Session 04 – The CO2 Laser Tube

The Concise RDWorks Learning Lab Series

Welcome to the new Concise RDWorks Learning Lab Series with Russ Sadler. In this session, Russ describes the CO2 laser tube in detail and explains where and how the laser beam is generated. Find out the truth regarding tube life and the risk of purchasing B-Grade CO2 laser tubes.

Over the last 6 years, Russ has built up a formidable YouTube following for his RDWorks Learning Lab series which currently has over 200 videos.

The original RDWorks Learning Lab series on his “Sarbar Multimedia” YouTube Channel, follows Russ as he tries to make sense of his new Chinese laser machine and to sort out the truths, half truths and outright misleading information that is available on the web.

Six years later with over 4 million YouTube Views under his belt, Russ has become the go to resource for everything related to the Chinese CO2 laser machine user or wannabe user.

An ERF CO2 laser tube with HV-PSU
An ERF CO2 Laser Tube with HV-PSU

In this new series, Russ has condensed his knowledge and experience of the last 6 years to provide valuable information and insights into the purchasing, understanding, use, repair and maintenance of the Chinese CO2 laser machines and their key component parts.

Previous VideoNext VideoSeries Menu

Watch Session 04 – The CO2 Laser Tube, through the Panopto Viewer;

Watch this video through the Panopto Viewer (free sign-up required for full functionality) for a more interactive viewing experience. The viewer will allow you to:

  • Change the Captions to show translated subtitles if English is not your first language.
    • Currently available languages include: Chinese (Simplified), Danish, Finnish, French, German, Hungarian, Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Spanish, Swedish and Thai . These are Google translations, so if you spot any errors, please let us know.
  • You can search the video for specific keywords and jump to the relevant section.
    • This can work both within an individual video, across all videos and across all translated languages.
  • Post public comments on the video as well as private comments to the moderators.
  • Add your own notes, synchronised to what you are watching
  • Add bookmarks to remind you of important items.

Podcast Download for the CO2 Laser Tube

You can download the audio file for this video here, just click on the three dots to the right of the player:

Podcast Session 04 – The Laser Tube

Video Resource Files

There are no resource files associated with this video.

External Resource Links

There are no external resource links associated with this video.

Transcript for the CO2 Laser Tube

Click the “Show More” button to reveal the transcript, and use your browsers Find function to search for specific sections of interest.

1
00:00:06,440 –> 00:00:11,280
The Concise RDWorks Learning Lab with Russ Sadler.

2
00:00:11,280 –> 00:00:22,690
Session 4: The Laser Tube. Now here we’ve got the subject of the next two sessions, the laser tube and the high voltage power supply.

3
00:00:22,690 –> 00:00:26,770
Now the laser tube in itself is quite a large subject to tackle.

4
00:00:26,770 –> 00:00:32,380
So I’m going to push the power supply aside and we’ll deal with that as a separate entity.

5
00:00:32,380 –> 00:00:33,670
Now, in the last session,

6
00:00:33,670 –> 00:00:43,150
we spoke about the laser beam itself and the purpose of this session is to show you where and how that laser beam is generated.

7
00:00:43,150 –> 00:00:48,880
Well, in the first session, we talked about atoms. It didn’t have all this little complicated in the middle.

8
00:00:48,880 –> 00:00:49,960
It was just one lump.

9
00:00:49,960 –> 00:00:58,270
You’ll see that there are equal number of electrons which are negative, balancing a set of protons which are in the core, which are positive.

10
00:00:58,270 –> 00:01:04,690
So everything is nicely in equilibrium. Not all these orbits are the same as shown in this diagram here.

11
00:01:04,690 –> 00:01:07,060
Some of them are further out than others,

12
00:01:07,060 –> 00:01:18,520
which means that these electrons that are further out from the core are vulnerable to being attracted or displaced out of their orbit,

13
00:01:18,520 –> 00:01:29,740
which is going to make the atom a little bit unstable. Gas does not conduct electricity, and that’s because everything is nicely stable.

14
00:01:29,740 –> 00:01:39,190
There are no free electrons. There’s a continuous stream of very high energy particles that are flying through space.

15
00:01:39,190 –> 00:01:51,400
And those very high energy particles may or may not pass cleanly through this ninety nine point nine percent space that is in an atom.

16
00:01:51,400 –> 00:01:58,450
There are so many particles flying around that one or more of those particles will collide and it will

Transcript for the CO2 Laser Tube (Cont…)

17
00:01:58,450 –> 00:02:05,920
knock one of those nitrogen electrons out of its orbit and it will then become a free floating electron.

18
00:02:05,920 –> 00:02:15,220
We’ve got here a connection for the called the Anode in which we put 25000 volts or something like that,

19
00:02:15,220 –> 00:02:23,170
D.C. And here we got the return back to the power supply so that we’ve got a circuit here.

20
00:02:23,170 –> 00:02:29,020
But of course, this is gas in here and gas is non conductive.

21
00:02:29,020 –> 00:02:35,890
So how can we have a circuit when we don’t have something here that conducts the electricity?

22
00:02:35,890 –> 00:02:42,340
We’ve got our nitrogen, 10 percent of it, remember, mixed in with 10 percent carbon dioxide and 80 percent helium,

23
00:02:42,340 –> 00:02:46,420
which is just literally existing in our laser tube.

24
00:02:46,420 –> 00:02:54,250
We haven’t switched anything on yet, but there are still free electrons floating around in there.

25
00:02:54,250 –> 00:03:00,040
One, a hundred, a million? Who knows how many there are, but there only needs to be one.

26
00:03:00,040 –> 00:03:04,480
And remember, it is an electron is negatively charged here.

27
00:03:04,480 –> 00:03:12,640
Here we’re going to add 25000 volts across this electrode here and this electrode is sitting at zero.

28
00:03:12,640 –> 00:03:18,040
So we’ve got 25000 volts difference across this part here.

29
00:03:18,040 –> 00:03:18,670
Now,

30
00:03:18,670 –> 00:03:30,430
what’s going to happen is, this one negative electron is going to be violently attracted towards this positive Anode. So by the time it’s wizzed down this tube,

31
00:03:30,430 –> 00:03:31,660
at nearly the speed of light,

32
00:03:31,660 –> 00:03:40,120
we start to generate a cascade effect whereby it’s colliding with more nitrogen electrons and producing a bigger and bigger shower of electrons,

33
00:03:40,120 –> 00:03:51,400
that’s being attracted to this positive Anode. So by adding 25000 volts to that column and attracting and creating a flow of electrons,

34
00:03:51,400 –> 00:04:01,390
we’ve actually turned this piece of non conductive gas that’s in here into effectively a piece of wire to complete the circuit.

Transcript for the CO2 Laser Tube (Cont…)

35
00:04:01,390 –> 00:04:07,810
Now, that gas reservoir, which is around the outside there, the big tube, is containing the gas mixture.

36
00:04:07,810 –> 00:04:19,960
And that gas mixture is 10 percent nitrogen, 10 percent carbon dioxide and 80 percent helium, is busy flowing in a circular motion around this tube,

37
00:04:19,960 –> 00:04:26,650
spinning out, getting hot and traveling back along the tube and recirculating through here.

38
00:04:26,650 –> 00:04:32,740
So we’ve got a continuous circulation of the gas mixture through this central core because remember,

39
00:04:32,740 –> 00:04:38,980
we’ve got electrons which are effectively driving the gas flow from negative to positive.

40
00:04:38,980 –> 00:04:43,270
What we’ve got here with this ionized nitrogen, it is lightning.

41
00:04:43,270 –> 00:04:50,950
That’s exactly what lightning is. It’s ionized nitrogen, which is conducting electricity between the clouds and the ground.

42
00:04:50,950 –> 00:04:54,400
The atmosphere is about 80 percent nitrogen.

43
00:04:54,400 –> 00:05:04,840
We’ve got a second tube that sits around that central core and it carries water to carry the heat away from the core to the water jacket.

44
00:05:04,840 –> 00:05:12,880
And to do that, they add 80 percent helium, because helium is a very, very good conductor of heat.

45
00:05:12,880 –> 00:05:19,530
And that’s all the helium is doing. The helium will never run out, the nitrogen will never run out.

46
00:05:19,530 –> 00:05:28,410
We’ve got a third gas in there, carbon dioxide, which could run out even though this is a completely sealed system.

47
00:05:28,410 –> 00:05:33,330
It can’t leak out and it can’t leak in. Nothing is going to go anywhere.

48
00:05:33,330 –> 00:05:38,790
But as I will explain to you later, we can destroy the carbon dioxide.

49
00:05:38,790 –> 00:05:42,180
None of what I’m going to explain is physics perfection.

50
00:05:42,180 –> 00:05:48,750
These are concepts that would enable you to understand how your tube works without ever being a physicist.

51
00:05:48,750 –> 00:05:54,840
What we really got there is lightning in a bottle. So let’s take a few moments out and look at a real laser tube.

52
00:05:54,840 –> 00:06:01,620
This thick wire tells you there’s something going on here. This red wire can carry anything up to about 40000 volts.

Transcript for the CO2 Laser Tube (Cont…)

53
00:06:01,620 –> 00:06:11,880
But most of the time, twenty to twenty five thousand volts is enough of a voltage to stimulate the nitrogen to go into ionization mode.

54
00:06:11,880 –> 00:06:17,280
Once the ionization has taken place and stimulated and got triggered, as they call it,

55
00:06:17,280 –> 00:06:25,230
the actual voltage in here will drop down to some slightly lower value of something like maybe 15 to 17000 volts.

56
00:06:25,230 –> 00:06:30,150
If you want to move your tube or change your tube or do something with your tube.

57
00:06:30,150 –> 00:06:35,340
I suggest that you leave your machine switched off for about half an hour before you touch this wire.

58
00:06:35,340 –> 00:06:45,240
And that might be oversimplifying the situation, but better to be safe than sorry. That 25000 volts is connected into this electrode here.

59
00:06:45,240 –> 00:06:54,260
As you can see, it’s a tubular electrode that allows the gas to flow through and then carry on back through this tube here.

60
00:06:54,260 –> 00:07:05,270
And wizz around in a spiral motion. That will then cause the gas to spin as it travels back along the tube and lose some of its heat.

61
00:07:05,270 –> 00:07:10,700
Now, it won’t ever feel, this tube will never feel hot. It might feel warm.

62
00:07:10,700 –> 00:07:18,410
Now, I think we’ve caught the tube in the light right there. So you might be able to see the three tubes, this outer tube, the second tube in there,

63
00:07:18,410 –> 00:07:21,920
and then the third inner tube, which is the ionization tube in the middle.

64
00:07:21,920 –> 00:07:29,870
If ever you change your tube, there is no specific orientation for what happens at this end of the tube.

65
00:07:29,870 –> 00:07:37,760
But at this end of the tube, which is the negative end of the tube, this has basically got zero votes sitting here.

66
00:07:37,760 –> 00:07:45,860
So this is not dangerous this end. We’ve got a metal cathode sitting in there, which is tubular, which allows the gas to flow through it.

67
00:07:45,860 –> 00:07:57,170
And here we’ve got a water jacket, which is allowing the water to escape out of the tube and return to the reservoir through a water jacket.

Transcript for the CO2 Laser Tube (Cont…)

68
00:07:57,170 –> 00:08:04,910
This end of the tube, when you put a new tubein, is important that you orientate that tube

69
00:08:04,910 –> 00:08:11,120
there vertically, because bubbles always sit on the top.

70
00:08:11,120 –> 00:08:15,860
They will always hang on the ceiling of this inner tube here, the water jacket.

71
00:08:15,860 –> 00:08:22,130
And so what you want, any air bubbles to come along here and escape upwards?

72
00:08:22,130 –> 00:08:29,810
Many machines I’ve seen have been assembled like this or like this,

73
00:08:29,810 –> 00:08:35,870
and that’s absolutely useless because the air bubbles get trapped in the water jacket.

74
00:08:35,870 –> 00:08:40,910
So that’s an essential point to note when you assemble a tube.

75
00:08:40,910 –> 00:08:44,540
Now, there’s one other interesting thing that you should note.

76
00:08:44,540 –> 00:08:51,380
They often put a marker on here that says bracket placement or bracket position, and then there’s one at the other end.

77
00:08:51,380 –> 00:08:54,830
You don’t have to be too fussy about those bracket positions.

78
00:08:54,830 –> 00:09:04,070
If I put a pivot point in the middle there to support that tube, I think you can fairly clearly see that that tube is going to want to sag like that,

79
00:09:04,070 –> 00:09:08,840
because half the way is this way and half the weight is this way.

80
00:09:08,840 –> 00:09:18,410
So by dividing the tube approximately into quarters like this, if I move that pivot point to there and that pivot point to there,

81
00:09:18,410 –> 00:09:26,360
then what I’ve done, I’ve made that very short seesaw now and that very short seesaw there.

82
00:09:26,360 –> 00:09:31,100
We’ve got 50 percent of this hanging this way, 50 percent of the hanging that way.

83
00:09:31,100 –> 00:09:41,390
So it’s nicely balanced and that’s nicely balanced. So the stress in the middle here is nil because both sides are balanced about the center point.

84
00:09:41,390 –> 00:09:48,380
So there is no tendency for that tube to want to bend. And that is a very important point.

85
00:09:48,380 –> 00:09:55,790
These ends here are very accurately manufactured parallel to each other.

Transcript for the CO2 Laser Tube (Cont…)

86
00:09:55,790 –> 00:10:03,740
And so if the tube bends in any way, shape or form, it means these could go like that.

87
00:10:03,740 –> 00:10:07,610
And that’s going to destroy the lasing action within your tube.

88
00:10:07,610 –> 00:10:11,750
Don’t get too stressed about it because the glass is very, very stiff.

89
00:10:11,750 –> 00:10:15,080
You haven’t got to be exact with these quarters.

90
00:10:15,080 –> 00:10:23,480
OK, let’s come back to our simple model of the tube, because this is much easier to explain what’s going on without any additional complexity.

91
00:10:23,480 –> 00:10:29,270
The key thing that we’re after is this nitrogen, ionized nitrogen in the tube.

92
00:10:29,270 –> 00:10:33,830
Without that nitrogen, you cannot generate a laser beam.

93
00:10:33,830 –> 00:10:38,690
That mauve beam that you see in the tube is not the laser beam.

94
00:10:38,690 –> 00:10:45,200
If that was the laser beam, it would be pink all the way round the front and you would see it.

95
00:10:45,200 –> 00:10:53,720
The laser beam is invisible and coexists inside this ionization tube with the nitrogen.

96
00:10:53,720 –> 00:10:59,750
The nitrogen is basically the engine that we’re going to use to create the lasing action.

97
00:10:59,750 –> 00:11:03,470
The helium, as I said, it’s doing nothing. It’s only carrying the heat away.

98
00:11:03,470 –> 00:11:13,310
So it’s not part of the lasing action at all. We’ve just got these two key gases involved, ionized nitrogen and carbon dioxide.

99
00:11:13,310 –> 00:11:17,660
What I’m going to describe to you now is going to horrify any physicist that’s listening.

100
00:11:17,660 –> 00:11:24,980
Don’t worry about them. What you need is the nice, simple model that you can carry in your mind of how this system works.

101
00:11:24,980 –> 00:11:29,090
Now, let’s go back to one of the first principles that I described to you.

102
00:11:29,090 –> 00:11:39,970
Heat is what? Molecular motion, if I can stimulate the molecules in here to vibrate faster.

103
00:11:39,970 –> 00:11:52,000
So more current flow through here, means that these ionized nitrogen atoms are vibrating faster and as they vibrate fast,

104
00:11:52,000 –> 00:11:56,290
what happens is, mixed in with this gas mixture

Transcript for the CO2 Laser Tube (Cont…)

105
00:11:56,290 –> 00:12:02,840
you’ve got the carbon dioxide molecules. One carbon bonded to two oxygen atoms.

106
00:12:02,840 –> 00:12:12,160
And what will happen is that some of the energy that’s in this nitrogen will be transferred to the carbon dioxide molecule.

107
00:12:12,160 –> 00:12:16,330
It’s a bit like billiard balls or snooker balls colliding.

108
00:12:16,330 –> 00:12:20,230
There will be an energy transfer. That’s the model that I’d like you to carry.

109
00:12:20,230 –> 00:12:23,320
But it isn’t exactly how it works in physics terms.

110
00:12:23,320 –> 00:12:33,800
So we’ve now transferred some of the energy that this very violent nitrogen vibration has got and we’ve added it to a carbon dioxide molecule.

111
00:12:33,800 –> 00:12:39,310
That carbon dioxide molecule does not really want to carry this extra energy.

112
00:12:39,310 –> 00:12:43,600
It will find any excuse to get rid of it.

113
00:12:43,600 –> 00:12:48,670
Physics is very strange and a very peculiar thing happens.

114
00:12:48,670 –> 00:12:52,930
So we’ve added some extra energy to the carbon dioxide molecule.

115
00:12:52,930 –> 00:12:57,670
And basically what we’ve done, we’ve made one or more of the electrons,

116
00:12:57,670 –> 00:13:03,460
it’s jumped from one orbit to another orbit, and it doesn’t really want to be at that different orbit.

117
00:13:03,460 –> 00:13:11,440
It wants to get back to where it was, get back to stability. If nothing happens within a millionth of a second, the movement of this electron,

118
00:13:11,440 –> 00:13:16,450
which has gone out to a slightly bigger orbit, drops back to its normal orbit.

119
00:13:16,450 –> 00:13:23,710
And as it drops back to its normal orbit, it gives up the energy that it acquired during the collision.

120
00:13:23,710 –> 00:13:35,110
And that energy appears in the form of this strange little thing here, a little pulse of light called a photon, which has got a certain frequency.

121
00:13:35,110 –> 00:13:44,410
And that frequency is ten point six microns wavelength. Or put it another way, twenty eight thousand billion hertz.

122
00:13:44,410 –> 00:13:47,980
That’s the frequency of that little pulse there.

123
00:13:47,980 –> 00:13:58,540
Now, this is where physics gets really strange because remember, we are not just going to have one electron raise to a high level.

Transcript for the CO2 Laser Tube (Cont…)

124
00:13:58,540 –> 00:14:03,970
We’ve probably promoted several of them, because we’ve got all these nitrogen collisions taking place.

125
00:14:03,970 –> 00:14:10,900
And so we’ve got lots of atoms in our ionization tube which have got extra energy that they do not want.

126
00:14:10,900 –> 00:14:16,850
As this photon, just one photon travels along the ionization tube,

127
00:14:16,850 –> 00:14:25,810
it will pass by atoms which have got electrons which have got too much energy, and they want to drop back to their lower orbit.

128
00:14:25,810 –> 00:14:33,280
And what will happen is, this, like the Pied Piper of Hamelin will just collect photons

129
00:14:33,280 –> 00:14:41,270
as it travels along the tube and all those photons will be synchronized like this.

130
00:14:41,270 –> 00:14:46,540
Okay. They will all be fully synchronized in terms of their phases.

131
00:14:46,540 –> 00:14:53,680
Remember what I said? Coherent light. Well, this is how coherent light has been created within the tube.

132
00:14:53,680 –> 00:14:59,150
One photon will stimulate another photon to join it.

133
00:14:59,150 –> 00:15:05,270
And of course, now we’ve got two photons which are creating more stimulation for other photons to join it.

134
00:15:05,270 –> 00:15:11,990
And so, again, we’ve got this massive cascade effect whereby you’ve got millions and billions of photons

135
00:15:11,990 –> 00:15:18,380
attracting millions and billions of photons and they’re all traveling in one direction.

136
00:15:18,380 –> 00:15:24,980
And here they are traveling in this direction and they travel here at the speed of light.

137
00:15:24,980 –> 00:15:30,650
And photons have not got any charge. So they’re not positive or negative.

138
00:15:30,650 –> 00:15:34,850
They’re just packets of light. So they won’t stop at the anode.

139
00:15:34,850 –> 00:15:43,220
They will pass right through the anode, leaving the pink beam ionized nitrogen behind and they will fly out to the end here.

140
00:15:43,220 –> 00:15:54,590
And on the end here, what we’ve got is a mirror. And remember, Mirror Metal, that will reflect the light and it reflects the light back down here.

141
00:15:54,590 –> 00:16:03,590
In the meantime, we’ve got all this energized nitrogen which is busy creating more and more energized carbon dioxide atoms.

Transcript for the CO2 Laser Tube (Cont…)

142
00:16:03,590 –> 00:16:11,030
And as those photons passed down here, they will collect more and more photons, more and more energy,

143
00:16:11,030 –> 00:16:18,590
and they’ll fly at the end of here as well and bounce off this mirror and then they will go back and collect more photons.

144
00:16:18,590 –> 00:16:24,380
So we’ve got this continuous process of backwards and forwards photon reflection.

145
00:16:24,380 –> 00:16:31,370
This mirror here is 100 percent reflective, but this mirror here is not 100 percent reflective.

146
00:16:31,370 –> 00:16:37,570
All these photons that are flying backwards and forwards, some of them are escaping out here.

147
00:16:37,570 –> 00:16:44,530
Because we’ve got 90 percent mirror, so we’ve got, say, 10 percent of these photons which are flying out the end here,

148
00:16:44,530 –> 00:16:53,770
and that is our laser beam, that’s the invisible collection of coherent photons which make up the laser beam.

149
00:16:53,770 –> 00:16:58,630
So this is where the word laser comes from. It’s an acronym.

150
00:16:58,630 –> 00:17:03,790
And what it stands for is light amplification.

151
00:17:03,790 –> 00:17:08,710
And here we’ve got photons of light which are bouncing backwards and forwards, remember?

152
00:17:08,710 –> 00:17:13,420
And as they bounce backwards and forwards, they collect more light, collect more light.

153
00:17:13,420 –> 00:17:17,860
They’re amplifying the light by bouncing backwards and forwards between the mirrors.

154
00:17:17,860 –> 00:17:24,400
So we have light amplification by stimulated emission of radiation.

155
00:17:24,400 –> 00:17:32,470
Now the radiation is the photon that’s created and the stimulated emission is what happens

156
00:17:32,470 –> 00:17:41,410
when a photon passes by an energized carbon dioxide atom and triggers it to drop down.

157
00:17:41,410 –> 00:17:49,840
That’s the stimulated emission. You only get the radiation of light because you have stimulated the emission of it.

158
00:17:49,840 –> 00:17:59,170
If it’s not stimulated, it’s random and random light is not going to be any use to us at all.

Transcript for the CO2 Laser Tube (Cont…)

159
00:17:59,170 –> 00:18:03,880
So that’s the marvelous physics that takes place inside the laser tube itself.

160
00:18:03,880 –> 00:18:09,670
I did say to you that the carbon dioxide is not forever.

161
00:18:09,670 –> 00:18:12,060
It can be destroyed.

162
00:18:12,060 –> 00:18:23,790
And under normal circumstances, that destruction will take several years current passing through the tube makes the nitrogen atoms energetic,

163
00:18:23,790 –> 00:18:30,900
vibrating faster, getting hotter. It is that interaction, the billiard ball collisions, if you like,

164
00:18:30,900 –> 00:18:36,840
with the carbon dioxide transferring energy to them, which creates the lasing action.

165
00:18:36,840 –> 00:18:43,410
So if you put too much current through this circuit, the nitrogen will go bonkers.

166
00:18:43,410 –> 00:18:53,160
There will be so much energy in the nitrogen that when it, if you like your cueball, hit’s a carbon dioxide molecule.

167
00:18:53,160 –> 00:18:57,270
It won’t just collide and send it to a different pocket.

168
00:18:57,270 –> 00:18:59,880
It will collide with it and smash it to pieces.

169
00:18:59,880 –> 00:19:10,530
Now, in physics terms, what that really means is you hit it so hard that you’ve broken away one of the oxygen atoms from the carbon dioxide.

170
00:19:10,530 –> 00:19:17,370
And it’s no longer carbon dioxide, it’s carbon monoxide and a free oxygen atom.

171
00:19:17,370 –> 00:19:22,990
Now the free oxygen atom will float around in here and it will eventually try and join with something else.

172
00:19:22,990 –> 00:19:28,110
And the chances are what it’s going to do, it’s going to start oxidizing this cathode.

173
00:19:28,110 –> 00:19:37,110
If you overdrive your tube with too much current, you will destroy the one thing in that tube which you need, which is carbon dioxide.

174
00:19:37,110 –> 00:19:43,770
You will still have your pink glow because the nitrogen is still in there. You can’t destroy the nitrogen, you can’t destroy the helium.

175
00:19:43,770 –> 00:19:49,080
So everything will appear to be working, but you get nothing out the end here.

176
00:19:49,080 –> 00:19:52,290
So be very careful how much current you put through your tube.

177
00:19:52,290 –> 00:20:02,670
I encourage anybody and everybody to fit a very cheap analog ammeter into their circuit to monitor the current flow in this circuit.

Transcript for the CO2 Laser Tube (Cont…)

178
00:20:02,670 –> 00:20:08,460
Now, you don’t need a very special ammeter because we’re not going to put the meter in this high voltage line.

179
00:20:08,460 –> 00:20:13,710
What we do, we put the ammeter in here. We just break that line and put the ammeter in there.

180
00:20:13,710 –> 00:20:19,020
And that monitors the current flow back to the high voltage power supply.

181
00:20:19,020 –> 00:20:23,550
And it’s the same current flow that’s coming out, but it’s just at a different voltage.

182
00:20:23,550 –> 00:20:32,250
Current flow remains the same. The voltage doesn’t. Now, there are some basic guidelines for current that I can give you. Up to a certain point,

183
00:20:32,250 –> 00:20:41,610
the power of the tube goes with the length of the tube. Now, the most common thing that you will find is that you are being sold a 50 watt tube.

184
00:20:41,610 –> 00:20:46,350
And if you’re being sold a 50 watt tube, it will be a thousand millimeters long.

185
00:20:46,350 –> 00:20:52,490
I can absolutely guarantee it’ll only be 800 millimeters long because it’s what fits into the machine.

186
00:20:52,490 –> 00:20:55,190
And that’s, in reality, a 40 watt tube.

187
00:20:55,190 –> 00:21:06,080
It may well be capable of running at 50 watts maximum test power, but you mustn’t use it at that, because you will be then over driving the tube.

188
00:21:06,080 –> 00:21:15,860
So you must stay to the current, that’s basically the size of your tube, not what the tube is rated to.

189
00:21:15,860 –> 00:21:23,580
So, for example, a 30 watt tube will be 600 millimeters long and it will typically be 50 millimeters diameter,

190
00:21:23,580 –> 00:21:33,150
fifteen milliamps. A 40 watt tube, 800mm long, 18 milliamps. A 50 watt tube, a thousand millimeters long, 20 milliamps.

191
00:21:33,150 –> 00:21:35,340
Now things start to get a little bit flaky.

192
00:21:35,340 –> 00:21:46,770
At 70 watts, you will find that maybe it’s twelve hundred and fifty long and 55 millimeters diameter. At 80 watts

193
00:21:46,770 –> 00:21:52,800
it may well be only 1450 long and 80mm diameter, and these numbers here will change.

194
00:21:52,800 –> 00:22:00,720
These are the sorts of values, the old school values that used to exist when all tubes were 50 millimeters diameter.

Transcript for the CO2 Laser Tube (Cont…)

195
00:22:00,720 –> 00:22:09,960
They’re not that way anymore. So you might need to check up on your manufacturer’s specification to the actual current that they will allow.

196
00:22:09,960 –> 00:22:18,990
So under normal circumstances, this system is well controlled and you will get a constant current passing through here.

197
00:22:18,990 –> 00:22:29,790
A constant current means a constant level of vibration and a constant level of vibrational energy means a constant number of collisions,

198
00:22:29,790 –> 00:22:39,750
which means we get a constant flow of power out of the end here. Now provide you don’t overdrive the current through here.

199
00:22:39,750 –> 00:22:45,810
You will get five, six, seven years life out of this tube.

200
00:22:45,810 –> 00:22:50,400
But if you overdrive the tube, then I’m afraid that could be down to months.

201
00:22:50,400 –> 00:23:01,410
Every time the program switches this tube on, there is a very, very high frequency and surge of current pulses that pass through here.

202
00:23:01,410 –> 00:23:05,430
This is a particular zone that you can exploit and use.

203
00:23:05,430 –> 00:23:14,400
It’s called the Pre-ionisation Zone. And during that pre-ionization zone, which normally exists between about four and six milliamps,

204
00:23:14,400 –> 00:23:21,900
you’ve got very, very high frequency, very, very high power pulses of energy. Now,

205
00:23:21,900 –> 00:23:27,510
very high pulses of power means we must be generating that power with very high

206
00:23:27,510 –> 00:23:34,110
current flows and very high current flows means we are destroying the CO2.

207
00:23:34,110 –> 00:23:36,570
But it happens for such a short period of time.

208
00:23:36,570 –> 00:23:45,810
Every time we switch on that, it really doesn’t have a major over driving effect, but it will build up over time.

209
00:23:45,810 –> 00:23:50,730
And that is the main reason why your tube will eventually die.

210
00:23:50,730 –> 00:23:55,620
The manufacturers know this and they do two things.

211
00:23:55,620 –> 00:24:01,680
First of all, they introduce a small amount of maybe hydrogen or water,

Transcript for the CO2 Laser Tube (Cont…)

212
00:24:01,680 –> 00:24:08,010
into the gas mix, and that acts a bit like a marriage counselor.

213
00:24:08,010 –> 00:24:19,530
These dissociated oxygen and carbon monoxide atoms are encouraged to rebond to create carbon dioxide.

214
00:24:19,530 –> 00:24:30,270
And so that helps to prolong the life of your tube. Now, there will be something else that you will notice in a tube that is not switched on.

215
00:24:30,270 –> 00:24:37,830
Some of your tubes, well you’ll find that it’s got a very slight pinky hue to the ionization tube.

216
00:24:37,830 –> 00:24:44,640
That’s a very good sign because it does mean to say that the tube has been coated on the inside with

217
00:24:44,640 –> 00:24:53,160
an atomically thin layer of gold and gold does exactly the same thing as the water in the gas.

218
00:24:53,160 –> 00:25:00,330
It encourages recombination to try and prolong the life of the gas inside the tube.

219
00:25:00,330 –> 00:25:07,200
Unless you are reckless with your tube an A-Grade tube, as I said, should last you between maybe five and seven years.

220
00:25:07,200 –> 00:25:10,500
So that’s about as much as I really want to tell you about the laser tube.

221
00:25:10,500 –> 00:25:15,090
But there are a couple of little teeny weeny things that I think would be of interest to you.

222
00:25:15,090 –> 00:25:19,920
First of all, this laser tube will never just drop down dead.

223
00:25:19,920 –> 00:25:28,350
It doesn’t have a heart attack and stop. What will happen is, it will gradually, over a few weeks, maybe a month, lose its power.

224
00:25:28,350 –> 00:25:35,010
You will know that because all of a sudden, something that you cut a 10 millimeters a second doesn’t cut anymore.

225
00:25:35,010 –> 00:25:43,680
Don’t wind the power up because you’ll be over driving the machine, slow the speed down.

226
00:25:43,680 –> 00:25:51,840
That’s the way to deal with it. And then note the warning signs and think to yourself, I’d better start saving up for a new tube.

227
00:25:51,840 –> 00:25:57,330
There’s a second myth around that, Tubes have got a shelf-life.

228
00:25:57,330 –> 00:26:01,740
Tubes do not have a shelf life. They’re hermetically sealed.

Transcript for the CO2 Laser Tube (Cont…)

229
00:26:01,740 –> 00:26:11,490
There’s all sorts of old wives tales about this. In reality, this tube can sit on your shelf for ten years and then you can use it.

230
00:26:11,490 –> 00:26:15,270
The only thing that will go out of life is the warranty.

231
00:26:15,270 –> 00:26:21,630
And so really when you buy a brand new A-Grade tube, you really need the longest life you can possibly get.

232
00:26:21,630 –> 00:26:28,740
You want something that’s only a few months old because at the time they charged the tube with gas and test it,

233
00:26:28,740 –> 00:26:34,080
that’s when the warranty starts. Doesn’t start from the point in time when you buy it.

234
00:26:34,080 –> 00:26:39,510
And of course, different manufacturers of tubes have got different warranty periods.

235
00:26:39,510 –> 00:26:44,820
And that brings me round to a final point, which is the manufacturer.

236
00:26:44,820 –> 00:26:49,230
Now, this tube clearly says it’s from a known manufacturer.

237
00:26:49,230 –> 00:26:55,260
It says LASEA on there. But in fact, that is an EFR brand.

238
00:26:55,260 –> 00:27:00,060
That is a quality tube and any quality tube,

239
00:27:00,060 –> 00:27:06,070
first of all, it will have a manufacturer’s name on it. It’ll have a manufacturer’s address.

240
00:27:06,070 –> 00:27:13,720
It won’t just say model number 1200 millimeters, it’ll have a model number on it, not the length of the tube.

241
00:27:13,720 –> 00:27:18,330
It will generally have a serial number. It will have a date.

242
00:27:18,330 –> 00:27:23,100
And it will have some sort of reference to the person that checked the tube.

243
00:27:23,100 –> 00:27:33,510
Many tubes that you buy with your laser machine will be B-grade tubes that will be factory rejects which have been relabeled,

244
00:27:33,510 –> 00:27:40,440
and one cannot say what quality of beam you’ve got and how much power you’ve got.

245
00:27:40,440 –> 00:27:47,430
All we can say is the tube will work and you, in your naivete, will think that you’ve got a good tube.

246
00:27:47,430 –> 00:27:56,760
But in fact, it’s a virtual certainty that you have not. One of the major names that you’ll find on tubes which are carrying out this,

247
00:27:56,760 –> 00:28:03,770
let’s call it fraud, because it is. Is a company called KH laser.

Transcript for the CO2 Laser Tube (Cont…)

248
00:28:03,770 –> 00:28:10,520
Now, they’re not a company because they don’t make laser tubes, they pick up reject tubes,

249
00:28:10,520 –> 00:28:19,220
retest them to make sure they work in some way, shape or form, stick their label on, put them in a machine, ship them into warehouses around the world,

250
00:28:19,220 –> 00:28:24,760
and then they get somebody in China to sell them to you for commission.

251
00:28:24,760 –> 00:28:29,590
That somebody in China is also being duped because they have not seen the machine,

252
00:28:29,590 –> 00:28:34,900
they don’t know anything about the machine, they just selling a product for commission.

253
00:28:34,900 –> 00:28:41,710
So both you and he are being scammed by the manufacturer of the machine.

254
00:28:41,710 –> 00:28:51,400
Why do they do that? These tubes are quite expensive, if you can buy a reject tube for nothing or just the price of scrap glass.

255
00:28:51,400 –> 00:29:04,981
That’s a good deal. Now, that’s about as much as you need to know about Laser tubes to give you a pretty good start in life.

Transcript for the CO2 Laser Tube

Disclaimer

Last updated August 26, 2021

WEBSITE DISCLAIMER

The information provided by n-Deavor Limited, trading as Laseruser.com (“we,” “us” , or “our”) on (the “Site”) is for general informational purposes only. All information on the Site is provided in good faith, however we make no representation or warranty of any kind, express or implied, regarding the accuracy, adequacy, validity, reliability, availability or completeness of any information on the Site.

UNDER NO CIRCUMSTANCE SHALL WE HAVE ANY LIABILITY TO YOU FOR ANY LOSS OR DAMAGE OF ANY KIND INCURRED AS A RESULT OF THE USE OF THE SITE OR RELIANCE ON ANY INFORMATION PROVIDED ON
THE SITE. YOUR USE OF THE SITE AND YOUR RELIANCE ON ANY INFORMATION ON THE SITE IS SOLELY AT YOUR OWN RISK.

EXTERNAL LINKS DISCLAIMER

The Site may contain (or you may be sent through the Site) links to other websites or content belonging to or originating from third parties or links to websites and features in banners or other advertising. Such external links are not investigated, monitored, or checked for accuracy, adequacy, validity, reliability, availability or completeness by us.

WE DO NOT WARRANT, ENDORSE, GUARANTEE, OR ASSUME RESPONSIBILITY FOR THE ACCURACY OR RELIABILITY OF ANY INFORMATION OFFERED BY THIRD-PARTY WEBSITES LINKED THROUGH THE SITE OR ANY WEBSITE OR FEATURE LINKED IN ANY BANNER OR OTHER ADVERTISING.
WE WILL NOT BE A PARTY TO OR IN ANY WAY BE RESPONSIBLE FOR MONITORING ANY TRANSACTION BETWEEN YOU AND THIRD-PARTY PROVIDERS OF PRODUCTS OR SERVICES.

AFFILIATES DISCLAIMER

The Site may contain links to affiliate websites, and we receive an affiliate commission for any purchases made by you on the affiliate website using such links. Our affiliates include the following:

  • makeCNC who provide Downloadable Patterns, Software, Hardware and other content for Laser Cutters, CNC Routers, Plasma, WaterJets, CNC Milling Machines, and other Robotic Tools. They also provide Pattern Files in PDF format for Scroll Saw Users. They are known for their Friendly and Efficient Customer Service and have a comprehensive back catalogue as well as continually providing New Patterns and Content.
  • Cloudray Laser: a world-leading laser parts and solutions provider, has established a whole series of laser product lines, range from CO2 engraving & cutting machine parts, fiber cutting machine parts and laser marking machine parts.
DMCA.com Protection Status Follow @laseruser_com