CNC Routing VS. Milling

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If you’re interested in learning about woodworking, you’ll want to read on. If you’re looking for clarity within the tradespersons’ community, keep reading as we’ll discuss the differences and similarities between CNC routers and CNC miller machinery. 

What is a CNC Router?

A CNC router is a computer numerically controlled router that cuts wood, plastic, foam, and sometimes aluminum. Routers cut softer materials, as they do not have enough torque to cut into metal and steel. It’s a diverse CNC machine that can help create furniture pieces and prototypes with engravings. Woodworkers use routers more commonly for the mass production of products that require less detail, like signs. This isn’t to say that a CNC router is not precise or detailed machinery for our industry. We’ll explore that detail and others further on. 

Routers have a spindle that travels along the X- and Y-axes at high speeds while the material is on the Z-axis. Since routers are limited to the Z-axis, they have shorter machine cycles. Occasionally, CNC routers can have more than three axes, up to six, which makes those routers ideal for more complicated projects. Despite the added axes, routers lack the torque for thicker materials and tasks, which may not be suitable for your project. 

What is a CNC Mill? 

A CNC mill is a computer-numerically controlled mill used for heavy-duty materials like titanium, steel, and other metals. It has high torque, and workers use this CNC machinery for precision and detailed project manufacturing. Mills operate more slowly than routers, as their cutting technology moves fewer revolutions per minute (RPM). A CNC mill creates more delicate and detailed cuts due to its impressive precision. According to Custom Components, mills can achieve accuracy within one 1,000th of an inch. CNC mills operate on an axis system, making the movements more closely detailed. 

A CNC mill’s unique axis system creates more detailed and accurate movements. These computer-ran industrial machines have a 3-axis, 4-axis, and 5-axis system, allowing each system to move linearly. A 3-axis mill machine can move side to side, front to back, and up and down (X, Y, Z). These milling machines are excellent for drilling, threading holes, creating angles, and making surface features. A 4-axis machine has the same capabilities as the 3-axis machine, with the X, Y, and Z movements; however, an additional rotation movement is included. These movements become much more integrated depending on the project. The 4-axis machine rotates around the X-axis, allowing a fixed piece to complete four sides. According to Datron, “There are two types of 4th axis milling: indexing and simultaneous. Indexing in 4-axis milling, known as 3 + 1, has the workpiece rotate into a position where 3-axis milling strategies are then used. For simultaneous machining, the part rotates, and the machine cuts it at the same time.” As for 5-axis milling? The index milling is a 3 + 2, while the simultaneous milling has the workpiece and the spindle rotating. CNC milling at a 5-axis is sheer genius. 


Noteworthy Differences: Routers and Mills 

Though both have CNC programming and are CNC machinery, they are different machines. Tradespeople can interchange their uses for various projects; however, these machines have uses for specific materials. As we discussed before, businesses use routers for fabrication materials lighter in weight and thinner in thickness. Router parts are not intended for heavy or thick materials, whereas mill parts work through steel and metal. The inner workings of mills are made with specialty pieces to accommodate such materials. 

CNC Routers typically found in woodworking shops

  • have a faster, spinning cutting tool that works more quickly through materials and products
  • have a larger plane, better suited for more extensive materials and mass fabrication
  • have spindle power ranges from 5 to 15 horsepower
  • run up to 13,000 to 24,000 RPM
  • have dust collectors
  • are generally used with multiple programs tailored to woodworking 
  • run on an X-, Y-, and Z-axis system 4-6 axis machines are available

CNC Mills typically found in metal fabrication shops

  • have a slower cutting tool designed to work more steadily through materials
  • generally use more torque to cut into heavier materials like steel
  • cater to detailed designs and engraving, more for accuracy and precision 
  • run on multiple axes from 3- to 5-axis system 
  • can be used similarly to a router but with more options like bits, etc. 
  • have unbeatable precision 

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