank with fat head and big ears, due to the large allowance, the deformation after processing is also large. If the surplus part of the blank is processed in advance and the margin of each part is reduced, it can not only reduce the processing deformation of the subsequent process, but also release part of the internal stress after being placed for a period of time. 2. Improving the cutting ability of the tool, the material and geometric parameters of the tool have an important impact on the cutting force and cutting heat. The correct selection of the tool is very important to reduce the machining deformation of the part.
1) Reasonably select tool geometric parameters. Rake angle: under the condition of maintaining the strength of the blade, the rake angle should be appropriately larger. On the one hand, it can grind a sharp edge, and on the other hand, it can reduce the cutting deformation, make the chip removal smooth, and then reduce the cutting force and cutting temperature. Do not use negative rake tools. Back angle: the size of the back angle has a direct impact on the wear of the back cutter surface and the quality of the machined surface. Cutting thickness is an important condition for selecting back angle. During rough milling, due to large feed rate, heavy cutting load and large calorific value, it is required that the tool heat dissipation conditions are good. Therefore, the back angle should be smaller. During finish milling, the cutting edge shall be sharp to reduce the friction between the flank and the machined surface and reduce elastic deformation. Therefore, the back angle shall be larger. Helix angle: in order to make milling smooth and reduce milling force, the helix angle should be as large as possible. Main deflection angle: properly reducing the main deflection angle can improve the heat dissipation conditions and reduce the average temperature of the processing area.
2) Improve tool structure. Reduce the number of milling cutter teeth and increase the chip holding space. Due to the large plasticity of aluminum parts, large cutting deformation in machining and large chip holding space, it is better to have a large radius of chip holding groove bottom and a small number of milling cutter teeth. Fine grinding of cutter teeth. The roughness value of the cutting edge of the cutter tooth shall be less than RA = 0.4um. Before using a new knife, gently grind the front and back of the knife teeth with a fine oilstone to eliminate the residual burrs and slight serrations when grinding the knife teeth. In this way, not only the cutting heat can be reduced, but also the cutting deformation is relatively small. Strictly control the tool wear standard. After tool wear, the workpiece surface roughness increases, the cutting temperature increases, and the workpiece deformation increases. Therefore, in addition to the selection of tool materials with good wear resistance, the tool wear standard should not be greater than 0.2mm, otherwise it is easy to produce chip buildup. During cutting, the temperature of the workpiece shall not exceed 100 to prevent deformation.
3. Improve the clamping method of workpieces. For thin-walled aluminum workpieces with poor rigidity, the following clamping methods can be adopted to reduce deformation: for thin-walled bushing parts, if they are clamped radially with three claw self centering chuck or spring collet, once they are loosened after processing, the workpiece will inevitably deform. At this time, the axial end face compression method with good rigidity should be used. Locate with the inner hole of the part, make a self-made threaded mandrel, insert it into the inner hole of the part, press the end face with a cover plate, and then tighten it with a nut. When machining the outer circle, the clamping deformation can be avoided, so as to obtain satisfactory machining accuracy. When processing thin-walled sheet metal workpiece, it is best to select vacuum suction cup to obtain evenly distributed clamping force, and then process it with small cutting parameters, which can well prevent workpiece deformation. In addition, the packing method can also be used. In order to increase the process rigidity of thin-walled workpiece, medium can be filled in the workpiece to reduce the deformation of workpiece during clamping and cutting. For example, fill the workpiece with urea melt containing 3% 6% potassium nitrate. After processing, immerse the workpiece in water or alcohol to dissolve and pour out the filler.


4. When the process is reasonably arranged for high-speed cutting, due to the large machining allowance and intermittent cutting, the milling process often produces vibration, which affects the machining accuracy and surface roughness. Therefore, NC High-speed machining process can be generally divided into: rough machining - semi finishing - corner cleaning - finishing and so on. For parts with high precision requirements, it is sometimes necessary to carry out secondary and semi finishing, and then finish machining. After rough machining, the parts can be cooled naturally to eliminate the internal stress caused by rough machining and reduce deformation. The allowance left after rough machining shall be greater than the deformation, generally 1 2mm. During finish machining, the finished surface of parts shall maintain a uniform machining allowance, generally 0.2 0.5mm, so that the tool is in a stable state in the machining process, which can greatly reduce the cutting deformation, obtain good surface machining quality and ensure the accuracy of products. 2 In addition to the above reasons, the operation method is also very important in practical operation.
1. For parts with large machining allowance, in order to have better heat dissipation conditions during machining and avoid heat concentration, symmetrical machining should be adopted. If a 90mm thick plate needs to be processed to 60mm, if one side is milled immediately and the other side is milled to the final size at one time, the flatness will reach 5mm; If repeated feed symmetrical processing is adopted, each side is processed to the final size twice to ensure that the flatness reaches 0.3mm. 2. If there are multiple cavities on the plate parts, the sequential processing method of one cavity one cavity should not be adopted during processing, which is easy to cause uneven stress and deformation of the parts. It adopts multiple processing in layers, and each layer shall be processed to all cavities at the same time as far as possible, and then the next layer shall be processed to make the parts bear the force evenly and reduce the deformation. 3. Cutting force and cutting heat can be reduced by changing cutting parameters. Among the three elements of cutting parameters, the back draft has a great influence on the cutting force. If the machining allowance is too large and the cutting force of one-time tool walking is too large, it will not only deform the parts, but also affect the rigidity of the machine tool spindle and reduce the durability of the tool. If we reduce the amount of back knife, the production efficiency will be greatly reduced. However, in NC machining, high-speed milling can overcome this problem. While reducing the back draft, as long as the feed is increased accordingly and the rotating speed of the machine tool is increased, the cutting force can be reduced and the machining efficiency can be guaranteed.
4. Pay attention to the order of cutting. Rough machining emphasizes the improvement of machining efficiency and the pursuit of cutting rate per unit time. Generally, reverse milling can be used. That is to cut off the excess material on the surface of the blank at the fastest speed and in the shortest time to basically form the geometric contour required for finishing. The finishing emphasizes high precision and high quality, and forward milling should be adopted. Because the cutting thickness of the cutter teeth gradually decreases from the maximum to zero during forward milling, the work hardening degree is greatly reduced and the deformation degree of the parts is reduced at the same time. 5. The deformation of thin-walled workpiece during machining due to clamping is difficult to avoid even finish machining. In order to minimize the deformation of the workpiece, the pressing part can be loosened before the finish machining is about to reach the final size, so that the workpiece can be freely restored to the original state, and then slightly pressed, subject to the ability to clamp the workpiece (completely by hand feeling), so as to obtain the ideal machining effect. In short, the action point of the clamping force is best on the bearing surface. The clamping force should act in the direction of good rigidity of the workpiece. On the premise of ensuring that the workpiece is not loose, the smaller the clamping force, the better. 6. When machining parts with cavity, try not to let the milling cutter directly plunge into the parts like a drill bit, resulting in insufficient chip holding space of the milling cutter and unsmooth chip removal, resulting in overheating, expansion, tool collapse, tool breakage and other adverse phenomena of the parts. First drill the cutter hole with a drill of the same size or larger than the milling cutter, and then mill with a milling cutter. Alternatively, the spiral cutting program can be produced with CAM software. The main factor affecting the machining accuracy and surface quality of aluminum parts is that such parts are prone to deformation in the machining process, which requires operators to have certain operation experience and skills.
Original title: process measures and operation skills to reduce aluminum processing deformation! Machining super practical knowledge!The source of the article: WeChat official account: world advanced manufacturing technology forum, welcome to add attention! Please indicate the source of the article.

Aluminum is a rich element in nature. It has the advantages of light weight, good ductility, easy processing, corrosion resistance and so on. In addition to aluminum, the main material of aviation aluminum also adds magnesium, which is a metal of aluminum alloy. Aluminum alloy is an important raw material in industrial manufacturing. It has low density but high strength. It is close to or higher than high-quality steel. It has good plasticity. It can be processed into various profiles. It has excellent conductivity, thermal conductivity and corrosion resistance. It is widely used in industry. Especially in the field of automobile industry, aluminum alloy parts account for the vast majority.


Due to the particularity of material, aluminum alloy parts have high requirements for processing technology. Burr is produced by the extrusion of metal by cutting tools in the machining process. Deburring aluminum alloy machined parts is an essential step in the production process. The quality of deburring process directly affects the product quality of parts. Robot loading sycotec high-speed motorized spindle has high deburring efficiency and high precision, and realizes industrial automation, which is of great significance to the long-term development of processing enterprises.The principle of deburring aviation aluminum parts by industrial robot spindle is similar to manual deburring, but it changes the power into robot. With the support of programming technology and force control technology, flexible grinding (transformation of pressure and speed) is realized, and the advantages of robot deburring are prominent. This is a very popular automatic deburring method for aviation aluminum parts.The deburring of aviation aluminum parts has little requirements on the output of the main shaft, but has great requirements on the precision and speed of the main shaft. If the speed is low and the precision is low, the effect of deburring will be insufficient. Kasite 4036 DC-T ER11 high-speed motorized spindle has a maximum speed of 60000 rpm, a maximum power of 850W, and a cone runout of no more than 1 m. It is equipped with ER11 chuck, which can be applied to industrial robots such as abb, KUKA, stauber, etc.
Kasite 4036 DC-T ER11 is a deburring high-speed motorized spindle with radial axial flexible floating system. The contact pressure with the workpiece can be pneumatically adjusted to keep the pressure consistent at 360 . When machining parts with complex shapes or positioning dimensions have certain errors (within a certain range), the spindle will automatically offset and float radially or axially, so as to achieve the effect of accurate deburring.

By WILLIAM G. CONNOLLYDEC. 16, 1973 This is a digitized version of an article from The Timess print archive, before the start of online publication in 1996. To preserve these articles as they originally appeared, The Times does not alter, edit or update them. Occasionally the digitization process introduces transcription errors or other problems. Please send reports of such problems to archive_feedback@nytimes.com. DENVILLE, N.J.Fate, with a small hand from the railroads and the petroleum industry, has dealt Alfred Schneier Jr. a cruel blow.Fourteen years ago, Mr. Schneier decided to relocate his family business, the Advance Pressure Castings Corporation, from Brooklyn to this Morris County town nestled between the Erie Lackawanna Railroad and Interstate 80.There were several reasons for his decision to move. In addition to providing no room for expansion, the old Brooklyn plant lacked a railroad siding, and all of the company's raw materials were shipped by rail.Mr. Schneier rejected some otherwise suitable buildings because they did not have sidings.His business, producing intricate zinc and aluminum parts for all mantier of machinery, also requires a great deal of water to cool heavy equipment that handles molten metal with temperatures ranging up to 1250 degrees Fahrenheit.AdvertisementThe Denville property had a railroad siding, and with a bit of welldrilling and pumping it could produce 80gallons of pure water a minute.AdvertisementMore than anything else, though, Denville had energy electricity to run pumps, blowers and control devices, and natural gas, which Mr. Schneier's casting machines and huge reverberatory furnaces consume at the rate of 50 million cubic feet a year.The gas company and the electric company were just rubbing tnetr hands with glee when we decided to come, Mr. Schneier said the other day as a workman removed half the fluorescent tubes from the ceiling fixtures in his paneled office.The abschtely primary factor in our choice of a site was the availability of unlimited energy.Advance Pressure Castings moved in 1959.On Jan. 1, 1960, Mr. Schneier said with a wry smile, the entire metals industry shifted from rail to truck transportation. We've never had a boxcar on that siding.Worse yet, the executive saidwithout a smileIt has been a number of years since we have had unlimited gas.Mr. Schneier was hardly unique in using energy availability as the basis for his decision on where to locate his business.Since the day when textile manufacturers built their brick mills along the New England rivers that would drive their machines and the steel magnates constructed their vast complexes in the bituminous coal fields that would feed tons of coke to their hungry furnaces, the availability of energyalong with proximity to the market, the labor force and the raw materialshas played an important role in determining where industryAdvertisementNow, when almost all forms of energy are in short supply, leaders of industry may have to think in unac customed terms. With suppliers of fuel oil and natural gas turning away new customers and with the labor force under the threat of gasoline rationing, the pastoral settings and cheaper land of suburbia and exurbia may seem less attractive.Joseph 4ramanda, the president of the J. I. Kislak Realty Corporation, one of New Jersey's largest industrial and commercial real estate operations, sees the beginning of a trend toward moves to existing buildings in the older central cities.He said that his concern, which was involved in 150 industrial moves in the state during the last year, has been receiving a growing number of inquiries about plants in such cities as Newark, Jersey City, Bayonne, New Brunswick and Paterson.Many factorsall in one way or another relating to the energy crisis influence this trend, he said, adding that existing plants may have established sources of oil, electricity and natural gas; are usually close to a concentrated labor pool that would have to drive considerable distances to a suburban plant; are often served by mass transportation systems, and are close to such shipping facilities as truck depots, rail yards and docks.Alfred Schneier, the president of Advance Castings, is not planning to move back to the city or anywhere else. If I move out of the gas company's trunk line, he said, that's it. I think I'd have trouble moving across the street.The energy crisis began for Mr. Schneier when the New Jersey Natural Gas Company informed him about 10 years ago that it would periodically cut off his interruptible service because of peak demands from higherpriority users.After that warning, Advance Castings installed a backup fuel oil system. And it subsequently negotiated a new contract with New Jersey Natural Gas, re placing its agreement for interruptible service, which is commonly used by industrial customers who have alternate sources of energy, with a contract for noninterruptible service.It's about 20 per cent more expensive, Mr. Schneier said, but the gas company warned us that the in terruptible customers would be the first ones cut off. And what's the point of having fourcent gas if there isn't any? We might as well have 11cent gas.AdvertisementEnergy accounts for 2 per cent of the sales dollar, and I can foresee that number's doubling.Even though his service cannot technically be interrupted now, Mr. Schneier switches to oil if the gas company asks him to do so. We can cut our gas usage about 60 per cent, he said, and when they get in trouble we do it. After all, they can just shut you off for the public good if it comes to that.The three oil storage tanks installed by Advance Cast ings hold a total of 14,000 gallons enough, the company president said, to keep the plant running for two or three weeks.What happens if gas service is shut off and Mr. Schneier's two oil suppliers limit him to a percentage of the fuel he bought In 1972, as Federal regulations apparently require they do, beginning late this month?I could probably navigate for six to eight weeks. That's a guess.Thereafter, the 200 employes of Advance Pressure Castings Corporation would begin losing their jobs, and that, says the president of the company, would be just the beginning: Everything we make is used by someone else to make something else, so there would be a domino effect.Among the plant's diverse products are butts for hunting knives, frames for apartment mailboxes, rings for recessed lighting fixtures, housings for photographic enlargers, parts for the transport mechanisms in copying machines, heat sinks, cowls for the change slots in vending machines and parts for microscopes and toy electric trains.Virtually none of Advance Pressure Castings 400 regular customers has an alternate source of supply. Depending upon the size and intricacy of the casting to be produced, one industry offi cial said, the making of a die, or form, for it can cost anywhere from $2,500 to $20,000 or more, so we don't run around making extra ones.Because Advance Castings is the only source of some parts, its customers could continue full operations only as long as their inventories held out if Advance closed down.AdvertisementIn certain areas, said Paul J. Rosenblum, the director of purchases for Lightolier, Inc., of Jersey City, which makes lighting fixtures using parts supplied by Advance Castings, we could not go on beyond a month or a month and a half.Mr. Rosenblum said that as many as a third of Lightolier's 900 employes in Jersey City, Fall River, Mass., and Elgin, Ill., might be thrown out of work by a shutdown at the diecasting plant.And if we can't operate without those parts, he added, we wouldn't need a lot of other parts, so we would be cutting back or stopping orders from our other suppliers. In some cases, the effect on them would be devastating.Jules Prager, a vice president of the Charles Beseler Company of Florham Park, N. J., which buys from Advance Pressure Castings parts for photographic enlargers and projectors, estimated that 120 Beseler employes would be laid off if Mr. Schneier had to close his plant.So far, Mr. Schneier has not had to stop production, and he has been getting sufficient supplies of fuel. In the interest of conservation, he is cutting back the lighting in his office and plant, and the usual Christmas display will not appear this year in front of Advance Pressure Castings.He is consideringand discussing with the United Auto Workers, who represent his production employesa shift to a fourday, 40hour week. It would allow us to run our equipment 20 hours a day instead of 16 and shut it down three days a week instead of two, he said.So far, the main effects of the energy crisis for Mr. Schneier are financial. It has made us look hard at what we will accept as new business, he said.It has also meant higher costs: We spend more than $100,000 a year on energy, and that's up 25 per cent over the last three years and still rising. Energy accounts for 2 per cent of the sales dollar, and I can foresee that number's doubling.AdvertisementBecause he can pass along to his customers his major cost increases, Mr. Schneier is not overly worried. The utility bills are up, he said, but I don't think it's been staggering. It won't be a huge problem if it's universal.Not all businessmen are so sanguine. Peter Heide, the vice president and operations manager for Henry Heide, Inc., a New Brunswick company that manufactures jelly beans and such other childhood delights as Jujubes and Jujyfruits, the gumbased candies, has watched his fuel bills go up 18 per cent over the last year.The candy industry is one of the lowend industries relative 4.o the rate of return, he said. The net after taxes is about 3 per cent for the industry. And it's so competitive that we have not been able to recoup our cost increases, even where that is allowable.Beginning last year, Mr. Heide said, the interruption calls from Public Service Electric and Gas Company came more often and the interruptions were not always prompted by falling temperatures. We were effectively off gas for two solid months, he said.At several points last winter, he added, the Heide plant was within an hour or so of closing down.This year, Mr. Heide said, gas service has been interrupted three or four times for several days. It's just like last year. The interruptions are certainly not predicated on the weather. And this year the oil situation is really critical for us.The company's oil sup plier has reduced its allocation for December by 30 per cent, he added, and there's no guarantee that he might not have to cut it further.The Heide company's oil tank has a capacity of 20,000 gallons, which, the operations manager said, is enough to keep the plant going for no more than a week.A version of this archives appears in print on December 16, 1973, on Page 411 of the New York edition with the headline: . Order Reprints| Today's Paper|Subscribe

Aluminum was considered a "precious" metal during the first half of the 19th century due to its relative rarity. At the Paris Exhibition of 1855, a bar of aluminum was exhibited as a marvel. Nowadays, of course, aluminum is common. Yet in some regards, it seems somewhat dear when it comes to applications in North American vehicles, at least if we absent engine blocks and wheels. In fact, when you look at the body applications in the U.S., as compared with the doors, hoods, fenders, and deck lids produced for European manufacturers, the difference is nothing short of astonishing. According to Thomas P. Gannon, vice president, Sales & Marketing, Industrial and Automotive Products, Alcan Aluminum Corp. (Farmington Hills, MI), there are no aluminum doors produced in North America. Meanwhile, over in Europe, aluminum doors are produced for vehicles ranging from the $350,000 Maybach (A) to the $12K VW Lupo. The vehicle manufacturers that are taking advantage of the lightweight material include not only the prestigious brands like Jaguar (B), Aston Martin, Lotus, and Audi, but also the much more accessible ones like smart and Peugeot. In effect, perhaps, the Europeans have gotten over the aluminum bar in the glass case, while U.S. manufacturers, with few exceptions, are still looking at aluminum through the grass. Which is not to say that aluminum isn't being used in significant quantities in North America. It is. According to Gannon, the overall transportation market is the biggest user of aluminum in North America and that the passenger vehicle market is the biggest within transportation, accounting for some 5.3 billion pounds of the stuff. And when cars are looked at from a weight standpoint, aluminum is the third most-used material, following steel and iron. Says Gannon: "It overtook plastic in 2001 by two pounds. We're widening the gap and are just a few pounds away from iron. We'll probably overtake iron by 2007." The steel producers probably shouldn't be inordinately worried, as they tip the scales at around 1,800 lb. in a car, and second place is just a bit more than 300 lb. According to a report by Ducker Worldwide, "Global Automotive Aluminum Content Forecast Through 2010," it is projected that there will be 318 lb. of aluminum used in North American light vehicles by 2010. Gannon says that they're a bit more optimistic at Alcan, thinking that the average is more likely to be on the order of 350 lb. The argument for greater use is based on weight savings and the fact that consumers are apparently looking for vehicles that are (1) full of amenities and (2) large. So, in order to have powered doors, seats, windows, etc., nav systems, third rows of seats (C), and so on, all of which add weight, vehicle manufacturers must find the ways and means to reduce mass elsewhere, which could lead them to select aluminum rather than steel because a rule of thumb is that one pound of aluminum can be used in place of two pounds of steel. Second, there is the size issue. One of the issues with sport utility vehicles is their high center of gravity. Gannon suggests that one way to maintain the size of the vehicle yet to lower the center of gravity is to use aluminum body panels: "You can reduce the weight of your vehicle without sacrificing size or strength." Although aluminum may be lighter, he argues that aluminum handles crash energy quite well, in a predictable manner, so "light" doesn't equate to "flimsy" or "unsafe." One of the considerations that can be made about what is arguably still a premium material (and one that is likely to remain so, at least compared with steel) is retaining its value. Gannon cites a closed-loop recycling process that Alcan has developed with Ford at the Ford Chicago Stamping Plant. There, hoods are stamped, some 1.3 million annually. There is offal. And there is (probably) some scrap. The AA6111 scrap is kept segregated from other materials. It is bundled and shipped to Alcan's Oswego, NY, plant, where it is melted, then rolled back into aluminum sheet. The sheet is then shipped back to chicago Stamping, where it can be transformed into more hoods. The material doesn't degrade, so it is hood-to-hood, not, say, hood-to-engine block (which would be the case, Gannon admits, if other aluminum alloys were mixed in with the AA6111). So the issue here is that there can be value realized by reusing the material. (In Europe, where there is a requirement for the OEMs to handle the recycling of used products, this can help justify aluminum use.) A.) The Maybach 57 has a wheelbase of 133.5 in.; the Maybach 62 has a wheelbase of 150.7 in. The latter is claimed to be the longest production car in the world (total length: 242.5 in.). The doors are a study to aluminum. Not only are the door outers made with aluminum, but so too are other components. The window surrounds are produced with multi-chamber extrusions that are laser welded together. Superplastic forming, which involves both heat (up to 500[degrees]C) and pressure, was used to produce the internal components and the hinge reinforcements. Other aluminum panels on the Maybach body shell are the roof, hood, and front fenders. The overall weight of the body shell of the Maybach 57 is 1,289 lb.; it's 1,368 lb. for the Maybach 62. B.) The XJ8 is an aluminum-intensive vehicle that is apparently the Forerunner for things that Jaguar will be doing as time goes on, such as in producing the XK replacement (the X150). Shown here is the R-06 concept. It has an aluminum chassis. The body combines both aluminum and composite materials. The 21-in. wheels are of course, aluminum, as well. It doesn't, however, have an aluminum engine block. Rather, the V6 diesel (which will be used in the 5-Type mid-2004) has a compacted graphite iron block. C.) Apparently, in order to offset the weight of the third row of seats in the Yukon, GM engineers moved to aluminum for the lift gates for its GMT 830 vehicles. According to Gannon, the stamped aluminum parts are run at the same rate that the steel components had been.

(Bloomberg) - A metals manufacturer faked test results and provided faulty materials to NASA, causing more than $700 million in losses and two failed satellite launch missions, according to an investigation by the U.S. space agency.The fraud involved an Oregon company called Sapa Profiles Inc., which falsified thousands of certifications for aluminum parts over 19 years for hundreds of customers, including NASA.The bad parts were used in the making of Taurus XL, a rocket that was supposed to deliver satellites studying the Earth's climate during missions carried out in 2009 and 2011. The launch vehicle's fairing, a clamshell structure that carries the satellite as it travels through the atmosphere, didn't fully open, causing the unsuccessful launch, according to a statement from NASA."When testing results are altered and certifications are provided falsely, missions fail," said Jim Norman, director for launch services at NASA in Washington. He added that years of scientific work were lost because of the fraud.News of the satellite failures comes a week after Norsk Hydro ASA, the current parent company of Sapa, agreed to pay $46 million to NASA, the Department of Defense and others to resolve criminal charges and civil claims related to the fraud, which took place from 1996 to 2015.The company admitted that employees had faked test results related to the metal's strength and reliability under pressure. Sapa Profiles, now known as Hydro Extrusion Portland Inc., also agreed to plead guilty to one count of mail fraud and is barred from U.S. federal government contracting."Corporate and personal greed perpetuated this fraud against the government and other private customers, and this resolution holds these companies accountable for the harm caused by their scheme," said Brian Benczkowski, assistant attorney general of the criminal division at the Department of Justice, in an April 23 statement.A spokesman for Norsk Hydro said the case has been settled. Last week, it said it has invested "significant time and resources to completely overhaul our quality and compliance organizations.