When the selling price of aluminum profile remains unchanged, the higher the production cost, the lower the profit. In the current harsh environment such as rising raw material prices, rising wages of workers, appreciation of the renminbi, rising energy prices, and increasing tax burdens, competition in the same industry has entered a “white-hot” and the era of refined cost control has come.
Cost control is the key and core of business management.Only by constantly discovering weak links and tapping the internal potential,Use all means and ways to reduce costs,Full participation, starting from the details, starting from the reduction of waste, and meticulously implementing the cost control of aluminum profiles, can effectively broaden the enterprise’s survival space, improve the state of enterprise management, and enable the enterprise to develop continuously and remain invincible.
The cost control of aluminum profile is guided by the value chain, and the cost control is divided into design cost, purchase cost, manufacturing cost, sales cost and service cost. Because cost control involves a wide range and content. From the perspective of manufacturing, I will talk about how to increase the production yield rate and reduce production costs.
Proved by data analysis and practice,Improving the yield of aluminum alloy profiles is one of the most direct and effective methods to reduce production costs.Take the extrusion workshop as an example,For every percentage increase in the yield rate,The production cost per ton of aluminum will be reduced by 25-30 yuan,And this reduced part is the net profit of the enterprise.
How to increase the yield of aluminum profiles, reduce aluminum waste, and increase productivity? We summarized the extrusion waste:
The waste of aluminum profiles is divided into two categories:
Geometric waste and technical waste.
Geometric waste is an unavoidable waste of aluminum alloy profiles in the extrusion process.
Such as squeezed residual material,
The chucks at both ends of the product during stretching,
The cut-to-length material is discarded because it is not enough to be the cut-to-length,
Cut the necessary samples,
The aluminum block remaining in the cavity of the split combined mold,
Ingots and products are cut from cut-to-length sawing aluminum shavings and aluminum ingots consumed during mold trial.
Technical waste is caused by unreasonable technology in the production process of aluminum alloy profiles.The equipment is faulty, and the worker’s improper operation is caused by man-made waste.It is different from geometric waste products. Through technical improvement and strengthening management, it can effectively overcome and eliminate the generation of technical waste products.Technical waste can be divided into:
Organization waste: overburning, coarse crystal ring, coarse crystal grain, shrinking tail, slag inclusion, etc.
Mechanical properties unqualified waste: strength and hardness are too low, not meeting national standards: or plasticity is too low, not fully softened and not meeting the technical requirements.
Unqualified surface quality waste products: layering, bubbles, extrusion cracks, orange peel, structure streaks, black spots, longitudinal welding lines, horizontal welding lines, scratches, metal indentation, etc.
Geometry scraps: waves, twists, bends, plane clearances, size tolerances, etc.
The yield is divided into process yield and comprehensive yield.
The process yield generally refers to the main process,The calculation is usually based on the workshop.Melting and casting process (melting and casting workshop), extrusion process (extrusion process), oxidation coloring process (oxidation workshop), powder spraying process (spraying workshop).Its definition is:The ratio of the qualified output of the workshop to the input of raw materials (and possibly semi-finished products) in the workshop.
Yield rate and equipment quality,Ingot quality,product structure,Variety and specification conversion frequency,
The advanced level of process technology,The level of enterprise management is related to factors such as the quality of the operating workers.
The key to improving the of aluminum alloy profiles is to reduce and eliminate waste.Although geometric waste is inevitable,But you can try to minimize it.Technical waste is a human factor,It can be eliminated by analyzing item by item,It can also be reduced to the lowest level.For this reason, the following measures can be taken to effectively control and improve the yield of extruded products.
1. Measures to reduce geometric waste
The correct selection of the length of the ingot is the main measure to reduce process waste.The length of the ingot is not calculated after extrusion,Instead, you have to calculate before squeezing.
Most companies now use long rod hot-shear aluminum rod heating furnaces,Compared with the short rod heating furnace, it reduces the loss of aluminum chips,Due to the change in the wall thickness of the mold, the control of the casting length is more flexible and accurate.Greatly improve the yield rate,However, many companies ignore the calculation of the length of the cast rod after using the long rod hot shear furnace.And directly hand over this work to the operator to control.Operators often make the next bar based on experience.Observe the length of the output material,If the difference is large,Continue to adjust,Usually it takes about 3 rods to get the exact length.
In this process,Has produced a lot of waste,This reduces the production efficiency,It also reduces the yield.
The correct approach is to calculate the length of the ingot by the process control department during the initial production of the mold. When the mold is produced on the machine multiple times, add about 5 to 10 mm according to the last production rod length recorded on the mold card. Observe the length of the material when it is drawn. Fine-tune if there is a difference.So the second rod is very accurate.According to data, the use of long rod hot shear can increase the yield by 4%.It is completely feasible to increase by 2 to 3 percentage points in actual production.
In addition, when selecting the number of fixed lengths or the length of the product, under the premise of ensuring the smooth extrusion of the extruder. When the length of the cooling bed is long enough, increase the number of fixed lengths or the length of the product as much as possible, that is, it is possible to choose a longer ingot. This is also an effective way to reduce the percentage of process geometry waste and increase the yield.
2. Measures to improve the yield rate from the technical level
Improving the level of mold design and manufacturing, and reducing the number of mold trials are important technical measures to increase the yield. Generally, each trial mold consumes 1 to 3 ingots, which reduces the yield rate by 0.5 to 1%. Due to the design of the mold, the manufacturing level is low, and some products need to be repaired.The finished product can only be produced after 3 to 4 mold trials or even more times, which invisibly reduces the yield by 2 to 5%, which not only causes economic losses, but also prolongs the production cycle due to repeated mold trials.
Modern molds put forward the concept of zero trial molds, that is, after molds are manufactured, no trial molds are required, and qualified products can be produced directly on the machine. Using simulation design software, finite element analysis, the design can all be completed in the computer. It is also possible to simulate the test mode through the computer. The mold cavity processing is completed in the automatic machining center, and the entire mold processing is completed with high precision, so the quality of the mold is very high. The pass rate on the machine is above 90%. The yield rate can be increased by 2 to 6%.
3. Appropriately increase the aluminum extrusion coefficient to increase the yield
Each aluminum material factory has a series of machines. According to the extrusion ratio of the product, the length of the cooling bed, the outer circle of the product, and the length and diameter of the extrusion cylinder, each factory determines the product to be produced on the corresponding machine. Practice has proved that products of the same specification are produced on extruders with different tonnages. Due to the different extrusion coefficients, the structure and production efficiency of the products will be greatly affected, and the yield will also be different. When the tonnage of the extruder is larger, the extrusion coefficient is larger, the yield is higher, and the extrusion cost is close.
4. Improving the quality of ingots is the prerequisite for improving the yield
Ingot casting is the raw material for extrusion production. The ingot structure is uniform, with small grains, no slag inclusion, pores, segregation, cracks and other defects, which can not only reduce the extrusion force, increase the extrusion speed, and improve the internal quality of the product. Moreover, it can reduce defects such as bubbles, pores, scratches, cracks, and pitting on the surface of the product. Smaller slag can be discharged through the slits of the mold working belt, but it will cause cracks on the surface of the profile and cause a certain length of waste. Larger slag inclusions will be stuck in the slits of the working belt and cannot be eliminated, causing plug molds or product cracks. Changing molds will seriously affect the yield. Use corresponding pads when stretching and straightening to reduce the cutting length of the head and tail material
When the profile is stretched and straightened, many companies do not design corresponding cushions, especially some large cantilever profiles and hollow profiles. As a result, the deformation of the profile head and tail is too large, and when the finished product is sawed, the deformed part must be cut off. This has caused a drop in yield.
Hardwood or aluminum blocks can be used for the cushions, and the specifications of the cushions are minimized in the design to increase the versatility of the cushions. For a profile with a long cantilever wall and a closed cross-section, a support frame should be placed on the cantilever part when the cushion is inserted into the closed cavity during straightening. Thereby reducing the amount of deformation in the longitudinal direction. The fixture must be designed by a dedicated person, managed by a dedicated person, and guide workers to use it.
At the same time, in order to prevent workers from being unwilling to use pads because of troubles, a reward and punishment mechanism must be established in which the yield rate is linked to wages.
5. Strengthen the management of aluminum extrusion dies and original production records
The mold card and the original production record are very important. The mold card must be able to truly show the mold nitriding, maintenance, and output conditions. The original record must be able to truly show that the weight, casting length, and quantity, and they are provided reliable basis for the next production.
Many companies have also implemented computerized data management, but there is still a long way to go in practical applications.
6. Use non-overpressure extrusion to reduce geometric waste
The fixed pad is squeezed without excess pressure, which is to fix the squeeze pad on the squeeze rod and make certain changes to the two. When the squeeze cylinder does not retreat, the pressure pad is also easy to separate from the ingot. Then directly push the next ingot into the extrusion cylinder. Squeeze together with the surplus of the previous ingot, thus avoiding the surplus of each ingot being cut once. The number of casting shears can be determined according to the quality requirements and the order quantity. Usually 40-50 roots are cut once.
7. Optimize aluminum extrusion process to reduce technical waste
There are many aspects of the extrusion process that affect technical waste, and it covers the entire extrusion production process. Mainly include: ingot quality, process temperature, extrusion speed, extrusion tools, molds, transfer loading and unloading, aging heat treatment, etc. In addition to formulating advanced and scientific production processes, it is also necessary to strictly implement operating procedures to improve the proficiency and sense of responsibility of workers.
Try to reduce the varieties produced per shift. It is best to arrange only 3 to 5 varieties per shift to increase the output of a single set of molds on the machine at a time. The more varieties on the machine, the more aluminum molds are taken away, and the lower the yield rate.
The impact of molds on the yield rate is mainly in two aspects: the use of new mold trial molds and production molds
The more mold trials, the more mold aluminum will be taken away, and the lower the yield rate will be. Therefore, the design and production level of the mold must be improved.
The production mold must be carefully repaired, reasonably nitrided, and timely maintained. Ensure that the pass rate is high every time. Good formability and high durability. If each shift fails due to unqualified mold repairs and causes 3 to 4 varieties to fail on the machine, the yield rate will be reduced by at least one percentage point.
Aluminum profile extrusion tools include: extrusion barrel, extrusion rod, extrusion pad, die pad, etc. Mainly ensure that the extrusion barrel, rod, and die are concentric at three points. The second is to maintain the squeeze cylinder reasonably, heat it correctly, and ensure that the end surface of the cylinder is flat. Eliminate the phenomenon of poor fit between various extrusion cylinders and molds. Regularly clean the residual aluminum on the inner wall of the extrusion cylinder, check the inner hole wall for damage, and use the mold pad correctly to improve the support strength of the mold.
Extrusion temperature, extrusion speed and cooling have a great influence on the product structure, mechanical properties, surface quality, and also affect the yield. In addition, the three factors will affect the length of the product. When the temperature of the cast rod is high, the extrusion speed is fast, and the cooling rate is low, the length of the product after extrusion will increase, and the growth rate can reach 0.5% to 1%, which also affects the profile Linear density, so a stable process can improve the yield.
Improve the subsequent process of extrusion to avoid technical waste. The transfer of the subsequent processes of extrusion, mainly pay attention to the scratches of the profile.
7. Optimize aluminum extrusion process to reduce technical waste
There are many aspects of the extrusion process that affect technical waste, and it covers the entire extrusion production process. Mainly include: ingot quality, process temperature, extrusion speed, extrusion tools, molds, transfer loading and unloading, aging heat treatment, etc. In addition to formulating advanced and scientific production processes, it is also necessary to strictly implement operating procedures to improve the proficiency and sense of responsibility of workers.
Try to reduce the varieties produced per shift. It is best to arrange only 3 to 5 varieties per shift to increase the output of a single set of molds on the machine at a time. The more varieties on the machine, the more aluminum molds are taken away, and the lower the yield rate.
The impact of molds on the yield rate is mainly in two aspects: the use of new mold trial molds and production molds
The more mold trials there are, the more mold aluminum will be taken away, and the lower the yield rate will be. Therefore, the design and production level of the mold must be improved.
The production mold must be carefully repaired, reasonably nitrided, and timely maintained. Ensure that the pass rate is high every time. Good formability and high durability. If each shift fails due to unqualified mold repairs and causes 3 to 4 varieties to fail on the machine, the yield rate will be reduced by at least one percentage point.
Aluminum profile extrusion tools include: extrusion barrel, extrusion rod, extrusion pad, die pad, etc. Mainly ensure that the extrusion barrel, rod, and die are concentric at three points. The second is to maintain the squeeze cylinder reasonably, heat it correctly, and ensure that the end surface of the cylinder is flat. Eliminate the phenomenon of poor fit between various extrusion cylinders and molds. Regularly clean the residual aluminum on the inner wall of the extrusion cylinder, check the inner hole wall for damage, and use the mold pad correctly to improve the support strength of the mold.
Extrusion temperature, extrusion speed and cooling have a great influence on the product structure, mechanical properties, surface quality, and also affect the yield. In addition, the three factors will affect the length of the product. When the temperature of the cast rod is high, the extrusion speed is fast, and the cooling rate is low, the length of the product after extrusion will increase, and the growth rate can reach 0.5% to 1%, which also affects the profile Linear density, so a stable process can improve the yield.
Improve the subsequent process of extrusion to avoid technical waste. The transfer of the subsequent processes of extrusion, mainly pay attention to the scratches of the profile.
8. One-mold porous extrusion can increase the yield
For some products suitable for porous extrusion, use porous extrusion as much as possible, which can not only reduce the extrusion coefficient, reduce the extrusion force, but also increase the yield. In the case of zero technical waste, double-hole extrusion can increase the yield by 3% to 4% compared with single-hole extrusion.
Extrusion speed is an important process parameter in the extrusion process, which is related to the quality of the product and the level of production efficiency. Extrusion speed is not like mastering the process temperature. One kind of alloy and one heat treatment process can basically choose the temperature, and the extrusion speed is a very empirical process parameter. For profiles with different alloy states and different sections, the extrusion speeds are different. The same product is affected by temperature changes during the extrusion process, and the extrusion speeds before and after are different. To properly control the extrusion speed, the following should be done:
Skillfully and flexibly master the extrusion speed range of various alloys and various cross-sections (including wall thickness), and pay attention to the influence of the extrusion speed on the aluminum profile, such as surface quality, forming degree, etc.
Familiar with the ability of extrusion equipment to control extrusion speed. Some extruders have constant velocity extrusion control and PLC control, some only have PLC control, and some do not have both. When an extrusion speed is given, some extruders can begin to squeeze at this speed. As the billet in the extrusion cylinder gradually decreases, the extrusion force decreases, and the product flow rate becomes faster and faster. Sometimes Will cause cracks in the back of the product. Therefore, it is necessary to adjust the extrusion speed in time. Only by knowing the status of the equipment can the extrusion speed be adjusted and controlled appropriately.
Understand the influence of different dies on the extrusion speed. Generally speaking, the extrusion speed of the flat die (solid profile) is higher than that of the split die (hollow profile). However, products with the same type of mold and the same cross-sectional shape have different extrusion speeds due to different design and manufacturing levels. Especially semi-hollow profiles with different wall thicknesses or openings have a great relationship with the mold. Only a certain extrusion speed designed by the mold is the best. If the speed is too fast or too slow, it is easy to twist. The phenomenon of opening and closing.
9. Reduce the generation of waste by strengthening the first inspection and process inspection
The aluminum shape and dimension waste products such as wall thickness out-of-tolerance, twisting, plane clearance, opening or closing, etc., are mainly checked by the host hand after the first bar after the test mold is discharged and the quality inspector after the stretching. Put an end to the generation of such waste products. Generally, the wall thickness tolerance should be controlled from the negative tolerance, because as the products are successively produced, the wall thickness of the products will gradually become thicker due to the gradual wear of the mold. For large cantilever profiles, check carefully against the drawings when stretching and straightening, and control a reasonable amount of stretching.
Surface waste products such as scratches, orange peel, texture, dark spots, bubbles, etc., often not all appear on every product. It is necessary to check each other through the host hand, quality inspector, and sawing process of the stretched product, and jointly supervise the removal of the waste products on the surface.
If the quality inspector finds no scratches on the product on the discharging table, and the product is found to be scratched when the finished product is sawed, it must be checked during the conversion process of the cooling bed to see if it is transporting belts, feeders, etc. There are hard protruding parts that cause scratches on the product.
Quality management is the management of all employees and the whole process. Each process must be quality controlled, and the combination of self-inspection, mutual inspection and special inspection can effectively eliminate technical waste in the bud. Artificial control and improvement of yield.
Through the above measures, geometric waste can be reduced. It can be seen that reducing geometric waste is an important technical management measure for enterprises, which is of great significance to high economic benefits.
Improving the yield rate of aluminum extrusion blanks requires a comprehensive and meticulous work process in extrusion production. Not only the technical process must be in place, but the management must also be in place and practical. There is still a lot of room for the improvement of the yield of aluminum profile enterprises in my country. The improvement of the yield will be a continuous process. The improvement of the yield and the improvement of product quality and output are closely linked. It is a comprehensive manifestation of an enterprise’s technology and management level.
Post time: Dec-30-2021