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6 Things A Brand New CNC’er Should Learn to Get Started

Machinist's Mate Diploma

Machinist’s Mate Diploma

So you’ve just gotten interested in CNC, and you notice the waters look a little deep.  How do you get started?

Here are 6 things you should learn about first, before you buy a CNC machine, before you do anything else, just to get oriented and see what this CNC thing is all about.  It won’t take you long to get through them, and when you’re done, you’ll know enough to be dangerous.

Pretty cool, eh?

More importantly, you’ll know enough to understand what’s being talked about as you dig down into the next level.  You’ll have the mile-wide-but-inch deep map of the territory to help guide your learning efforts to the next level.

1.  Understand the CNC Software Stack

There’s a fair amount of different software that is involved when making a part with CNC.  At the very least that includes a CAD program with CAM (or perhaps Conversational CNC instead of CADCAM, but let’s start with CAM as a newbie) to generate the g-code, and your machine controller, which turns that g-code into machine motions that make your part for you.  There’s a lot of other software out there that you’ll hear about and wonder about.  It’s helpful to get a mile-wide-but-inch-deep overview of what all that software does and how it fits together.  You won’t need all of it to get started, but it’s still worth understanding it because it’ll help you understand a lot more about the workflows going from a design concept to a finished part at the software level.

To help folks understand the CNC Software Stack better, we wrote an article called CNC Software: Digital Tooling for CNC that explains all about what kinds of CNC software are available and how it all fits together.  Here’s a diagram that shows how the most important pieces of software work together:

That article gives you the overview and background.  Even better is our Beginner’s Guide to the Best CAD CAM Software.  It’s laser-focused on exactly the software Beginners need to get started.  Even better, it’s chock full of buyer’s guides, evaluation tips, learning help, and even a guide to the secret deals on the Internet that will let you buy the most popular software uber cheap.  Check it out!

2.  Find Out About the Different Kinds of CNC Machine

This one is for the DIY CNC beginner.  You want to create a machine of some kind.  Perhaps you’ll buy a finished machine, perhaps you’ll build a machine or convert a manual machine to CNC.  Try reading “What Type of DIY CNC Should I build?

CNC Mill, 3D Printer, CNC Router: Which machine is right for you?

This article goes over the different kinds of machines available to the DIY CNC’er and talks a little bit about the pros and cons of each for beginners.  Each machine is described, examples are shown, and the machine section winds up with a summary that describes what such a machine costs, the difficulty of building one, time required, disadvantages to that machine, and what sorts of projects you’ll be able to tackle with the machine.

Isn’t that all important stuff you’d like to understand before you get started building a machine?

3.  Basic Feeds and Speeds

Having gotten to this point, you’ll have a decent idea about the software side of CNC.  Now it’s time to get into the mechanical aspects, where the rubber meets the road, or more properly, where the cutter starts to make chips of the workpiece.  Once again, we offer a free tutorial on Feeds and Speeds.  There’s some really important information here that every machinist should know.  For example, how does run the cutter super slow and taking very light cuts actually wind up being harder on the cutter than going faster and taking heavier cuts?  The answer, explained more fully in the tutorials, is that at certain speeds, the cutter quits slicing bits of material off cleanly and starts to plough or rub across the top of the material when it can’t get enough bite.  Beginners always want to slow down, but doing so might be the cause of your problems.

Here’s a quick intro video on Feeds & Speeds for beginners…

Like our G-Code course, the Feeds and Speeds course is organized into bite-sized sections.  I recommend knocking down at least the basics, and then take a look at the other categories.  See what catches your eye and graze on the information appropriately.  Some is very specialized and not relevant to a beginner, and some is handy to have gone over.  Along the way, pull down a trial copy of our G-Wizard Feeds and Speeds Calculator.  Play with some actual cuts and see how the variables interact in the calculator.  You’ll start to get a sense of what your machine can or can’t do and the interaction between the cutters and the different materials you may want to cut.  Also pay attention to the CADCAM Wizards in GW Calculator.  These things were tailor-made for beginners (they’re great for experts too) because they don’t require you to know as much to use them.  They even recommend what type of tool will be needed for the operation as well as a host of other things you may not know how to figure out for yourself.  There’s a video tour in that link that makes it easy to see what they do and how to use them.

4.  Basic Measurement and Setup

You need to understand basic measurement as it’s done by machinists and basic setup–those things you do to the machine to get it ready to make your part.  I strongly suggest  you seek someone out who is local to your area and ask them to walk you through these things.  They’re basic skills that are not at all hard to learn, but as I say, they’ll make much more sense if you can do them hands-on with someone that knows what they’re doing.  Hopefully you have a friend who is a machinist, a local Maker Space, or perhaps a local club of some kind.  Perhaps there is a Community College course you could take that will offer these skills, or a vocational program.  More and more of these are popping up as Manufacturing starts returning to our shores and there continues to be a serious skills shortage.  If you have to pay someone to spend an hour or two with you on this, it’ll be well worth the money spent.

Here’s a brief list of things you should be able to do:

–  Use a calipers properly, know what it can measure, know how accurate it is, and know when to use one.

–  Use a micrometer properly, know what it can measure, know how accurate it is, and know when to use one.

–  Use a dial test indicator for sweeping various things.   Learn to sweep vise jaws to they’re parallel to the axis of the milling machine.  Learn to set up a 4 jaw chuck on a lathe so the part is centered.

–  Use an edge finder or other tool to find the corner of a part or an edge of a part on a mill.

–  Use the tool of your (or your mentor’s) choice to find the center of a bore or hole.

The latter examples, starting with setting the vise and 4-jaw up, are your setup tasks.  Yes, there are many more, but these are basics to start from.  It won’t take a machinist very long to show you these things.  I suggest you video them with your smartphone and ask lots of questions.

You might even consider purchasing at least a set of calipers that you can work with.  You’ll find them handy starting day one when using your CNC machine.

5.  Make a Part from Start to Finish

This is the absolute best one to get with someone who has a machine and do it hands-on.  This is your graduation exercise.  You’ll still be a beginner, but once you have made your first part, you will know the basics of how it’s done from start to finish.  The rest is refinement and proficiency.  You will have had to do a fair number of things, including learning some CAD program well enough to input your design and some CAM software well enough to get g-code back out.  Your friend may work with you on these two tasks, but don’t let them do it all.  Get your fingers on the keyboard and mouse and have them look over your shoulder to prompt and answer questions.  As before, video the whole thing with your smartphone so you can refer back to it–hard to remember everything that happens in the heat of the moment.

If this all seems hard, consider two things.  First, there is a pretty wide breadth of things you need to know to make parts and there’s no getting around it.  3D Printers do have a little less learning curve, but they have significant limitations too.  Second, many many people have traced these footsteps successfully.  Yes, there is some work to do, but you don’t become a scratch golfer in a day either.  We live in an age when it’s possible to learn so much entirely for free via the Internet.  We live in an age when CNC machinery has become so common that hobbyists have the machines now.  They’re everywhere.  Get yourself a good mentor, get a cup of coffee (or your favorite beverage), sit back and dig into what’s there for you.  It’s fun to learn and you’ll soon be feeling the dual push of the satisfaction in knowing a lot of questions you’d been wondering about together with having thought of a whole new set of interesting questions to dive into.

To get an idea of what’s invovled, go through our Beginner’s Step-By-Step Guide to Making CNC Parts.  It walks you through these things and would be a good orientation before you go through the process of making a part for real.

6.  Basic G-Code

Okay, you made your first part–CONGRATULATIONS!

The very next thing you should look into is G-Code.

G-Code is the programming language that makes the CNC machines go.  Understanding g-code at a basic level is handy for two reasons.  First, you can put that knowledge to work operating the machine either when you’re typing in MDI commands (this is where you give the machine a hand typed g-code to execute) or when you’re trying to understand why your CAM software and your machine are not communicating properly, for example, to debug a post.

Wait, what’s a post?  It’s short for “postprocessor”.  You’ll learn what that is reading about the Software Stack in #1. See, making these connections is what this set of 6 things is all about.  Second, once you know that your CNC Machine “thinks” in g-code, some of the things it does will make a lot more sense to  you.

G-Code can seem obscure or even scary when you see it.  It looks like gibberish to the uninitiated.  There are some who know g-code cold and can write an entire part program by hand without recourse to CAM software.  Or, they can take the g-code that comes out of their CAM system and make it far better (faster or better suited to their detailed needs or easier for the operator or better in many more ways).  You don’t need to be that kind of g-code programmer at this stage.  You just want to get the basics.

Fortunately, we offer a free g-code programming course.  It’s written in bite-sized tutorials that don’t take long at all. If you do nothing else, go through these basics:

Introduction for Beginners: More on what you can do with g-code, basic concepts, and an interactive tool to help you learn faster.

The Coordinate System: Is it a right-handed or left-handed coordinate system?

G-Code Dialects, Post Processors, and Setting Up GWE: The great thing about standards is there are so many to choose from.

MDI: CNC For Manual Machinists: Pretend your CNC is just a manual machine with DRO’s and Power Feeds on every axis.

One-Shot G-Codes and Modal G-Codes: Some things in g-code are sticky and others are not.

CNC Editors: Tools of the Trade

CNC Simulators, Backplots, and Viewers: Getting a Second Opinion

Part Zero, Touch Offs, and Zeroing: Helping the machine understand where the part begins and ends.

Understanding everything from coordinate systems to part zero and touch offs will be a big step up for your understanding.  You’ll also be shown how to use tools like our G-Wizard Editor to play with some g-codes and see what they do on your own.

conversational cnc wizards

Here’s something that’s cool about G-Wizard Editor–it includes Conversational CNC Wizards.  These make it possible for you to generate g-code for simple things without CADCAM.  If you’re a manual machinist transitioning to CNC, the Conversational Wizards let you perform the familiar operations of manual machining on your CNC.

None of this is very hard, I promise.  In fact, if you use G-Wizard Editor to work along with the examples, it has a feature we call “Hints” that shows you what each line of g-code does in plain English.

If you get through that and you’re still hungry for more, keep going.  At least go through the Basics section.  That’ll enable you to look at the g-code produced by your CAM software and have a pretty good idea what it does.

Bonus Resource:  CNC Dictionary

Here’s an additional resource to keep at hand during your research:  The CNCCookbook CNC Dictionary.  Like a lot of things, CNC involves a fair amount of jargon and specialized terms.  The CNC Dictionary offers concise definitions to make it easier to understand what’s being talked about when you come across an unfamiliar term.



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