A conventional laser cutting machine is disclosed in FIG. 6, and generally includes a base with a top surface and a laser head driven by a polarized shaft is connected to the top surface. A cover is securely mounted on the top of the base by extending screws through sidewalls of the cover and connected to the base. The cover is made of metal boards and a transparent window is embedded in the cover. The cover is 30 kilograms in weight and all the wires connected to the panel on the cover have to be extended from an inside of the cover so as to be connected to the base. Once the machine requires maintenance, all the screws are unscrewed and the wires are disconnected from the base, two persons are required to remove the heavy cover from the base so that the maintenance can be proceeded. After the maintenance is done, the cover is lifted and installed to the base and the wires are connected to the base again. This is time consuming.
The transparent window in the cover is made to be as large as possible so that the range of movement of the laser head can be observed via the window. Nevertheless, when the object to be machined is a large one, the arrangement of the cover makes the positioning of the object difficult and inconvenient.