Extrusion Minimum Runs Measured in Tonnes Rather than Pieces
Extrusion runs are quoted in tonnes because start-up scrap, thermal equilibration, and bulk resin compounding operate as continuous mass processes.
Saw Kerf Scrap
Meaning
Material lost as fine dust or chips during the cutting of an extruded profile or sheet to its finished length. This volume of wasted plastic is determined by the thickness of the saw blade and the number of cuts made per meter of product. Managing saw kerf scrap is a necessary part of material yield calculations, especially for high-value resins or complex profiles.
Yield Loss
Total resin consumption includes not only the weight of the finished part but also the weight of the material removed by the blade. On a high-speed production line making thousands of small parts, saw kerf scrap can account for several percentage points of the total material used. Thinner blades can reduce this loss but may struggle with the heat and friction of heavy sections.
Recycling Challenges
Collection of the fine dust generated during cutting is often difficult and creates a messy work environment. If saw kerf scrap is contaminated with floor debris or lubricant, it cannot be easily fed back into the extrusion process as regrind. Dedicated vacuum systems are used to capture the dust at the source to maximize its potential for reuse.
Cutting Quality
Heat generated by the blade can melt the edges of the profile if the saw speed is not correctly set. This melting not only changes the dimensions but also alters the density and shape of the saw kerf scrap produced. Proper blade selection and cooling are required to ensure a clean cut and a manageable waste stream.