05 – We Have Lift Off – Laser Tube Upgrade

0:00um welcome to another session with my little tangerine tiger um today i think we’re going to have to

0:05have a little bit of a tidy up day hopefully by the end of this session

0:11we’ll actually be able to fire up the actual laser tube itself i just need to make sure everything’s tidy before i

0:17do the final bits because i don’t want to be tempted into using the machine and having it half

0:23finished that’s why i’ve been a little bit meticulous about tidying things up as i

0:28go so one of the first things we’re going to have to do is go in and modify the vendor settings because if you remember

0:34the last time when we swapped the belt over to the flexible rack and pinion system then everything

0:42was reversed in the x direction a similar situation will occur whenever you get a failure of one of

0:48these micro switches when you turn the machine on it’ll go bonkers and do silly things

0:54so one of the first things i’m going to do is to put the head to the middle of the machine or even to

1:00the front of the machine in the case of the y-axis more or less because it’s going to move slowly in these

1:06directions this one’s going to go in the wrong direction and away from that but this one’s going to be correct and

1:12move towards that if it’s out of control the simple solution is

1:18once it starts to move just press the escape button and it will stop finger on the escape

1:24button and there we go so the machine is now stopped safely

1:32it says all sorts of strange numbers on the keyboard but that’s not important we’ve still got power to the machine and it’s under my control

1:38so we’re already hooked into rdworks and we’ll go to vendor settings rd888

1:48so the first thing we’ll do is press read and that will also test that we’re connecting up to the machine properly

1:53and there we go we are it tells me we’ve got 500 in x

2:00and y 300 which is correct okay so the x axis

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

2:07at the moment direction polarity is negative

2:13so we need to make that positive and that will change its direction

2:18we’ve got to change this keying because our direction keying is the wrong way round

2:24so invert direction we’ll remove that tick and we’ll write

2:31the information back to the machine now press the reset button and see what happens

2:40so wires homed x is honed [Music]

2:47we’re back in control just check the keys left wrong way around

2:54right so we need to go back into the vendor settings and just put that tick back okay so

3:01we’ve reverted the key and let’s check check and now everything’s going the right way

3:07left right backwards forwards but we could just see

3:13where our limits are now so if i press the down arrow key we’ll find out how close y is to the

3:20front of the machine and look we can have at least another 10 millimeters here

3:25and we’re clear of everything let’s go over to the extremity over here and see what happens

3:32and on this side look i can get my fingers in there so i’m not going to hit anything there

3:37so i could add another 10 millimeters to the width and another 10 millimeters so i can make this table now 310 by

3:45t so back into the vendor settings and x we can make the breadth across here

3:54five ten five one zero and then we can make y three one zero

4:05and write that back to the machine so we should be able to drive this another ten millimeters in this direction now

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

4:14and there we go we’ve still got five millimeters clear there we’re not hitting anything and then we should be able to go that

4:20way another 10 millimeters as well and

4:27sure enough we’re completely clear here as well as you can see i’ve managed to find some

4:33five volt leds self-adhesive it’s amazing what you can find when you

4:39dig around in cupboards and there just happens to be enough to run

4:44backwards and forwards so i can have two strips underneath there so we can now see how beneficial this

4:50side entry is so yeah i’ve had to make a small modification here as you can see i’ve had to put a cut out in

4:56this motor plate to allow the cables to track down underneath into the cable tray otherwise

5:02they would have stood out the side here and they kept on getting caught on various things so yeah everything’s worked out quite

5:07neatly in the end what i’m going to do here is i’m not going to rely on the thread

5:13in this plastic here to lock this nut in what i’m going to do is i’m going to use some m5 half nuts now

5:19these are very thin nuts so we’ve put our lock nuts on there

5:24and then this five millimeter thick material i’ve counter-bored it about hmm

5:31three-quarters of the way through so that it fits over the nuts and then we’ve got

5:39some wing nuts on here so that it’s easy to take them off now notice as i was pulling under there that the

5:45solenoid valve for the air assist was warm and of course then i checked here and

5:51found that it was manual on so i’ve turned it back to auto and that

5:57means now the solenoid is off which it will be most of the time it’ll only be overridden

6:03when you need it i also remembered we’ve got a little bit little bit of tidying up to do in here but we’ve got this this big gap in here

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

6:10where i tried to fit this back plate and i didn’t need it so

6:16we’re gonna have to cover it over because we need something to do this y-axis switch properly it wasn’t done

6:23properly before as soon as you undid the connection this fellow into the back

6:28well it won’t any longer because i’ve made a proper connection here and then i remember to put the nut in

6:34the washer on the back here nothing’s going to hit the clash no

6:42there’s nothing wrong with the camera look you can see the control panel over here on the right

6:48but i just want to show you this you can see the table without getting

6:53blinded

6:59okay apart from playing with the lights what else have i been doing you don’t need to see me doing this i’ve

7:04just made a lovely name plate to go on the side here i’ve repacked and tidied up all the cables in there

7:11okay well we’ve wired the tube up now would you believe and everything is tidy and

7:19ready to go but before we do that we’ve got to set the vendor settings now we’ve got to go

7:25into laser the first thing we’re going to select is one tube oops the first thing we’re

7:31going to do is select is read forgot about that glass tube

7:38no it’s going to be an rf laser with pre-ignition so the pre-ignition

7:45voltage is set within the laser system itself so it’s one tube and the attenuation is

7:52going to be zero so we’ve got minimum power set at one percent which is fine

7:58maximum power 99 the laser frequency now that’s the actual base

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

8:05frequency of the pulse width modulation that’s exactly the same as was set for the glass tube

8:11where the only thing that was changing was the duty cycle it was a constant 5 volt dc

8:18that was when switching on and off proportionately with the pwm signal to give us an output

8:24voltage of anything from zero to five volts if you don’t know quite what the duty cycle means

8:30then go and take a look at duty cycle on wikipedia pre-ignition frequency uh preset to 5000

8:37and i think that’s the value that i was recommended to use and the

8:43pre-ignition pulse half a percent i think again that was what was set

8:50water protect we don’t need water to protect because we haven’t got any water protect so we should be able to write that back

8:57we should be ready to give this thing a little pulse so i think we’ll start off by setting the pulse

9:04max power to 10

9:12enter and then we’ll just go and check

9:19somewhere else which is the laser set

9:25and we’ll see how that is configured at the moment it’s set to continuous

9:33which means as long as i put my finger on the button it will pulse

9:40i’m happy with that because it then means it’s under my control before we do that let’s put a target on

9:45the mirror should we and see how well we’ve got the tube set up in relation to

9:51mirror center now this is supposed to be a very small two millimeter diameter beam and if that is the case then we have on

9:58a 25 millimeter mirror we’ve got a lot of scope for being off center and it really won’t matter

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

10:04well here we are we’ve reached that big moment there’s a certain amount of anticipation

10:10on my part um because i’ve got no idea what to expect i don’t know whether these fans are

10:16going to suck or blow i’m expecting to see a couple of lights here but

10:22let’s turn it on and see what happens later on

10:31green light

10:39so they’re sucking that’s good news because it means all we

10:46need is ventilation holes in here to allow the air to come out

10:56we’ll have a quick press of the pulse button

11:02maybe i’m missing by a mile let’s see where we are shall we

11:14well that’s a long way off center why why why am i so far out i wonder well the good

11:21news is we know it all works the bad news is i’m not the perfect

11:27engineering expert you think i am good news is that we’ve only got two fixing screws on here

11:36to clamp it in place

11:42i should be able to just swing this out like this because there’s a screw at the other end

11:47there which is holding this in

11:52and now i can get access this mirror the good news is

11:58i can run it like this because all i’m trying to do is to align mirror one to the laser tube i

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

12:04should be able to find [Music] almost a perfect center position now

12:10because the mirror is just standing there doing nothing

12:20that’s not bad that’s perfect central alignment

12:30[Music] so what we need to do there’s nothing

12:35more than put something like a five millimeter hole in there i suspect

12:41and that will allow me to lock that mirror in that one position which is all i need but hey i’m a long

12:47way out so i’ve got to move the center of that pattern across there 12 millimeters

12:53to line up with the settings that i’ve got i’ve designed this piece of channel here

12:59to suit a glass tube and this lines up with the center of that channel

13:07okay so here’s the channel

13:20and i’ve made the center of my fixings here the slot

13:28so that i can adjust it backwards and forwards on the center of the tube center line what i’ve done

13:35i’ve very conveniently mounted the four fixing pillars for this laser machine symmetrically

13:44on that same center line but the laser beam is not on that center

13:52line the laser beam is on a different center relative to the

13:59mounting points in trying to be a bit of a cheapskate and use this piece of equipment for

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

14:05two purposes i’ve created a bit of a problem for myself so yeah it’s easily overcome

14:14with just one fixing hole

14:21just in case you’re worried i’ve covered over the output window for the laser when i did that blowing i’ll just remove

14:27the tape again it’s a lot easier to rotate the part

14:32than it is to rotate the screw

14:39you might as well have a front row seat might

14:59that’s good enough it’s a very small beam so it’s not going to worry us if we’re very slightly off

15:05center now comes the second problem because now what we’ve got to do is to move this whole thing

15:12backwards and forwards here’s my mirror

15:17the corner of that mirror is a certain distance

15:23away from the wall of the machine now my number two mirror is exactly the

15:30same style mirror as that and it’s sitting at 45 degrees

15:36out here i’m pretty sure that that corner and that corner will finish up at

15:41virtually the same dimension so i’ve got to go around to the front of the machine now and measure how far

15:47the number two mirror is away from the wall of the machine and set this one to that same dimension you

15:54don’t need that noise on for the moment in practice it’s easier to measure that

15:59corner 91.4 so it’s got to come this way quite a long way

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

16:09it’s about 91. so that’s not far off now the reason why i need to know that

16:16is because i’ve got to punch a hole through here fairly accurately and to do that what i’m going to do is

16:21to stick that on there i’m going to check the gap on my mirror

16:31to make sure they’re all approximately the same

16:37here here and here my mirror almost in a vertical plane at

16:4345 degrees and caused the reflection to bounce onto here in pretty close to

16:49the correct position for me to drill a hole through because i want the smallest hole

16:54possible through there to point to mirror number two once i’ve got this thing set

17:00i don’t need a big hole for adjustment

17:06so we’ll let the laser do the work for us

17:14there it is

17:21[Applause]

17:47yep that’s pretty good so now we go and check how that beam is hitting mirror number

17:52two now i’m going to loosen the slide at the back here

17:58i’m going to drag the laser back by a quarter of an inch

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

18:05turn the laser on and see what effect we’ve had

18:13gone too much now minor adjustment and

18:24a little bit more we don’t have to be perfect but we can be because i’ve got all the

18:30adjustment in the world that i want and that should be just about spot on center

18:40now that i’ve tightened the laser up and clamped it down

18:46spot on center basically made sure that the beam is in approximately the right place at this end

18:51to put a target on there and start aligning it with the x-axis for real so there’s our target burn

19:00pretty central and here comes our alignment burn now

19:06we’re not on the mirror

19:12it’s not too far off it’s probably right on the right hand edge of the target it’s right over here now

19:21we’re pretty close now you can never set this

19:27in one because it is an iteration process well i’ve just shut down the machine for

19:33a few moments because i feel i need to explain what i’ve just said iteration process

19:41many people set their machines up and they follow this routine of target set target set but they don’t

19:47actually realize what they’re doing let me try and take a few moments just explain the technique that you’re

19:54actually using here’s a bearing rail and what we’re trying to do is set the beam at the moment it’s a

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

20:02red beam because it’s reflected off this mirror here at a funny angle we’re trying to set that red beam to

20:10this position here which is the dotted move line which is actually completely parallel in both the vertical

20:17and the horizontal direction with the bearing rail so that’s our target that we’re

20:23eventually trying to achieve the first time we put mirror 2 close to mirror 1 we don’t know

20:30how this beam is reflecting off of mirror 1. and the first time we do this

20:35we’re going to produce a green target burn on mirror 2. so we move mirror 2 a long way away and

20:43hey here’s our green target and our beam is nowhere near the green target so our burn is out here so we

20:50adjust mirror one to bring this beam onto target so now what we’ve got

20:59we’ve got a blue beam and you could easily be forgiven for thinking that you’ve now set your machine correctly

21:04because you’ve actually set the beam onto the target and it perfectly matches it’s not quite

21:12as simple as that because now when we move this mirror back to position one

21:19we shall find that the blue beam when we fire it again for the second target is actually making

21:25a target burn here the first target burn was here but the second target burned is here

21:32so now we move this mirror away and here’s our target that we’re aiming

21:37for and of course look the beam is pointing here at the previous target

21:44so now we have to adjust the beam yet again at mirror 1 so that it points to

21:50the blue target which is our second target and as you can see now that we’ve gone

21:56and set the orange beam to target number two

22:02we’ve got a lot closer to perfection we’re not perfect yet and if we go

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

22:09through one more iteration i.e one more set of corrections we should be pretty

22:16close to perfection so you’re not a failure if you didn’t do it in one

22:22you’re pretty lucky if you manage to get it in two

22:28the chances are you’re going to have to have three attempts or maybe even four attempts to get your distant burn

22:34the same as your target burn this is a what i describe as an iteration process

22:40a process of gradually creeping towards perfection

22:50and we’re going to have to make probably one more adjustment now if we’re not

22:56interested in absolute position for center we can turn the target over

23:05do the same thing again

23:15that’s pretty good because we’d like to be a little bit more perfect than that we can now move the beam back slightly

23:23across that way without affecting the adjustment that we just made to the y-axis we just

23:30set the y-axis up but what we haven’t done is set the set the beam so that it’s on the center of that mirror

23:37so we’d like to move the beam across about three millimeters well it’s on center we’re high remember but

23:43don’t don’t get upset because we’ve got to clamp the beam back down again

23:48and we should be back on center in more or less both planes

23:54and there we go the one thing i will say to you is once you have been playing with this

24:00beam you’ll notice that there’s some condensate formed on the mirror there

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

24:05the fumes come through the paper it will eventually disappear

24:11but i’ve got some toilet tissue here or some lens tissue whichever you fancy

24:18the proper stuff is lens tissue we’ll just clean that mirror there’s nothing more than just a hazy

24:25residue on the mirror at the moment you’ll note i haven’t even got a mirror in number

24:30three it doesn’t matter i can still set up

24:37x without that mirror in place now the galaxy lights in this instance

24:44are annoying when i switched the gantry lights off

24:49all of a sudden you could see this target they were causing the aperture to close down

24:55there’s a good logical reason for me at least to have my lights switchable pulse

25:05it’s way way low when i look at these i can see that i’m right at the top of the adjustment it’s

25:12not important at the moment but we will just drop that down to roughly

25:18the halfway point in the adjustment which is about here

25:25right let’s not worry about where it is in relation to center at the moment what we’re more interested in is where

25:33it is when we get over to the other side there and suspectually quite low so let’s just

25:39test it

25:53we’ve lost quite a lot of power as well and the beam has grown we need to raise

25:59the beam up we need to send it across we now need to lift it up a little bit

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

26:05okay now we’ll compare it to our target

26:16to get that hole there roughly on the same center line as the target because that is

26:23approximately the center that we’re aiming for

26:28so it’s quite a nice sharp beam there and yet when we come across to this end

26:38well we’re well lined up but the theme itself is pretty poor

26:46i’ll show you what i mean it’s no longer

26:52a crisp black bean look it’s taken a long time to burn

27:00mirror too is causing some sort of problem

27:07i’ll just go and get some proper lens tissue depending on the sort you get

27:15they all feel slightly different this particular stuff feels similar to toilet tissue

27:23which is why in an emergency i will use soft toilet tissue never use kitchen

27:29rolls this kitchen roll has got kale in it and kaolin is an abrasive

27:35and it will scratch the surface of your mirror without fixing the mirror on let’s just see if we’ve improved the

27:41pulse at least it’s the same size now not quite as dark and i noticed i had to

27:47press more on the pulse button to get to that texture so i i know from

27:52a field point of view that it’s lost power by the time it gets to this position here i might change

27:57that later but for the moment we’re not going to get too concerned

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

28:03we’ll just go back we’ll put the screws in and we’ll just check that we haven’t messed the alignment of

28:08x just fitted up the mirror holder onto this head and to put the mirror in it’s normally

28:14pretty easy because look you undo these two screws that are diagonally opposite and you should be able to just drop the

28:20mirror in you might need to undo the screws just to shade more

28:30but the mirror should go in without the screws coming out you set these grub screws

28:36here so that we’ve got an even gap along the top and the bottom around

28:42about a mil and a half that will be determined by this screw here

28:48so you’ve got a pivot screw in the corner here which doesn’t do anything but you need to make sure that you start

28:54off with it in about equal equal now just remember the nuts on the top here are loose so put your

29:00finger behind here when you tighten these up right so what we’re more interested in at the moment now

29:06is firing this beam across here and going down onto the table anywhere onto the table

29:13just put our piece of card down shall we we’ll have a go up burning well first of all we’re going to bring the table up as

29:19high as that we can pathetically slow isn’t it and bringing the table up high

29:24is revealed i’ve got a potential clash here i’ve still got an inch to come on the table but i’ve only got about half an inch

29:30here so i’ve got to take some material off the bottom of this sensor switch and also tie this cable back that’s high

29:37enough for what we want at the moment so let’s make a mark on there

29:50and drop the table down that’s quite a long way off where i expect it to be but hey let’s not worry at the moment

29:59oh what’s happening

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

30:04something is jamming

30:10pretty tight that felt but it’s still something is very stiff

30:15here and it’s not driving very well at all that is

30:22four or five millimeters lower there than it is here

30:30shut that off while we try and sort this problem out this is not part of the plan but hey the

30:36way in which you adjust these take to make the table level

30:41is on these pulleys normally somewhere you should find a couple of grub screws

30:48fixing the pulley to this shaft

30:55[Laughter]

31:01you need to undo those grab screws if you can get to them you need to

31:08rotate this to take the table up or down

31:19wow this table is out by a long way about the same level as that one and then that one at the back is totally

31:27wrong as well but that one looks as so the grub screw is loose and that may well be what the problem is

31:33so the back one is about right now it’s reasonably level now so they shouldn’t be jamming

31:39[Music] so now we’ve got to diffuse this little

31:45time bomb that our chinese friends have sent me

31:51i’ve taken the belt off so that i can actually feel each one of

31:57these and that one is pretty free

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

32:03the one at the back there [Applause]

32:08marginally stiff but not as free as i’d like it certainly not as free as this one

32:16this one over here is pretty free as well this one at the back here is extremely

32:26sticky as it goes up it gets sticky as i move it down to out of level

32:35it frees up i’m suspecting that this bearing here

32:44is not lined up properly and it’s clamped out of position take

32:50all those screws loose and see what this feels like now no it’s getting tight again

32:58it’s getting very tight and these these threads are bent because i can feel them

33:03going tight and loose as i rotate them the gauge i’ve got here measures to

33:08within 0.1 of a millimeter so i’m going to set that to exactly 11

33:13here on each corner of the table they’re level as far as the nozzle is

33:21concerned or as far as the head is concerned it doesn’t mean you say the level with the bottom of the machine of course i’ve

33:26now taken the motor off and i can see why this doesn’t rotate it’s got a planetary

33:32gearbox associated with the motor right but what i’ve now done i’ve taken

33:37the original gear off which was pathetically slow remember at raising and lowering the table

33:43and i’ve found this matching gear from another machine and

33:50look at the size difference it’s going to go up and down like a rocket now i’ve just come to fix this motor back on

33:56and several things you can see first of all it’s very unstable

34:01you can see how it’s actually only fixed to a very paper thin floor of the machine

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

34:07and m4 screws through a piece of metallic paper is not exactly a very

34:13good idea is it i mean i’ve already stripped three of the four threads on there

34:18and let me just demonstrate something there we go that’s how strong those

34:25threads are so it’s something else i’ve got to fix so with the torque on this motor and the

34:31flex no wonder it’s not possible to tension it up properly and it keeps going click

34:36click click click i’m very lucky and i’ve got all sorts of kit i’ve got a piece of three millimeter

34:42stainless steel plate there that i will be able to just conveniently fix in there and

34:49bolt that too that will stop it from flexing well this larger

34:55pulley which hopefully was going to make the thing run faster was just asking

35:02too much of the torque available from this motor so i’ve had to put the original small

35:07drive pulley back and it it looks and feels a lot better

35:13now that we’ve got the motor mounted really stiff it can’t jump teeth

35:20with this amount of tension on the system so what we’ve got to do now is to go around the other side of the machine and

35:27again we’ve got to set the table level now while i’ve been messing around with this table and leveling it all up

35:35i keep getting bugged by this loss of power increasing billing beam

35:42size look we’ve got a lovely tight beam there and yet by the time we get to the end of the stroke we’ve got a fuzzy beam

35:49just across this x-axis is it a mirror problem or is it a distance problem from the

35:55tube that’s causing the beam to grow i don’t believe it is

36:00but of course i will never know until i prove it so we’re going to have a look and see

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

36:06how this beam grows with distance i can do that on this machine because of the way in which i’ve designed the tube

36:12so let’s go and have a look and i’ll show you what i mean having set this beam up in the x-axis to give

36:17the correct position on mirror number two i don’t really want to lose that so what

36:23i’ve done i’ve marked at this end the position and i’ve also put a mark

36:29that end at the end of my tube mounting so what i can now do i can with impunity

36:37undo my tube because i know that it’s referenced off the back face and i can always put it back

36:43into the correct position on the back face we take the front clamp screw out and i’ve very slightly

36:49loosened the rear one so that means i can now do this with my tube

36:56i can pull it out like this so all i’ve got to do is remove my mirror now

37:09[Applause] and provided i push it back just a little bit more

37:18i can move my beam out beyond the end of the machine because it will fire through the mirror now

37:25and if i line you up properly you are looking down the barrel of a gun what i’m going to do is i’m going to

37:31fire the laser at various distances into a piece of card and we’re going to see how the beam

37:37changes shape with distance so by the time we get to mirror number

37:42three we are 1260 millimeters away from the face of the laser

37:48now i’ve got some large sheets of card here which are used for making boxes we

37:54shouldn’t be able to miss this should we so there we are we’re roughly 1300 millimeters away

38:00from the laser tube now so let’s turn it on

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

38:12same 10 power and let’s see what we can do at 300 millimeters there it is there

38:19look let’s just see whether or not it is the dot

38:26so that i can look at it from a distance

38:33let’s see if i can make it bigger

38:41no the dot is actually here look

38:49there’s my dot there

38:56so we are not overly impressed are we it’s losing power with distance

39:05and it’s also the beam is is growing quite substantially with distance

39:10and i’m having to hold the power on for quite a long time now i could push the power up and see

39:18what effect that has we could move this across a bit

39:23and i’ll push the power up to 100

39:35wow that’s a pretty abysmal beam isn’t it that’s not

39:42a mode zero beam

39:48i was sent this test certificate with this laser now look at all this data up

39:55here and i can’t find anything about distance away from the head

40:02when they measured this data that you can see here this very clearly

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

40:08shows a lovely what they call tem00

40:14proper gaussian shaped beam and then they do all sorts of statistics on this graph down here about

40:20the gaussian fit but at the end of the day we don’t have

40:25a gaussian beam 1.3 meters away from the laser

40:33as i said a gaussian beam as described as a tem000 mode

40:38what we have here is um well it’s the shape of my bottom almost so

40:44it’s a 10 0 1 beam that we’ve actually got and i can do nothing with that i mean it may

40:52cut okay it may weld okay but it certainly won’t be any good for laser engraving because there is no

40:58sharp point this is not going to work for me so i’m not going to go any further with

41:04this exercise until i’ve spoken to cloud ray as i was editing my video and remember

41:09we looked down the barrel of the gun if the beam was small and compact and passing right through the center

41:15there there would not have been a problem but bear in mind i think this beam is

41:22expanding and therefore there is the possibility that i could be getting reflections off

41:28the side of as it passes through this mirror aperture so what i’m going to do is to remove the

41:35mirror before i finish up with egg on my face

41:41and we’ll try the same thing again not entirely sure where it’s going to land but it’s going to be somewhere about

41:47there oh that’s the current since it’s right in the same spot let’s just move that

41:53across a little bit that’s just a quick single pulse we have still got a 100

42:02beam at 1.3 meters after all which is excellent news we’ll just stick

We Have Lift Off – Laser Tube Upgrade Transcript (Cont…)

42:09one of my paper targets on there so that we’ve got a nice consistent material to work with

42:19i’m not going to touch it i’m going to do it again and see if i can just burn the center

42:31so we’ll just watch for the red glow is it in the center

42:39yes so we have got quite a nice beam after all

42:46yeah look at it it’s huge

42:51so that beam is almost 10 millimeters diameter we certainly don’t need any beam expanders on here

42:57the beam expands on its own thank you so for the time we get to our lenses we

43:03have got a relatively low energy density so that’s good news because

43:08hey anything that we interpose in the path is going to absorb power and we’ve only got 30 watts here

43:16anyway so you know we want to make the most of that so i’m very happy that we’re not

43:21going to have to use a beam expander so this has been a very interesting exercise

43:26down up down up and eventually what you carry on so what

43:33we’ve just found out is that the beam grows as it reaches mirror three by the time it gets there

43:40it’s 10 millimeters diameter now you’ve got a 25 millimeter mirror

43:45which is canted over at 45 degrees that means the effective height of that

43:51mirror that the beam can see is only around about 14 or 15 millimeters so we’ve got to be

43:56pretty accurate with our alignment onto mirror 3. but the good news is because of the way

44:04in which we are lying mirror 3 with the center of the axis of the lens tube

44:10then we’re automatically going to put the beam onto the sweet spot of mirror 3 which is the central point

44:18if i’ve designed it correctly so things are looking pretty good for the

44:23next week or two i’ve got other projects that i’ve got to get involved with i might not be

44:29completing this work for a little while yet so you’ll have to be a little bit patient but now you’ve seen that we’ve got a working

44:35machine we’re flying and on that happy note i’ll say cheerio for now

44:40thank you for your time and patience and I’ll see you in the next session