DIY CO2 laser cutter thin form factor

Design and or Build your Own Laser in part or Whole
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Nicolas Raynaud
Posts: 6
Joined: Mon May 17, 2021 8:01 am
Location: Grenoble
Country: France
Laser Machine Make or Type: None
Laser Power: 0
Laser Bed Size: 0x0
Home Position: TL
Control Software: LIGHTBURN
RDWorks Version: 0
Ruida Controller: Other
Windows Version: mac

DIY CO2 laser cutter thin form factor

Post by Nicolas Raynaud »

Hi all, I am starting a new project, that would be a CO2 laser cutter but thin enough to be used as table/desk when not running. I just checked a secretary, I think I can get away with 15/20cm thickness while still being able to use the thing as a sitting table.

I am thinking of going for a 1250 x 80mm Reci tube and the associated power supply. For the control I'm thinking of using a grbl-LPC board, because I like to be able to read the code source and the communication protocols of my gear (unless I get convinced otherwise).I am envisioning a 1220 x 650mm envelope, which is a little bit bigger than a standard sheet good size in my neck of the woods (120x60 cm), but I think with all the space around the cutting area we reach a comfortable bench table size of 150x80cm. For access when stuff is on top, I'm thinking of having a flapping door in the apron as well as the usual top door access.

I think the highest thing inside the machine has to be the laser beam (to pass over the rails) which would make the tube axis quite high, I could either just leave it there and have a table with a bump at the back, or lower it and add a mirror wrt. the usual configuration and have a vertical beam at the second segment. I think the second "thick" thing is the focal length, which brings me to a question: why are lenses so far from the mirror in the Z axis in a lot of designs? I feel like it's lost space.

I have not yet thought out the Z axis, I want a motorized system that would have to be moved up to make space for my knees when used as a table.

The budget might be a bit spicy, but I am at peace with that. I enclose a first draft of the kinematics and optical design.

What do you think of all those points? have you seen designs on the internet that go for flat that I should look for inspiration?

Image
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Rodney Edington
Posts: 91
Joined: Wed Feb 24, 2021 12:38 am
Location: Leavenworth Ks
Country: USA
Nickname: Rodney
Laser Machine Make or Type: K 40 Building a 22"X 38"
Laser Power: 60 watt
Laser Bed Size: 22"X38"
Home Position: TL
Control Software: RDWORKS
RDWorks Version: NA
Ruida Controller: RDC6445
Windows Version: 7

Re: DIY CO2 laser cutter thin form factor

Post by Rodney Edington »

Nicolas Raynaud wrote: Mon May 17, 2021 10:15 am For the control I'm thinking of using a grbl-LPC board, because I like to be able to read the code source and the communication protocols of my gear (unless I get convinced otherwise).

You will need a control that has "backlash compensation" to get any precision out of the machine.
I don't know that much about grbl (I looked at when I built my CNC router a few years ago and it didn't have it then).



Nicolas Raynaud wrote: Mon May 17, 2021 10:15 am why are lenses so far from the mirror in the Z axis in a lot of designs?


I think the main reason is that the beam needs to withstand the forces of a tight belt. I used 2040 extruded aluminum for my X and I have over .025" deflection in the center.
Rodney

Here is my build
viewtopic.php?f=159&t=5526&start=20
Nicolas Raynaud
Posts: 6
Joined: Mon May 17, 2021 8:01 am
Location: Grenoble
Country: France
Laser Machine Make or Type: None
Laser Power: 0
Laser Bed Size: 0x0
Home Position: TL
Control Software: LIGHTBURN
RDWorks Version: 0
Ruida Controller: Other
Windows Version: mac

Re: DIY CO2 laser cutter thin form factor

Post by Nicolas Raynaud »

Thank you, I had not though about that, I will be sure to address those points.
Nicolas Raynaud
Posts: 6
Joined: Mon May 17, 2021 8:01 am
Location: Grenoble
Country: France
Laser Machine Make or Type: None
Laser Power: 0
Laser Bed Size: 0x0
Home Position: TL
Control Software: LIGHTBURN
RDWorks Version: 0
Ruida Controller: Other
Windows Version: mac

Re: DIY CO2 laser cutter thin form factor

Post by Nicolas Raynaud »

this belt tension thing is on my mind, I intend to use a rectangular section beam, I guess I should try to put the compression plane inside the beam to limit the arcing.
something like that:
Image

it's not perfectly aligning the compression and the axis of symmetry, but at least all the walls of the beam would be in compression.
Rodney Edington
Posts: 91
Joined: Wed Feb 24, 2021 12:38 am
Location: Leavenworth Ks
Country: USA
Nickname: Rodney
Laser Machine Make or Type: K 40 Building a 22"X 38"
Laser Power: 60 watt
Laser Bed Size: 22"X38"
Home Position: TL
Control Software: RDWORKS
RDWorks Version: NA
Ruida Controller: RDC6445
Windows Version: 7

Re: DIY CO2 laser cutter thin form factor

Post by Rodney Edington »

That looks like it will work. I'm sure you'll be going through some trial and error as you build. The only way to find out is build it and see unless you have the software and know how it to figure deflection .
Rodney

Here is my build
viewtopic.php?f=159&t=5526&start=20
Nicolas Raynaud
Posts: 6
Joined: Mon May 17, 2021 8:01 am
Location: Grenoble
Country: France
Laser Machine Make or Type: None
Laser Power: 0
Laser Bed Size: 0x0
Home Position: TL
Control Software: LIGHTBURN
RDWorks Version: 0
Ruida Controller: Other
Windows Version: mac

Re: DIY CO2 laser cutter thin form factor

Post by Nicolas Raynaud »

I have a question regarding camera and optics, I see a lot of products with cameras onboards, but the inside of the machine gets coated with tar over time, how does that play with the optics?

Do people use shutters or do they simply clean them up a lot?
Rodney Edington
Posts: 91
Joined: Wed Feb 24, 2021 12:38 am
Location: Leavenworth Ks
Country: USA
Nickname: Rodney
Laser Machine Make or Type: K 40 Building a 22"X 38"
Laser Power: 60 watt
Laser Bed Size: 22"X38"
Home Position: TL
Control Software: RDWORKS
RDWorks Version: NA
Ruida Controller: RDC6445
Windows Version: 7

Re: DIY CO2 laser cutter thin form factor

Post by Rodney Edington »

Nicolas Raynaud wrote: Wed Jun 02, 2021 11:07 am but the inside of the machine gets coated with tar over time
If you have good ventilation to the rear, all the tar and other gunk should stay away from the camera (if it's mounted up front).
Rodney

Here is my build
viewtopic.php?f=159&t=5526&start=20
Nicolas Raynaud
Posts: 6
Joined: Mon May 17, 2021 8:01 am
Location: Grenoble
Country: France
Laser Machine Make or Type: None
Laser Power: 0
Laser Bed Size: 0x0
Home Position: TL
Control Software: LIGHTBURN
RDWorks Version: 0
Ruida Controller: Other
Windows Version: mac

Re: DIY CO2 laser cutter thin form factor

Post by Nicolas Raynaud »

thanks. I need to read on the topic of ventilation as I'd like to mitigate the noise.
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