How Aluminum CNC Machining Center Improves Product Quality And Precision

How aluminum CNC machining center improves product quality and precision

Reasonable selection of tools and cutting parameters

Aluminum alloy materials with a soft texture and high viscosity are prone to produce built-up edge during processing. When choosing carbide tools, pay special attention to the rake angle. Excessive rake angle will weaken the strength of the blade. In the actual machining process, we recommend using coated high-speed steel tools because the coating can reduce friction heat. The cutting speed is usually controlled within the range of 200 to 400 meters per minute, and the feed rate is maintained at 0.02 to 0.05 mm per tooth. Cutting at too high a speed will cause the aluminum alloy to soften rapidly, resulting in out-of-tolerance dimensions of the workpiece. An auto parts factory once blindly increased speed, resulting in a batch of parts worth 50,000 yuan being scrapped.

The rigidity of the machine tool is a factor that must be considered when setting the feed speed. Those old machine tools have poor rigidity and will cause vibration if the feed speed is too fast. We once encountered customer feedback that chatter marks appeared on the processing surface. After inspection, it was found that the feed speed was too fast. After making adjustments and reducing the feed rate from 300 mm per minute to 200 mm, the vibration marks disappeared instantly. The choice of coolant is also very critical in this matter. Emulsion has a better cooling effect than pure oil and can effectively take away heat. It is recommended to check the cutting temperature every 30 minutes. Use the back of your hand to get close to the workpiece to feel the temperature. If the temperature is too hot, you need to adjust the parameters.

Carefully designed workpiece fixture solutions

The machining accuracy is directly affected by the design of the fixture. For thin-walled aluminum alloy parts, we recommend using vacuum suction cups and pressure plates to fix them. When we customized the fixture for a medical equipment company in 2025, we used a multi-contact support structure to control the deformation of the part within 0.02 mm. The positioning datum of the fixture must be consistent with the design datum, otherwise cumulative errors will occur. In actual cases, some factories use three-jaw chucks to clamp round aluminum parts. As a result, the clamping position deviation each time caused the roundness to be out of tolerance. Later, the problem was solved after using elastic jackets.

It is necessary to ensure that the clamping force of the clamp is uniformly distributed. We have conducted tests before. When four pressure plates are used for fixation, the pressure should be controlled within the range of 50 to 80 Newtons per square centimeter. If the pressure is too high, the thin-walled parts will be crushed. If the pressure is too small, the workpiece will move. For mass production, it is recommended to use pneumatic clamps. After an electronics factory changed the manual clamp to pneumatic, The time used for clamping is shortened from 45 seconds to 8 seconds. At the same time, the repeatability of clamping is increased from 0.1 mm to 0.03 mm. The anti-rust treatment of the clamp cannot be ignored. During the processing of aluminum alloys, the coolant is highly corrosive, and the surface of the clamp needs to be chromium plated or oxidized.

Strictly control the quality inspection process

Just using calipers to measure a few key dimensions for quality inspection is not enough. After we introduced the three-dimensional coordinate measuring machine, we found that many parts that seemed to be qualified actually had problems with geometric tolerances. In March 2026, a customer complained that parts could not be assembled. Through three-dimensional coordinate inspection, we found that the position of the hole exceeded the tolerance range by 0.03 mm. It is extremely necessary to establish a first-piece inspection system for each batch. Only after the first piece is qualified can batch processing be carried out. The inspection frequency is recommended to select 1 piece from every 10 pieces for inspection, and for key processes, 1 piece from every 5 pieces should be selected for inspection.

The results of data inspection must be recorded in detail and archived. For our company, it is clearly stipulated that each part must have its own inspection report. This report covers a series of indicators such as size, roughness, hardness, etc. By 2025, we will assist a robot company to optimize its inspection process. After that, the company’s product qualification rate increased from the original 92% to 98.5%. Once problems are discovered during the inspection, The machine must be stopped immediately to make adjustments, and machining operations must not be continued with a sense of luck. We once encountered situations where chips caused scratches on the surface of the workpiece. After that, we added a visual inspection process to the inspection process. We used a magnifying glass to observe the surface, so that we could detect the problem in time and adjust the position of the coolant nozzle.

Optimize aluminum alloy material selection plan

Different grades of aluminum alloys have very different performances in terms of processing performance. 6061 aluminum alloy is suitable for structural parts. Its strength is moderate and it is easy to process. 7075 aluminum alloy has high hardness but high brittleness, so the cutting speed needs to be reduced. In 2026, when we were selecting materials for a drone manufacturer, based on its load-bearing requirements, we recommended the 7075-T6 model. The processing speed was set at 150 meters per minute and the feed rate was controlled to a standard of 0.01 mm per tooth. The 5052 aluminum alloy has good corrosion resistance and is suitable for use in outdoor equipment. However, burrs are prone to occur during processing, so the feed per tooth needs to be reduced.

Choosing a material supplier is also critical. We have been using the plates produced by Southwest Aluminum for a long time. They have the characteristics of low internal stress and the deformation after processing is relatively small. In 2025, a customer purchased poor-quality aluminum alloys on their own, and most of the parts warped after processing. We advise our customers to clearly specify their requirements in the contract and require materials to provide chemical composition reports and mechanical property reports. When storing materials, you need to pay attention to moisture-proofing, because aluminum alloys will oxidize in a humid environment, which will affect the cutting effect. Inventory materials are best stored in a warehouse with constant temperature and humidity, and the temperature should be controlled at 20 to 25 degrees Celsius.

Carry out routine maintenance of equipment

The core of the machining center lies in the accuracy of the spindle. We instruct the operators to preheat the spindle after starting the machine every day, and perform idling operation for 5 minutes at a speed of 1,000 rpm. The spindle runout is checked weekly using a dial indicator. Once it is found to exceed 0.005 mm, it needs to be adjusted. In April 2026, the machining surface of a machining center showed periodic ripples. After inspection, it was found that the spindle bearing was worn. After replacing the bearings and returning to normal condition, the guide rail lubrication system needs to be cleaned once a week to prevent chips from clogging the oil circuit.

Equally important is the coolant system. We stipulate that the coolant should be replaced once a month and the filter should be cleaned once a week. In 2025, the coolant of one piece of equipment deteriorated and smelled, causing rust spots on the workpieces. After replacing the coolant and cleaning the pipeline, the problem was solved. The lead screw and grating scale need to be cleaned regularly and wiped with absolute alcohol. Equipment accuracy calibration is carried out every six months, and the positioning accuracy is detected with the help of a laser interferometer. When the error exceeds 0.01 mm, it must be compensated in time. Maintenance records need to be detailed, covering time, content, and operators to facilitate traceability of problems.

Develop systematic process flow

The process flow cannot be arranged at will. We generally carry out rough machining first to remove most of the margin, then semi-finish machining, and finally finish machining. After rough machining, a margin of 0.5 to 1 mm should be left to leave corresponding adjustment space for finishing. In 2026, when we processed the lens barrel for an optical equipment company, we added a stress relief annealing process to release the internal stress of the part, and the final flatness was controlled within 0.01 mm. Cooling time should be arranged between the processes so that the workpiece temperature can be lowered to room temperature before processing can continue.

Our company requires process documents to be detailed down to every step. The process card must state the tool model, rotation speed, feed, depth of cut, cooling method and other parameters to this extent. In 2025, we optimized the process of a part and reduced the original 12 processes to 8. The processing time was also reduced from 45 minutes to 28 minutes. However, the yield rate increased by 3%. After process optimization, trial cutting verification must be carried out, and at least 5 qualified products must be processed before mass production can be achieved. Every time there is a process change, quality inspection and operators must be notified to update the process card and testing standards.