24132 – Polyurethane Foam Application Workstations

An automated cell for producing polyurethane (PU) foam parts used in car upholstery. Two Cartesian manipulators with a dispensing head serve a total of 8 workstations with mould carriers. This speeds up the process and keeps product quality consistent.

Intended use of the machine

The cell automates the application of PU foam into moulds. The operator places the upholstery components in the mould and removes the finished product. The line does the rest: it dispenses the foam along a programmed path, closes and locks the mould, monitors the curing time and cleans the dispensing head.

Each manipulator has side service doors and front sliding doors, through which moulds are changed using the built-in hoist.

Description of operation

Simplified work cycle of one workstation:

loading the upholstery components into the mould and starting the cycle with the button at the station;
closing the roller shutter that separates the operator from the working area;
the manipulator moves in, the upper frame of the carrier opens fully and the table is levelled;
foam is applied at points or along a line, according to the points saved for the mould;
the manipulator moves away, the upper frame is closed and locked, and pneumatic cushions close the mould;
the dispensing head is cleaned while the foam cures in the mould;
the mould opens, the table tilts, and the upper frame is unlocked and opened;
the roller shutter opens and the finished product is removed.

While one workstation is in the curing phase, the manipulator serves the next one. This keeps the dispensing head in constant use.

Machine design

CARTESIAN MANIPULATORS

The gantry is built from aluminium profiles on steel columns. The X, Y and Z axes are driven by servo motors via pinion and rack, and the linear carriages are lubricated by automatic lubricators. The head of the dispensing machine is mounted on the Z axis. Each manipulator has a head-cleaning station with three cleaning discs and a mechanical brush.

MOULD CARRIERS

The 900 × 1430 mm worktable tilts from 0° (foam application position) to 18° (operator position). The upper frame carrying the second mould half is opened by a geared motor with brake: to 60° in the intermediate position and to 89° when fully open. The mould is closed by five pneumatic cushions that raise the table by 60 mm; the pressure is adjustable from 0 to 3 bar. The carriers also have an option to heat the upper and lower mould halves, as well as service locks.

AUTOMATIC ROLLER SHUTTERS

Roller shutters made of transparent PVC film separate the operator from the working area of the carrier and manipulator. The shutter beam has a pressure-sensitive edge that stops the movement if an obstacle is detected.

HOIST

A hoist on a beam above the workstations is used to change the moulds on the carriers. An optional lifting beam (capacity 350 kg) makes it possible to level the mould being transported.

CONTROL SYSTEM

An air-conditioned electrical cabinet and an HMI panel with adjustable tilt are used to manage product references. For each reference, the gantry speed during pouring, the program and shot size of the dispensing machine, the pouring points for each carrier (taught by moving the gantry over the mould) and the cooling times are set. Access to the settings depends on the permissions of the logged-in user.

TECHNICAL DATA

Power supply: 400 V AC, 50 Hz
Installed power: 70 kW
Compressed air: 0.55–0.8 MPa
Cell dimensions (W × D × H): 7620 × 11300 × 3200 mm

Safety level

The line was designed in accordance with EN ISO 12100 on the basis of a risk assessment, and it has an EC declaration of conformity and CE marking. Safety measures applied:

horizontal light curtains monitoring the presence of a person between the carrier and the roller shutter;
workstation guarding with doors monitored by safety switches;
service doors with a safety bolt, LOTO bar and escape handle;
emergency stop buttons, main switch and LOTO padlock points;
an enabling switch activating safe speed of the gantry drives during manual work.