Do you know the difference between making a simple hole and carving a masterpiece on a piece of metal? While it might sound like shop jargon to some, both of these actions present two important machining processes, i.e., milling and drilling. Both of which play an important role in the world of CNC machining, in particular when you are looking for a complex part or mass production.
Knowing the difference between CNC milling and CNC drilling is more than just knowing their technical trivia, as they can affect the outcome of your parts, your production speed, and even your budget. Regardless if you are using a CNC milling machine to shape a flat surface, or a drilling machine to create holes, each process has a unique part to play in modern manufacturing.
Would you like to know more about these procedures? Excellent, because we will do a deep dive into the main difference between milling and drilling, and share everything from machine setup to surface finish, to tool wear, and how you can use these machines to make precise holes. Thus, allowing you to make informed decisions when it comes to choosing between a milling machine over a drilling machine.
What is Milling?
This is a flexible subtractive machining process that removes materials from your workpiece using a rotating cutting tool. During CNC milling, the cutter tool spins at an exceptionally high speed while moving across numerous axes at the same time, thus allowing it to shape, slot, and contour complex parts with high precision. This is also a big reason why it is the most used tool in custom manufacturing services, since it is easily able to produce flat surfaces, slots, and intricate features.
Usually, milling operations use face milling, which allows it to smooth the workpiece surface, and end milling, thus making it ideal for cutting edges and pockets on a piece of metal. It doesn’t matter if it’s a simple milling machine or a CNC milling machine, both of them are widely used in a number of fields including automotive, aerospace, and electronics industries.
Advantages
As noted, CMC milling has an impressive amount of flexibility, which allows it to offer a wide range of operations, from shaping flat surfaces to carving complex shapes. If you have the right milling cutter and cutting tool, you can achieve tight tolerances and an excellent surface finish, making it an ideal tool for more detailed, high-quality parts.
Disadvantages
While it is praised for its precision, the setup for milling involves a very complex procedure, along with a hefty cost because of its advanced CNC machine tools and automatic tool changers. Moreover, in contrast to a CNC drilling machine, these perform much slower for basic hole drilling, in particular when making simple cylindrical holes.
What is Drilling?
Drilling is a simple machining process that requires a drill bit to create holes in materials. This can be seen in a CNC drilling machine, where its drill bit penetrates the workpiece vertically, cutting the material to create cylindrical holes with consistent diameters. While simple, this procedure is really fast and crucial in almost all manufacturing settings.
Whether it’s creating automotive parts for assembling electronics, CNC drilling is vital to achieve precise holes effectively. Regardless of whether you are using a drill press, an upright CNC drill press, or an automated CNC technology, its drilling operation is typically effective for deep holes and respective hole drilling grinds during assembly production.
Advantages
Easily the biggest pro of CNC drilling is its simplicity and speed. It’s the best tool for creating precise holes, especially cylindrical holes, using either a twist drill or a standard drill bit. Moreover, machines like the upright CNC drill press or the customary drilling machine are excellent for continuous drilling operations during mass production.
Disadvantages
Although highly efficient, CNC drilling does have its limitations when it comes to flexibility. These issues include not being able to produce complex shapes and complicated outlines like a milling machine. Not to mention, its drill head and drill bit are limited to straight vertical cuts, thus making it unfit for parts that need detailed machining operations or curved surfaces.
What is the Difference Between Drilling and Milling?
Machine Setup
Placing a drilling machine is usually pretty straightforward —a drill press or upright CNC drill press holds the drill bit in its position while the workpiece is secured beneath it. Afterwards, the drill head lowers in a vertical axis, which allows it to make quick, repetitive drilling operations, i.e., hole drilling or making cylindrical holes. Therefore, it is the ideal tool for shops that require speed and simplicity.
On the flip side, CNC milling machines require a much more complex setup, since the milling spindle can move across a few different axes, plus its cutting tool can also be automatically changed using its automatic tool changers. This flexibility allows the CNC milling to cater to a number of operations, which include face milling, end mills, and contouring, while also offering greater flexibility and control. Even with its tedious setup, its versatility alone makes it an unmatched tool in custom manufacturing services.
Tool Motion
As noted, in CNC drilling, the drill head and drill bit usually move in a straight line, on a vertical axis. The drilling operation milling involves its drill bit penetrating the material in a downward motion to create holes, in a single-axis motion. While simple, this procedure makes drilling machines much faster and effective for creating cylindrical holes, especially if you are looking for a quick and continuous hole drilling.
In contrast, CNC milling has a far more “dynamic motion” — its cutting tool uses a milling cutter that moves along multiple cutting points , thus allowing it to carve complex shapes, slots, and flat surfaces more smoothly. Furthermore, its multi-directional movement is controlled by computer numerical control, which encourages operations like face milling and peripheral milling, both requiring high precision.
Also, it doesn’t matter if you are using horizontal milling machines or a vertical milling machine — this amazing range of motion gives CNC milling machines the edge they need to provide unmatched flexibility in almost all machining operations.
Capabilities
CNC milling machines are best at creating complex shapes and fine details. Using tools such as end mills, a milling cutter can execute numerous types of milling operations, such as contouring, pocketing, and face milling to mill flat surfaces or carved profiles. Due to innovative CNC technology and multi-axis motion, CNC milling can even achieve tight tolerances in complex components.
By comparison, CNC drilling is all about ease and efficiency. It’s best used for creating cylindrical holes, particularly in mass production applications where volume is high. The drill bit and drill head are designed specifically for vertical, one-axis movement, so drilling machines are ideal for producing uniform and precise holes. Although the CNC drilling operation is less flexible than milling, it’s extremely useful for situations where straightforward hole drilling is necessary.
Precision and Tolerances
These cutting tools employed by CNC milling machines, like end mills and face milling cutters, achieve tight tolerances and high detail on even the most intricate shapes. No matter whether a vertical milling machine or horizontal milling machine is used, the multiple-axis control and sophisticated software that power CNC milling provide unparalleled consistency and surface detail.
In contrast, CNC drilling is generally confined to less demanding use. Although it may create precise holes, the procedure depends on the drill bit tracing a single vertical trajectory guided by the drill head. This restricts its capacity to conform to surface topology or deal with material with irregular densities. Therefore, although drilling machines are accurate for hole drilling, they fail to catch up with the dexterity of milling operations.
Material Flexibility
CNC milling machines are known for being really versatile, especially for material compatibility. It doesn’t matter if you are working with aluminum, steel, plastic, or composites, CNC milling can adjust easily to almost any material density and hardness level. Similarly, it uses different cutting tools like end mills and milling cutters to optimize its feed and speed, thus making the milling process perfect for both soft and tough materials.
Conversely, CNC drilling is a bit more limited, although it can definitely create holes in a few different materials. It is usually best to be used on medium to soft materials where the drill bit can perform efficiently without any tool wear. The simple motion of the drilling machine simplifies its adaptability when it comes into contact with more resistant materials. This is why milling lies at the essence of more demanding machine operations.
Depth of Cut
One more massive advantage of the CNC milling machines is their ability to easily adjust the depth of cut. Whether you are performing face milling, peripheral milling, or slotting, this cutting tool can be programmed to differentiate depth through its milling operations. This handy function allows for better flexibility when you are sculpting complex shapes or machining parts that have considerable layers or contours.
CNC drilling, on the other hand, works with a fixed depth setting, with its drill head and drill bit vertically descending in a predefined position, thus making hole drilling comparatively less adaptable. Likewise, while it is an amazing tool for making cylindrical holes or creating precise holes in large quantities, it lacks the same creativity and functional flexibility as a milling cutter. If your work demands variable-depth features, then CNC milling is an excellent choice for your subtractive machining process.
Surface Finish
If you are looking for an exceptional surface finish, then CNC milling machines are the ideal choice. These machines use a rotating cutting tool, like a milling cutter or end mills, to slowly shape the workpiece, which results in a smooth, molded shape. Plus, techniques like the face milling process further help in delivering even finishes on flat or irregular surfaces, thus allowing you to give each component a professional, high-quality appearance.
In comparison, CNC drilling mostly focuses on drilling holes, instead of shaping the surface — even though it can create precise holes, its drill bit isn’t designed to finesse the surface encircling the hole. While it cysts quickly and cleanly, the end result isn’t usually very refined. Although drilling machines are perfect for making functional holes, they can match the same level of surface finish that accompanies skilled operations using modern CNC machining technology.
Production Cost
When it comes down to budget-friendly machining processes, CNC drilling is typically the frontrunner. Drilling machines have a simpler installation, utilize fewer tools, and consume less energy. It makes them suitable for mass production of cylindrical holes, particularly with a standard drill bit and fixed parameters such as spindle speed and feed rate.
Conversely, CNC milling tends to have a much higher cost of operation. The versatility and accuracy provided by CNC milling machines usually necessitate more costly cutting tools, extended setup times, and sophisticated programming. Although milling is ideal for complex shapes and close tolerances, that is a costly advantage.
Machining Speed
For simple hole drilling operations, CNC drilling is generally the faster way to go. A drill bit merely travels vertically to create holes and is therefore perfect for quick and repeat operations. With equipment such as the upright CNC drill press, operators can effectively turn out several precise holes with little setup time.
CNC milling, on the other hand, sacrifices speed for flexibility. While it’s often slower than drill machines, it can accomplish a plethora of operations, everything from cutting complex shapes to attaining an excellent surface finish. Due to the multi-axis motion and interchangeable cutting tools, CNC milling machines are ideal for detailed work that demands more than just speed.
Application
CNC drilling is extensively utilized in manufacturing sectors where speed and efficiency in drilling holes are of primary importance, e.g., electronics, woodworking, and metal fabrication. The CNC drilling machine is very efficient at making precise holes in printed circuit boards, sheet metal, and small parts, thus proving to be a first-choice machine for repetitive, high-volume drilling operations.
However, CNC milling has a leading position in aerospace, automotive, and custom fabrication industries where precision shaping of complex shapes is critical. Using CNC milling machines, manufacturers are able to execute sophisticated milling operations, such as face milling, peripheral milling, or contouring, thus making it perfectly suitable for customized, high-tolerance applications.
Conclusion
It is necessary to understand the fundamental differences between CNC milling and CNC drilling in order to make the appropriate machining process selection. Drilling machines do best at rapid, precise hole drilling, yet CNC milling machines provide unrivaled versatility for complex shapes and a better surface finish. Match the process to your project’s requirements for optimum outcome.