Two-Piece Sliding Boxes

Friction fit alone is rarely secure enough for rough transit. Vibration or drops can cause the inner tube to slide open. Parcel shipping generally relies on an outer seal, such as a clear wafer seal, strapping, or shrink wrap.

While the rectangular blanks use corrugated board very efficiently, the inner and outer tubes must be glued on separate machine runs. You are paying for two manufacturing setups and handling two separate components at your packing bench.

The clearance allowance between the inner and outer tubes is precisely calculated based on the exact board thickness. If you switch to a thicker or thinner board without adjusting the template, the inner tube will either bind and jam, or become too loose and fall out.

Standard case erectors struggle with the linear sliding insertion of two tight-fitting tubes. This style is almost always squared and assembled by hand at a manual packing station.

Yes, but adding windows or thumb notches means the blanks must be cut on a flatbed die. Simple rectangular tubes without cutouts can often be produced more economically using inline rotary scoring.

Glossy coatings and heavy varnishes reduce the surface friction between the two tubes. If the surfaces become too slick, the inner tube may slide out under its own weight, requiring tighter tolerances or an outer seal.

If you keep the design as two simple rectangular tubes, it can often be produced without a flatbed die using inline rotary scoring. Adding thumb notches, windows, or angled cuts will shift the job to a flatbed die.

Concentric mating means the tubes slide together along the same axis, leaving the ends open like a sleeve. Orthogonal mating means they slide together perpendicularly, so the solid walls of one tube cap the open ends of the other, forming a fully enclosed container.