Laser Cutter Notes

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There is a serious risk of getting blind when working with lasers. Always wear appropriate laser goggles!
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Laser Cutter

Release status: unknown

turnkey or DIY laser-cutter toolheads
CAD Models
External Link

RepRap Research/Writeups

See the Laser Cutter Working Group@forum.reprap for discussion.


See Laser_Cutter/Background

Cost Estimate

- comercial 'naked' diodelaser with [email protected] and 0.1mm atached glass fibre: ~230 Euros (in quantities above 5 pcs).

- turnkey-system with [email protected], a visible red pilot-laser and jack for the glass fibre: ~1000 Euros (in quantities above 5 pcs).


Laser Light Sources

- Different laserdiodes:

1 watt pigtail diode laser with optical head (focus ~50 microns):

1Watt Diode-laser with focussing head all laserdiodes

- IR-diodes internal assembly:

opened 5Watt-, 9Watt- and 25Watt-diodelasers

Internal Assembly 5Watt- and 9Watt-Diodelasers Internal Assembly 25Watt-Diodelaser

- Complete modules:

5 watt pigtail diode laser with 4xLM317-driver atached and lighting on a beam-indicator without optics:

5Watt-Diodelaser with 4xLM317-driver

complete 5 watt pigtail diode laser-module with 4x or 5x LM317-driver, MOSFET, microcontroller, armored tube and an optic head - prototype on the left, V2 on the right:

5Watt-Prototype1 5Watt-Prototype1

- Applications:

'real blue' 445nm-diode with 1Ampere current and roughly 1Watt output power. - left = focussed beam, middle = burning without filter, right = UV-filterplate:

445nm von Vorne kl.jpg 445nm - 1Watt ohne Filter.jpg 445nm - 1Watt mit Filter.jpg

1. Laser-source:

- CO2-lasertube ... sealed (RF) or 'naked' glass-tube

- diode-laser ... best with atached glass fibre (=pigtailed)

- ...

beam-feeding optics

2. beam-feeding optics:

- CO2: - mirrors

- diode-lasers: - glass fibre and/or lenses and mirrors

- ...

focussing optics

3. focussing optics:

- CO2: - Germanium- or ZnSe-lens for CO2-laser ... concave mirror is possible too

- diode-lasers: - 'normal' optical lenses

- ...

3.1. Embedding a Pilotlaser as guide or beam-indicator:


power source and output-power control

Main article: Bright Light Circuit

4. power-source:

- CO2: - mostly monolithic PS, good when below 40 Volts for RF-CO2-lasers, 'naked' and DIY-CO2-tubes need above 1000 Volts

- diode-lasers: - constant-current-driver (e.g. more LM317 in parallel)

LM317 parallel

- a 5xLM317-driver with switching MOSFET:


- modified driver with 2xLM317 with 1Ampere each and 3xLM338 with 2, 2, and 2.6 Ampere for free combinations from 1 to 8.6 Amps:


- ...

5. output-power controller:

- CO2: - embedded in RF-CO2-lasers - mostly TTL-input capable of switching the laser output with some ten kHz

- diode-lasers: - current-modulation and/or PWM-switching for diode-lasers until some kHz

- diode-lasers: - AOM (AcoustoOpticalModulator) switching until some hundred kHz

- ...

6. controlling the output-power:

- generating geometrically defined pulses from the XY-clocks of the CNC-controller:


- calculating the needed power relative to moving speed of the laser focus

- ...

air jet

While not strictly necessary, many laser cutters have a blow a jet of air at the point being cut. Is it better to use (a) relatively cool room-temperature air, or (b) hot air?


CO2-laser cutting acrylic:

CO2-cutting encoder-disc


- cutting:

VDX-RepLas2.jpg Hase celtic.jpg

- brazing / hard soldering:

hard soldered gold-paste


- similar to an inkjet-printer, where many nozzles ar aligned in an array to print many dot-lines synchrone, you can align multiple diode-lasers in an array to process parallel lines simultanuous.

With falling prices of laserdiodes it should be possible to build a head with 8 hating/burning spots in a line with a distance of 5mm (diameter of typical small collimator-lenses) between them (or less, when arranging in a zigzag-array) in a DIY-range below 1000 Euros.

With a software separating the processing data for the single lasers you can speedup the time per sheet along with the count of lasers ...



Nitrogen tank or clean dry compressed air.

Cutting speed

The primary factors affecting cutting speed v are laser beam power P, the material being cut and its thickness h. The dependence of v on P and h is approximately proportional, i.e. severance energy P/hv is approximately constant for a fixed material and cutting process. Severance energy can be thought of as the laser beam energy needed to make a cut of 1 mm2 area (i.e. 1 mm cut length × 1 mm thickness). Note that 1 Watt power is 1 Joule of energy per second, so a 36 W laser should cut 3 mm acrylic sheet (P/hv=1.2 J/mm2) at the speed of about v = P/h / (P/hv) = (36 W) / (3 mm) / (1.2 J/mm2)=10 mm/sec.

Severance energies (10.6μm CO2 laser) from [1], p. 159
Material Typical severance

energy (J/mm2)

Min-max severance

energies (J/mm2)

Cardboard 0.5 0.2–1.7
Acrylic sheet 1.2 1–3
Plyboard 31 20–65

Health and Safety

Laser-goggles are essential when working with lasers!

This laser-goggles have blocking ranges of 700-1100nm (for diode-lasers and NdYAG) and 10600nm (for CO2-lasers)


Fumes and vapours are extremely toxic and carcinogenic!

You can absorb the toxic vapours by exhausting the fuming area through a charcoalabsorber - e.g. the disc-shaped filters often used in deep fat fryers, or filtering units for soldering ...

Common laser-fume absorbers are really big parts but much more capable than absorbers for soldering vapours:


When using inert (and other) gases in an enclosed room you have to test for leakage or monitor the oxygen-concentration in the room.

Similar projects

There are some similar projects to create an Open Source laser cutter, some of them already shipping devices:

External links

  • Steen, Mazumder. Laser Material Processing, 4th ed, Springer-Verlag, 2010.
  • Retrieved from ""