29 – How To Laser Cut Parts Bigger Than Your Bed Size (15:18)

0:15 Well welcome to another Lightblade learning lab, today I’m going to show you

0:21 how to do something impossible with this machine that sounds a bit of a

0:26 contradiction doesn’t it okay if you want to get picky it’s difficult and you

0:30 have to think about it what I’m going to do I’m going to finish up cutting a

0:34 approximately 600 circle with a machine that’s got a bed cutting size of only

0:39 600 by 400 so sit back and I’m going to show you how I go about solving this

0:44 problem okay now what you see here is a sign that a friend of mine has asked me

0:49 to make now you can see from the size of those that those letters are a

0:54 reasonable size that I can cut on my machine on the end that bluey looking

1:02 circular piece is about 600 millimeters diameter now all along that bar those

1:09 letters have been cut in ten millimeter thick acrylic and they’re bolted to the

1:15 bar at the bottom and I’ll show you the drawings for those in a minute

1:18 it’s all made in small pieces not individual letters and on the front of

1:25 the clear acrylic letters I’ve cut some white separate letters that will be

1:31 covered in vinyls now the crown at the top is separate and will be covered in

1:36 vinyl and I’ve made that bluey looking piece on the left hand side in several

1:42 pieces as I said but if you want to cover it with vinyl then you don’t want

1:46 any cracks or gaps to show no screw fixings or anything you need a nice flat

1:51 surface so somehow I’ve got to manufacture that shape in one piece bear

1:59 in mind we can only cut 600 by 400 on this machine so each one of these

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

2:05 rectangles that’s on here is a 600 by 400 rectangle to try and work out how it

2:10 could break the job down and make it cuttable with this machine now all of

2:14 these ten millimeter perspex letters are going to be mounted on a bar steel

2:21 tubular bar that’s shown below here and so here’s how I went about cutting it

2:27 from seven pieces of material but the next challenge was to get this

2:31 blue shape as one piece the first thing I did was to copy it the next thing I

2:38 can do is I can put an enclosing rectangle around it which just makes

2:43 life easy for me because I can go like that and then I can put a dividing line

2:51 across it across the center so f7 is a center line on there vertical and f7 is

2:58 a center line on that vertical and there we go I’ve now divided that object into

3:02 two nice equal parts and I can remove the rectangle now what I’m going to do

3:11 is to copy this

3:18 like that I should now be able to trim

3:25 these two objects we’ll take the bottom off of that one and the top off of that

3:32 one and then we’ll throw away the dividing line so the plan is to put the

3:45 material in the machine and cut this top half first then we turn the material

3:53 round and if I turn the material round then what I’ve got to do is to turn this

3:59 second part round as well so I shall save those to a DXF file and then we’ll

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

4:09 put them into RDWorks well here they are in RDWorks and we don’t want

4:15 them both at once so we take one of them away and we’ll just do the top half

4:19 first now you’ll note let’s just pop that onto the work area and you can see

4:29 that it’s a snug fit but you’ll note where my green square is that bottom

4:36 right hand corner now I’ve done that by going to config system settings and

4:41 there it is there I’ve set the datum of the head position

4:45 where it’s convenient for me to see it so we save that to a U-file and we’ll

4:51 call that one seal one and then we do ctrl Z ctrl Z to get back to the pair of

5:00 them and we delete that one and then we’ll do the same with this we’ve got

5:08 cut parameters up here which I have got to set and I’ve set it to six

5:13 millimeters a second which for a 60-watt tube is probably comfortably slow maybe I

5:21 can go at eight or even nine but six is really comfortable I don’t want to fail

5:27 on this one okay and we’ve got it set to 78 percent power

5:31 which is 60 watts maximum output for this machine

5:35 okay let’s save that one to a U-file as Seal Two – and then we’ll jump on to the

5:39 machine well here we’ve got a piece of acrylic

5:42 as you can see clearly marked perspex and this piece of material is 610

5:49 millimeters wide so it’s wide enough to fit neatly in the machine. What I’m going to

5:53 do is cut it off at about the same sort of size 610 620 then I’m going to use

6:01 the machine to cut it off with so we’ll cut it off at 6:20 because I think what

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

6:09 I’ve got to cut is around about five eight five now there is a backplate in

6:17 there that would allow me to push this right the way through but okay

6:21 I’m lazy I’m not going to take that back plate out let’s turn it round instead and

6:29 there’s my cut line there. Lets find out approximately where it is, it;s about there

6:37 then we run the head to one end and we set the power up manually I’ve got that

6:45 set to 67% I can go up to 78% so that’s maximum power enter and now we set

6:54 the speed for five millimeter acrylic I would think probably should be able to

7:01 do that about six millimeters a second now it doesn’t matter if it doesn’t cut

7:06 through completely you’ll see what I mean

7:09 obviously it’s not going to cut all the way across because this is 610 and the

7:12 machine is only 600 wide capable so if I press the pulse button and the arrow key

7:18 at the same time. I’d better go and put some extraction on.

7:28 Yep, Lets see what we’ve got. now regardless of whether this power

7:32 has cut through and all we’re going to do is crack the ends. So it’s cut through Nicely

7:40 okay now I’ve got my steel table on here, but it doesn’t have to be the steel table, it could be anything

7:49 I’ve raised the table up so that it’s level with this boarder around the outside there

8:03 That sits on there nice and flat now I’ve got the first part of my

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

8:0 6program in there which I called Seal One

8:1 2and because it’s very very tight on the material

8:1 6I need to have my Datum as far across to the left as possible and I might take it back about 5mm

8:2 5I’ve got scope to play with backwards and forwards, but I’ve got very little Scope this way so I’ve got to be

8:30 fairly accurate with my material and the program in the

8:37 x-direction otherwise I could get a slop error

8:41 so we’re showing a slop error in Y this basically means my program is running

8:46 off the back of the table. so I’ve got to bring

8:49 my datum a bit further forward, my origin.

8:58 Origin, now I’ll probably get a frame ok

9:05 so now what I’ve got to do is pull my material forward

9:09 to where the back part, there so I’ve pulled this forward so that it stays

9:15 just on the material at the back of the machine.

9:25 Lets Try that again. it stays on the material down at the right hand size there

9:34 it’s on the material on the left-hand side, it does not run off the back

9:44 okay so we’re ready to run the first part of the program I’m running at 78%

9:49 power and six millimeters a second

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

10:07 okay that’s the easy bit done. now I’m gonna load in part two which is Seal two and to do

10:16 this second part I’m going to have to turn the job round and that’s why I

10:22 reversed the program

10:28 So take the job out of the machine and pop it back in

10:33 and now what we’re trying to do now

10:39 we can see the end of the cut here , here

10:44 we’re going to try and line the laser beam up to pick up exactly where that

10:50 cut finished up and this one and this is where I’m going to show you a few tricks

10:54 one thing you’ll notice is I’ve got my red dot pointer taped up I

11:00 don’t use it I find it very very annoying but there are times when it

11:06 might be useful to be honest this is not one of those

11:10 times because I’ve got to have exact accuracy

11:14 and the only way I can get exact accuracy is to actually use the pulse button. The Pulse button tell me

11:21 exactly where the head will hit. Now we know that the head has stopped at our origin

11:29 position so the first thing we’ve got to do is we’ve got to make sure that the

11:33 end of that cut lines up exactly with that nozzle we can do that almost by eye

11:41 to start with what I’m going to do now is to not worry

11:47 about this end I’m going to go to the other end do more or less the same sort

11:52 of thing at this end now I’m not not interested in trying to find out exactly

11:57 where the end of the cut is like there that’s not what I’m trying to find what

Transcript for How To Laser Cut Parts Bigger Than Your Bed Size (Cont…)

12:03 I’m trying to do is I’m trying to find the line that the end of the cut the

12:10 origin point at the other end will decide where the program comes back and

12:13 joins all I’ve got to do is swing this job this way here to make sure that it

12:18 sits in line with the nozzle it’s got to come back a bit

12:28 and then I’ll put a pulse down, I’ll get

12:32 a little bit closer

12:36 and I’ll put another pulse down and see how close I am to the end of the line

12:42 and I would say looking at those two marks they would intersect exactly with

12:50 the end of my line as I said I’m not interested in finding the exact position

12:55 I’m interesting getting it lined up that way so do two or three pulse dots and

13:01 make sure that it lines up don’t do it on the job do it outside the job I’m

13:07 happy that the other end of the job lines up exactly in the right plane that

13:13 way but now I’ve lost my datum here so what I should do is I shall press the

13:19 frame command again and that will drive around and when it settles of course it

13:25 will settle back at my datum position which is there so let me just check that

13:30 the pulse is in

13:37 I would say that that’s right in the beam

13:41 pull it just a shade

13:44 I would say I’m pretty well lined up

13:59 well if we’ve got it to join

14:11 it should lift off I have to say, there is

14:16 nothing more than what you would consider a normal start/finish point at

14:21 either side well that’s a bit quieter um I did promise you a short session today

14:28 and here we are we’re at the end of this session hopefully this has been a very

14:34 useful trick that you might be able to utilize in the future if you’d like to

14:38 extend this from being just a 600 millimeter diameter circle bear in mind

14:44 the depth of this bed is 400 so technically I could extend and use a

14:50 piece of material up to 800 millimeters I could get an 800 millimeter by 600

14:55 millimeter shape out of this machine using this trick in the 800 millimeter

15:01 direction I wouldn’t guarantee it to be better than about maybe half a

15:05 millimeter but that really depends upon your ability and your eyes to set up

15:11 that little start point well thank you very much for your time and I shall see

15:16 you in the next session