Pass-Through Cutting & Long Stock

Most CO2 lasers ship with a pass-through slot, front and back doors that let you load material longer than the bed. The technique: cut a section, slide the material forward, align, cut the next section. With careful registration you can cut 8-foot-long material on a 24-inch bed.

What pass-through enables

• Long sign stock: store-front signs, decorative panels, fence panels.
• Lumber dimensioning: cut a long board into multiple smaller pieces in one continuous job.
• Repeating panels: laser-cut storage cubbies, racks, repeating ornament strips.
• Roll-fed material: paper, fabric, leather rolls (with a roll-feeder accessory).

The two pass-through techniques

Technique 1: Manual sectioned cut

Split the design into bed-sized sections. Cut section 1, manually slide material, align, cut section 2.

1. Open your full-length design in Lightburn.
2. Add registration marks at the section boundaries, small + or □ shapes that you'll align to.
3. Cut section 1 (the part within the bed).
4. Open the front and back pass-through doors.
5. Slide the material forward through the bed by exactly one section length.
6. Use the registration marks to align: lower head over a known-position registration mark from section 1, jog the head until the laser dot lands on the mark, set X=0.
7. Cut section 2.
8. Repeat for additional sections.

Tolerance: typically ±0.5-1mm between sections. Acceptable for most signage; not for fine inlay.

Technique 2: Lightburn pass-through workflow

Some Lightburn versions support a "pass-through" job mode that automates the section split. Available on Ruida controllers; requires the job size to exceed the bed size.

1. Open Lightburn → Edit → Settings → Pass-Through.
2. Enable; set the section overlap (typically 5-10mm).
3. Open your long file. Lightburn auto-splits at section boundaries.
4. Run section 1.
5. Lightburn pauses; prompts you to slide the material.
6. Slide and confirm; Lightburn runs the next section.

Registration mark design

• Cross-shaped marks: most common. 5-10mm cross, 0.5mm line width.
• L-corner marks: for parts that have natural corners.
• Numbered marks: labels each section so you don't lose count.
• Place marks in scrap zones (where they'll be discarded after the cut) when possible.

Alignment tools

• Jig walls: fixed boards along the side of the bed that the material slides against. Maintains lateral (Y) alignment automatically.
• Pin stops at the back: for material that has a clean back edge.
• Magnetic strips: for ferromagnetic stock or wood with steel inserts.
• Laser red-dot pointer: your primary alignment tool. Drop the head onto a known registration mark. Verify red dot lands on the mark center.

Material handling considerations

• Bed support beyond the cabinet: long material sags off the back of the bed. Use roller stands at the same height as the bed.
• Material flatness: warped lumber doesn't slide cleanly. Pre-flatten by stacking + weighing overnight.
• Sliding friction: wax the bottom of the material lightly with paste wax to slide cleanly without scratching the bed.
• Speed of sliding: slow and even. Sudden jerks shift the material laterally and ruin alignment.

Common pitfalls

• Visible step at section boundaries. Your section overlap is too narrow OR alignment is off. Increase overlap to 10mm and re-test.
• Lateral drift accumulating across sections. Material is sliding off the side as it moves forward. Use jig walls.
• Air assist disrupted at pass-through. Open doors break the cabinet seal. Close briefly; air assist re-pressurizes; then cut.
• Smoke escape through open doors. Always run extraction at high during pass-through; consider a small fan blowing AWAY from the doors to push smoke back into the cabinet.

Pass-through-friendly machines

• Thunder Nova Plus series: built-in pass-through doors.
• Glowforge Pro: front + back slots; "Passthrough" feature in their software.
• OMTech Polar+, AF series, AF2028: varies by model.
• Boss Laser: most models.
• Aeon: most models.
• Trotec Speedy: pass-through optional.

Glowforge Pro's pass-through has an automatic alignment camera that registers between sections. Most other machines require manual alignment per the techniques above.