Since 2000
Polystyrene cutting machine
FoamCutCNC
After several mechanics made, here is my latest version, the result of all the experience made.
Simple, spartan and functional, it has a cutting capacity of 620 mm in length, 420 mm in height and a width of the cut that is a function of the positioning distance between the two structures, I do not recommend going beyond 1400 mm
Automatic zeroing on 4 axes
Thanks to the presence of 4 micro switches, it is possible to automatically reset all four axes in the lowest point at the extreme end of the machine, it will therefore be easier to always have the wire in the cutting position and parallel and orthogonal to the plane. thanks to the combination in the setting with the soft limits of the axes, the axes stop before they accidentally stop against the machine structure, and the program, when loading the processing file, if this exceeds the dimensions maximum cutting, the program gives a warning and does not allow the start of the machining.
Possibility of the 5th rotary axis
If complex 3D machining is to be carried out, there is the possibility of connecting the 5th axis to the machine, consisting of a rotary table managed automatically by the control electronics and by the machine control program.
The limitation of 3D machining is obviously due to the always straight cut that hot wire can make.
The electronics always have the output that manages the 5th axis mounted as standard, regardless of whether the rotary table is present.
Automatic and lateral tensioning of the wire
As we know, when the wire is heated by the passage of low voltage current, according to a physical law, it stretches, so to have it always taut and straight, a traction spring is used.
Normally the spring is put in the direction of the wire, but some useful cutting length is lost, to remedy this, I put a pulley system with a lateral spring, I also avoided unnecessarily passing the current through the spring but directly to the wire, the wire used is in chrome / nickel diameter 0.2 mm
Machine structure in aluminum and steel
The sliding guides, a very important part of the structure, are made of anodized aluminum which allows greater resistance to wear, these guides have a special profile that allows the sliding of particular shoes with inserts of plastic material, with a low coefficient of friction and anti-wear .
To control the movement of the four axes, suitable screws with trapezoidal steel threads are rotated by the stepper motors connected by means of flexible aluminum joints.
Each threaded screw has a ball bearing at its end to facilitate rotation and support the axial load.
Suitable milled aluminum blocks support the stepper motors or ball bearings.
The whole structure is then screwed for easy disassembly in case of any maintenance.
