Many people wonder if machining aluminum and milling aluminum parts using a CNC metalworking machine are different from machining and machining other materials. When starting this type of machining, you will very quickly find out that it is not as easy as it seems. This is due to several factors. Here are some tips that you will certainly find useful when machining aluminum.
Where to start with aluminum?
Aluminum requires less cutting force than harder materials such as steel. We are talking here in terms of milling and general machining. At the same time, it is important to remember that aluminum is softer and melts at lower temperatures. This means that loose chips of material can easily overheat and melt into the tool. In small quantities, this causes dulling of the cutting edge, more mechanical stress on the tool, and further heating of the tool. This situation can result in premature tool failure. How to prevent this? Find out below!
The right feed and speed
You should be aware of the fact that the softer the material, the higher the recommended cutting speed. At 300-600 meters per minute (using carbide tools) aluminum can be cut at a speed similar to wood. But unlike cutting wood, the optimal feed rate and speed for your setup will be in a much narrower range. Aluminum machining is often characterized by high spindle speeds. Focus on this, as combining high spindle speeds with too low feed rates can produce unwanted action. This is because the tool will spend more time rubbing against the aluminum than cutting it. This will increase the operating temperature and significantly shorten the life of the tool. Simply cutting any material too fast will result in broken tools. High-speed machining of aluminum results in the rapid production of large quantities of chips.
Proper clearance, and machining of aluminum
One of the biggest problems when machining aluminum is getting the chips out quickly and correctly. Especially when cutting deep penetrations in the material. The deeper the cut, the more difficult it is to remove chips from the bottom of the pocket. A pile of spent material at the bottom of the pocket is the quickest way to ruin a knife. Unfortunately, when this happens, the chips not only stick to the tool, but also to the workpiece when heated. This causes the surface of the material to harden. It also deteriorates the surface finish and can affect part tolerances. Using a shallow depth of cut with compressed air cleaning will help keep chips away from the tool.
The right number of teeth in the tool
The most important factor in choosing an aluminum cutting tool is the need for maximum chip evacuation. The more grooves a tool has, the less room there is for chip evacuation. Two groove cutters are ideal, but tools with one and three grooves are also effective. Remember that the fewer the grooves, the less rigid the tool will be. So use the shortest possible tool for CNC machining and be aware of the tool’s bevel. Especially when milling with small diameter face mills.
The right material for machining aluminum
High-speed steel is not strong enough to handle the cutting conditions required for aluminum alloys. Because aluminum alloy has certain properties and is relatively soft, tool hardness must exceed tool ductility. Harder tool materials maintain the sharpness of the cutting edge longer. By keeping the edge sharp, a better finish of the workpiece material occurs. This will also reduce friction and reduce the amount of aluminum deposited on the cutting edge. Carbide tools should be used for machining aluminum. The higher the speed, the sharper and longer the carbide tool and the higher the shear force. This will reduce the number of sticky chips that can contaminate the tool. It’s important to keep the aluminum milling process free of residue from the alloy cutting and machining process.
Aluminum milling and other aspects
Aluminum is cut with uncoated carbide tools or special coatings such as ZrN, DLC, or TiB2. Aluminum is an good material in CNC machining, which has high corrosion resistance and strength. This material is used in parts that need to be lightweight and strong. Other elements to shield the product are not necessary. In general, it can be said that the machinability of aluminum is very good, but there are several aspects to pay attention to. Knowing how materials behave is the best way to know how to handle them more efficiently. Make sure the feed rate and speed are correct. Use double-edged tools made of uncoated carbide that do not clog with aluminum chips. The basis of good aluminum machining with a CNC machine is the proper speed in terms of rotational as well as feed concept. The cutting speed should be adapted to the surface effect. When machining aluminum or doing aluminum milling we should remember an extremely important aspect which is cooling. This is important because overheating the CNC machine can destroy the material. Cooling should be taken into account on the cutter as well as the working feed. The element of machine cooling, the use of appropriate parameters, heat dissipation, and appropriate tools are factors that will certainly have a positive impact on the professional finish of the material and improve the production of plastic.