_CNCTableDesign

Brandon Campbell’s

CNC Table Top Hot Wire Foam Cutter

Not only is he willing to show you how he created his own CNC hot wire foam cutter, he has also created a website that sells custom made RC wings for the hobby community!

Their products are superior quality to any other website to date, and are available at a fraction of the price! Check out their website for more information and their store for ordering.

Originally this page was written by Brandon Campbell from CustomRCWings.com

But over the last year or so, his website has come down and his email is no longer functional. It appears a youtube channel is still available, but I have not been able to contact the original author.

I have decided to leave this page up because it still may prove helpful to some of you who wish to build your own CNC hot wire foam cutter. Personally, I have no idea, but it seems straight forward enough if you have some knowledge of machine code.

Each of the four motors are controlled by a 4-axis drive box which is attached to the parallel port of a dedicated PC.

Mach3 is a CNC control software that interprets “G-Code” and sends the interpreted data & control signals to the 4-axis drive box.

“If you are willing to invest a lot of time and money, then following my example will leave you with a machine that is capable of cutting a large variety of foam wing cores with excellent accuracy and quality.”

A few words from the author...

The concept is simple. The machine has two separate sides that are free to move individually on both the horizontal & vertical axis and are held in place to the wooden rails with C-Clamps.

Having the C-Clamps in place, it allows adjustment to cut wings of any width, rather than being confined to a standard size at all times.

The bulk of the CNC cutter is built with 1/2 inch MDF to maintain strength and rigidity while attempting to be as light weight as possible.

To maintain a smooth movement of each cutting arm, full extension drawer slides are used to guide the motion on the horizontal axis.

At it’s heart, this CNC hot wire foam cutter uses a 30 gauge NiChrome Wire suspended between the two sides of the machine. Tension is maintained on the NiChrome Wire by use of a simple extension spring.

The threaded rods are coupled to the stepper motors using flexible PVC tubing and small hose clamps. This provides a coupling that can accommodate some misalignment between the rod and the motor shaft.

An ‘L’ shaped extruded aluminum bracket is used to attach the cutting wire & spring to the wooden assembly

The drive box are available through

Each axis’ movement is powered by a total of four 269 oz-inch stepper motors which each rotate a 1/4” 20 TPI threaded rod to precisely control motion and cutting.

Partly indicated by its model number, but this is a standard bench top power supply that is capable of outputting 30 volts and 3 amps.

Mastech HY3003D DC Power Supply

Check out the Power Supply Purchasing Page for suppliers and ordering information.

You may click this banner for a direct link.

It will also function in reverse, where you may set the voltage and it will adjust the amperage to satisfy Ohm’s Law.

The Mastech series of bench top power supplies allow you to set your output amperage, and it will automatically adjust your voltage dependent upon your circuit’s overall resistance.

As you should be aware at this point, setting the amperage of your power supply determines the NiChrome wire’s temperature.

But having a power supply that automatically adjusts the voltage will allow you to change your cutting wire’s length on the fly, without having to calculate a set of new values while maintaining an adequate cutting temperature.

For 30 gauge NiChrome Wire, this cutter is set between about 0.89 - 1.1 amps. This achieves a temperature between 400-500°F which can cut approximately 8 inches per minute.

More NiChrome data & information is available on the Calculations Page.

To generate the G-Code, the Mr. Campbell wrote his own personal software which allows him to input a variety of wing-related data which include:

- Root Airfoil

- Tip Airfoil

- Root Chord

- Tip Chord

- Twist

- Tip Kerf

- Root Kerf

- Sweep

- Span

4 Axis Systems Available Through

Using these inputted values, the software generates the G-Code into a text file which is then imported into the Mach3 software which is ready to cut!

When building a CNC Machine, use the old cliche - “Measure Twice, Cut Once.” Your cuts need to be exact, your angles need to be perfect and your machine needs to be sturdy.

When the craftsmanship is less than perfect, it will not be capable of high accuracy which will translate to imperfections in the wing such as ripples, divots, excess melting points and others...

Don’t take shortcuts or settle for less than perfect cuts, if you do you’ll end up spending a lot of money on a lousy machine

Tips from the author...

1.)

Ideally, the NiChrome wire should be hot enough that it never actually touches the foam. The foam should be cut or melted by the radiant heat from the wire. This will ensure a smooth cut throughout the automated process

While the listed amperage and temperature works for this cutter, it may require a lot of experimentation to achieve the best combination of wire temperature and cutting speed.

Once you’ve found that perfect combination, it will give a super-smooth cut with as small of a kerf as possible.

2.)

Check out the Supplies Page for more information on NiChrome Wire and other small components.

24VDC 5A Power Supply

If you wish to obtain the software written by Mr. Campbell which generates the G-Code, you will have to try and contact him directly. So far, he has fallen off the grid and I have not been able to get back in touch with him.