K40 laser cutter 🚧

Your new laser cutter may attempt to kill you in a number of way… - The k40 laser resource / r/lasercutting / K40laser.se / Laser Gods

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  1. Never fire the laser with the cover open.
  2. Never operate the laser without the water pump functioning, and proper ventilation.
  3. Never look at the laser directly. Reflections from the laser can permanently blind you. Even reflections off of a wall or material being cut can be incredibly dangerous.
  4. Never leave the operating laser unattended.
  5. Have a fire extinguisher on hand, and be able to kill power to the unit immediately in case of emergency.
    • Have a properly maintained CO2 fire extinguisher close at hand
    • Keep a spray bottle of water to hand to supress small flames that may char your material (and which might grow into a major fire)

During operation the tube also produces non-laser light in other frequencies including ultra-violet which can shine out from the tube in many directions and also reflect off the laser mirrors.

Hardware

Fred Gift

A 3020 model

the beast

CO2 Laser

high voltage - [Approx 20kV arc are powering the laser]

Before doing anything, remove all power cords and let the machine sit at least 30min before even thinking about touching something close to the power supply.

laser CO2

Customisation

Analog Control

Buttons are just a digital version of the potentiometer, so it works good. Easy to set the power. But you need a mA-meter to keep a eye on power output. 100% on the panel is 140-150% on the tube – and you will kill it quick.

In order not to shorten the life of your laser you need to keep the current below c. 15mA (for A 30-35W tube).

analog meter

schema

new panel

see also

Cooling

The k40’s laser tube is liquid-cooled. Never operate the laser, even for an instant, without active liquid cooling.

It is important that you keep your laser tube below 25°C during use (generally recommended between 15°C and 20°C),

The water will gradually warm up as the laser is operated. When it starts to get warm, either stop using it for a while, or cycle in cooler water.

How much cooling is enough?

  • Enough cooling to keep your cooling water bucket under 20°C and enough pumping to keep about one liter of water per minute flowing through your laser tube.
  • Avoid frozen water => Doing this flirts with causing thermal expansion/contraction cracks in the glass.
  • The K40 has to get rid of 160W to 200W of waste heat
  • Move about liter of water per minute through the K40 tube, and cool it to between 18°C and 20°C in the cooling tank.
  • Always make sure your return hose end goes under the water level in the coolant bucket. This creates a siphon effect which makes your pump work much better.
  • Keep in mind that you have to cool the water in your bucket, too, as well as running the water through the laser. Use the largest practical cooling water tank. Most people seem to use 18 to 20 litters and that works well.

bucket

It is also essential that the water you use is non-conducting. The easiest way to achieve this is to use deionised water, (we get ours in 5 litre bottles from our local LIDL store at c. 0.70€ per bottle)

Make sure that the outlet of the water cooling tube (the circled bit) is pointing up to let the air escape (raise the machine):

air escape

Thermal Sensor

  • Connecting the temperature sensor to the M3 nano board?
    • The two button cells in the thermometer module which came with my K40 are in parallel. It turns on with just one cell. So, it’s 1.5V.
    • Anyhow, some quick googling suggests an LR44 cell has a capacity of 150 mAh. So, 300 mAh for two of them. One AAA cell got 1200 mAh (4x) and an AA cell about twice as much (8x). Either one would last for something like 8+ years.

Tube

tube

Software

With a K40, you can set the power of the laser from the front panel, but the controller board is only able to turn the laser on and off.

MeerK40t

A replacement for both the software supplied with the K40 and the K40 Whisperer software. It is designed specifically to drive the popular K40 class of (chinese built) laser machines which have an Lhymicro controller board. In the meantime Meerk40 is able to drive other controller boards (e.g. Gerbil based boards, Fibre Lasers and others), and aspires to support even more in the future. - wiki

UI

OpenBuilds

K40 Whisperer

A free open source program alternative to the Laser Draw (LaserDRW) program that comes with the cheap Chinese laser cutters available on E-Bay and Amazon. K40 Whisperer reads SVG and DXF files, interprets the data and sends commands to the K40 controller to move the laser head and control the laser accordingly. K40 Whisperer does not require a USB key (dongle) to function.

VisiCut

use LibLaserCut, a platform independant library for Lasercutters.

Tutos

Source

see also

Written on November 30, 2020, Last update on December 6, 2024
cnc laser laser-cut in-progress