Buying a CNC Mill
The CNC mill is still one of the most common ways to manufacture metal parts. The most common CNC mill machines are the vertical machining center and horizontal machining center. Types of vertical and horizontal CNC machining centers range from 3-axis benchtop CNC mills to 5-axis CNC mills, short to long travels, and fast to heavy-duty RPM spindle speeds. Some of the top CNC mill manufacturers include Citizen, DMG Mori Seiki, Doosan, Daewoo, Fadal, Ganesh, Haas
, Hitachi Seiki, Hurco, Makino, Mazak
, Milltronics, Okuma, Samsung, OKK and other brands.
Vertical Machining Centers Vertical mills
are more common than horizontal milling machines in part because of their cost and ease of use. With vertical milling machines, you can see more of what youre doing compared to a horizontal milling machine. They tend to be less complicated to program and offer more flexibility, so they are better if you have unorthodox pieces of one-off needs. Another advantage is that they require less floor-space than an HMC. Vertical milling machines
are usually for smaller parts and the super-size parts are made on horizontal machining centers. Because of the ever-increasing complexity and features being added to both kinds of machines, both kinds may be referred to as machining centers. Most CNC milling machines have the ability to move the spindle along the Z-axis which allows for freedom to engrave and make much more complex parts. When a fifth axis is added, making the machine a 5-Axis machine, the B axis controls the tilt of the tool to make extremely complicated geometries. Most selections for CNC milling machines begin with the size parts you plan to machine. Some of the benefits of Vertical Machining Centers include: You can see what youre doing. Horizontal milling machines generally have a blocked view, VMCs are less expensive than HMCs, Vertical Machining Centers tend to be easier to program than Horizontal Milling Machines lastly, Vertical milling machines tend to be smaller
Horizontal Machining Centers
Even though from the list above, a VMC may seem to be the answer, its not that simple. One horizontal milling machine
can be as productive as three vertical milling machines. The spindle utilization on an HMC is 85% compared to a typical 25% for a VMC. The Horizontal machining center uses better chip evacuation methods when compared to vertical mills, which means less re-cutting and longer tool life. The surface finish from a horizontal mill machine is often better too. These machines are very sturdy and built to withstand vibrations, so the work environment is quieter, and the machine tends to last longer. Many owners believe that the additional initial investment in an HMC well-worth it since parts are less costly coming off the machine. Depending on the project, it might make sense to buy an inexpensive used HMC and use it exclusively for production. There is software available to help you program and run it to its full capacity. If you have access to the talent to run a horizontal machining center and associated programs (like CAD/CAM), consistent mid-to-high runs of parts and the capital to invest, a horizontal milling machine may be the best choice for you. However, if you are just getting started with machining, have many varied jobs for a wide range of parts and tend to make smaller parts youll probably want to select a used vertical milling machine.
5-Axis CNC Mills: Comparing Vertical Machining Centers and Horizontal Machining Centers
For complex geometries that are high-volume and require precision as well as great flexibility, you may want to consider a 5-axis machining center. 5 axis mills
have up to 95% spindle utilization and run overnight and weekend unattended, putting money directly in your pocket. Different HMCs are designed for various size parts and types of materials. 5-axis VMCs reduce cycle times and add to the complexity of parts that can be produced. As with the HMCs some are designed for tougher materials than others. The VMCs tend to be for smaller parts as compared with the HMC.