Automated system and method of cleaning moulds, blow moulds, and accessories used in the production of glass packaging

The invention concerns an automated system and method of cleaning moulds, blow moulds, and accessories, such as troughs, deflectors, bottom plate, plunger, and funnels used in the production of glass packaging.

Moulds, blow moulds, and accessories used in the production of glass packaging get soiled in the packaging production process, particularly with residues of graphite grease which is placed in moulds, blow moulds, and accessories as a lubricant to enable correct formation of glass packaging. In the course of the production process graphite grease deposits on the surface of a mould, blow moulds, or accessories and in time substantially reduces the quality of glass packaging.

Therefore, moulds, blow moulds, and accessories must be regularly cleaned.

Currently, the process of cleaning moulds, blow moulds, and

accessories used in the production of glass packaging is performed by mechanical methods which consist in cleaning the soiled surfaces with a stream of compressed air containing an abrasive agent. The cleaning is achieved by imparting the kinetic energy to the abrasive grit. When hitting against the cleaned surface, the abrasive grits remove any dirt deposited there. The method causes gradual damaging of the base material of the cleaned glass moulds, blow moulds, and accessories. After many cleaning cycles the elements must be subject to regeneration or disposed of.

Another form of cleaning moulds, blow moulds, and accessories is a chemical method which consists in immersing moulds, blow moulds and accessories in specially prepared baths containing chemical agents.

The bath is intended to remove any residue of graphite grease. The glass mould, blow moulds, and accessories cleaning methods described above involve mechanical or chemical aggressiveness towards the cleaned surface.

The purpose of the invention is to develop a method of cleaning moulds, blow moulds, and accessories used in the production of glass packaging characterised by high cleaning power while causing no damages to the base material, environmentally friendly and requiring no manual labour.

An automated method of cleaning moulds, blow moulds, and

accessories made of metal, cast-iron in particular, used in the production of glass packaging, where the method consists in removing any dirt, graphite grease in particular, from the cleaned surface according to the invention is characterised in that the cleaned surface is treated with laser ablation using a pulsed laser, where first the surface subject to cleaning is scanned with a 3D scanner to read the shape of the cleaned surface, and the obtained scan used to automatically generate, using a specialist software, the movement paths of the laser head mounted on a robot wrist; and/or the movement paths of the said laser head are generated based on specially-prepared input files containing the geometry of the surface subject to cleaning; moreover, the cleaning

parameters such as angle, speed, and shape of the laser beam are set, following which the laser radiation beam is directed onto the surface subject to cleaning in accordance with the generated movement paths and parameters. Preferably, the pulsed laser is of the nanosecond, femtosecond, or picosecond type.

The laser pulse generated in the source is supplied to the laser head,

preferably via an optical fibre of preferably circular cross-section

with the diameter ranging from 50pm to 600pm, or square cross-section with the side length ranging from 50pm to 600pm.

Preferably, the duration of the laser pulse ranges from 0.1ns to 100ns, the preferable energy of the laser beam ranges from 0.1 mJ to 200mJ, the preferable pulse repetition frequency falls within the range from 5kHz to 50kHz, and the preferable length of the laser radiation wave ranges from 532nm to 1070nm.

The laser beam is focused in the laser head by a lens the focal length of which preferably ranges from 120mm to 1000mm, and the laser dot size preferably falls within the range from 0.01 mm to 2mm.

Preferably, the cleaning process is conducted in a robotised cell.

An automated system for cleaning moulds, blow moulds, and

accessories made of metal, cast iron in particular, and used in the production of glass packaging according to the invention is characterised in that it contains a 3D scanner, a robotised cell incorporating the cleaning zone and the mould/blow mould/accessory loading zone fitted with technical means for positioning of the moulds, blow moulds and accessories subject to cleaning and for their placement in and removal from the said zones; it further contains at least one robot installed in the robotised cell, where at least one robot is fitted with a laser head mounted on its wrist. Moreover, the system

incorporates a robot controller, source of the pulsed laser, preferably of the nanosecond, femtosecond, or picosecond type, its cooling unit, and a filtering and ventilation device to serve the robotised cell. The source of the pulsed laser is interconnected with the laser head via an optical fibre which is preferably circular in cross section with the diameter ranging from 50pm to 600pm, or square in cross section with the side length ranging from 50pm to 600pm.

The laser head is fitted with a focusing lens, the focal length of which preferably ranges from 120mm to 1000mm.

Preferably the 3D scanner is mounted on the robot wrist.

The solution according to the invention provides a fully automated system and method of laser cleaning of soiled surfaces of moulds, blow moulds, and accessories used in the production of glass packaging, based on the process of ablation of dirt from the treated surfaces, accompanied by conveying minimum volume of heat to the treated item without damaging its base surface. Moreover, the solution according to the invention ensures quick and precise treatment of the cleaned surface. The system according to the invention can cooperate with an automated stock of treated items and can be fully served by robots. The automated cell guarantees safety of the cleaning process involving focused laser radiation.

The automated system and method of cleaning moulds, blow moulds, and accessories made of metal, cast iron in particular, used in the production of glass packaging is shown in an exemplary variant schematically presented on the drawing (Fig. 1), and described below as an exemplary embodiment.

An exemplary system contains:

- a robotised cell 1 having the cleaning zone 2 and the zone 3 for the loading of moulds, blow moulds and accessories 4, fitted with the rotating working table 5 featuring technical means, e.g. seats, for positioning the treated items, where the table 5 is positioned within the said zones;

Industrial six-axis robot 7 with a laser mirror head 6 mounted on the wrist and the head 6 fitted with a lens of the focal length of 250mm, where the dot size ranges from 0.8 to 1.2mm;

3D scanner (12) mounted on the wrist of the industrial robot 7;

controller 8 of the industrial robot 7;

- source of the pulsed laser 9 interconnected to the laser mirror head 6 with an optical fibre square in cross-section, where the side length is 400 pm;

- cooling unit 10 of the source of the pulsed laser 9;

- filtering and ventilation device 11 serving the robotised cell 1.

Soiled (with e.g. graphite grease) moulds, blow moulds, and

accessories made of cast iron and used in the production of glass packaging are placed on the rotating working table 5 fitted with technical means for the positioning of the treated items, e.g. seats, fitted in the loading zone 3, whereupon the table rotates so that the items subject to cleaning find themselves in the cleaning zone 2. The 3D scanner 12 mounted on the wrist of the six-axis industrial robot 7 placed in the cell 1 reads the shape of the surface to be cleaned, and the specialist software automatically generates the movement paths for the robot 7. In addition, based on the 3D scan the software automatically adjusts the cleaning parameters such as the angle, speed, and shape of the beam. Once the information about the shape of the item subject to cleaning has been obtained, and the paths and parameters have been automatically generated, the cleaning process is initiated. The cleaning process is based on ablation and consists in using a focused nanosecond laser pulse to evaporate graphite grease from the surface of the treated item. The laser pulse is generated in the source 9 and supplied to the laser mirror head 6 mounted on the wrist of the industrial robot 7 via an optical fibre square in cross-section with the side length of 400pm. Using the mirrors and lenses in the laser mirror head 6, the pulse is directed and focused on the surface of the treated item. The laser beam is focused by the lens the focal length of which amounts to 250mm, where the dot size falls within the range from 0.8 to 1.2mm.

The energy carried by the laser radiation pulse removes the layer of dirt without damaging the base layer (surface) of the treated item.

In the described exemplary embodiment the duration of the laser pulse is 30ns, the energy of the laser radiation beam is 33mJ, the pulse repetition frequency is 30kHz, and the length of the laser radiation wave is 1070nm. Once the cleaning process has been completed, the working table 5 rotates so that the items are moved out of the cleaning zone and collected.

In another exemplary embodiment of the invention, in the method described above the robot movement paths may be generated based on the specially-prepared input files containing the geometry of the surface subject to cleaning; alternatively, the robot movement paths may additionally be generated based on specially-prepared input files containing the geometry of the cleaned surface.

Other exemplary embodiments of the invention may employ

femtosecond or pictosecond pulsed laser, and the optical fibre which interconnects the laser head and the laser source may be either circular in cross-section with the diameter ranging from 50pm to 600pm, or square in cross-section with the side length falling within the range from 50mih to 600pm.

The focal length of the laser head lens which focuses the laser beam can range from 120mm to 1000mm, where the dot size can fall within the range from 0.01mm to 2mm.

The duration of the laser pulse can range from 0.1ns to 100ns, the energy of the laser beam radiation can fall within the range from 0.1 mJ to 20OmJ, the pulse repetition frequency can fall within the range from 5kHz to 50kHz, and the length of the laser radiation wave can range from 532nm to 1070nm.