supra cnc milling machine

How to Purchase The Best Milling Machine

Milling machines are among the most commonly used machine tools in modern manufacturing. You’ll find them in everything from major assembly lines to small tool-and-die shops, and just about anywhere in between. Just about every industry uses milling machines, from small mills in high-end scientific labs to machining centers in the automotive industry.

Milling machines are popular with manufacturers and engineers as they help produce parts that are more complex than the average 3D printer can handle. They’re commonly used by consumers, too, as many people also purchase their first milling machine to use at home or in a small workshop.

In this guide, we will give you some background on milling machines including what they are used for, how they work, and what features to look out for when purchasing your next one. With this guide, you’ll have everything you need to purchase your own milling machine with confidence.

What is a milling machine used for?

Milling machines are powered machine tools designed to mill or carve material like metal, plastic, or wood. Mills use a variety of cutting tools, including rotating blades, drills, and even abrasives. The best mills feature high-quality cast iron construction, variable speed engines, power feeds, and cutting tools that move along the x- and y-axis. Milling machines are used in a variety of roles from woodworking to metalworking.

A milling machine is designed to hold material securely in a vise or otherwise secured to the bed of the mill. The cutting tool itself typically has either horizontal or vertical movement, which in turn gives its name to the two basic kinds of milling machines; horizontal and vertical milling machines.

Vertical mills use a rotating cutting tool that most closely resembles a drilling machine or drill press. The drill chuck is mounted on a gantry above the bed of the mill and is lowered into the workpiece.  The cutting tool is generally a single-pointed milling cutter. Depending on the specifications of the particular mill, milling machines have a tool head speed of anywhere from 500 to 50,000 RPM.

A horizontal milling machine functions similarly to a vertical mill with the exception that it uses a rotating table instead of a gantry and its main cutter is generally three- or four-pointed. The cutting speed for these mills also varies according to specifications but can be as fast as 20,000 RPM.

The exact milling machine operations can depend both on the structure of the mill (horizontal or vertical) and the tooling equipped to it. End milling requires a tool that closely resembles a drill bit; face milling uses one with a wider cutting end, more suitable for finishing surfaces. End mills and face mills aren’t entirely separate kinds of milling machines, but rather machines that have been equipped to perform certain operations.

Milling machines differ from metal lathes by the rotation of the tool rather than the part. And unlike lathe machines, where a workpiece is mounted between the headstock and tailstock but above the bed, most mills fasten the workpiece directly to the bed.

Rather than lathes, vertical mills in particular closely resemble wood routers in their function, but heavy-duty milling machines are more likely to be found in a metal machinist’s shop rather than a woodworker’s workshop.

What are the main types of milling machines?

There are a number of machine tools that combine elements of a milling machine with other common tools. Small mills certainly aren’t the only variation on the milling machine theme. Here are the most popular types of milling machines and their uses

Mini Milling Machines

Milling machines traditionally are found as part of heavy industry. These small milling machines are simply smaller versions of their larger counterparts, suitable for use in small machine shops or home workshops. These are also known as table or desktop mills, benchtop mills, and a variety of other terms.

Most mini milling machines are vertical mills, making them highly versatile. The addition of CNC – Computer Numerical Control – technology to mini milling machines means that modern mini mills can be used for a wide variety of applications. Variable speed control allows operators to adjust for cutting different materials, adding more versatility.

The world of mini milling machines is the same as larger versions, just smaller. The most common types of work done by these devices are sand casting patterns for metal foundries and selective machining such as drilling holes or making slots in a material. These models often feature an indexable table that moves up and down to allow access to the workpiece.

Mill Drills

A mill drill closely resembles drill presses or a simplified vertical milling machine. They’re less expensive than traditional “true” milling machines but are more simplified. They’re used almost exclusively for drilling, tapping, or boring into various workpieces and don’t have the necessary features that most machinists need from a milling machine. While a drill press might get the job done, there are plenty of milling machines in the same price range that can ultimately do much more.

Specialized grinding machines or grinders take some elements from horizontal mills and combine them with a step-down process to slowly remove material from a workpiece, creating a flat surface.

Knee Mills

When it comes to “proper” milling machines, there are a number of choices. Knee mills are smaller milling machines, often designed as benchtop mills, that are equally at home in the home workshop or industrial machine shop. The most well-known brand/type of knee mill is a “Bridgeport” milling machine. Knee mills are also popular as “spare machines” or toolroom mills for basic, one-off jobs.

Manual Milling Machines

Most people cut their teeth on manual milling machines. Manual mills are still very common and used in machine shops. They are mills that lack the “CNC” (or computerized control) aspect.

CNC Milling Machines

CNC machines are the top-end option, providing a high-precision solution to parts manufacturers. These complex 4-axis and 5-axis milling machines feature software and programming that helps “run” the milling machine and coolant systems for prolonged protection. These types of mills are often very large and start in the $150,000+ range, but some can be smaller, like our line of desktop CNC mills.

For more information on these CNC machining centers, read our guide on CNC machines to understand them completely.

diagram of milling machine parts

Diagram of milling machine parts

What are the parts of a milling machine?

While milling machines come in many varieties, here are the core parts of a milling machine:

  • Motor
  • Column
  • Base
  • Spindle
  • Monitor
  • Head
  • Swivel
  • Worktable

What to consider when purchasing a milling machine

When it comes time to purchase a milling machine, what are the most important things to consider? There’s no one universal milling machine; every machine will likely be better at some milling operations than others. But before you make your choice, consider these three primary considerations:

Price

While it’s true many milling machines are costly >$10,000+, there are many affordable options to fit every budget.

So, how much does a milling machine cost?

  • For a hobbyist router, the price is roughly $2,500-$3,500 for a solid machine.
  • CNC Routers start as low as $5,000 and rise to >$75,000.
  • 3-Axis Mills are generally $45,000 and go as high as $100,000
  • Professional product mills and lathes are $250,000+ depending on size and features. These machines are found in enterprise shops and for machining complex, large parts.

Size

Size matters. If you need a machine that can handle industrial-sized workpieces, you need an industrial-sized machining center. You might want a reinforced milling head on a vertical mill, or you might decide to jump straight to a horizontal mill.

Mini milling machines are smaller than their full-size counterparts, but just how small do you need? Some mini mills are your typical benchtop mills; still capable of handling sizeable parts, but small enough to fit on top of a worktable in your shop.

On the other hand, some mills fall into the “micro milling machine” category; truly small mills for intricate or detailed work, for example on jewelry. Most home milling machines fall into this category.

Remember also that there’s a stability trade-off with smaller mills. In general, the larger the mill, the more stable it is. Mills can be clamped to the top of a workbench or bolted directly to the floor; the latter is preferable if you need precise and heavy-duty cutting. Metal fabrication shops handling larger pieces of metal will want either full-size mills or larger benchtop models. While clamping your mini mill on top of a bench offers substantially more accessibility and ease of use, it comes at the expense of some stability.

Advanced Features

It’s no surprise that most ads for milling machines start with a list of features. Milling machines need to be useable, and the more features your mill has, the more useable it will be.

What features should you look for? A shortlist should include:

  • Digital readouts (DROs) – while not entirely necessary, digital readouts make a mill much more user-friendly. They’ll also help the operator keep cuts accurate and precise.
  • 3- or 4-axis movement – the more axes of movement, the greater the range of operations possible on that mill. X-axis, Y-axis, and Z-axis movement is the standard. Tools with more axes will likely be able to swivel the cutting tool around the part, engaging it from different angles. Or, in the case of mills with a rotary table, the workpiece itself can swivel, providing access without re-mounting the part.
  • Cast-iron construction – cast iron isn’t just sturdy, it’s heavy. Weight, on a mini mill, is a good thing. It adds stability and improves precision.
  • Spindle speed and horsepower specs – high-speed spindles and heavy-duty horsepower engines increase drilling capacity.
  • Head tilt – many mills have geared heads capable of cutting at an angle, adding flexibility.

Precision

For the ultimate in precision cutting, you’ll want a CNC mill. Computer numerical programming allows an operator to program the exact series of operations for the mill to make, allowing extremely precise and accurate cuts.

However, adding CNC capabilities will make your new mill considerably more expensive. It will also add to the learning curve for your new mill. On the other hand, you’ll be able to create more precise cuts and smooth finishes with the aid of CNC programming, and the actual operation of the mill is simplified.

CNC mills can also be more easily integrated with design workflows. A hobbyist might design a custom part on a CAD program, export the vector file to his or her CNC mini mill, and create a custom program to fabricate his part.

However, in many applications, the task at hand does not require CNC capabilities. For these tasks, a manual mini mill will suffice and may be cheaper to purchase than a CNC machine. Manual mills are designed for use by only one person and have no computer-controlled movement of any kind. This makes them more affordable than their CNC counterparts, though they are also correspondingly less precise.

Tips To Buy the Right Milling Machine

Now that you know what you need from the milling machine itself, what should you look for in a good milling machine manufacturer?

  • Wide product range
    • Look for companies catering to the machinist industry, selling high-quality lathes and mills of all shapes and sizes.
  • Excellent customer support
    • Customer support doesn’t just come after a sale; reach out to companies for advice, and look for the companies who are willing to guide you through the purchasing process, not just sell you a more expensive machine. Also, check the warranty policy for each machine and manufacturer.
  • Detailed specialist knowledge
    • The world of machine tools includes some specialist and hobbyist fields, such as micro mills, jewelry machine tools, or DIY. If applicable, look for a company that serves your niche.
  • Quality construction
    • From collet to shank, the best machine tool manufacturers use only the best parts. Look for a company that doesn’t skimp on quality components, and you’ll find one that produces high-end milling machines.

Our Choice: The Supra CNC Vertical Knee Mill

cnc supra
CNC Supra Milling Machine

The SUPRA CNC vertical knee mill from CNC Masters will make any shop more productive. This versatile machine works for hobbyists, machine shops of all sizes, product development, high production work, engraving, and teaching tools in vocational-technical schools and science labs.

Look at a few of the specifications for the CNC SUPRA 10×54 Vertical Knee Mill:

  • Table travel (Longitudinal X-axis): 35.5”
  • Saddle travel (Y-axis): 15.5”
  • Knee travel (Z-axis): 18”
  • Table size: 10” x 54”

Summary

What do you need to know before you purchase a milling machine? Remember the following:

  • What you will use the milling machine for
  • Exact specifications/capabilities required
  • Qualifications of the manufacturer

Follow those guidelines, do your research, and you’ll be well on your way to getting the most out of your new milling machine.

Other commonly asked questions

About Peter Jacobs

Peter Jacobs is the Senior Director of Marketing at CNC Masters, a leading supplier of CNC mills, milling machines, and CNC lathes. He is actively involved in manufacturing processes and regularly contributes his insights for various blogs in CNC machining, 3D printing, rapid tooling, injection molding, metal casting, and manufacturing in general. You can connect with him on his LinkedIn.

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Slide 1

MX Software – Easy to Use, Easy to Learn – Included with your machine purchase
The MX software is designed to work seamlessly with your CNC Masters machine. It is made to work with Windows PC – desktop, laptop, or an all in one – on standard USB. Use it on Windows 8 or 10 64-bit operating systems.
No internal conversion printer/serial port to USB software or additional conversion hardware is used with the MX.

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2. Clutter Free Interface
The MX is engineered for the CNC MASTERS machine so you do not have to fiddle with a detailed complicated configuration that can be overwhelming. Just load in the MX and start machining!2. Clutter Free Interface
The MX is engineered for the CNC MASTERS machine so you do not have to fiddle with a detailed complicated configuration that can be overwhelming. Just load in the MX and start machining!

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3. Features Tour and Tutorials Included
The Features Tour will give you a quick run-down on all the features the MX can do for you. The Tutorials are easy to follow even for the first time CNC machinist.
Feel free to download the MX on any of your computers. We recommend downloading the MX along with your CAD and CAM software there at the comfort of your office computer to generate your tool path programs. You don’t need to be hooked up to the machine either to test your program in simulation mode.

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4. Navigate and Edit Your Program through the MX interface with Ease
With a few clicks of the mouse or using touch screen technology, you can easily navigate through the MX interface importing saved programs into the Editor from the File drop down menu. Using standard windows features to edit your program you can then lock the Editor Screen to avoid accidental editing, and if you need to insert a line in the middle of a program, just click on [ReNum] to re-number your tool path list.
You can create a program or import CAM generated G-code tool paths into the Editor
The X Y and Z W arrow jog buttons are displayed from the point of view of the cutter to avoid confusion when the table and saddle are moving. You can also adjust your spindle speed and coolant control while jogging each axis.

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5. Feed Hold – Pause in the Middle of your Program
Feed Hold lets you pause in the middle of a program. From there you can step through your program one line at time while opting to shut the spindle off and then resume your program.
You can also write PAUSE in the middle of your program and jog each axis independently while your program is in pause mode.

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6. Hot Keys
Hot Keys is an alternative method to easily control your machine using your hard or touch screen keyboard. One can press P to pause a program, press S to turn Spindle On, G to run a program, Space Bar to Stop, J to record your individual movements one line at a time to create a program in teach mode.

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7. Pick Menu – for conversational mode programming
Write FANUC style G-codes directly into the Editor or select commands off the [Pick] menu and write your tool path program in conversational mode such as what is written in the Editor box. You can even mix between conversation commands and G-codes in the same program.

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8. Pick Menu List of Options
Use commands such as MOVE, SPINDLE ON/OFF, COOLANT ON/OFF, PAUSE, DELAY, GO HOME…. to write your tool path programs in conversational mode.

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9. Draw the Tool Path to verify it before pressing Go
Hit Draw to view your tool path program drawing, check out its run time, or even simulate the tool path in 3D mode. This can be helpful to quickly verify your program before running it. You can also slow down or speed up the drawing or simulation process.
You can also hit Go within the Draw Window itself to verify the cutter’s position on the machine. The current tool path will be highlighted and simultaneously draw out the next path so you can verify what the cutter will be doing next on the program.

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10. Run each tool path independently to study its movement
1. Run the machine on Trace mode. You can run each tool path independently, one line at a time to study the tool path movement on the machine to verify the position of the application and if any fixture/vise is in the way of the cutter’s path.

2. You can also verify your program by clicking on the Trace and Draw buttons together. This will allow you to view each tool path independently one line at a time in the Draw Window.

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11. Counters display in Inches or Millimeters – Continuous Feed
1. When running a program, the counters will display a “real-time” readout while the machine is in CNC operation without counting ahead of the movement.
2. The current tool path is highlighted while the machine is in operation without causing slight interruptions/pauses as the software feeds the tool path to the machine. The MX internally interprets a program ten lines ahead to allow for “continuous machining” avoiding slight interruptions as the machine waits for its next tool path command.
3. “Run Time” tells you how long it takes to run your tool path program.

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12. Use the “Go From Line” command to start in the middle of your program
If you ever need to begin your program from somewhere in the middle of it, use [Go From Line] which you can find under Tools. The Help guide will walk you through how to position the cutter without losing its position on the machine.

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13. Exact Motion Distance without over-stepping on an axis while jogging
Use “Relative ON” to enter a specific coordinate to jog any of your axes to an exact location without having to write a program. It’s like using “power feed” but easier. You can jog an exact distance on any of the axes without needing to keep the key pressed down and mistakenly over-step the movement releasing your finger too slowly off the jog button.
Let’s say you need to drill a hole exactly 0.525” using the Z. So you enter 0.525 in the Z box. Next, adjust the JOG FEED RATE slider for the desired feed rate. Then “click once” on the +Z or -Z button to activate the travel. In this case you click once the -Z button first to drill the hole exactly 0.525”. Then click once on the +Z button to drive the axis back up 0.525”.

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14. Teach Mode – Jog Input
You can create a tool path program by storing each point-to-point movement by simply jogging an axis one at a time. Click on either of the Jog Input buttons to store each movement on the Editor Screen. You can then add Spindle ON, feed commands, and press GO to run the new program as needed. This is a great feature to help you learn to create a program by the movements you make on the machine without necessarily writing out an entire program first.

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15. Override on the fly to adjust the Jog Feed to Rapid or the Spindle Speed during the middle of a program
1. Jog Feed and Rapid with Override: You can adjust feeds using the slider from slow minimum 0.1″ per minute to a rapid of 100″ per minute of travel. You can even micro-step your jog as low as 0.01”/min. The [-][+] buttons allow you to fine tune feeds in 5% increments while the program is in motion.
2. Spindle Speed with Override: You can adjust speeds using the slider from a slow minimum RPM to the max RPM according to the machine setup. The [-][+] buttons allow you to fine tune feeds in 5% increments while the program is in motion.

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16. Adjust Counters using Pre-Set if you cannot begin the program from 0.00
In a situation where you cannot begin your cutter at it’s 0.00 location, you can “Pre-Set” directly into the counters by typing in your beginning coordinate. You can press Go from here to run your program. You can also “zero all” or “zero” your counters independently. With one click of the [Return to 0.0] button, all axes will travel back to its respective 0.0 on the machine.

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17. Set and Save your 0.00 position for future runs
Set and save your 0.00 position on the machine. These coordinates will be recorded as the first line of the program in the Editor Screen. Should you desire to return to this program at a later date, you only have to click on the Set Zero Return button. This will command the machine to automatically jog each axis to its saved “set” 0.00 position according to the recorded coordinates at the first line of the program.

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18. Create a “Home” position to clear your application and run multiple times
Let’s say you need to machine one application times 100 pieces. This usually requires a jig to retain that physical 0.00 position. But in this case, you want the program to end with a clearance of the axes to easily switch out the next piece of stock and start again. With Save Home, you have the ability to save this offset (home) position while still retaining your Set Zero position where the machine will mill your part out. Pressing [Save Home] will record this new position under the Set Zero line in your program.
Pressing [Go Home] will jog your axes back to your “saved home” position where you originally pressed the Save Home command. You can also input GO_HOME from the Pick Menu as its own tool path in your program. At the completion of your program the axes will end at your Home position. Replace your part, then press [Return to 0.0] button to allow the axes to return to its zero position, and press Go to start your next run.

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19. Disable the axis motors to manually hand crank each axis into place
Easily de-energize the axis motors by clicking [Disable Motors] to crank each axis by hand, and then press [Reset Control] to re-energize the axis motors.

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20. Change up to 30 tools with compensation, and store your tool offsets for other programs
The MX supports…

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21. Use the optional ATC rack up to 8 tools for milling, drilling, and rigid tapping applications
The CNC Masters Automatic Tool Changer Rack and Tools (US Patent 9,827,640B2) can be added to any CNC Masters Milling Machine built with the rigid tapping encoder option. The tutorial will guide you through the set-up procedure using the ATC tools.

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22. Use the optional Rigid Tapping Wizard without the need for tapping head attachments
When you order your CNC Masters machine, have it built with the optional rigid tapping encoder. You can take any drill cycle program and replace the top line with a tapping code created by the wizard to tap your series of holes up to 1/2” in diameter.

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23. Use the optional Digital Probe to scan the profile and/or pockets of your fun/hobby type designs to write your tool path program and machine out a duplicate of your original design To “surface” scan an object, you can program the probe along the X or Y plane. The stylus will travel over the part starting on the left side front corner of the object and work its way to the end of the part on the right side. Depending on how the stylus moves, it will record linear and interpolated movements along the X, Y, and Z planes directly on the MX Editor.
To “pocket” scan an object containing a closed pocket such as circles or squares, the scan will start from the top front, work its way inside of the pocket, and scan the entire perimeter of the pocket.
Under the Setup of the MX software you will find the Probe Tab which will allow you to calibrate and program your probe. Your “Probe Step”, “Feed”, and “Data Filter” can also be changed on the fly while the probe is in the middle of scanning your object.

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24. Use work offsets G54-G59 for nesting applications
The work offsets offer you a way to program up to six different machining locations. It’s like having multiple 0.0 locations for different parts. This is very useful especially when using sub-routines/nesting applications.

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25. Create a Rectangular Pocket / Slot with our selection of Wizards to help you build a tool path program
The Cycle Wizards for the mill or lathe makes it easy to create a simple tool path without needing to use a CAD and CAM software.
On this Wizard, the Rectangular Pocket / Slots, can be used to form a deep rectangular pocket into your material or machine a slot duplicating as many passes needed to its total depth.

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26. Create a Circular Pocket Wizard
Input the total diameter, the step down, and total depth and the code will be generated.

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27. Do Thread Milling using a single point cutter Wizard

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28. Cut a gear out using the Cut Gear Wizard with the optional Fourth Axis

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29. Create a Peck Drilling Program in Circular or Rectangular Patterns
Using the Circular or Rectangular Drilling Wizards, you can program the machine to drill an un-limited series of holes along the X and Y planes. Program it to drill straight through to your total depth, use a high-speed pecking cycle, or deep hole pecking cycle. You can program the cut-in depth and return point for a controlled peck drill application to maximize chip clearance.

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30. The MX interface can easily be interchanged from Mill Mode to Lathe Mode
Use this interface for your CNC Masters Lathe. It contains all the same user-friendly features and functions that comes in Mill Mode. Simply go to the Setup page and change the interface.

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31. Use Tool Change Compensation or the optional Auto Tool Changer Turret if your application requires more than one tool in a single program
You can offset the length and angle of each tool and record it under Tools in your Setup. The program will automatically pause the lathe’s movement and spindle allowing you to change out your tool, or allowing the optional ATC Turret to quickly turn to its next tool and continue machining.
On the MX interface, you also have four Tool Position buttons. Select your desired T position, and the auto tool post will quickly turn and lock itself to that position.

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32. Use the Lathe Wizard Threading Cycle to help you program your lathe’s internal or external threads in inches or metric

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33. Use the Lathe Wizard Turning / Boring Cycle to help you program simple turning and boring cycles without having to go through a CAM or writing a long program with multiple passes

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34. Use the Lathe Wizard Peck Drilling Cycle to help you program your drill applications or for face grooving

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35. Facing / Grooving / Part Off Cycle Wizards – with Constant Surface Speed
These cycles can be used with Constant Surface Speed allowing the spindle speed to increase automatically as the diameter of the part decreases giving your application a consistent workpiece finish. With CSS built into the wizard, there is no need to break down the cycle into multiple paths and multiple spindle speed changes.

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36. This is our list of supported G and M codes which can be found under Tools > G Code/ M Code List in the MX
If you plan to use a third-party CAM software to generate your tool path program, use a generic FANUC post processor and edit it to match our list of codes. As an option, we also sell Visual mill/turn CAM software which comes with a guaranteed post processor for our machines to easily generate your tool path programs based on your CAD drawings.

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37. Our pledge to you…

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