Mar. 08, 2022
In the machine shop a CNC turning Center is a valuable machine only equaled by the versatility and power of the CNC Milling or Vertical Machining Center. Here we take a look at how to choose the right CNC turning center for your needs, application and budget.
A CNC Turning center is a more advanced adaptation of a very old process of machining, the lathe. This process holds the material within a clamping device called a “chuck” and rotates the chuck & material then introduces a static or counter rotating tool to the material, shaving off part of it until the desired shape and size is realized. Utilizing the function of a CNC (Computerized Numerical Controller) the tool can complete standard routines to turn, tap, thread and perform many other functions of the turning center. Often equipped with a bar feeder and parts catcher, the CNC turning Center is quickly and easily automated to provide hours of precision production requirements.
CNC Turning as described above is the basis of the part rotation while a static or counter rotating cutter approaches on a controlled axis. Although there are many types of CNC turning centers that vary in design in order to accommodate a variety of specialty applications, they all rotate the material in the machining process. These designs are;
1. Horizontal: The horizontal CNC Turning center is by far the most popular design and is capable of most job shop applications handling the very small parts of ⅛” to over 30” in general. These machines are easily equipped with a myriad of options and accessories to allow them to be even more productive and capable.
2. Vertical: Often called the VTL (Vertical Turret Lathe) or VTC (Vertical Turning Center) the vertical design allows for larger parts (some massive) to use their weight in conjunction with clamping to rest upon a flat table like surface. These machines typically handle parts 30” and greater with some versions capable of turning parts weighing several tons and covering several building stories in size.
3. Inverse Vertical: Inverting the chuck from the flat position of the VTL to the vertical “hanging” position of a spindle-type machine allows some unique advantages. This design typically lends itself very well to machining castings or pre-cut parts where the automation needs to be accomplished for each individual part or slug. These machines can be automated with carousel parts stacker, conveyor belts and other robotics to assist in the loading and unloading of parts. Their inverse design helps remove the cut chips easily by gravity
4. “Swiss” Type: In CNC Turning there is another machine we know as the “Swiss Type Lathe” but more correctly should be called the sliding headstock machine. Capable of very high production, these accurate machines can produce many parts very accurately in a short period of time. They are based on the Horizontal CNC Turning Center design as described previously but they add several unique features; first a headstock that slides the material through a synchronized rotating collet while multiple tools engage the workpiece at once leading to the highest levels of automation available in turning. Capable of milling, drilling, turning, tapping, and some unique processes like thread whirling the Swiss Style CNC Turning Center is definitely a popular choice.
Selecting the right CNC turning Center for your application is not as hard as you might think. It, like all machining processes, starts with identifying the results you are trying to achieve. Part sizes, accuracies, quantities etc all play an important factor in selecting the right machine.
1. Identify the Material Sizes You'll Be Running in the Turning Center
When you're looking for a CNC turning center you need to look at capacity first. If your parts never exceed 2” in diameter then you're a great candidate for a Horizontal or Swiss style CNC Turning Center. If your parts are 30-4” in diameter or greater you likely will be looking at a Vertical Turning Center option. If parts are cast or “slugged” you would be better suited for the Inverse Vertical Design Turning Center. Also the Material type can play an important factor as softer materials like Aluminum generally need a higher RPM driven machine to achieve the best reproduction rates
2. Determine Your Desired Results
As a turning center of any type can be equipped with a myriad of options for automation, and capability you will need to determine the options and capabilities needed on your machine. Common questions you will need to ask are:
· Do you need milling capability?
· Will your parts require off center drilling?
· Does your part require to be machined on both sides?
· Does the quantity of parts needed require material handling?
· Are your parts long enough to require additional support from a second chuck or tailstock?
3. Consider All Aspects of CNC Turning Centers
Once you have determined the features and capabilities your ideal CNC turning Center should have, you will need to determine the optional features that can enhance your operation by removing material faster, providing more capabilities and production output volume. Several features to consider are;
· Horsepower: generally the higher the power, the higher the material; removal rate capabilities
· RPM: The higher the rpm the better suited your machine is for small parts and softer materials.
· Chip Control: Your machine will need some sort of waste management system to remove the chips from the workzone, chip augers or conveyors.
· Live Tools: Adding powered or driven tooling allows many features to be machines in one setup without having to remove your parts to a second machine or subsequent setup.
· Additional Axis: A CNC Turning Center starts with a basic X & Z Axis that controls the Diameter and length of your parts features. Additional axis such as a Y-Axis can allow for advanced feature machining such as off center hole drilling, special pocket machining and much more.
· Automation Upgradeability: Another futuristic aspect of your machine tool search should include the machine's capability to be upgraded with more advanced automation and features down the road as new work and needs arise.
4. Narrow Down Your Options for New and Used CNC Turning Centers
Once you have looked at all the features and capabilities your machine needs it’s time to compare whether or not your operation is better suited for a new machine or used. While new machinery offers some level of comfort, used machinery can be a great value and allow you to add many more features into your selection and stay within your budget. A value priced used machine can be a great option for any shop providing much more capability and value.