How to Improve Aluminum Profile Yield and Reduce Scrap

In aluminum profile production, profit equals sales revenue minus production costs. The total cost of aluminum profiles is divided into fixed costs and variable costs. Fixed costs, such as factory rent and machine depreciation, remain constant. Variable costs, however, have significant flexibility.

In the case of constant aluminum profile selling prices, higher production costs lead to lower profits. Nowadays, with adverse factors such as rising raw material prices, increasing labor costs, RMB appreciation, higher energy prices, and heavier tax burdens, competition within the industry has reached a "white-hot" stage. The era of refined cost control has arrived.

Cost control is the key and core of enterprise management. Only by continuously identifying weaknesses, tapping internal potential, utilizing all means and channels to reduce costs, encouraging full employee participation, starting with details, beginning with waste reduction, and implementing meticulous aluminum profile cost control, can enterprises effectively expand their survival space, improve their management status, achieve sustainable development, and maintain a competitive edge.

Aluminum profile cost control is guided by the value chain, which divides cost control into design cost, procurement cost, manufacturing cost, sales cost, and service cost. Due to the extensive scope and diverse content of cost control, I will discuss from a manufacturing perspective how to improve production yield and thereby reduce production costs.

Through data analysis and practical verification, improving the yield rate of aluminum alloy profiles is one of the most direct and effective ways to reduce production costs. Taking the extrusion workshop as an example, every one percentage point increase in the yield rate will reduce the production cost of aluminum materials by 25-30 yuan per ton, and this reduced portion represents the company's pure profit. To improve the yield rate of extrusion, the primary task is to reduce extrusion waste.

How to improve the yield rate of aluminum profiles, reduce aluminum scrap, enhance productivity, and decrease production costs? We have summarized the extrusion defects as follows:

Aluminum alloy extruded profiles can be classified into two main categories of defects: geometrical defects and technical defects. Geometrical defects are inevitable in the extrusion process of aluminum alloy profiles. These include residual materials from extrusion, clamps at both ends of the product during stretching, materials discarded due to insufficient length for fixed-size products, necessary samples cut for testing, aluminum blocks remaining in the porthole of porthole dies, aluminum chips consumed during sawing of fixed-length billets and products, and aluminum ingots consumed during die testing.

Technical scrap is the waste generated in the aluminum alloy profile production process due to unreasonable processes, equipment malfunctions, and improper worker operations. It differs from geometric scrap in that technical scrap can be effectively overcome and eliminated through technological improvements and better management. Technical scrap can be classified into:

Woven waste products: over-burning, coarse grain ring, large grains, shrinkage tail, slag inclusion, etc.

Mechanical properties non-conforming products: Strength and hardness are too low, failing to meet national standards; or plasticity is too low, without sufficient softening to meet technical requirements.

Surface Defects: Delamination, Bubbles, Extrusion Cracks, Orange Peel, Structural Streaks, Black Spots, Longitudinal Weld Line, Transverse Weld Line, Scratches, Metal Inclusion, etc.

Geometric Dimensional Defects: waviness, twisting, bending, flatness gap, dimensional deviation, etc.

Yield can be divided into process yield and overall yield.

The Finished Product Aluminum Rate (FPAR) generally refers to major production processes, usually calculated on a workshop basis. This includes processes such as melting and casting (melting and casting workshop), extrusion (extrusion workshop), oxidation and coloring (oxidation workshop), and powder spraying (spraying workshop). The definition of FPAR is the ratio of qualified output to raw material input (or semi-finished products) in each workshop.

The yield rate is related to factors such as equipment quality, ingot quality, product structure, frequency of product specification changes, advancement of process technology, enterprise management level, and operator qualifications.

The key to improving the yield rate of aluminum alloy profiles lies in reducing and eliminating defects. While geometric defects are inevitable, they can be minimized through proper measures. Technical defects, which are caused by human factors, can be analyzed and eliminated item by item, or reduced to the minimum level. To achieve this, the following effective methods can be adopted to control and improve the yield rate of extruded products.

6.1.3.1 Reducing geometric waste is a crucial prerequisite for improving yield.

Measures to Reduce Geometric Defects/Scrap

Proper selection of ingot length is the main measure to reduce process scrap. The ingot length should not be calculated after extrusion, but should be calculated before extrusion.

Nowadays, most enterprises have adopted long rod hot shearing aluminum rod heating furnaces. Compared with short rod heating furnaces, they have reduced aluminum scrap loss. Due to changes in mold wall thickness, the control of casting length is more flexible and accurate, greatly improving the yield rate. However, after using long rod hot shearing furnaces, many enterprises neglect the calculation of casting length and directly hand this task over to operators for control. Operators usually rely on experience to start with one rod, observe the output length, and if there is a significant difference, they continue to adjust. It usually takes about three rods to get the accurate length. In this process, a considerable amount of waste has already been generated, which not only reduces production efficiency but also lowers the yield rate.

The correct approach is as follows: During the initial production of molds, the process control department should calculate the ingot length. For molds used in multiple production runs, refer to the previous rod length recorded on the mold card and add approximately 5-10MM. Observe the material output length during production and make fine adjustments if there are any differences. This will ensure high precision for the second rod. According to available data, using long rod hot shearing can increase the yield rate by 4 percentage points, and in actual production, improving the yield rate by 2-3 percentage points is entirely feasible.

When selecting the number of fixed lengths or product length, under the premise of ensuring smooth extrusion by the extrusion machine, and when the cold bed length is sufficient, the number of fixed lengths or product length should be increased as much as possible, that is, longer ingots should be selected. This is also an effective method to reduce the percentage of process geometric waste and improve the yield.