EPS Processing 101

For those who are new to the EPS industry, we've provided here some information on how EPS is produced and processed

What is EPS?

EPS stands for Expanded Polystyrene. It is a plastic material made from polystyrene beads and a 'foaming' agent. These tiny beads are then expanded and fused in a large 'block mold' when heat is applied through steam. EPS, a generic chemical term, is sometimes called Styrofoam™, which is a trademark name for extruded polystyrene from Dow Chemical.

How is EPS cut? What is a hot wire cutting?

EPS is conventionally cut with a hot wire. A special type of wire has an electrical current passed through it. This current causes the wire to heat, raising it's temperature above the melting point of EPS, which is about 240 °C or 464 °F. This wire is then moved through the EPS, or sometimes the wire is stationary and the foam moves. The wire causes the EPS to melt and separate, thus producing a cut.

Sometimes EPS processed with methods other than a hot wire cutter. Edges can be cut with a router tool to make tongue and groove EPS boards. A router can also cut channels or even 3D features into an EPS blank.

What is a contour cutter?

Contour cutters also known as profile cutters, pantographs, xydroids, and cnc cutters. Contour cutters are the most versatile machines for foam shape fabricating. Hot wire(s) are attached to a large harp which straddles a block(s) of foam. In a manually operated system, known as a pantograph, the operator makes a pre-cut template of the part and secures it to the table that holds the foam block. He then moves one end of the harp slowly around the template and the attached hot wire cuts out the shape. Some pantographs have a motorized device that moves the wire around the template which improves the quality of the cut but the production rate is still very slow. These systems are most often used by hobbyist for small projects such as model airplane profiles, custom displays, etc... Most commercial and industrial contour machines use some sort of automated motion control system to drive the hot wire(s) harp. These systems consist of stepper or servo motors driving belts, gears or screws to move the wires in a coordinated motion. The operation of these machines requires an operator to prepare a cutting file that includes the commands for the motors into the motion controller.

What is a slabber?

A slabber is a machine that produces straight cuts in the horizontal direction. Typically an EPS block is slabbed on a slabber with multiple wires, and this process makes single large blocks into many slabs. This is a common process used to produce insulation panels.

What is a downcutter?

A downcutter is a machine that produces straight cuts in the vertical direction. Typically an EPS block is downcut (or upcut) with multiple wires, and this process makes single large blocks into many EPS rectangular cubes. This is a common process used to produce packaging pieces and insulation.