Custom Aluminum Alloy Manufacturing Process
At Transformación Puebla, S.A. de C.V., every aluminum alloy that leaves our plant in San Pedro Cholula, Puebla, Mexico, is the result of a rigorous manufacturing process designed to deliver exact chemical compositions heat after heat. With over 35 years of experience and an installed capacity of 4,000 metric tons per year, we have perfected every stage of the process — from raw material receiving to finished product solidification — under the standards of our ISO 9001:2015 certified quality management system. Our approach combines state-of-the-art analytical technology, such as the Thermo Scientific ARL 3460 optical emission spectrometer, with the metallurgical knowledge accumulated over decades serving Mexico's automotive, electrical, steel, and extrusion industries. The result is a premium alloyed aluminum with low iron content and tight alloying element levels that meets or exceeds our customers' specifications. Below, we present the seven stages that make this level of precision and reliability possible in every batch we produce.
Receiving & Sorting
Our entire process begins with strict raw material control. Upon receiving recovered aluminum at our San Pedro Cholula plant, every load is inspected with a radioactivity detector to ensure the material is free from radiological contamination — a safety protocol that forms an integral part of our quality certificate. Next, the material is manually sorted by alloy family, separating, for example, 3xx.x series casting aluminum from 1xxx and 6xxx series extrusion aluminum, and non-metallic components such as plastics, rubber, steel, and organic contaminants are removed. Careful separation by alloy family is critical: mixing high-copper alloys with high-silicon, magnesium-free alloys would produce an off-spec composition. Sorted material is stored in designated, labeled areas, ready for melting. This first step is the foundation of the traceability and quality control we maintain throughout the entire process.
Furnace Melting
The sorted aluminum is charged into our melting furnaces, where it reaches temperatures above 700 °C until it becomes liquid metal. We operate three furnace types selected according to the volume and alloy required: the reverberatory furnace, ideal for large volumes and maintaining stable metal baths; the rotary furnace, which facilitates the melting of light scrap and turnings with high metallic recovery; and the tilting furnace, which enables controlled and precise pouring of the molten metal. The operation of each furnace is supervised by personnel with years of aluminum smelting experience. During melting we monitor bath temperature and dross behavior to optimize aluminum recovery and minimize oxidation losses. This combination of equipment gives us the flexibility to handle everything from small trial batches to large-scale production runs within our 4,000 MT/year capacity.
Fluxing & Degassing
Once the aluminum is molten, specialized fluxes are applied to the surface of the liquid bath. These fluxes serve several critical functions: they separate aluminum oxides (Al₂O₃) and other dross from the clean metal, promote the agglomeration of non-metallic impurities for removal, and protect the bath surface against reoxidation. Immediately afterward, rotary degassing is performed by injecting high-purity nitrogen through a submerged rotor lance into the molten metal. The fine nitrogen bubbles rise through the bath, carrying with them dissolved hydrogen — the primary cause of porosity in cast aluminum parts. This treatment dramatically reduces hydrogen levels and improves the internal quality of the metal, producing alloys with lower porosity and better mechanical properties in our customers' final castings.
Composition Adjustment
With the aluminum bath clean and degassed, our technical team proceeds to fine-tune the chemical composition. Based on a preliminary spectrometric analysis of the bath, we calculate the required additions of each alloying element to reach the target composition specified by the customer. Elements we typically adjust include Silicon (Si), Copper (Cu), Magnesium (Mg), Manganese (Mn), Zinc (Zn), and Titanium (Ti), added either as pure metals or as master alloys conforming to the EN 575 standard — such as AlTi5B1 for grain refinement, AlSr10 or AlSr15 for eutectic modification, and AlTi10 for titanium adjustment. Each addition is precisely weighed and incorporated into the bath with controlled stirring to ensure homogeneous dissolution and distribution. After each significant addition, a new sample is taken for spectrometric verification, ensuring the final alloy meets the exact required ranges.
Spectrometric Analysis
Chemical composition verification is the heart of our quality control. We use a Thermo Scientific ARL 3460 spark optical emission spectrometer (spark-OES) capable of analyzing more than 12 elements simultaneously with high precision and repeatability. The instrument is calibrated with certified reference materials (CRMs) and is periodically verified to maintain metrological traceability. During each heat we perform multiple analyses: a preliminary analysis after melting to determine the necessary adjustments, intermediate analyses after each alloying addition, and a final approval analysis before authorizing the pour. If at any point the composition does not meet the customer's specification, the bath is corrected and re-analyzed until the approved ranges are achieved. This multiple-analysis protocol is the reason our customers trust the consistency of our alloys.
Filtration
Before the final pour, the approved liquid aluminum passes through a filtration system designed to trap non-metallic inclusions that may remain in the bath. These inclusions — aluminum oxide particles, refractory fragments, flux residues, and other solid impurities — can cause serious defects in final castings, such as porosity, hard spots, and mechanical failures. The filtration system uses ceramic filters that retain solid particles while allowing the free flow of clean molten aluminum. Additionally, we evaluate metal cleanliness using the K-Mold method, a standardized test that quantifies inclusions present in a solidified sample. This step complements spectrometric analysis: while the ARL 3460 verifies chemical composition, filtration and K-Mold testing guarantee the physical cleanliness of the metal, ensuring a product of comprehensive quality.
Casting & Solidification
With chemical composition approved and the metal filtered, it is poured into the corresponding molds according to the product requested by the customer: ingot molds for ingots of approximately 11 kg, annular molds for donuts of approximately 1 kg, or the casting table for bars of 7-inch diameter and 3.7-meter length. Pouring temperature is carefully controlled to ensure complete fill and uniform solidification that minimizes shrinkage and internal defect formation. Once solidified, each batch is identified with its heat number for full traceability. A chemical analysis certificate is issued that includes the exact percentages of each element verified by our ARL 3460 spectrometer, together with the radioactivity measurement. The finished product is stored properly identified, ready for shipment to the customer with its complete quality documentation.
Quality Control at Every Step
At Transformación Puebla, quality control is not an isolated stage: it is a thread that runs through every step of our process. From radioactivity detection at raw material receiving to the issuance of the finished product analysis certificate, every critical point is backed by documented measurements and verifications in accordance with our ISO 9001:2015 quality management system. The core of our laboratory is the Thermo Scientific ARL 3460 optical emission spectrometer, a spark-OES instrument that simultaneously analyzes more than 12 elements — including Si, Fe, Cu, Mn, Mg, Zn, Ti, Ni, Sn, Pb, Cr, and Sr — with precision on the order of hundredths of a percent. The instrument is calibrated with certified reference materials (CRMs) from internationally recognized suppliers, and its performance is verified daily before operations begin. We perform multiple analyses per heat: a preliminary analysis to plan additions, intermediate adjustment analyses, and a final approval analysis. Metal cleanliness is evaluated using the K-Mold method for non-metallic inclusion detection. Each batch of finished product is accompanied by a chemical analysis certificate traceable to our calibration standards, including the complete element-by-element composition and radioactivity measurement. This level of rigor is what allows us to manufacture alloys with specifications as demanding as A356.2, where iron must be kept below 0.12%, and to confidently serve the requirements of Mexico's automotive, electrical, and steel industries.
Ready to request a quote?
Our process guarantees the exact chemical composition your process requires.