0:00well welcome to another RDWorks
0:02learning Lab this is Russ normally you
0:06only see these bits and maybe a little
0:08bit of this sometimes but today you’ve
0:11got the whole of me because we’re doing
0:12a review for one year I’ve had the
0:16machine just over a year now and it
0:21basically quite a good machine during
0:25the past year I’ve learned a hell of a
0:27lot about this machine and also a great
0:31deal about the way in which the Chinese
0:33operate and sell these machines on ebay
0:35now anybody that’s watching this and
0:39thinking about buying a machine the only
0:43thing that I would say to you is you’re
0:45not going to get quite what you expected
0:48if you buy a 50 watt machine it’ll be
0:52fitted with an 800 millimeter long 40
0:56watt laser tube they don’t have a 50 watt
0:58power supply in it but the laser tube that’s
1:02fitted won’t be very good it’ll work for
1:09a week a month six months
1:15but be prepared when you buy one of
1:18these machines to think about the cost
1:21of replacing the laser tube because that’s
1:24something you’re going to have to do
1:26fairly shortly after you’ve purchased
1:28the machine because either the laser tube
1:31won’t work or you’ll be very unhappy
1:32with its overall performance I kept my
1:36first laser tube for something like about six
1:40weeks and then I purchased a second laser tube
1:43which was to be honest not a lot better
1:48because at that point in time I was very
1:49naive and I didn’t understand how the
1:52Chinese system worked and I bought a
1:55replacement laser tube and it was a
1:57replacement almost like for like so I
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
2:01replaced rubbish with a little bit
2:03better rubbish and I soldiered on making
2:07my series up to about eight months where
2:10I tried to use the laser tube as a learning
2:14aid to try and investigate just how
2:17these machines work why the tubes up
2:19rated in the way that they did and
2:22eventually after eight months I bought
2:25myself a proper upgrade and as you might
2:28be able to see in the background this
2:30white lump hanging out at the back of
2:31the machine here is the extension for my
2:34proper 60 watt – well I ordered a 60
2:37watt laser tube but because I’ve done a little
2:40bit of negotiation beforehand we’d
2:42managed rather the people that I bought
2:44it from
2:46I think they saw the potential in in
2:49this particular channel that you’re
2:51watching and so in fact they sent me a
2:5370 watt laser tube instead of a 60 watt laser tube
2:56now that was both great and not great at
3:00the same time because a 60 watt laser tube is
3:031,200 millimeters long and I had built
3:07my little case here extended to take a
3:111200 millimeter long laser tube when the tube
3:14arrived and it was 1,250 millimeters
3:16long was I going to complain no I
3:20finished up remaking this so I’m
3:26actually very lucky in that I’ve got a
3:2870 watt laser tube and a proper 70 watt tube
3:30in this machine I bought a power supply
3:33to go with it and it’s an absolute dream
3:36I just absolutely love coming out here
3:38just turning on the switch dialing in
3:40some numbers and I get what I asked for
3:43now I’m just going to show you this
3:44because this is the calibration chart
3:47for the machine in other words the power
3:51characteristic is actually quite steep
3:53up to this point here which is something
3:56in the region of about 25 percent power
3:58so after this point although the
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
4:01milliamps are going up nice and steadily
4:02most of the gain in power is happening
4:05around this first third of the range and
4:08then we got to another two thirds of the
4:10range and we get to somewhere in the
4:12region of about 65 percent here and this
4:15is 22 milliamps which is the typical
4:17running current for a 60 watt tube and
4:20I’m up here just at about 70 watts so
4:23the tube delivers exactly what it says
4:25and I’m extremely pleased with it the
4:28only reason I’m showing you that
4:29characteristic is because a lot of
4:32people think that when i dial in 10% i
4:35get 10% power and when i dial in 20% i
4:38get 20% power
4:39why not dial in 80% like 80 percent of
4:42whatever the tube power is it’s a nice
4:45idea but it doesn’t work that way
4:47because of the non-linearity of the
4:48output of the tube so just remember that
4:52the other big lesson that I learnt
4:55was not to over stress the tube know
4:58what the current is that you’re supposed
5:00to be putting through attitude and make
5:02sure that you fit an ammeter to your
5:05machine now this is the best friend that
5:08you’re going to have because it would
5:09stop you destroying your tube now when
5:12you’re buying one of these machines you
5:16think you’re buying a 50 watt machine
5:19but in fact you’re buying a 40 watt tube
5:21a 40 watt tube should be run at 18
5:25milliamps maximum a 50 watt tube at 20
5:28milliamps maximum and a 60 watt tube
5:31typically 22 milliamps of maximum those
5:35are typical figures that you want to
5:36stick to and then you will not be over
5:39stressing or what they call overdriving
5:41the tube now I did a very in-depth study
5:44partway through the year of how a tube
5:46works and if you just put too much
5:50current through the tube you start
5:52causing the gas within the tube to break
5:55down into carbon monoxide and oxygen now
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
6:00in a few moments you’ll see the tube
6:02going pink there we go that pink is
6:04basically the idea the nitrogen being
6:06ionized it’s got nothing to do with the
6:09co2 that’s in there the fact that the
6:11nitrogen is excited brings the co2 into
6:15play just because you’ve got a pink beam
6:17doesn’t mean to say you’re going to get
6:19power out at this end of the beam here
6:20the pink beam is a necessary mechanism
6:22to make the lasing action happen but the
6:26lasing action is all dependent upon the
6:28co2 that’s in the gas mix now if you put
6:32too much current through your tube then
6:35what happens is this nitrogen excited as
6:38is has so much energy that it will start
6:41breaking down the co2 into carbon
6:44monoxide and oxygen and over a fairly
6:47short period of time if you start over
6:50driving your tube continuously then you
6:53will destroy all the carbon dioxide in
6:55that tube it will still glow pink but
6:58you’ll have less and less power coming
6:59out of this end of the tube
7:01so just heed that warning because I
7:03destroyed my first tube by doing exactly
7:06that not understanding
7:07that 100% was in the machine but you
7:11can’t use it so it’s very important that
7:13you understand you control your machine
7:15by whatever the maximum current is now
7:19it could be that you get to your maximum
7:21current of 18 milliamps and you can only
7:23use maybe 50 or 60% as the number that
7:27you can use well 60 percent is the
7:29maximum number that you’ll be able to
7:31use because 60 percent equals your
7:32maximum current 100 percent will start
7:35shortening a tube life dramatically so
7:38just a warning don’t go there
7:41it wasn’t until partway through my
7:43second tube that I realized my mistake
7:45and by then it was getting a bit too
7:48late anyway and my second tube was not a
7:50very good performer anyway so basically
7:52that’s the first and most important
7:54lesson that I’ve learnt this year that
7:56the Chinese oversell their machines and
7:59you don’t get what you’re expecting you
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
8:00need to buy the smallest machine that is
8:03big enough to do your job this
8:06particular size that I’ve got here 3450
8:08is actually a super size because
8:12everything is small and light and it
8:14moves around quickly it hasn’t got very
8:15much mass the next size up starts to get
8:18bigger stepper motors bigger beams that
8:21everything gets heavier and the whole
8:23thing has to get mechanically bigger
8:25because it gets bigger so with this
8:27machine we’ve got five hundred
8:28millimetres of a second that we can use
8:30in this axis and 400 millimeters a
8:32second that we can use in this axis and
8:34I do find when I’m even running at 4 or
8:38500 millimeters a second on scanning I
8:40get very little problems of overshoot or
8:43anything like that it’s a really tight
8:44little machine to use so I’m really very
8:47pleased with the mechanics of this the
8:50other thing about it is if you buy this
8:52as a 50 watt machine it’ll come with a
8:5440 watt – as you can see with a small
8:56amount of extension over here I can put
8:5960 watts into this machine and all of a
9:02sudden it becomes an absolute dream of a
9:03machine I bought my power supply direct
9:06from from China and it cost me about
9:10just over 200 pounds for a power supply
9:12and a 2
9:14excellent value for money but it also
9:16cost me just over the same amount two
9:18hundred pounds plus to get it from there
9:20to here via DHL it arrived in four days
9:23super but it doubled the price but I’m
9:28not complaining couple of three other
9:30things I need to just quickly talk about
9:32first of all we can see down here I just
9:36move my power measuring device oh the
9:43last time you saw this instrumentation I
9:45probably had a rather expensive
9:48microprocessor controlled temperature
9:50display at the top here I borrowed it
9:52off of a job and after six months the
9:55client came along and he wanted to build
9:57his machine so I don’t take it off my
9:59machine and redo this so what I’ve now
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
10:01got is a very cheap little meter here
10:05which is around about six or eight pound
10:07for a digital thermometer with its own
10:11temperature probe and it’s got a relay
10:12in it so I can use it to control various
10:15things around the machine I’m using it
10:17to control lights for heating during the
10:19winter now this tank as you can see it’s
10:25hanging on the lid just going to turn
10:27the hold of the Machine off and I’m
10:30going to take the lid off of this tank
10:31snug fit everything’s a snug fit and
10:35normally what I’ll do maybe once a month
10:39I’ll take this out use it as a dip stick
10:41which is my thermometer and I’ll both
10:46smell and feel the water now this is
10:49distilled water I will just take that
10:58off there for the time being just
11:01because it’s easy to move it we take a
11:04look in here and what do we see in there
11:08clean water now this is distilled water
11:13and I just taste it
11:17tastes perfectly fine to me it’s clean
11:21it’s clear and would you believe it it’s
11:25been in there for a year now I haven’t
11:28even topped it up it’s getting a little
11:31bit low so this is the first time in one
11:34year that I’ve opened this lid some
11:46people are finding it difficult to get
11:47hold of but the easiest place to get
11:48distilled water is at the pharmacy so I
11:51just thought you’d be interested to know
11:52in this particular country most of the
11:54year we’re anything between 10 8 on a
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
12:00really hot day we might get up to 28 or
12:0330 degrees C but that is very very rare
12:05you can see the ambient temperature in
12:08that water is 23 if we take a look
12:11here’s the return line here and you’ll
12:15see that I’ve got my temperature probe
12:17strapped to the end here so the water
12:20returning from the tube passes down here
12:22and over that NTC measuring probe that’s
12:27about 5 pounds for a 5 liters but I’ve
12:31spent 10 pound and it will probably last
12:33me another year so 5 pounds a year is
12:36not bad for a water cooling system as
12:39you can see it holds something in the
12:42region of around about 9 liters my
12:44system here and I find that perfectly
12:46adequate to deal with my 60-watt too
12:48because I don’t use it continuously
12:50I’m not production shop I’m just playing
12:53so it’s very rare that I used my machine
12:56for more than maybe two three hours at a
12:58time those were the guys will have
13:00noticed that I have removed my
13:03extraction plan my centrifugal bouncy
13:06castle fan a word of warning a couple of
13:11weeks ago it started smoking the fan
13:17stopped working
13:19well I burnt the motor oh how did I do
13:22that well if we take a look here
13:25something I forgot to do I forgot to
13:28remove the grill
13:30and we got also lots of little bits of
13:31paper and dust stuck on the grill it was
13:36seriously restricting the airflow and
13:39I’ve had to replace it with a much more
13:41powerful fan now purely because it was
13:45cheap and plastic and more powerful the
13:50only problem is the more powerful fan
13:53it sucks better but it also makes a lot
13:57of noise as you can hear it’s got a
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
14:00really annoying wine which is going to
14:03annoy everybody including yourself
14:08and so what I’ve had to do
14:11I’ve had to go for myself
14:13silence ebooks
14:24and watching the sea down at the bottom
14:26there is where the air is now coming out
14:28so consequently what I can do is I can
14:31close my workshop door
14:34just about there
14:37it’s now down to a whisper out here so
14:40it’s not too bad at all this is still
14:42that wine there but it’s not a terrible
14:44loud wine now so that’s a significant
14:51change that I’ve had to make no just
14:54underneath here you’ll see I’ve actually
14:56purchased a bigger air assist pump now
15:03it delivers about probably 10 times as
15:06much flow as this one but at the end of
15:09the day but the time you try and force
15:11it down the pipe work you can only get
15:13about twice as much flow through the
15:14through the nozzle but this one has been
15:17working for a year now and it’s been
15:19working quite hard and somehow I think
15:22it seems to be little bit labored so I
15:24thought well I’ll get this one so that
15:26when this one packs up I could fit this
15:29one so in the not-too-distant future
15:31there will be a video of me fitting and
15:33testing that as a part of improving the
15:37general performance of this machine I
15:39finished up making my own copper mirrors
15:41and those copper mirrors have been in
15:43here for about five months now yeah
15:47February March April May June July
15:50August yeah best part of six months now
15:52they’ve been in so this is the first
15:55time that this mirror has been out since
15:58I put it in and in fact you saw me
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
16:00fitting it on video there is a small
16:03amount of oxidation on the surface a
16:06very small amount but it’s only when you
16:11catch in the light I’m absolutely sure
16:14the reflectivity at ten point six
16:17microns wavelength is not going to be
16:20affected by that at all because when I
16:23did my reflectance tests with very crude
16:26raw copper which was well and truly
16:29oxidized on the surface it was still
16:31giving something like about 96 or 97
16:33percent reflectivity and so I’m very
16:36confident that that is still delivering
16:38quite a reasonable amount of power I
16:40might have lost half a percent if that
16:42we will go back and check that very
16:45shortly and I’ll do a proper test on it
16:48to see just what the power drop has
16:51across these mirrors in six months so
16:53summer after year would I go through the
16:57same thing again well that’s a very
17:02difficult answer to give because because
17:05the machine was not perfect and I found
17:08so many small Nikoli problems with it
17:10and there was so much that I didn’t
17:11understand I have learned a huge amount
17:14in the last year if I’d have had the
17:17perfect machine and I needed to run it
17:20for a business then I’d have probably
17:22been can I be crude and say pissed off
17:26with the machine because all I want to
17:28do is use it for me it was a
17:31recreational exercise for my retirement
17:33and it served its purpose extremely well
17:36and apart from the videos that I’ve made
17:39I’ve also made hundreds of really very
17:43good friends from around the world and
17:45all I’d like to say is thank you very
17:47much for all of you who have spoken to
17:49me and written to me and participated in
17:51this learning experience that I’m I’m
17:54having and I’m still learning so thank
17:58you all again for participating and
Transcript for 1 year of owning a Chinese Laser Engraver (Cont…)
18:00joining me in my trip in my venture and
18:03the story continues
