50 Watt CO2 Laser

During the last years, the Co2 Laser has become an indispensable tool for many areas of my hobby activities. Compared to the 3D printer, it provides faster, cheaper prototype models and compared to the CNC milling machine saves the sometimes very complex workpiece clamping and tooling costs. Surely he can not completely replace these devices - but whenever possible I construct laserable solutions today. Due to the variety of workable materials you can let your creativity run wild with the laser cutter. With me he cuts and engraves paper, cardboard, MDF, Kraftplex, plywood, foils or Plexiglas up to 6 mm thickness and engraves glass, ceramics, enamel, stones and tiles. A selection of my laser projects can be found at Laser-Cut.

Setup and first cuts in 2015

Since I knew that the China Lasers are delivered in solid (large) wooden crates and I wanted to have no trouble with the shipping company at home, I had it send it to my place of work where we have forklifts to do the heavy work. Unpacked, it just fit into my small BMW 3 Series.
Shenhui G350 CO2 Laser im Kofferraum
Shenhui G350 CO2 Laser in the trunk
Even from the operation of my CNC milling machines, I knew that such CNC-controlled X-Y machines could easily put a light table into uncomfortable vibrations. In my shop, I had already built a solid table for the laser from shelf profiles and a strong OSB panel. The orange sewage pipe leads the exhaust air through a short distance into the open air.
Shenhui G350 CO2 Laser im Kofferraum
Sewage pipe for the exhaust air
In order to be able to place the laser as close to the wall as possible, I removed the blue fan located in the rear wall of the laser and integrated it directly into the exhaust pipe. After some searching, I found suitable adapters in the hardware store. The three-phase fan is powered by the supplied capacitor in single phase. Here is the test setup.
Absaugung für Shenhui G350 CO2 Laser
Test setup of the exhaust fan
The electrical system of the Shenhui 350 laser is quite well structured. I have just replaced the usual 2-pin American 110 volt plugs with IEC connectors. This I installed recessed in an aluminum plate. Since there is no RCCB in the basement circuit, but the laser works with a water cooling, I have installed for safety an earth-leakage trip in the device. The box above the earth-leakage trip is the power supply of the CO2 laser.
Umrüstung mit Kaltgerätestecker und FI-Schutzschalter
Powersupply setup with earth-leakage trip and IEC connectors
The laser is equipped with an easy-to-read color display. The menu navigation is logical and simple. From the computer you can reach the laser via USB or LAN cable. But you can also print directly from an USB stick or from the integrated memory of the laser control. Interesting also the test seal from China with the test date 30.10.2014. The device was delivered to me on the 6th of January 2015 from the merchant's English Ebay warehouse.
Shenhui G350 CO2 Laser mit Farbdisplay
Shenhui G350 CO2 Laser mit Farbdisplay
The mirror head of the laser has a travel distance of 300 x 500 mm as factory default. In the firmware, I could expand it to 305 x 510 mm without any trouble while the large interior of the laser can easily hold raw material of about 360 x 570 mm. You never should place the raw material directly on the height-adjustable, slotted table top, since the combustion residues can not escape freely from the material. A fast soiling of the lifting table and strong traces of smoke on the underside of the material would be the result.
Shenhui G350 CO2 Laser – Arbeitsraum
Shenhui G350 CO2 Laser – workspace
As a cutting pad I use a honeycomb sheet, which is used for sandwitch structures in aircraft construction and racing. The combustion gases can thereby subtract well. The sheets are delivered in folded form - see below in the picture. The "visible" honeycomb thickness for the laser beam is only 0.05 mm. Consequently, only very little combustion residue can deposit on this small contact surface to the workpiece. The formation of traces of smoke on the underside of the workpiece is kept to a minimum.
Shenhui G350 CO2 Laser mit Wabenrost als Werkstückauflage
Shenhui G350 CO2 Laser with honeycomb workpiece tray
For the water cooling of the CO2 laser, a pond pump was included in the delivery. In the first tests I used normal tap water and a 5 Euro plastic trash can with lid as a cooling water tank and sunk in the pond pump. If you operate this setup for more than 60 minutes, the water heats up so much that even in my cool old building basement there is a drop in laser power. The water chiller shown here, must only be cooled py the PC fan in the summer.
Wasserkühlung
Water chiller for my 50 Watt CO2 laser cutter
In order to avoid possible algae formation and as frost protection, I later added antifreeze to the tap water. When my friend heard about my new laser, I was allowed to cut a few model train houses out of cardboard. The good fit of the parts is very impressive. In the supplied RDWorks cutting software, the beam width is added to the parts boundarys automaticly. By this you can archieve very accurate part dimensions.
Modellbahnhaus aus Pappe
Model train house made of cardboard
For the PCB production for my Wood-Walker robotic project, some SMD solder paste stencils made of foil and paper have already been created on my laser. This image shows the footprint for an ATMEL 32U4 processor with 0.8 mm connection distance. The slots for the solder paste are thus about 0.45 mm wide, the webs in between 0.35 mm. In the middle you can see the pattern for a motor driver with 0.6 mm pitch, which gives slits of 0.3 mm.
SMD Lötpastenschablone
SMD solder paste stencils made of foil

This video shows the cutting process in photo paper. If you only need the template for 1 or 2 blanks, plastic-coated photo paper will do the job! And of course I have already cut and labeled many parts for my Wood-Walker robot made of 4 mm thick beech plywood.

Wood-Walker Robot
Wood-Walker Robot made from beech plywood

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