How is a rigid box made? The six steps and the machine for each

What a rigid box is made of

A rigid box, also called a set-up box, has two layers. The structure is greyboard: a dense board that does not fold flat, which is what gives the box its stiffness. The surface is a sheet of printed or specialty paper glued over the board. Two consumables hold it together: tape on the corners of the board shell, and glue between paper and board.

The machines on this page take greyboard from 0.8 to 4 mm thick and cover paper from 80 to 350 g/m², depending on the machine. The table further down gives the range for each one.

The six steps of making a rigid box

1. 01

   Slit the board

   Full greyboard sheets are cut into blanks. The HF-1300 slits sheets up to 1200 × 800 mm at 20–80 sheets/min.

2. 02

   Groove the board

   V-grooves are cut where the walls fold. The HF-1200 cuts up to 8 grooves per pass, to ±0.05–0.1 mm, in 0.8–4 mm board.

3. 03

   Tape the corners

   The blank is folded into a shell and its corners are taped. The HF-500 tapes four corners at once at 30–55 pcs/min.

4. 04

   Glue the paper

   The cover paper is fed sheet by sheet and coated with glue. The HF-850A is a gluing machine only and runs 80–250 g/m² paper at up to 45 pcs/min.

5. 05

   Position the box

   The taped shell is placed exactly on the glued paper, by hand or by machine. The HF-1050 glues the paper itself and positions by camera and Yamaha robot to ±0.1 mm, so it covers steps four and five together.

6. 06

   Wrap and fold

   The paper is wrapped up the walls, the ears are folded and the paper is turned in. The HF-450 does this at 15–20 pcs/min.

Why the board is V-grooved

Greyboard is too stiff to fold cleanly. Bent as it is, it gives a rounded, cracked edge. A V-groove removes a wedge of board along the fold line and leaves a thin skin as a hinge, so the wall folds up to a sharp, square corner. The grooves have to be straight and evenly deep for the walls to fold square.

The HF-1200 grooves board from 100 × 120 mm to 950 × 1000 mm at 25–50 m/min. Its two clamped blades are adjusted on the machine, in the ranges 80–120° and 120–140°, so a different angle does not need a different blade. The offcut comes out as a continuous strip rather than dust.

Why the corners are taped

Once the walls are folded up, nothing holds them together until the paper is on. Tape across each corner fixes the shell in shape so it can be handled, stacked and wrapped. The HF-500 tapes all four corners in one stroke with PVC, PET or paper tape, 15, 19 or 24 mm wide. The hand-fed HF-40 tapes one corner at a time, at 10–20 pcs/min.

How the paper is glued and positioned

The cover sheet is coated with glue over its whole face, then the shell is set down on it while the glue is still open. This is the step that decides how the finished box looks: if the shell lands slightly off, the print runs crooked along an edge and the turn-in is uneven.

The HF-850A and the HF-1050 are alternatives, not two machines in a row: the HF-1050 already glues. More on camera positioning in what is a visual positioning machine.

What happens in the forming machine

The forming machine wraps the paper up the four walls of the shell. It then folds the corner ears, turns the top edge of the paper over the rim and down the inside, and presses the surfaces to drive out air bubbles. On the HF-450 the ears can be 10–90 mm and the turn-in 10–80 mm deep, and the settings follow from the box size typed on the touch screen.

Speed of each rigid box machine

The six machines in process order, with the board and paper each one takes.

Parameter	HF-1300	HF-1200	HF-500	HF-850A	HF-1050	HF-450
Speed	20–80 sheets/min	25–50 m/min	30–55 pcs/min	Servo version: 7–45 pcs/min · Standard version: 7–40 pcs/min	15–30 sheets/min	15–20 pcs/min
Board thickness	1.2–3 mm	0.8–4 mm	0.8–4 mm	—	1–3 mm	0.8–4 mm
Paper weight	—	—	—	80–250 g/m²	100–350 g/m²	—
Power	2.2 kW	2.2 kW / 220 V	2.5 kW / 220 V	—	7.5 kW	2.5 kW / 220 V

One machine instead of four

The HF-5040 combines steps three to six. It feeds and glues the paper, tapes the corners, positions the shell by camera and wraps all four sides, at 18–25 pcs/min, for boxes from 65 × 65 × 20 mm to 500 × 400 × 120 mm. Board still has to be slit and grooved before it.

How other rigid box styles differ

The six steps describe a lid-and-base box. Other styles reuse some of them and add their own.

Machines in this guide

HF-1300Automatic Cardboard Slitting Machine20–80 sheets/min

HF-1200Automatic V Grooving Machine25–50 m/min

HF-500Automatic Rigid Box Corner Pasting Machine30–55 pcs/min

HF-850AAutomatic Paper Gluing Machine7–45 pcs/min

HF-1050Automatic Visual Positioning Machine for Rigid Box and Hardcover15–30 sheets/min

HF-450Automatic Rigid Box Forming Machine15–20 pcs/min