Cable Tray Expander from 200 to 400 mm

Define the openings and reference lengths

This centered expander connects a 200 mm inlet to a 400 mm outlet over a 500 mm axial length. Both side walls stay 50 mm high and the tray floor remains level. Identify the narrow inlet and wider outlet in the formed view before marking the developed panels.

The centerline remains aligned because the total width increase is distributed equally. Each floor edge moves outward by (400 − 200) / 2 = 100 mm. Measure the axial length along the route direction between the two end planes. The true joining edge follows the diagonal across that length and the outward movement.

Use the worked inputs as a complete set. Increasing outlet width increases both outward movements. Increasing axial length spreads the same width change over a longer fitting. The model updates the three developed panels and their assembly from those dimensions.

Calculate the true developed dimensions

For each wall, calculate the true length S = √(L² + Δ²), with L = 500 mm and Δ = 100 mm. This gives S = 509.90 mm. Each side panel is a rectangle with that true length and a 50 mm height. The floor is an isosceles trapezoid whose end edges measure 200 and 400 mm.

The floor area is (200 + 400) × 500 / 2 = 150000 mm². The two walls contribute 2 × 50 × √(500² + 100²) = 50990.20 mm². Their combined ideal area is 200990.20 mm². Calculate using full precision and round the displayed dimensions after the calculation.

The 500 mm axial dimension and 509.90 mm wall dimension describe different physical lines. Follow the floor axis when checking installation length and the oblique floor edge when checking the wall joint. The floor edge and matching wall edge have equal lengths throughout assembly.

Worked example dimensions

Mark the panels and inspect assembly

Use Original and Mark to inspect the three panel blanks, then Cut to see their finished outlines. Form rotates and positions the two walls around the level floor. Follow the wider outlet through the animation and verify that both wall tops remain open.

Mark both end widths and the axial separation on the floor. Center the widths on one common axis, join corresponding corners and match each oblique edge to its side panel. Label the inlet and outlet on all pieces before separating them to preserve the intended orientation.

This layout gives ideal panel geometry. Panel area measures the finished geometric surfaces. Procurement and workshop layout also depend on available sheet sizes, nesting, seams and fabrication allowances. Use the linked reducer example to inspect the corresponding inward width change.

Review the fabrication detail

Review actual thickness, seams, kerf, rolled edges and fabrication allowances before cutting. The model gives ideal geometric panel surfaces.