Patent Application
20190143456
This invention concerns a laser cutting machine for the working of material in sheet and reel form.
In laser cutting systems, there are overall two machine configurations: laser cutting gantries and laser cutting lines from reels of material.
Describing these two systems in more detail, it is important to establish the terminology.
In these cutting systems, the X and Y axes are generally perpendicular to one another. The use of a laser cutting head involves an additional axis in order to set a constant distance between the output of the laser beam and the surface of the metal sheet (the plane defined by the X and Y axes); this additional axis is generally called Z. In some cases, the additional Z-axis cutting head may have additional axes which we will call Xa and Ya, which are used with a very short travel to carry out very small cuts such as holes, which avoids using the X and Y axes on very short distances and increases cutting accuracy and speed.
It is worth noting that the laser cutting head may also be used to carry out marking, engraving or any other operation compatible with the machine's overall kinematic configuration.
These machines are not only used on metal materials but also on other materials. It should be noted that this patent application is specifically intended for work on thin metal sheets (a few tenths of a centimetre thick, up to 2 to 3 mm maximum). Typically, but not exclusively, the concept described is particularly suitable for the cutting of metal sheets and the production of shaped parts used in the air treatment, ventilation, HVAC and thermal insulation sectors.
A) Cutting gantry—or commonly called an X-Y table: In such a configuration, the material to be cut (called the blank) is laid on a table either manually, or by a robot.
This table may be fixed or movable to facilitate material loading and unloading operations. The material is immobilised during the cutting operation and the laser head moves along an X and Y route and carries out the cutting in an order which allows movements to be restricted while optimising any scrap. The most common dimensions of blanks are 1500×3000 mm, and can even go up to 2000×4000 mm.
The advantages of such gantries are numerous: the material is immobilised on the table and because of the rigidity of the gantry, the laser cutting head can therefore move at very high speeds. These cutting gantries are particularly intended for the cutting of thicker materials (steel up to 20 mm, for example) and, to a lesser degree, very thin materials. The most significant advantage on the X-Y gantry is that the metal sheet can be cut and is accessible over its entire surface. On the other hand, after the cutting operation, the waste which appears in the shape of a skeleton must remain easy to extract, and therefore should give a certain rigidity, which results in a greater loss of material.
High costs, particularly with regard to the kinematics required to move the cutting head over a large surface area, can be specifically indicated as a disadvantage of cutting gantries. The surface area occupied on the ground is also significant.
The unloading cycle (=recovery of cut parts) can only be carried out once the full cutting cycle is completed. For large-sized tables, this can be tedious, especially if small parts have to be recovered from the centre of the table. Generally speaking, the unloading cycle constitutes a significant loss of time in the machine's usage cycle. The skeleton (=sheet metal scrap) must also be discharged, generally manually. It should be noted that the skeleton should be as large as possible in order to make it easy to handle, but the skeletons must be stacked/stored/discharged. All these operations require storage space and time.
B) Laser Cutting Line from a Reel of Material
One advantage of these systems is that the material on reels is more economic to purchase than material purchased in the form of blanks. Furthermore, interleaving of pieces (=listing) along the x-axis, corresponding to the length of the material, allows scrap to be substantially reduced compared to the cutting gantry configuration.
One disadvantage of these cutting lines from reels is their footprint on the ground. In effect, the configuration of such an installation is as follows: reel-loop 1-straightener-loop 2-cutting machine-static discharge table (delivery table).
The change from one reel to another is complicated and requires the part already unrolled to be completely rewound, therefore in this direction: cutting machine>loop 2>straightener>loop 1>reel.
The purpose of this invention is to remedy the problems above and particularly aims to offer a cutting machine which can operate in gantry mode, that is to say by using precut blanks of material and, when functioning in on-line mode, uses material in the form of reels.
With these objectives in mind, the subject of the invention is a laser cutting machine comprising:
In one preferable embodiment, the unit incorporating X2 and the straightening/de-cambering/levelling system is provided in its upper part with a compatible material which limits friction on the material to be cut. This material which limits friction on the material to be cut shall preferably include brushes.
The unit incorporating the X2 axis and the straightening/de-cambering/levelling system may include a parking or resting position, in which an upper surface of the unit is aligned with the machine's pass line.
The unit incorporating the X2 axis and the straightening/de-cambering/levelling system may also include a working position (top position) in which the unit is positioned so that the X2 axis is at the same level as the pass line.
The sheet may be laid manually or from an automatic system, for example a robot or a loading/unloading gantry. The origin of this blank may be external to the machine, or this blank may be generated, e.g. cut to size by the machine even from a reel. Finally, the X1 axis enables the material to be moved along its axis to the left or to the right.
A Z-axis and the Xa and Ya axes may also be applicable.
X1 and X2 may move the material in the same axis to the left or to the right.
The top position may correspond to a position from the mode for unrolling the metal sheet from the reel. In this position, the X2 axis rollers are coincident but do not interfere with the X1 axis clamps. The sheet metal may be unrolled and the clamps may be positioned so that taking hold of the material is possible with the minimum of clamping.
The bottom position may correspond to a parking position for the X2 axis and to a working position for the upper surface of the unit (X2+de-cambering). This upper surface is at the level of the machine's pass line.
The exact point where the cut elements are discharged (scrap and good pieces) is called the picking zone. Discharge may be carried out by a person in manual mode or by a robot or a loading/unloading gantry.
Alternatively and/or in addition to the motorised discharge table, a collecting tray, which may be a simple tray or a motorised conveyor taking the pieces away from the machine, may be installed below the laser cutting head. The pieces or falling scrap will therefore be of the size which relates to the width of this conveyor/trade, i.e. approximately 100 to 300 mm. The primary function is to discharge scraps of material which are extracted in an internal form to the cut sheet metal and which therefore cannot be discharged by the motorised discharge table. It should be noted that this operating method may also be applied for the evacuation of small pieces, with the sorting of these pieces therefore being done outside the machine.
Other special features and characteristics of the invention will emerge from the detailed description of an advantageous production mode of the machine.
In effect, this machine configuration combines the separate operating modes of the cutting gantry (A) and the cutting line from reels (B), that is to say that the machine enables the material to be worked on from flat blanks but also from reels.
The proposed machine configuration makes it possible to discharge cut pieces and waste in a continuous flow, as the discharge of pieces is localised at a specific point using a motorised discharge table and/or a collecting tray and motorised conveyor.
The discharge of pieces may be easily automated using a handling robot. Alternatively, an operator may recover the piece manually and carry out a shaping operation such as rolling for producing a ferrule, or moulding, etc. The flow of cut material is continuous, so it is not necessary to wait for the entire metal sheet to be cut (as it is for the cutting gantry).
The machine therefore operates in a continuous flow but it also takes up less space than configuration B and the reel-straightener distance is shortened; therefore only one control loop is necessary.
In a preferred configuration, the machine comprises:
The machine can operate in two separate operating cycles.
Sheet by sheet: the operator lays down the blank and positions it in the clamps. The combination of the movements of the X1 and Y axes combined with the cutting head enables cutting to take place. Operation in conjunction with the motorised table/discharge conveyor tray enables the discharge of cut pieces and scrap.
To this end, cuts always take place with the movement of X1 from the right to the left, with each cut element falling naturally onto the table. Once the complete length of the sheet metal is cut, the latter makes an unladen movement from the left to the right. Once this movement has been carried out, the laser cutting head positions itself and the cutting operation takes place by moving the X1 axis from the right to the left, etc. it is clear that the machine may also be configured with a passing direction of the material from the left to the right,
From reels: the unit including X2 and the straightener is positioned in height so that the X2 axis is at the same height that the machine passes. X2 and then unroll the reel over a length optimised according to the pieces to be produced.
Once the desired length is reached, the clamps are activated to hold the sheet metal, and the laser head cuts the sheet metal. As soon this happens, the unused piece reverses via X2 to a position which allows the X2 and straightening/de-camping/levelling unit to be lowered to the bottom position.
In fact, the sheet metal which is held in the clamps on the X2 axis may undergo a cutting cycle according to the sheet-by-sheet mode described above, with the latter being on the pass line.
The machine makes it possible to have a true operating mode sheet-by-sheet and from reels, which is unique.
The combination of the discharge table/tray and discharge conveyor and cutting cycles makes it possible to have efficient discharge of cut pieces in a continuous flow, which is not the case with configurations A and B.
Other special features and characteristics of the invention will emerge from the appended drawings in which:
The cycle can continue, the X1 axis moves the remaining sheet metal (represented by hatching and positioned to the right), and the next cut can start etc.
To sum up, this laser cutting machine makes it possible to cut from reels, the suitable clamping of the flat blank and the suitable discharge of cut pieces and scrap result in the most optimised solution which can exist on the market in order to:
Control System and Software
This patent application does not describe the automation and the system which allows the shape and dimensions of the pieces to be cut to be determined. The most generally used software system described as a dedicated CAD/CAM within the applicable sector (HVAC, thermal insulation, etc.) combined with a “nesting” type application to limit material scrap. These CAD/CAM and nesting systems are used in all modern cutting systems, whether these are cutting gantries, or systems that cut from a reel. These CAD/CAM and nesting systems can be easily adapted by a skilled person to correspond to the machine's functionality and geometry.
Cutting Strategy
A technique used for the cutting of thin sheet metal and low-resistance material (e.g. thin aluminium from 0.4 to 0.7 mm used in thermal insulation) consist of leaving micro-fasteners between the various pieces. When the cutting process on a metal sheet of determined dimensions is finished, the blank is extracted from the machine and the pieces are detached manually, the micro-fastener then being broken by a repetitive cracking movement or by a pair of scissors. The shaped pieces to be recovered and the scraps are then sorted manually. This working method may sometimes be preferred depending on the type of user. For example, blanks may be precut with micro-fasteners in a centralised workshop and then be sent flat to a decentralised site to be processed there.
This laser cutting machine can clearly accept this working method which is fundamentally connected to the cutting pass which will be generated by the CAD/CAM system.
| Number | Date | Country | Kind |
|---|---|---|---|
| 93 134 | Jun 2016 | LU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/066242 | 6/30/2017 | WO | 00 |
