Unit 14 Competency 2 - Design and create an object using NC code

Suggested Objective a:  Evaluate safety issues of programming and controlling a CNC machine

 

CNC machines are very safe to use as they are designed to be as safe as possible. One of the main advantages of CNC machines is that they are much safer than manually operated machines. The animation below shows a Boxford A3 HSRi² CNC Router with many of its safety features labelled.
1. Most modern CNC machines are designed so that the cutting tool will not start unless the guard is in position. Also, the best CNC machines automatically lock the guard in position whilst the cutter is shaping material. The guard can only be opened if the cutter has stopped. 2. It is essential that pupils / students / machine operators receive ‘quality’ instruction before attempting to use any CNC equipment.  3. CNC routers, used for shaping materials such as woods and plastics, have built in extraction. Dust can be very dangerous if inhaled and can also cause eye irritation. The CNC Router shown above has an outlet for an extraction unit. As the router is fully enclosed, dust cannot escape into the atmosphere. If an extraction unit is attached the dust is removed automatically. Most manually operated machine routers have very limited extraction systems which leave some dust in the air. 4. The CNC router above has a single phase electrical supply. Most older machines such as manually operated milling machines and centre lathes have three phase supplies. A single phase electrical supply can be ‘plugged’ into any available socket. The electrical supply for the machine comes through a residual circuit breaker (RCB). If an electrical fault develops the RCB will cut off electrical power immediately.  5. Single phase CNC machines can be moved more easily because they are simply unplugged and relocated. Three phase machines are specially wired by an electrician into the electrical supply and cannot be unplugged. 6. Most CNC machines work behind a guard or even a closed, transparent safety door. This means that the operated cannot be hurt by 'flying' pieces of sharp/hot material. 7. Commonsense applies to the use of all machines including CNC machines. Basic safety training regarding working in a workshop and with other machines applies to CNC machines as well.

Information copied from http://www.technologystudent.com/cam/cncman3.htm Links to an external site. on December 15, 2014

 

CNC Tutorial 1 of 3: Introduction to Machining (19 minutes) Links to an external site.

CNC Tutorial 2 of 3: Using the CNC Mill (34 minutes) Links to an external site.

CNC Tutorial 3 of 3: Making the Nameplate (39 minutes) Links to an external site.

CNC Machine Safety pdf Download CNC Machine Safety pdf from http://server2.smithy.com/media/pdf/CNC%20Machine%20Safety.pdf Links to an external site.on December 15, 2014

 

Suggested Objective b:  Analyze the components of the CNC machine and their uses

 

Several documents are provided below.  They are lengthy but contain a wealth of information on the parts of the CNC machine.  Also, some of the documents trace the history of the CNC and give advantages and disadvantages of the CNC machine.  Take notes as you look at the information.  Each is downloadable.

Unit 7:  CNC Machining Centers Download Unit 7:  CNC Machining Centers

CNC Machining Download CNC Machining

Unit 3 CNC Machine Tools Download Unit 3 CNC Machine Tools

All about the CNC Router 101 - Drawing Your Project - Part #2 Links to an external site.

 Standard NC Programming Codes Links to an external site.

 

Suggested Objective c:  Calculate how CNC machines are programmed

 

 

What is G-Code?

G-Code is the language used to control CNC machines. Your machine's CNC controller probably executes g-code, although there are other possibilities--Heidenhain, Mazak, and others have proprietary formats. Some machines with proprietary formats can also run g-code. It is the Lingua Franca (working language) of CNC.

In order to make a part on a CNC machine, you tell it how to make the part using a G-Code Program.

 

Basics Every CNC Machinist Should Know

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

The Coordinate System Links to an external site.: Is it a right-handed or left-handed coordinate system?

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

MDI: CNC For Manual Machinists Links to an external site.: 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 Links to an external site.: Some things in g-code are sticky and others are not.

CNC Editors Links to an external site.: Tools of the Trade

CNC Simulators, Backplots, and Viewers Links to an external site.: Getting a Second Opinion

Part Zero, Touch Offs, and Zeroing Links to an external site.: Helping the machine understand where the part begins and ends.

Basic G-Code Program Structure Links to an external site.: Blocks, sequence numbers, words, addresses, and the basic nuts and bolts of g-code line.

Linear Motion: G00 and G01 Links to an external site.: Moving your CNC in straight lines.

Circular Arcs: G02 and G03 Links to an external site.: Moving your CNC along arcs.

Running the GWE G-Code Simulator Links to an external site.: Using a G-Code Simulator to view and debug your programs.

Tool Changes and Tool Offsets Links to an external site.

Basic CNC Lathe Programming Links to an external site.

 

Intermediate

Relative vs Absolute Moves Links to an external site.

Polar Coordinates Links to an external site.

Canned Drilling Cycles Links to an external site.

Custom Deep Hole Drilling Cycles Links to an external site.

G96: Constant Surface Speed Programming Links to an external site.

Precise Timing and Speed: Dwell, Exact Stop, Backlash Compensation Links to an external site.

The G-Code Coordinate System Pipeline Links to an external site.

G20 and G21: Unit Conversions Links to an external site.

G54 and G92 Work Offsets: Making multiple parts easily Links to an external site.

Helical Interpolation: Making holes bigger than any cutter you've got Links to an external site.

Programming Haas Controls: Haas's unique g-codes and other differences

Tapping:

       Rigid tapping

       Tapping heads and tension compression holders

Thread Milling: How to thread mill, NPT and tapered threads, When to thread mill instead of tapping

 

Intermediate Lathe Programming

Lathe Simple Canned Cycles: G90/G92/G94

Lathe Repetitive Roughing Cycles: The Poor Man's Turning CAM

G71: Rough Turning Cycle: Links to an external site. Type I

Using Mill CAM to Create Profiles for Lathe Cycles Links to an external site.

G71 Type II: Rough Turning With "Pockets" Links to an external site.

G70: Finishing Cycle

G72: Rough Facing Cycle

G73: Pattern Repeating Cycle

Using IF and GOTO for a Poor Man's G71 Links to an external site.

G75 and Peck Parting Off for Lathes Links to an external site.

Lathe Threading Cycles

Gang Tooling for Lathes

 

Advanced

G28: Return to Reference Point Links to an external site.

Tool Compensation: The Poor Man's Milling CAM

A Mini-Tutorial on G-Code Macro Programming and Fanuc Macro B:

Parameterized Programming Links to an external site.: Macro Variables

Subprograms and Macros: Links to an external site. Packaging G-Code Into Building Blocks

Conditions and Looping Links to an external site.: Making Decisions and Handling Repetition in G-Code

Accessing Modal Data Links to an external site.: Making Subprograms Clean Up After Themselves

Modal Macro Calls

       Macro Example: Digits Links to an external site. (Work in progress)

G10: Programming Tool and Work Offsets in G-Code

Scaling the Coordinate System

Rotating the Coordinate System with G68 and G69 Links to an external site.

Mirroring the Coordinate System

G-Code Scaffolding: Making CAM Better With G-Code Help

       Multiple Part Strategies

              G52: Temporary programmable work offsets

Interacting With the Operator

Tweaking CAM Programs: Right Angle Heads and More

Mill 4th Axis Programming

Lathe C-Axis Machining and Live Tooling

Reference Motions

In-Process Probing

 

Information copied from http://www.cnccookbook.com/CCCNCGCodeCourse.htm Links to an external site.on December 15, 2014 - many links above are clickable and take you to more information on that subject.

CNC Programming G-Code Basics #1 Links to an external site.

iExplore CNC Programming Career Video Links to an external site.