A good flat-pack kit is compact to produce and ship, but remains logical to assemble. This requires more than just placing parts on a sheet: fit, sequence, numbering, and how parts are removed from the sheet must all be correct.
Start with the assembled construction
Determine which parts bear loads, which surfaces remain visible, and how the user assembles the construction. Then choose connections that match the material, thickness, and desired disassembly.
Test connections in the actual material
A click, press, or finger joint reacts to actual material thickness and kerf width. Create a small series of tests before finalizing all connections in a large kit. Also test whether parts remain usable after multiple assemblies if necessary.
Use numbering and orientation consciously
Line engraving can add part numbers, assembly direction, or a short marking without separate labels. Place information where it is visible during assembly and does not need to remain obtrusive in the final product.
Break-off tabs keep a set together
Small tabs in the cut line can temporarily keep parts in a sheet. This makes sorting and packaging easier. However, the user must still be able to push out the parts without damage. Therefore, choose the position and number based on part size, material, and the acceptable edge after detachment.
Check the complete set
First order one complete prototype. Check not only whether each part individually is correct, but also whether quantities, numbering, assembly sequence, and final dimensions match. Only then adjust the file for a larger print run.