The minimum thickness of the profile wall
The minimum wall thickness aluminum profile, which can still be profitable and pressed. This question is always exciting Extruders, they did not work at whatever extrusion press.
- Should you take on an order for profiles with an excessively low wall thickness?
- What price should I charge?
- How to ensure an acceptable level of marriage?
- Is it bad for the press?
Network LinkedIn on aluminum extrusion
Recently, we, Like many in our time, steel often happens in social networks. more precisely – one of them, little social, and in the overwhelming proportion - professional, network LinkedIn. Network LinkedIn allows registered users to create and maintain a list of business contacts in the most diverse areas of human activity. It employs a lot of interest groups, in which there is a discussion of the various professional issues.
One such group – Group Aluminium Extrusion Professionals. In total, this group – more 3700 Participants from around the world. From time to time there appear interesting discussions on important technical issues for the entire cycle of production of pressed aluminum products. These discussions are interesting by the fact, that reflect the most current state of a particular issue. What has adjusted the regions of the world - the United States, Europe, Asia (mainly India and China) and even Africa, at least, South. And a little Russian. Communication is in English, sometimes very broken, but professionals understand each other perfectly.
Somewhere in the last year flared up there, and still warm so far, discussion about a minimum wall thickness of extruded sections for industrial production, which can provide for industrial production batches. The reason for this debate was the cry for help of one of the band members from the Indian plant for extrusion of aluminum profiles.
"We are trying to press firmly 900 tons and a diameter 5 inches (127 mm) to extrude from alloy 6063-T6 in four strands, a profile of 23x23 mm with a wall thickness 0,4 mm. Pressed all of suitable profile 100 kg. We are waiting for opinions, tips and tricks ".
discussion turned, I will tell you, very lively. Therefore, free style discussion is partially preserved.
Opinion is divided somewhere in half. Half of the participants in the discussion considered, that for such an order does not need to be taken both for technical reasons, and because of its obvious unprofitability. Members of the second group were more optimistic and expressed some tips and recommendations on equipment and technology for pressing such a profile. Several people even said, that they have carried out such orders.
Extruding aluminum profile thickness 0,4 mm?
Arguments of "pessimists" were, primarily, of such kind:
- Prudent to refuse the order. Even if, in principle, turn out to press, still will not be able to avoid fluctuations in the thickness of the wall and will be a lot of marriage.
- This wall thickness is only possible when drawing.
- Pressing Profile thickness 0,4 mm, "bad" for the press, and can lead to breakdown and decrease the life of the matrix.
- Basically, The pressed tube with a wall 0,4 mm may be possible to. However, to produce such a profile to order and make a profit is hardly possible.
Extruding aluminum profile thickness 0,4 mm!
"Optimists" for his part expressed a lot of useful tips and tricks. To carry out such an order to force the press 900 tons in four points, they consider the following conditions necessary:
- Apply the special design of the matrix to reduce the pressure on the matrix. Called matrix type "micro bridge".
- Manufacturer Matrix - Only an experienced and proven.
- The length of the belt should be zero.
- Carefully azotirovat matrix. Nitrided layer works like Lubricant.
- Apply matrix tool, which is optimized for the matrix, to provide her with the best support. Especially to control the flatness of the bolster.
- To measure and control the temperature of the workpiece, die, the container and the profile at the output of matrix.
- Use preform with a temperature at the front end 50-60 ° C higher than the rear - the so-called, gradient heating.
- Use only high-quality primary blank, held the full homogenization.
- When pressing to avoid long stops.
- Longer apply, than usual press residue.
- Selling such a profile very high price. And sell the meters, instead of kilograms.
less stress, smaller diameter, Only one point
Some balers have proposed more drastic measures: to reduce the diameter of the container, reduce the number of points or even go the press with less effort. for instance, such:
- Such a wall profile 0,4 mm better compressed into one point and press about 600 tonnes. Four points is very difficult for such a thin wall. We tried many times - almost never happened.
- Change container 4 inches and compressed into four points.
- Press the product must comply with. Therefore, it is economically feasible to produce a profile with such a low linear weight (about 100 g / m) as follows. Press 200 tons - matrix with one point (there are such only in India and China) - specific pressure 80 kg / mm2 - the ratio of pressing 67 – performance 60 kg / h,
Previous extrusion of aluminum profiles with ultrathin-walled
Several people shared their experience of pressing such profiles:
On the Alcoa plant in Brazil 2000 year produced aluminum pipe with a wall of cars 0,4 mm, the truth of aluminum alloy 3003. Press 1650 tonnes, 6 inches, 6 points, 1000 tons per month.
- Pressed aluminum profile similar to the ram speed 10 mm / min, velocity profile 40 m / min. Alloy 6063 no special requirements.
- Extruding the wall profile 25x25 0,5 mm 6 points on the press 7 inch performance 1050 kg / h. With good spotter - it is quite possible.
- Press size (900 tons – 5 inches) too large for this type of profile. We made pipes for heat exchangers with micro-cavities, wall thickness 0,3 mm, width 25 mm and a height 5 mm. Coiling in the bay. Used a 500-ton press. The biggest problem - the metal breaks on this ultrathin wall. Ratio marriage directly dependent on the quality of the metal in terms of the content of the intermetallic particles and inclusions.
- We produce such profiles in Spain. normal alloy 6063 without special requirements, puller speed 30 m / min. produced already 1000 tonnes.
- Typically, the profiles having a wall thickness 0,4 mm (for example, multi-cavity flat pipes for air conditioners) are made from alloys of the 3xxx series and from primary metal. Press usually - 2000 tonnes. AND, of course, the price of aluminum profiles high. Do their alloy 6063 - bad idea.
Progress in the pressing profiles with thin walls
One of the panelists correctly noted, that there is clear progress in the minimum wall thickness of extruded aluminum profiles. To 1980 years it considered impossible to produce profiles aluminum alloy 6063 with a wall thickness of less than 2,2 mm. By the year 2000 this limit was already 1,5 mm, c 2006 year - 1,1 mm, and 2010 – 0,9 mm. Note, what 0,9 mm still not 0,4 mm.
Such is the debate. The conclusions one can make himself. And the fate of the order remains unknown.
by the way, the minimum wall thickness of extruded aluminum profile - is the theme of a thorough Seminars ET 2000.