Linear Material Cutting Guide — Bars, Rods, Pipes & Extrusions
Linear materials like extrusions, pipes, and timber require careful layout planning. Without it, you end up throwing away perfectly good material as costly offcuts. Learn how to optimize your cuts instantly.
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What Are Linear Materials?
Linear materials are products where the width and height are constant, and you only need to calculate the length. Common examples include:
- Timber lengths (e.g., 2x4s, skirting boards)
- Steel bars and hollow structural sections (RHS/SHS)
- Aluminum profiles and extrusions for window frames
- Copper pipes and PVC conduit
The One-Dimensional Cutting Problem
In mathematics, arranging smaller lengths within standard longer lengths is known as the 1D bin packing problem. It is deceptively complex. When you have hundreds of parts to cut from 6-meter bars, finding the perfect combination manually is nearly impossible.
By using a linear cutting optimizer, you let an algorithm process millions of combinations in seconds, ensuring you get the absolute maximum yield out of your material. For continuous materials, see roll cutting optimization.
Example: Window Frame Fabrication
Let's look at a realistic example. You need to cut window frame extrusions from 6000mm standard stock bars.
- Required: 8× 1500mm, 6× 1200mm, 4× 900mm, 10× 600mm
Manual approach: Often results in using 5 bars with around 18% waste because operators take the easiest cuts first.
Optimized approach: Uses exactly 4 bars, packing cuts efficiently to reduce waste to around 6%.
Key Factors in Linear Cutting
- Blade Kerf: The thickness of the blade consumes material. Always factor this in.
- End Allowances: Factory edges are rarely perfectly square; plan for a trim cut on the ends.
- Offcut Reuse: A 1500mm offcut is highly reusable, but ten 150mm offcuts go straight to the bin. Optimize for larger contiguous remainders.
How CutWize Handles Linear Optimization
CutWize uses a multi-phase First-Fit Decreasing algorithm. It automatically tracks your offcuts and prioritizes using them on your next job before cutting into fresh stock. Try it out on our steel & aluminium calculator.
Frequently Asked Questions
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Related Tools: Linear Cutting Optimizer | Length Cutting Optimizer | Cut List Optimizer
Related Guides: Steel & Aluminium Layouts | Steel Calculator | Cut List Calculator | Best Practices