Many users notice waves on the cut surface and look for the cause in the machine or material. In most cases the cause lies elsewhere: the wire vibrates in the material. This vibration transfers as a wave onto the cut surface. The good news: the causes are well known and the solutions usually simple.
XPS and Styrodur react considerably more sensitively to unstable wire conditions than standard EPS Styrofoam. The material has a more uniform structure than EPS – this makes surface defects immediately visible. Even the smallest wire vibrations leave visible marks. Anyone cutting XPS must pay particular attention to short wire lengths, correct cutting speed and correctly chosen springs.
The most effective solution against wave formation is a shorter wire length. A short wire vibrates considerably less than a long one – even if the wire briefly catches on the material, the vibration is negligible. Anyone cutting XPS regularly should choose the shortest possible wire length for their workpiece format.
Cutting speed that is too high frequently contributes to wave formation. At too high a speed the wire briefly catches on the material – enough to trigger a vibration. Keep to guideline values: XPS and Styrodur approx. 350–400 mm/min, EPS approx. 450–500 mm/min. Then match temperature accordingly until the cutting gap is consistently approx. 2 mm. Do not increase speed and temperature arbitrarily – this pushes the wire into the borderline range and causes exactly these waves.
A frequently overlooked cause of wave formation is springs that do not match the application or have exhausted their compensation travel. The cutting wire expands when heated and contracts when cooling – the spring must continuously compensate this length change. Two typical problems: First – old wire: over time the cutting wire becomes permanently longer. Eventually the spring travel is no longer sufficient to compensate the length change. The wire sags and vibrates. Solution: replace the wire. Second – wrong spring: for 4-axis cuts, soft springs are needed that can absorb wire length changes of up to 150 mm – the wire must be able to be different lengths during contour cuts. For 2-axis parallel cuts, hard springs are used that keep the wire taut. If the wrong spring is fitted it cannot absorb the length change and the wire vibrates.
Sometimes the cause lies in the material itself. EPS blocks can be damp inside – particularly when freshly produced or stored incorrectly. Damp areas have a different cutting resistance than dry ones. The wire then encounters varying resistance, catches briefly and vibrates. When all other causes have been ruled out: check material for moisture and homogeneity. Allow fresh or damp blocks sufficient drying time before cutting.
Waves appear when the wire vibrates in the material. The most common causes: wire length too long, cutting speed too high, old wire that has become too long, wrong springs or inhomogeneous material.
XPS and Styrodur react considerably more sensitively to wire vibrations than EPS. The uniform material structure makes even small vibrations immediately visible as waves. Solution: shorter wire length and keep cutting speed to approx. 350–400 mm/min.
The shorter the wire, the less it vibrates. Always choose the shortest possible wire length for the workpiece format. Short wires produce cleaner surfaces than long ones – especially with XPS and Styrodur.
Yes. Over time the cutting wire becomes permanently longer. Eventually the springs can no longer compensate the length change – the wire sags and vibrates. Solution: replace the wire.
It depends on the application. For 4-axis contour cuts: soft spring – it can absorb wire length changes of up to 150 mm. For 2-axis parallel cuts: hard spring – it keeps the wire taut. A wrong spring cannot absorb the length change and the wire vibrates.
Yes. Damp EPS blocks have locally different cutting resistance. The wire encounters varying resistance, catches briefly and vibrates. Allow fresh or damp blocks sufficient drying time before cutting.
Waves on the cut surface are avoidable. We help with root cause analysis and correct settings – from real production experience.
Get advice now