Foam Cutter Usage Instructions

Steps for using the foam cutter:

  1. Create geometry in Profili Pro 2
  2. Output G-Code that generates geometry
  3. Run G-Code on foam cutter using Mach3

This guide is written to document this process and expedite the learning process. Note that you are not likely to get the right setup the first time, but hopefully with the help presented here some common mistakes can be avoided.

Generate G-Code using Profili Pro 2

First load Profili Pro 2. Make sure that the version is the Pro version, otherwise you won’t be able to export your G-code.

Profili Pro has a lot of capabilities which we will not use. All that we want to do is create a wing. In the top menu go to the Panels drop-down and select Wing Panels Management.

This will pull up a window with a bunch of wing panels that have been developed previously. Once you have created a wing panel you double click your wing panel in this menu to edit and/or inspect input parameters. To create a new wing panel in the “Panels Management” drop down choose “New foam panel for 4-axis CNC hot wire cutting…”. Enter an appropriate name. Chances are you will be creating several wing panel sections so it is best to name wing panels similarly (e.g. “YourName-leftwing”, “YourName-rightwing”, “YourName-htail”, “YourName-vtail”). Once your wing panel is created you will be taken through a series of windows defining your wing panel geometry. Notes regarding each window can be found in the following sections

General data and Wing Plan Settings

Panel length: The length of the wing section you would like to cut. Root and Tip Chord: Root and tip chord values Root and Tip Incidence Angle: Positive twist is equivalent to a negative incidence angle, you can and should check if this setting is right in a later window. Leading Edge Sweep Back: Used for sweep, with the help of the graphical interface this should be pretty simple to set correctly.

Airfoil Selection

Root and tip rib: Here is where you choose your airfoil. Chances are, your airfoil will already be loaded with the software. If you wish to import your own airfoil you can do so from the main screen.

Sheeting and Kerf Settings

Sheeting parameters are used if you would like to remove extra material from the outside of the airfoil. In the case of adding extra material, such as a composite layup, this would preserve the final airfoil thickness. Chances are you probably won’t need this option enabled. The tangential lengthening option should be set at about 20 mm. This tells the wire cutter to advance into the foam a certain distance before beginning to cut the profile shape. The default kerf values are probably fine, but appropriate values will largely depend on the amount of taper in your wing (due to one side moving more slowly than the other), the temperature the wire cutter is set at, and the cutting speed.

Spars Setting

Spar holes may be pre-cut to assist in assembly of your wing. The main key in this menu is using the three drawing views at the bottom to visualize the result. Otherwise this menu should be pretty self-explanatory. The only thing to note is that an upward hot wire cut should probably be used. This tells the hot wire cutter to cut the spar holes in the middle of cutting the airfoil, rather than at the beginning.

Lightening Holes Setting

Lightening holes may also be added to your wing to reduce weight. This is not recommended, however, as it compromises the structural integrity of the wing when working with foam. Stiffening of this weakness often leads to a heavier wing than you began with.

Foam Block Placement and Setting

Double check that the 4-Axis CNC Machine Settings are set to the proper bounds of movement for the left and right carriages. The maximum horizontal and vertical runs should be set to reasonable values, but unless your wing is extra-normal you shouldn’t have any need to approach the bounds of the machine and these bounds should not matter. Make sure to enter an appropriate foam block thickness and then modify the wing panel height settings to place your root and tip sections solidly inside your foam block. Center your part between the carriages and measure the distance from the left wire pulley to your foam block. Enter that value for the root section distance between carriage and block. Now switch to the wing planform view and take note of the value shown for Dx. Move your foam block away from the zero reference position by that amount. Otherwise you will end up wasting a decent amount of foam, or you might run out of foam. When rerunning your G-code you will probably need to return to this window to check this value and place your foam accordingly.

Leading Edge and Trailing Edge Cutting

Here you can slice off your leading or trailing edge. You can also choose the height above your foam which the wire cutter will move to when re-positioning itself. If you are using a weight, remember to move it out of the wire cutters way so you don’t break the machine. The defaults here should be fine.

Latest section: Cutting Path Simulation and Printing Format Settings

Click the 3D Simulation button. A window will appear similar to that which you will see when you export your G-Code, click ok. Here you may view a 3D simulation of your G-Code. You should always do this to make sure that at least theoretically, your code will do what you want it to do. Click the door to exit the simulation and then click finish.

Output G-Code

In the wing panels management window in Profili select your wing panel and under the “4-axis CNC” drop down choose the “Export G-Code for 4-axes CNC (foam cutting)” option. Here there is a choice whether the panel root should be on the left (default) or right side of the foam cutter (choosing the right side will flip your measured distance between the foam and carriage). You may also modify the speed if needed (the default should be fine for your foam and current settings). Save your G-Code in the proper class folder with a descriptive name (e.g.

Run G-Code using Mach3

Before you start a few notes:

Mach 3 is the program that loads your G-CODE once you have generated it from Profili Pro. The arrow keys and the wasd keys control the motion of the foam cutter manually. If the foam cutter does not respond to these inputs make sure that the foam cutter has power (turn the power strip on) and then hit the reset button on Mach 3. You should now be good to go.

Before starting your run you will need to zero all axes. Move the foam cutter manually where you want (with the arrow keys and wasd) and zero all axes. The best practice for this is to measure the distances between the carriages and their lower limits and make sure the measurements are equal. Click “Zero (x, y, z, or 4)” to zero the respective axis. If you click “GOTO ZERO” the foam cutter will rapidly proceed to this location now.

Load your G-Code simply by clicking File > Load G-Code. You should now see a list of coordinates and a preview of your airfoil.

The temperature of the wire should not usually need to be adjusted. If it becomes necessary, however, you may change the temperature by controlling the voltage on the power supply. Note that very minor adjustments to voltage will make a large difference in temperature. It might take some trial and error, which is why it is recommended to cut a test section (or several) before cutting your final part. As a safety measure, only power the wire when the wire is actively cutting a part. Never leave the foam cutters unattended when the wire or power strip is on.

Note that the wire can takes around 15 seconds to heat up so don’t get too trigger happy once you turn the power on.

When you’re ready you can hit the green button that says “Cycle Start”. Then watch and be ready to stop the run with the red “Stop” button in case something happens that you don’t like (not the Reset button). Also stop the run if you’re going to break the wire or the machine. The foam cutters are not cheap. Neither is the wire for the wire cutter. Make sure to turn off the wire as well before it melts a large hole in your wing. Stop the foam cutter before turning off the wire as you could break the wire if it cools, but is still being dragged through the foam. After doing a practice run you may click “Rewind” to start your G-Code over again. Make sure to also click “GOTO ZERO” if it is not already there.

Some advanced tips: