MickMake Meets Robots and Dinosaurs - Part 1: Laser cutters, CNC and other machinery


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YouTube video: MickMake Meets Robots and Dinosaurs - Part 1: Laser cutters, CNC and other machinery


Mick visits one of Tim's old school mates, Gavin Smith, who runs a MakerSpace called Robots & Dinosaurs in Meadowbank, Sydney, Australia. Part 1 looks at laser cutters, CNC machines and some old school stories.

Part 1: Laser cutters, CNC and other machinery

Check out Part 2 of this transcript and video.

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Transcript

Intro

Mick
April 30, 2017
M
Mick April 30, 2017
So, some bozo decided to delete the intro that we did previously.
Tim April 30, 2017
Yeah, that's right.
T
M
Mick April 30, 2017
Who was that, Tim?
Tim April 30, 2017
That was the guy holding the camera, because I can't do it. I'm driving.
T
M
Mick April 30, 2017
Oh yeah, right.
M
Mick April 30, 2017
So, we're on our way to Robots and Dinosaurs.
Tim April 30, 2017
Yup, R&D. I've already seen photos on Facebook and the website. I hear they've got some machinery, stuff that you would find really useful, but you wouldn't use too often. So, hard to justify buying.
T
Tim April 30, 2017
Also, the space, the garage, you couldn't. Laser Cutters are pretty big I understand. For those people who say a garage is for a car, you're mistaken. Where am I now?
T
M
Mick April 30, 2017
Turn right, yeah. Let's see what it looks like.
Tim April 30, 2017
Alright, looking forward to it, mate.
T
M
Mick April 30, 2017
Must be upstairs.
Tim April 30, 2017
On your phone I thought it was just there that way.
T
M
Mick April 30, 2017
If you look at Google Maps, you can actually see it's pointing roughly here. Okay, this is looking promising I think, maybe.
Tim April 30, 2017
Ten?
T
M
Mick April 30, 2017
Actually it should be ten, yeah.
Tim April 30, 2017
14. There we go.
T
M
Mick April 30, 2017
Ten. I don't think it's the Australian traditional medicine society. Maybe they've moved. What about this 8B?
Tim April 30, 2017
No. Have to give him a call.
T
Tim April 30, 2017
Hey, mate, I'm completely lost. I'm standing in the parking lot where there's a zodiac.
T
M
Mick April 30, 2017
There he is.
Mick
April 30, 2017
Tim April 30, 2017
Sorry, mate.
T
Gavin April 30, 2017
How's it going? Welcome. Come on in.
G
Tim April 30, 2017
Okay, cool.
T

Laser cutters

Mick
April 30, 2017
Gavin April 30, 2017
This is Robots and Dinosaurs. We are a place where people come together and just make things. We've got a whole bunch of bits and pieces to help with that. Got a pair a laser cutters over here.
G
Tim April 30, 2017
Alright.
T
M
Mick April 30, 2017
Nice.
Mick
April 30, 2017
Gavin April 30, 2017
I was actually just playing around making a Sudoku board this morning.
G
Tim April 30, 2017
Is this the cutouts from the board?
T
Gavin April 30, 2017
Yup, just little test pieces at the moment. I'm just playing with the scaling until I get the whole thing.
G
Tim April 30, 2017
What material are you cutting?
T
Gavin April 30, 2017
This is bamboo plywood. We've got MDF as well. It's really easy to cut wood. It's really easy to cut plastic.
G
Tim April 30, 2017
Obviously not too thick though.
T
Gavin April 30, 2017
Yeah, that's it. The plastic you can get a bit thicker. That's quite strong.
G
Tim April 30, 2017
That's perspex?
T
Gavin April 30, 2017
Yeah.
G

Magic mirrors

Mick
April 30, 2017
M
Mick April 30, 2017
Tim and I had a discussion on the way over. What would happen if we tried to cut a mirror?
Gavin April 30, 2017
See that glass tube at the back there?
G
M
Mick April 30, 2017
Yeah.
Gavin April 30, 2017
That is a CO2 laser tube. It makes an infrared beam. So, have a look at this... Electromagnetic spectrum. You've got blue light here. You've got red light here. Every piece of visible light you have ever seen and enjoyed in your entire life has been within this little range here. The CO2 laser is over here. It's so far away from visible light that what we think of is mirrors and what we think of as transparent doesn't quite apply, which is why you can have a see-through window on the top rather than a totally opaque box.
G
Mick
April 30, 2017
Gavin April 30, 2017
The way that you cut acrylic is that it melts and then it runs away through the gap where it vaporizes, so you're locally heating and melting. If you try and cut metal, it's too good at heat sink, so instead of getting one really hot spot that vaporizes and cuts, the whole thing just gets slightly warm.
G
Gavin April 30, 2017
These mirrors are magic metal of some sort.
G
M
Mick April 30, 2017
Magic metal?
Gavin April 30, 2017
The previous slice cutter we had, copper mirrors. It just polished copper.
G
M
Mick April 30, 2017
Oh, okay. Yeah, makes sense.
Gavin April 30, 2017
That works really well, because it's reflecting off the service, it's really efficient as opposed to a glass metal mirror where it's got to go through a layer and then out again so you're not heating the glass.
G
Mick
April 30, 2017
Gavin April 30, 2017
Inside the boxes is activated charcoal plus two layers of filtration on top of that. The idea is to just capture anything that comes out of the laser cutter, so we can be nice neighbors.
G
Tim April 30, 2017
Yeah, okay. I saw that coming outside, but no, but then you filtered it.
T
Gavin April 30, 2017
It's filtered, yeah. This is a commercial filter specifically for laser cutters. This behaves worse than the one we made ourselves, so this is why this thing is disconnected and in the corner. That's pushing in and that's pulling out.
G
M
Mick April 30, 2017
Okay.
Gavin April 30, 2017
There's a third fan inside there as well.
G
Tim April 30, 2017
I take it that this second fan has to be more powerful than the blower with the positive pressure.
T
Gavin April 30, 2017
No, no, it's easier to push than it is to pull because you can push as many atmospheres as you like, but you can't pull more than one atmosphere. If you're pushing water in a pipe up a hill, for example, you can push it as high up as you like, but you can't such water through a straw more than ten meters because ten meters of water is one atmosphere worth of pressure. You'd end up with a perfect vacuum at the bottom, and you can't have a negative pressure.
G
Tim April 30, 2017
Acrylic, Plywood, MDF and Bamboo sheets.
T

Trying not to kill yourself

Mick
April 30, 2017
Gavin April 30, 2017
Yeah. ABS is okay. It's a bit smelly.
G
Tim April 30, 2017
One of them puts off cyanide?
T
Gavin April 30, 2017
PVC.
G
Tim April 30, 2017
PVC, yeah okay.
T
M
Mick April 30, 2017
Is it chlorine gas?
Gavin April 30, 2017
Yes, it's chlorine gas.
G
Tim April 30, 2017
Chlorine gas.
T
M
Mick April 30, 2017
Polyvinyl chloride - Chlorine gas.
Gavin April 30, 2017
I'll show you how to test that if you got a sec.
G
Mick
April 30, 2017
Tim April 30, 2017
Oh, okay.
T
Gavin April 30, 2017
This is known as the Blowtorch Test. If you've got a bit of plastic, and you're not sure whether it's laser safe, this is a quick and dirty test you can do to see whether it contains chlorine. If it doesn't contain chlorine that doesn't mean it will cut well, but it just means it won't kill you in one specific way. So, it's a good first step.
G
Gavin April 30, 2017
Ordinary bit of copper here, and a bog standard blowtorch. Just heating this up to red hot just to make sure there's no plastic left on. We'll dab that in our test piece, and some of the plastic ends up stuck on the tip. Now what I'm gonna do is heat it back up again. If there's chlorine present, you'll see a green flame come up there.
G
Gavin April 30, 2017
That definitely contains chlorine, so-
G
Tim April 30, 2017
No laser cutting that.
T
Gavin April 30, 2017
No laser cutting that.
G
Tim April 30, 2017
Or burning of any kind really?
T
Gavin April 30, 2017
Yes.
G
Tim April 30, 2017
That controls the laser cutters?
T
Gavin April 30, 2017
That's it.
G
Tim April 30, 2017
Alright.
T

Making boxes

Mick
April 30, 2017
Gavin April 30, 2017
You can see these are my little Sudoku test pieces. I was playing around with tiles of different sizes before. I want to make a Sudoku where you put the tiles in places and tangibly play around with it, but I wasn't sure how large the slot should be compared to the tile itself. After playing around, I decided about a 20 mm tile is kind of easy to grip and play with and manipulate, and have a stack of them and not take up too much space. 21 mm pole is easy to get in and out. 3 mm clearance is enough.
G
Gavin April 30, 2017
Then after playing around with it, I'm actually like, '3 mm is ridiculously large.' 1 mm of clearance is perfectly fine.
G
Tim April 30, 2017
You design it on a special app?
T
Mick
April 30, 2017
Gavin April 30, 2017
This is Inkscape, which is open source. It's like Adobe Illustrator or something, but it's open source. We output in DXF format and then take it to the machine and import it there. There's a series of rain dance steps that we do. If you do all the steps in the rain dance, then generally your file is intact and you can cut stuff.
G
M
Mick April 30, 2017
That's a lot of fun.
Someone April 30, 2017
The cool thing about Inkscape though is it actually has a plugin which allows you to do boxes on the fly very quickly, square boxes with partitions, whatever.
S
Tim April 30, 2017
Oh, so the software actually allows you to-
T
Gavin April 30, 2017
Generates the, yeah. Say I want a box that's this wide, this deep, this high-
G
Tim April 30, 2017
It'll make it, right?
T
Gavin April 30, 2017
You can say, 'My material is this thickness,' and it says, 'Would you want that to be your inside or outside dimensions?' Yeah, it makes it ridiculously easy.
G
Mick
April 30, 2017
M
Mick April 30, 2017
That is so cool.
Gavin April 30, 2017
All you do to make the box is to just customize it and add the bits that you want. In this case, I added a nice level cutout, so I've got the-
G
Tim April 30, 2017
It's a cool box.
T
M
Mick April 30, 2017
Funny you should say that, but carpentry is all about how to make a box.
Gavin April 30, 2017
Yes.
G
M
Mick April 30, 2017
That's all it is.
Gavin April 30, 2017
Totally.
G

Carpentry

Mick
April 30, 2017
Someone April 30, 2017
That's Gavin's current obsession.
S
Gavin April 30, 2017
Yes, this is my current obsession. This is where I got up to recently.
G
M
Mick April 30, 2017
Nice.
Gavin April 30, 2017
I'm happy with that.
G
M
Mick April 30, 2017
Look at that.
Tim April 30, 2017
What's that? That's a dovetail or something?
T
Gavin April 30, 2017
Yeah, that's how I got up to it.
G
Tim April 30, 2017
Look how tight that is. What's the name of this joint here?
T
Gavin April 30, 2017
That's a box joint. Because the laser cuts vertically down, which is always in a straight line, you can't really do dove tails in the same way.
G
M
Mick April 30, 2017
Have you seen biscuits, biscuit joints?

Getting in trouble at school

Mick
April 30, 2017
Tim April 30, 2017
My first encounter with biscuits was with Gavin in high school where we-
T
M
Mick April 30, 2017
Ha ha. Oh no! Is this another story is it?
Tim April 30, 2017
Someone else had joined two bits of wood with a biscuit, and we both determined that we would snap the biscuit. We put both our weight on it and it snapped outside of the biscuit. The deputy principle came and found us, and he told everyone that two bright sparks, I still remember the phrase he used, 'Two bright sparks decided to break this, and they couldn't break the biscuit. They broke it just on the outside to show you how strong it was.'
T
Tim April 30, 2017
We were embarrassed to, 'See, we demonstrated something.'
T
Gavin April 30, 2017
I filtered that out, but I remember that.
G
Tim April 30, 2017
Yeah?
T
Gavin April 30, 2017
Yeah.
G

CNC machines

Mick
April 30, 2017
Gavin April 30, 2017
This is our Xcarve. This is a CNC machine. If you program in on a laptop what you want it to do, it'll go and cut it for you. Also, the secret to having any tool in a communal environment is you need to have all the accessories and all tools there and self-enforcing, so that people know they go back in that spot. If it's not obvious, it'll end up everywhere and you'll never have the machine working again.
G
Tim April 30, 2017
The spot has to be obvious.
T
M
Mick April 30, 2017
Something resting on the keyboard.
Tim April 30, 2017
The old dust in the keyboard. Press F3 to remove dust.
T
Gavin April 30, 2017
That's it.
G
Tim April 30, 2017
Do you have any samples of CNC material?
T
Mick
April 30, 2017
Gavin April 30, 2017
That's the circuit board.
G
Tim April 30, 2017
Oh, good old circuit board. Of course, the middle here means you can't laser cut it, so you'd use CNC.
T
Gavin April 30, 2017
What this is doing is having a v cutter that comes down and just gouges out the groove. Technically you're carving out the Voroni Diagram of the circuit.
G
Tim April 30, 2017
So the opposite?
T
Gavin April 30, 2017
The opposite, yeah. Normally you'd use three tools. You'd use v cutter to cut the actual traces out. You'd use a drill hole to put all the holes for your IC's and internal stuff. Then you'd use a router bit to cut the edge free and make a small circuit board. It's pretty convenient. You can do it in an hour or so, or less.
G
Gavin April 30, 2017
There's a sweet spot of like, 'Do I just solder up on protoboard?' Then if it's a little more complex, maybe I'll make a custom circuit board on CNC. Then if it's a little bit more complex, I'm gonna send it away to China and have it fabbed for ten dollars, but it's gonna take me three weeks or whatever. There's sweet spots where this machine becomes really useful.
G
Gavin April 30, 2017
You can draw it in Eagle or standard CAD stuff. There's a script for Eagle called PCB Gcode, and that will take your file and generate the motions of the cutter. To do that you can tell it how wide isolations you want and how deep.
G

Hacking vending machines

Mick
April 30, 2017
Tim April 30, 2017
Zero dollars from every purchase goes to special children.
T
M
Mick April 30, 2017
Have you internet connected it?
Gavin April 30, 2017
One of members is working on that actually.
G
M
Mick April 30, 2017
Alright good, excellent. I'd be surprised if it wasn't.
Gavin April 30, 2017
That's a big topic of discussion.
G

Check out Part 2 of this transcript and video.

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About Mick Hellstrom
Hacker. Maker. YouTuber.

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