Computer Numerical Control

CNC Machines

What is a CNC Machine? CNC stands for Computer Numeric Control. Sounds complicated, but it isn’t. Years ago, it was just NC, or Numeric Control. Since, they’ve added computers to control the machine.

In the simplest of terms, think of a drill press. It’s a machine that drills holes. But before you can drill the hole, you have to loosen the chuck, install the correct drill bit, drill the hole in the correct place, turn off the drill, and remove the drill bit. Manually, this could be time consuming and cause fatigue over the course of numerous parts. This is a simple example, but throw in some lathe or milling machining and you have a greater chance for error.

With the CNC machine, all of this drilling can be done automatically instead of the manual process listed above. Machining has to be precise, and whether you use a CNC lathe or milling machine, you have to make sure the part is right. The computer takes a lot of the guesswork out of the machining of these parts. In fact, a CNC programmer can sometimes get bored watching the machine do all the work.

But there is more programming for the machine than you would think. The operator has to enter a set of instructions. The programming uses about 50 words and tells the machine how fast, how deep, and location for machining.

What can you do with a CNC machine? In manufacturing, you can use this tool for milling, drilling, reaming, boring and counter boring. You can also groove and thread parts in a CNC turning center. You may have several setups including CNC lathes, CNC drill and tap area, CNC milling, or even CNC grinding.

EDM (electrical discharge machining) can also take advantage of CNC operations. EDM can be either vertical or wire. A vertical EDM machine uses an electrode to make a cavity for a plastic injection-molding machine. A wire EDM machine uses a wire to cut metal for a tooling operation for fabrication. EDM is more closely related to making tooling for other machines, people often overlook the use of CNC with these machines.

CNC machines can also be used with routers in the wood industry. CNC can also be used with lettering and engraving.

I hope this gave you some basic information about what a CNC machine is and what they are used for.

Stuart Simpson

http://www.cnc-machine-review.com

The 3 Options You Have in Obtaining Your Own CNC Router

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Deciding on the purchase of CNC Router is not always the most attractive prospect. The upfront cost of a router can be a bit intimidating and cause a great deal of reluctance.

What I will do here is discuss the top 3 choices you will have in the acquisition of a CNC Router.

1. Buy Brand New

This is the most obvious prospect. There are some major benefits to purchasing a brand new CNC Router, the 1st of which is that you can rest easy knowing that your machine is brand new and most likely will not have any major mechanical difficulties for some time. The 2nd is that in 9 out of 10 cases you will receive some type of warranty from the company you purchase from; a benefit you will not receive from the other two options.

2. Buy Used

This is probably the most popular option of the 3. You can find plenty of resources online that sell used CNC Routers and I'm sure that you can receive an excellent bargain.

In my opinion, this option should only be resorted to if you absolutely cannot afford a new machine.

Why?

Because you have no idea what you are getting yourself into. Traditionally, you will not get any warranty with your CNC Router purchase or any assurance that the machine has not experienced major mechanical challenges in the past. However, if you can be sure that your source is reliable and trustworthy, then go for it! This option will save you about half the cost of a new CNC Router.

3. Build your own.

What!?

That's right, I said it. Build your own!

Now if you are anything like me, this is not a very inviting option. However, if you are the naturally crafty type this project may be a lot of fun and very rewarding. Again, you will easily find all of the necessary resources for this task online.

Well, there you have it! The top 3 options mixed in with a little bit of my opinion.

For more information on CNC Router or visit http://www.ez-router.com.

Important information about CNC Hot Wire Foam Cutting Machines

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What is a hot wire cnc foam cutter used for?

Hot wire foam cutters will cut different types of foam, from insulation to fabrication, from logos, surfboards and signs to crown moldings and concrete molds

Hot wire foam cutters are designed to cut different types of foam

EPS – expanded polystyrene
XPS – extruded polystyrene
EPP – expanded polypropylene

Not to be used for cutting polyurethane – will result in toxic fumes

What are the main components that a foam cutter is made of?

The software is divided into two sections – design software to design the shapes to be cut, and the cutting software that controls the machine
The hot wire tensioning mechanism
Effective cutting sizes for the horizontal, vertical and the wire length
Number of axis – a 4 axis machine will be able to cut tapered shapes (like a cone or a jet wing)

Here are some features to look for in a hot wire foam cutting machine:

For production of crown molding:

Multiple wires – from 3 to 8 wires will increase the cutting capacity from 2 to 7 times
8 foot effective wire length – don’t settle for a 4’ machine
If primary use of the machine is to cut logos and signs – a smaller machine will do the job
Cutting speed – mostly material dependent – as a rule of thumb: the higher the foam density – the slower the cutting speed

Foam cutting machines have many applications. They can be used to cut architectural shapes, for packaging, building, construction, hobbies, RC Planes, sculptures, monuments, theme parks, props, aeronautics, aerospace and much more.

Hot Wire CNC Foam Cutter prices:

CNC foam cutters will range from $1500 to $50,000. The price is a factor of the machine size, the number of wires, the way the wires are kept under tension.

Other foam cutting machines:

Another way to cut foam is with a CNC router – this is mainly for machining the foam and not for cutting.

CNC routers for foam are mostly used for 3D shapes seen in Las Vegas, theme parts and even signs

Foam coating: EPS and XPS will melt if painted with oil-based paint. Painting is composed of two steps:

Preparing the foam for coating – a primer should be used to prevent the coating material to penetrate the EPS beads
Coating – Coating is usually Epoxy (usually brushed) or Polyurethane (brushed or sprayed)

Once the foam is coated – it can be painted with any type of paint.

Cutting EPS Foam:

Expanded polystyrene is very easily cut with a hot-wire foam cutter, which is easily made
by a heated and taut length of wire, usually nichrome due to nichrome's resistance to
oxidation at high temperatures and its suitable electrical conductivity. The hot wire
foam cutter works by heating the wire to the point where it can vaporize foam immediately
adjacent to it. The foam gets vaporized before actually touching the heated wire,
which yields exceptionally smooth cuts.
Polystyrene, shaped and cut with hot wire foam cutters, is used in architecture models,
actual signage, amusement parks, movie sets, airplane construction, and much more.
Such cutters may cost just a few dollars (for a completely manual cutter) to tens of
thousands of dollars for large CNC machines that can be used in high-volume industrial production.
Polystyrene can also be cut with a traditional cutter. In order to do this without ruining
the sides of the blade one must first dip the blade in water and cut with the blade at
an angle of about 30º. The procedure has to be repeated multiple times for best results.
Polystyrene can also be cut on 3 and 5-axis CNC routers, enabling large-scale
prototyping and model-making. Special polystyrene cutters are available that
look more like large cylindrical rasps.

by: Tal Barnea