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.

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.

Aluminum parts manufactured with falsified data are flying on Boeing jetliners today and were used extensively across all the company's commercial products, according to a person briefed on the impact to the plane maker. The material is unlikely to cause safety concerns, the person added. But the problem presents a significant headache for the plane maker, which will have to account for all of the suspect aluminum and ensure every component meets regulatory standards. Boeing (BA) acknowledged that it was notified about the issues with the Japanese metals company. Boeing "has been working closely and continuously with our suppliers ... to ensure timely and appropriate action, including comprehensive inspections and analysis throughout our supply chain," a spokesman said in a statement. "Nothing in our review to date leads us to conclude that this issue presents a safety concern," said Boeing. The Kobe Steel scandal has shaken corporate Japan and sparked concern across the global supply chain in aerospace as well as the automotive manufacturing and rail industries. Related: Kobe Steel shares crash again. Can it survive fake data scandal? Kobe Steel has admitted it fabricated data related to the quality and strength of aluminum and copper used in a range of products at hundreds of companies -- from cars to defense equipment and airplanes. The company said it was undertaking a broad investigation into its initial findings. The suspect aluminum has been used to make parts from Japanese manufacturers Mitsubishi, Kawasaki and Subaru, which make major structural portions of Boeing's jets, as well as Nabtesco, which supplies the plane maker with mechanical components called actuators that move the jet's flight controls. A spokesman for Subaru said, "We are still investigating this situation with our supplier base to see which parts contain this steel, and to see if there is any risk posed at all." Mitsubishi Heavy Industries and Nabtesco did not immediately respond to requests for comment. Kobe Steel is required to submit data attesting to the material properties of the parts it makes for companies that supply parts to Boeing's factories. A portion of material it is building with is set aside for testing. In many cases, data collected in testing didn't pass strength tests and were disregarded, the person briefed on the Boeing findings said. Kobe said in a report released on Friday that "a portion of the inspection items ... was not conducted, and inspection data was rewritten" on its aluminum products. Kobe said the aluminum parts in question were manufactured between September 2016 and August 2017, but Boeing and its suppliers are looking farther back to determine the extent of the impact. Mitsubishi Aircraft Corporation, manufacturer of the new Mitsubishi Regional Jet, said it affected parts are used on test aircraft it is flying today. Production standard aircraft won't be delivered until 2020. A spokesman for Boeing rival Airbus said it does not use Kobe aluminum on its airliners, but parts of the landing gear on its new A350 XWB is forged from Kobe's titanium. Kobe also supplies non-aluminum parts for engines that fly on many of Airbus's jets. Kobe has not indicated titanium is part of its inquiry into falsified data.