In the modern metal fabrication industry, milling is a popular process that offers skilled tradespeople a way of shaping and cutting materials expertly. It’s used to produce some of the most common and vital products we use every day. In this article, we’ll look at horizontal milling machines and vertical milling machines, comparing the two types and understanding their differences and uses.
To start, milling is the process where material is removed from a workpiece with the aid of a rotary cutter. A standard miller machine consists of a milling machine spindle that’s powered with a motor and makes the milling cutter revolve. Another integral component of a miller machine is the worktable, which is adjustable to help in feeding the workpiece to the cutter.
A milling machine is a device with a circular rotating tool with several cutting edges symmetrically positioned around its axis. The workpiece can be held in a vise or an identical device clamped on a table moving in three perpendicular directions. Disk-shaped cutters can be clamped through their center holes to the arbors attached to the machine spindle. Their teeth can be on the peripheries alone or both faces and peripheries.
What Are Milling Machines Used For?
Milling machines are versatile devices. They come in varying sizes ranging from small ones used in homes or garages to larger ones needing warehouse space to function. At their core, milling machines use a selection of tools to carve and drill into raw materials to make shapes and nearly finished products. They can add threads for bolts, drill holes or create precise shapes from any material.
Different tools are used for various types of cutting and for a wide range of materials. The drill is held in the collet, and while spinning, the head lowered to drill a hole in the material being milled. The tap is used to cut threads. When a tap has been used on a hole, you thread a bolt into it. A mill will be used for cutting the material through and around the workpiece. Various types and sizes are used for varying purposes.
To program the computer or make parts, a machinist will follow a blueprint. By choosing tools and doing several operations, the machinist will form material into a precise part within acceptable tolerances.
Precise Computer Numerical Control
A computer numerically controlled mill can make concise or production parts with little operator involvement. Special motors and precise measuring tools called stepping motors to choose tools, move the table and head, and machine the parts to exact dimensions that are either difficult or time-consuming to perform manually. To ensure the machine is functioning properly, set up correctly, and has the required tools for performing the task, the operator will have to be a certified machinist. If a mistake is made, the final product won’t be in the specifications required.
Popular Products Made With Milling Machines
Without a doubt, you use products made and formed by milling machines each and every day. Here are some of the most common and unknown products made by milling machines.
Pens and Pencils. Ever been in class, taking notes or signing a document at the office, and wondered where the writing utensil you are using came from? A milling machine is needed to make the parts of a machine that will produce your pencils or make the molds that will produce your pens.
Guitars. The operating system of a CNC machine is ideal for creating the exact cuts, which gives the instrument its attributes and unique looks. For the wooden clock to function properly, numerous separate and tiny parts are required to be cut precisely. And milling machines cut these clock parts.
Police Badges. The design of the badge will be inputted in the CNC milling machine operating system, which will then make unique small cuts representing the police emblem.
Surgical Tools. From scalpels to stretchers and advanced imaging equipment, milling machines produce intricate parts for the medical community.
Comparing Horizontal and Vertical Mills
So what are the comparisons/differences between horizontal and vertical milling? The job done by both types of machines is quintessentially the same, but the production process to complete a task is different. The main difference comes in the orientation of the spindle. There are advantages and disadvantages to both machining types, and it’s crucial to note milling functions can differ. Here is an overview of horizontal vs vertical mills.
What Is a Vertical Milling Machine?
A vertical milling machine is the most commonly used type and features a vertically oriented cutting head or spindle, holding as well as rotating the cutting tool against the workpiece. Since the cutting head is affixed in a vertical orientation, other machine parts will shift along a single or more axes to move the material in the right position for proper milling. The spindle will move up and down, removing material by pressing against the workpiece.
Vertical mills are ideal for projects worked on a single side like operating with large metal plates and sinking dies. There are basically two vertical milling machines types: bed milling machines and turret milling machines—the function a little differently from each other as well as offer unique advantages.
Turret Mill: Here, the table and spindle can move perpendicularly and parallel to the axis. A turret mill is very versatile, given how it can manipulate the material’s position in both directions. In fact, most manufacturing invests in a turret mill due to its ability to perform a wide selection of milling operations. Note that the two-axis movement supports smaller piece projects.
Bed Mill: A bed mill, on the other hand, moves the material perpendicular to the axis. In the case of this milling machine, the spindle is fixed to the vertical axis and can only move up or down as required. The spindle movement, coupled together with the horizontal movement of the table enables milling of a variety of depths and shapes. This mill is excellent for projects that need large, heavy pieces compared to turret mills.
The Best Features of Vertical Milling Machines
i). Popularity: These machines make up most of the milling machinery in the country. Typically, they are more affordable compared to horizontal mills, making it a shrewd investment that pays ten times over. Because of its low upfront cost, production cost savings will be passed to clients. Given how prevalent these types of mills are, skilled operators in the industry are surging.
ii). Ease of Operation: The structural design of vertical mills gives operators better visibility while working. This will give the operator(s) a higher chance of spotting and correcting potential problems easily as the milling commences. Also, programming is made simple by the user-friendly CNC controls. So operators won’t waste time setting up and programming; instead, they will concentrate on making sure that the specifications of the project are met to the highest of standards. Now, no matter what, milling machines should only be operated by experts with the experience to safely complete the project.
iii). Production Benefits: The visibility provided by vertical mills is excellent for finishing large plate metal fabrication. Given how easy it is to use the machine, it’s better suited for less complicated jobs that need low quantities. This machine is the ideal solution for quick milling jobs.
What Is a Horizontal Milling Machine?
This machine features a similar design where a spindle with a rotary cutting tool removes material by pressing against the workpiece. Horizontal mills differ from vertical milling equipment in a variety of ways. The significant difference between these two milling machines is the spindle orientation. Vertical milling machines feature a vertical spindle orientation. When it comes to horizontal mills, the spindle has a horizontal orientation. Simply put, the horizontal milling machine mounts the cutting head on a spindle that’s been horizontally oriented and able to remove material from the workpiece selectively.
Moreover, horizontal mills feature varying cutting tools compared to vertical mills. And while vertical mills have thin and long vertical cutting tools, horizontal mills, on the other hand, have thicker and shorter cutting tools. Compared to vertical milling machines, horizontal mills are capable of performing heavier and deeper cuts. This has seen many manufacturing companies apply them to cut slots or grooves into workpieces. They can also do milling operations while positioned at different angles.
The Best Features of Horizontal Milling Machines
i). Chip Evacuation: Due to the horizontal mills’ setup, when cutting is ongoing, gravity will aid in pulling the chips out. That will translate in the end products having cleaner surface finishes and need less fabrication or production later on.
ii). Solid Construction: Horizontal mills are constructed more heavily and can deal with bigger volume production jobs. The machine parts are built to last longer. Their rigid construction translates to the machine vibrating less, deflecting less and functioning more smoothly than vertical mills
iii). Productivity: The integrated pallet changer and 4th Axis Tombstone massively extrapolate the productivity of these machines, a feature that’s perfect for large quantities and complex workloads. The mechanical design of the horizontal mill allows it to do work equaling that of three machining tools. This is ideal for production cost and time efficiency.
Although they have similarities, horizontal mills are better suited for more complicated projects compared to vertical mills. These machines will complete the tasks much quicker, though it may require a significant financial boost.
Choosing between Vertical and Horizontal
As you’ve learned, both types of milling machines have their merits, and the choice between the two depends entirely on the kind of milling that needs to be done. The number of planes on which a piece needs to be worked, as well as the shape and size of the piece, are major factors in deciding whether the milling is more suited to vertical or horizontal milling. Heavier items and those that need to be worked on multiple sides lend themselves more readily to horizontal milling, while work such as sinking dies is best suited for a vertical milling machine. Many items, however, can be worked on either type of milling machine by using the correct techniques.
Both vertical and horizontal milling machines can make use of CNC (computer numerical controlled) technology to automate milling for fine control, especially on complex milling jobs or when exact repetition is needed. There are also various types of add-on parts and cutting heads that can be used to modify a horizontal mill to do vertical milling or vice versa. This is a great advantage to a small shop that usually needs one type of mill because it allows a wider range of milling on a single machine, especially for applications that are not often needed.
Armed with this information, you should have a strong understanding of the differences and strengths between horizontal and vertical milling machines.