Learn About CNC

10:48 PM SEAGAMES 2009


Little Did I know…

There was a steep learning curve with CNC. Building a frame for the machine is only a small part of the project. Today it is much easier. The software, components and suppliers are better. There is an entire cottage industry that has sprung up around CNC to support it. Some of the best people in the world make their livings servicing CNC Hobbyist needs.
For some reason I figured if I just build this machine it would spit out parts whenever I wanted it to. Simple, Simple, Simple ran through my head. Over time, I started to get it. I didn't have a teacher, but I started to learn the ins and out of what I was doing.
Other things I had to learn along the way:
CAD Software
Designing Parts
CAM Software
Preparing parts for machining
Simulating Machining
Machining Basics
Cleaning parts
So, where am I at today?
Today I have multiple CNC machines that I work with. Each have their own nuances, software, capabilities and functions. The point of it is that they are all CNC. They all follow the same basic process. That process is pure gold if you know it. You can move from machine to machine and know what is going on. That is what I want to teach you.


Computer Aided Design by Solidworks

9:23 PM SEAGAMES 2009

Solidworks is the main 3D CAD software used by our lab. It is mainly used in mechanical design and is the most popular CAD software on the market. Three main file types are used in Solidworks; Part files, Assembly files and Drawing files. Part files are a 3D representation of a single component. Assembly files are a 3D arrangement of Parts or other Assemblies. Drawing files are 2D engineering drawings of Parts, Assemblies or custom drawings. Solidworks also comes with some free analysis software, listed below.
1. COSMOSXpress is a limited static FEA solver that can be used on single part files. The full featured version is COSMOS.
2. COSMOSFloXpress is a limited computation flow dynamics (CFD) solver. The full featured version is COSMOSFloWorks.
3. DFMXpress is a design for manufacturing (DFM) program that checks if a part can be machined.
4. DriveWorksXpress is a rules-based design automation tool that allows creation of multiple variations of parts, assemblies and drawings quickly and accurately.
Learning Solidworks is beyond the scope of this guide, please consult the Solidworks help and tutorials if you would like to learn more.


G-CODE PROGRAMMING CNC

9:20 PM SEAGAMES 2009

Almost all CNC machine are controlled by a common programming language called G-code. Even though this standard language exists, not all machines can perform every G-code command. The list of G-code commands that our machine is capable of performing is located on the CNCMill wiki page. For simple parts it is not hard to manually write all of the G-code, but for complex parts, the number of lines of G-code can be in the millions. Fortunately, computer aid manufacturing (CAM) software can generate G-code based on a drawing or solid model eliminating the need to write the G-code manually. But, to further your understanding of CNC machining, you should review the G-code commands to get a sense for how the machine operates. Also, in some cases, the G-code generated by the CAM software is not perfect and has to be edited manually. This is particularly true for the canned drill commands.
Only a few commands are needed to make your logo. Please consult the CNC manual for all of the G codes available. An example G-Code program is listed below that cuts a square with an inscribed half circle shown as shown in Figure 1. The top of the part is assumed to be at a Z depth of 0.000in. The program will cut the shape 0.020in deep. Use notepad to write your G-Code and save it as a text file.

G-CODE PROGRAMMING CNC



Computer Aided Manufacturing (CAM) LazyCAM

9:16 PM SEAGAMES 2009

LazyCAM
Links to video tutorials for this software are located on the CNCMill wiki page. The only file type that can be imported into LazyCAM is a DXF file. Even if a drawing program is able to generate DXF files, it might not import properly into LazyCAM. For example, DXF files made with CorelDraw 12 will not import circular features into LazyCAM. The lines of a DXF file are interpreted as the toolpaths the CNC machine will follow. This means that the diameter of the tool should be know before starting on your DXF toolpath drawing


MeshCAM
MeshCAM has the ability to generate true 3D toolpaths from CAD files. It is fairly easy to use, but does not give as much control over the toolpaths as LazyCAM. If this program is used, please do a dry run to insure the toolpaths are what you intended. If program opens up as a demo version, enter the username: Mark Merlo and registration code as: 0201-02C8-0658-0000-8DAE


CNC Foam Cutter

9:13 PM SEAGAMES 2009

The CNC Foam Cutter consists of an electrically heated wirer that cuts (melts) through Expanded Polystyrene (EPS, XPS), Expanded Polypropylene (EPP), Expanded Polyethylene (EPE), and Semi-rigid polyethylene foam (XPE). The wire is guided by two XZ computer controlled traverses at each end of the wire. Any 3D object that can be defined by straight lines can be cut out. This includes rectangular, tapered and swept wings.


How To Work With CNC Equiment

7:25 AM SEAGAMES 2009

A CNC machine is used in woodworking shops and some other industrial settings. They are very expensive, so most individuals do not buy them, although used ones can be obtained more cheaply. They are important for speed and accuracy in large, repetitive tasks.

There are many uses in industry for CNC machines. Routers drill holes, for example. Many CNC machines can perform a number of tasks at once, improving efficiency in the manufacturing process.

The technology behind these machines is Computer Numerated Control. This technology was developed in the seventies and it allows for a machine to be programmed in advance so the operations are set up to work almost automatically. The initial setup is a little complicated, but once that is done the machine is easy to operate.

A CNC router would be programmed to drill a hole repeatedly at certain intervals. This is much more efficient than manual calculation and drilling and eliminates inconsistency due to human error or fatigue.

A CNC lathe would be used to cut pieces of wood of uniform size and shape. Lathes can have horsepower ranging from 15 to 40 HP, and how much power is needed depends upon the job being done. A good CNC lathe will allow you to work at various levels of automation, so that you can work all manual, or all automated, or any combination in between.

The best mill available is the Bridgeport mill. Mills are designed to be used in both large industries and small milling shops, and the Bridgeport mill is built to last in any situation. The price is prohibitive, however, for individual use.

A CNC mill is considered specialty equipment. The concept is to use computer programming and robotic operation for speed and accuracy. This kind of speed and accuracy would be impossible to achieve for an individual. The airline industry frequently uses the CNC technology of Bridgetown mills; specifications are entered, and the mill automatically determines which functions to perform and how.

Engravers can also be CNC machines. Engraving can be done on many materials, including wood or wood composite, metal, stone or glass. These machines can do very exact engraving on materials from the smallest to the largest, and have the same result over and over.

Since CNC machines are so expensive most individuals cannot afford them, there may be individuals who do a lot of repetitive machine work and would like to obtain one. An option in this case is a used CNC machine, which can be as low as half the price of a new one. It is important to make sure the used machine is in good condition, so you may be better off looking for a rebuilt machine. This is one that has had the major components replaced so it is almost a new machine. Frequently, rebuilt machines have a warranty of at least one year, so that you can be assured that it will be working, or you can get it repaired if it does not.


Posted in

Cnc Machining and Laser Cutting

7:25 AM SEAGAMES 2009

Laser or LASER is not a word. Rather, it is an abbreviated form standing for Light Amplification by Stimulated Emission of Radiation. In laser cutting, sheets of materials are cut by using a beam of high intensity light, so high that as it touches the metal surface, it cuts it by burning, melting, or evaporating it. Laser cutting mainly uses the carbon dioxide laser and Nd: YAG. However, the demand of semiconductor lasers is increasing due to their high efficiency.
Laser cutting is growing in popularity owing to its accuracy and high speed. CNC laser cutting is the combining of the computer robot with the laser system. CNC stands for computer numerical control. CNC lasers use an automated software guided system for the laser cutting process.
CNC laser cutting has enabled high precision in the cutting process and has effectively reduces related costs, because there is little human labor involved in the process other than setup. Consequently, it has also cut down the time required for the processes, thus enhancing its overall efficiency.
Before the metal sheet is cut into the desired shape, a hole is first made somewhere along the line to be cut. Then the laser beam is focused through this hole. After this, either the laser beam is moved keeping the sheet constant or the laser beam is fixed and the sheet is moved.
ALTERNATIVES: The possible alternatives that can be used in place of laser cutting are abrasive water jet cutting, plasma cutting and CNC machining. In CNC machining, however, there is a major disadvantage of production of micro-irregularly cut edges.
ADVANTAGES:
1. The laser systems do not contaminate the material being cut with the cutting machine’s metal.
2. It is also more precise because laser cutting is sharp and hence can claim more accuracy.
Laser cutting may heat some materials and cause distortion, but this depends on material thickness and temperature characteristic. Waterjet cutting may be an alternative, or even photochemical etching for very thin stock.
For more information on laser cutting and a wide range of other processes, please visit www.emachineshop.com. This website provides you an opportunity to design and order custom machined parts online. You can order any machine part by drawing it with the help of the free 3D CAD software provided on the site, and then placing the order if you like the pricing. Your order may be for one part, or may it be for a million. The service and our promptness will impress you. For more details, please visit