chapter two
2.2
i Mechanical Design:
Mechanical design represents the base for constructing the system because we take all basic principle for CO2 laser in to a count and related on it to design the system which include the size of system, type of material that must be used in each part of the system. Make sure that all quit good for optimal performance and min cost.
i
The mechanical design includes five different forms of electrodes configuration. One made from Bakelite and the other from Aluminum..
i
1.
i . The first Type Aluminum electrode used as the output couplers mirror holder that consists from four parts. The first part use as mirror holder, which has central hole of 20 mm in diameter for laser output. The output window has been placed in the hole of 52mm diameter and thickness equal 5mm and water surrounding the mirror from every direction except the face for cooling the mirror. Tape screw holes of 8mm in diameter for inlet and outlet cooling water have been used. .
i
An O-ring groove of 4mm thickness is made in front of the mirror for fitting and safety the mirror from broken and not let water to drain in front of mirror that because ZnSe mirror coating affected by water. Another O-ring groove of 4mm thickness has been made and used between first part and second part. This O-ring is important in the alignment of mirror. .
i
The second part is the mirror adjustment plates Three screw holes are placed 120 degree apart is made for mirror adjustment and thick O-ring groove to provide both high vacuum seal and enough play for mirror adjustment .It has a central hole of 21 mm in diameter..
i
The third part represents the cathode and tube holder that has central hole of 21 mm in diameter and hole of 10 mm in diameter from top of view of the electrode to enter the gasses to the plasma discharge tube. There is also groove of 4mm thickness for O-ring from one side and from far side there is cut of 45º for O-ring.An O-ring has been used for tightening the connection between the tube flange which is the fourth part of this electrode and with cathode to provide both high vacuum seal and decrease the pressure surrounds the tube..
i
The fourth part is the circular flange of central hole of 21 mm in diameter and three screw holes placed 120º for easy work and to providing high vacuum seal ..
i
2.
i . The second electrode is the aluminum rear mirror (HR) electrode which consist also from four parts .All parts of this electrode like the first electrode except the first part has one different from first electrode that the mirror cooled from back and also from sides..
i
3.
i . The third electrode is also made from Aluminum and have the same parts of second electrode except that it has the central hole of 61mm in diameter in third and fourth that because we use Pyrex tube of 60 mm in diameter and 80 mm length for joining these parts with the fourth electrode. .
i
4.
i . The fourth electrode (see figure 2.2) is the corner holder tubes electrode that represents new design shape for multi fold CO2 laser. Designing this shape depend on corner of 20º .It consist form main part that is used as cathode and holed two discharge tube with one connecting tube. At top view of this part there is hole of 12 mm in diameter for outlet the gas..
i
Also, there are three holes (one of 61mm in diameter and two of 21mm in diameter), the center of last one make a corner of 10º with strata line from face of the mirror on the third electrode..
i
Light should enter from center of one hole of inner diameter (ID) of 20 mm pass through tube ID of 60mm touch the center of the mirror (which represent the center of the corner) and then reflected back to the second hole of ID of 21mm. .
i
5.
i . The last and fifth electrode (see figure 2.3) is Bakelite electrode which is made from Bakelite material .It is very high electrical insulation .The main part (A) of this electrode has a cylindrical shape of diminution (100×100) mm with central hole of 21 mm inner diameter for holding two discharge tubes [one from each side]. Both tubes enter to 10 mm distance in the Bakelite. .
i
This part also has tip hole of 8mm inner diameter as inlet of gas from top view of electrode and there are two tips holes of 6mm diameter use for discharge pins where the last are made from stainless steel for high conductor and corrosion resistance..
i
The discharge pine have length of 60 mm. About10mm of it length left on top of the electrode used for connected anode wire comes from power supply with system..
i
Fig.2.2: Top View Section with Dimension for Holder Tubes Electrode
(New Design)..
i
Fig.2.3: Sides View Section with Dimension of the Bakelite Electrode.
مواقع النشر (المفضلة)