Introductionto CNCA detailed beginners guide to thebasics of CNC technology, processworkflow and terminologyVectric Ltd.Document V.1.0 – June 2013Page 1 Vectric Ltd. 2013 -

ContentsIntroduction . 3CNC Overview . 3Key Areas of Knowledge . 51.Computer skills . 52. Design & Toolpath Software . 53. Operating and Maintaining your CNC Machine . 54. Knowledge of Materials and Tooling . 6Workflow Overview of a typical CNC project . 7Detailed Workflow of a typical CNC project . 11Step 1: Concept . 11Step 2: Design (CAD) . 12Step 3: Toolpaths (CAM) . 15Step 4: Machining . 18Step 5: Finishing and Assembly . 21Summary . 22Help for Vectric Programs . 22Help for your CNC machine and its control software . 24Important CNC Concepts and Terminology (Glossary) . 25Page 2 Vectric Ltd. 2013 -

IntroductionThis guide is intended to be an introduction for people who are just entering theexciting and rewarding world of CNC (Computer Numerically Controlled)machining. Its purpose is to familiarize you with the typical steps required tocreate a CNC project from start to finish and also to provide a glossary ofterminology to help you better understand some of the jargon involved. Much ofthe information would apply to all CNC machines but the focus here is on whatare typically referred to as CNC Routers.If you’re a novice, then whether you’re looking at a CNC for a new hobby, to startyour own business, or are adding the technology to an existing company, then thisguide will be a good starting point.If you don’t have a machine yet but are considering a purchase, this documentwill also help you understand more about how they work and provide someimportant considerations to aid your decision. For the purposes of this guide,when we discuss the Design and Machining software it will be with regard toVectric’s software products – for more information on the range of softwareplease visit http://www.vectric.comPage 3 Vectric Ltd. 2013 -

CNC OverviewBroadly speaking a “CNC Router” is a computer controlled machine that has arouter or spindle mounted on it that holds a cutting tool (router bit). It is typicallyset up with 3 directions of movement referred to as the X, Y and Z axis. Theposition of the router is determined by a computer telling the motors mounted oneach axis how much to move in each direction.Using this method of positioning, any location within the machines work area(envelope) can be defined and the router can be moved within that space. As themachine is driven by a computer telling it where to move, the operator uses asoftware program to draw the shapes they want to cut and create the path that themachine will follow.For the purposes of this document we’ll just refer to the machines and technologyas “CNC”. As with any technical subject there are many variations and nuances inthe terminology but at this stage but we’ll try to keep it as simple as possible. Theimage below shows a typical layout for a CNC (there are many variations though)and a number of the key components along with an indicator of the possibledirections of movement (X, Y and Z).While CNC is not a simple subject it also does not require you to be a genius tomaster it. For many, CNC is an extension of an existing skill such aswoodworking and your knowledge in these related subjects will be helpful as youprogress along the learning curve. To start with though, the best way to approachCNC is as a completely new skill, begin with the basics, read, learn and practicewith the software as much as you can and use the many support mechanisms toask questions and get help. Over time you’ll be able to follow the same route tosuccess as the many 1000’s of other CNC users (addicts!) who have gone beforeyou.Page 4 Vectric Ltd. 2013 -

Key Areas of KnowledgeAs with any subject, the more time you invest in learning about CNC and therelated technologies, the more you will get from it. To achieve the best results,there are a few key areas which you should concentrate on:1. Computer skillsOne requirement common to all aspects of CNC work is how to use acomputer to perform basic tasks. You will be working with computers andcomputer programs during almost all the steps of the process as youdesign your parts and need to understand basic operations such as startingand stopping programs, saving, copying and deleting files, finding filesstored on your computer and installing programs and updates.Your CNC machine is also run by a computer, this may be a standalonePC or a dedicated Control Box.This guide will assume a basic knowledge of computers and the Windowsoperating system, if you don’t feel comfortable with your currentcomputer skills or are new to running a PC then it would be well worthtaking a basic course or buying a general guide to working with your PC.2. Design & Toolpath SoftwareBefore you can cut anything with a CNC, you need to first create thedesign layout that the machine is going to follow to cut the parts. Thesoftware you choose will play a significant role in successfully creatingprojects with your CNC. Simply put, the design software will allow you totransform “pencil and paper” ideas to a set of instructions used to run themachine. When done correctly, the end result will be a physical productyou can touch and hold that has value and purpose and a great sense ofachievement.Page 5 Vectric Ltd. 2013 -

3. Operating and Maintaining your CNC MachineIf you currently own or use a CNC machine, you already know howimportant it is to keep it properly maintained and adjusted, to know andunderstand its limitations and how to set it up correctly to run a job.If you don’t own a machine yet, then it’s important to spend time thinkingabout what you want your machine to be able to produce, this caneliminate a lot of future frustration. Cost will always be an importantfactor, but realize that you need to balance that with capabilities, becausenothing can be more expensive than a machine that cannot do what youneed. For example, if you want to cut large sheet goods then a desktopmodel will probably not be your best choice. However, if you only haveroom for a small machine this may be your only option and you need tounderstand its limitations on how large a part it can cut. Only you candetermine what this balance will be for your situation and budget.Some important considerations when researching the purchase of amachine or when looking at building one yourself include size, speed andaccuracy and the technical support offered both before and after thepurchase. As with software, the importance of a company’s reputation,support, and an active website and/or forum cannot be understated.Every CNC machine needs software to directly drive its movement; this iscommonly referred to as the ‘Control Software’. Some common genericthird-party packages that do this include “Mach3” and “WINCNC”. Manymanufactures create and use their own proprietary systems specific to theirown models and these may be installed on an external PC or be loadedonto a dedicated Control Box attached to the machine.Most control systems offer settings that can significantly improve thesmoothness and accuracy of your machine when correctly set. While thisgoes beyond the scope of this guide, it is something worth investigatingfor your particular CNC. Remember, the best designed project will not cutwell on an incorrectly “tuned” machine.4. Knowledge of Materials and ToolingWhen it comes to obtaining the best possible results, you cannot forget thematerial you are working with or the tool you are using to cut it. The typeof material will factor into every stage of the Project – from initial conceptthrough final finishing.The common materials people using CNC Routers work with include;wood, plastics, dense foam board and softer (non-ferrous) metals (brass,aluminum, etc.). If you are not already familiar with the type of materialyou want to use, there are many sources of information that can help you.Page 6 Vectric Ltd. 2013 -

Typical questions you must answer for the type of material include propertool (bit) selection, how fast you can move that tool through that material(Feed Rate and Plunge Rate), how much material you can remove at onetime (Pass Depth and Cut Depth) and how fast the bit should be rotating(Spindle or Router speed). Typically suppliers of tooling offer informationon the correct settings for the router bits they sell.You will also find many sources of information on other users experienceswith different tools, materials and settings on websites and user forumssuch as Vectric’s – 7 Vectric Ltd. 2013 -

Workflow Overview of a typical CNC projectWhen you step back and look at a complete project from start to finish, you canidentify a series of major steps that will form the “Workflow” to complete it.Having a good understanding of this process will help you start to appreciatewhere the different software packages and setup procedures fit into the overallcreation of parts with your CNCIn this section is a list of the basic process stages with a brief description of whatis involved for each one, in the following section is a more detailed description ofeach process stage.1: ConceptThis is the idea for what you are going to make. This may rangefrom a specific customer requirement, something you havesketched on a napkin or a ready to go file that someone hasalready prepared. At this stage you need to try and think throughthe other processes in the job to help to get the best approach toachieving it. You should also assemble any reference materialyou will use to help design the part such as photos, data from thecustomer, design sketches etc.2: Design (CAD – Computer Aided Design)For the design you need create the computerdata that will define either the 2D or 3D formsyou want to cut on your CNC. This is done inwhat is typically called “CAD software” andyou may also hear this type of softwarereferred to as a drafting, drawing or designprogram.The finish point of the Design stage is to haveprepared all the 2D data (Vectors) or 3D data(Components) you require to start calculatingthe specific movements the CNC machine will follow, these moves are typicallyreferred to as the “Toolpaths”.Most of our customers use one of the Vectricproducts (VCarve Pro or Aspire) to do theirdesign although there are many other design(CAD) programs available for either 2Ddrawing or 3D modeling and depending onthe file format export options available, thisdata can be saved and imported into theVectric programs for Toolpath creation.Page 8 Vectric Ltd. 2013 -

3: Toolpaths (CAM – Computer Aided Manufacturing)Once the design is complete, youwill start to calculate the actualpaths that will drive where the toolwill move on the machine, aspreviously stated these are called“Toolpaths”. Creating yourToolpaths is the key stage in goingfrom the virtual world of acomputer design to the reality of thephysical world. At this point youwill start to take into account theshape and size of the tool, the typeof movement you want the tool tomake (the shape you want it toleave in the material) andappropriate settings for how fast thetool can be moved and how much material can be removed safely.Once the Toolpaths have been calculated the software will let you Preview howthey will look in a virtual piece of material. This lets you check that they aredoing what you expected. Once you are happy the Toolpaths are correct then theycan be saved in a format that is appropriate for your particular CNC.All Vectric software can be used to calculate toolpaths to drive a CNC. Eachproduct is designed to work with different types of data depending what you planto make. Visit for information on the different products andtheir specific functionality.4: MachiningOnce your toolpaths have been saved thenyou transfer them over to the CNC. At thisstage you need to set the CNC to matchthe job setup you specified in theDesign/Machining software. This willinvolve setting up your material in theright orientation, and making sure it willbe secure while you’re cutting it. Thenyou need to load the correct tool and tellthe machine where the X, Y and Zreference position is for the tool tip(normally this is the zero position for eachaxis), again this will be to replicate how itwas set in the software so all the positionsand sizes you specified in the software will be replicated at the machine.Page 9 Vectric Ltd. 2013 -

Once the machine is setup correctly, the toolpath can be loaded and then executedfrom the CNC’s control software. The machine will feed the co-ordinates of thetoolpath to the machine to continually move its position and create the cuts yousetup in your toolp