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Articles
How to coat EPS foam (Crown Moldings)
How to build an EPS Foam Recycler
How to build an EPS base and Cap cutter
How is EPS manufactured - molded
How to make RC foam planes
How to cut EPS, XPS, EPP foam
How to cut Polyurethane foam ( PU )
How to cut Acrylics - Laser cutting
DIY CNC Foam Cutter Blog - New

What is - more info about foam
What is EPS foam
What is XPS foam
What is EPP foam - Expanded Polypropylene
What is PE foam - Polyethylene foam
What is Polyurethane foam
What is Memory Foam


 

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How is EPS foam blocks manufactured

                Please visit us again we are updating this page as we go along

EPS foam starts at very small beads - similar to sand in texture called polystyrene -
the raw material is called Styrene. Styrene can be found nearly everywhere. in you local
food store and the local electronics stores
The plastic utensils are made of - Styrene,
CD cases and cloth hangers - all made of Styrene
EPS which means Expanded Polystyrene, starts
as the small beads shown in the image to the left.
The next step in the process is to "blow" these small
beads into larger beads about 50 times its original
size. Depending on the density required, the beads
are blown using steam in a machine called "expander"
The expander can be a simple machine that a worker
places the raw material. and then turns on the steam, or an automatic machine
where the material is weighed automatically Steam, then is enables (automatically)
and then stopped.  At this stage, the beads are up to 50 times their original size.

Continuous pre- expanders are operated without pressure and are
equipped with an open- top agitator tank in which raw material is continuously
fed from the bottom by an adjustable screw conveyor.. Steam is "also fed
continuously into the pre- expanding room through
openings that are positioned shortly above the tank
bottom. An agitator and fixed breaker rods make it more
difficult for bead clusters to develop; they keep the beads
in motion and make sure that al ready pre-expanded beads
of lower density move to the top of the bead bulk and fall
into a shaft through a height- adjustable discharge opening.
Pre- expanders for the so- called "second pass expansion"
of already expanded materials, are equipped with an especially large feed screw in order
to transport the already expanded material to be steamed again. All pre- expanders have
in common that the completely expanded beads trickle into a so- called fluid bed dryer
where they are dried and
stabilized before they are transported into the storage silos.

                                                    Pre-Expander

The two most common blowing agents used are pentane and carbon dioxide - neither
contains CFCs. This process - polymerization - fills the polystyrene with millions of
air pockets, which helps it to expand and also gives it a low thermal conductivity.
During expansion, the product can be molded into a variety of shapes and sizes.
The final product is 90% air, but amazingly, EPS can have a compressed strength up to 40 psi.

                            
                                                         Slio System


Above is a typical foam plant layout which includes the Boiler, steam tank, pre-expander, Silos
and the block molds. To the left the drying area and the raw material storage.
EPS raw material should be stored in a cool place less then 70F.

The last step in the process is the mold machine. Mold machine are divided into two main categories
Block molds and shape mold machines.
Block mold machines create a block of foam - from 3' x 2' x 8' up to 5' x 5' x 24'

Above image shows a manual block mold - manual means that once the molding process is done
The workers need to open the doors of the mold in order to remove the block from the mold.
On the machine above, this process is done manually.

Picture above shows an automatic EPS block mold machine


Shape mold machines create different shapes -

bicycle helmets, surfboards, RC planes, packing foam
food packing and any shape imaginable that is not a block.