• gredpath

Getting started with CO2 laser cutting

About this time last year we decided that it would be useful to have our own laser cutter, clients ask us to make prototypes and test fixtures, and in my spare time I am helping my brother make a scale model of a local junction in the 1950s.

My first port of call for research was of course youtube videos, and I came across an Australian site MW laser, and if you are considering a purchase it is a good starting point.

So my first plan was to purchase a 80W machine from a site in Germany, and purchase the upgrades recommended by Matt, namely an upgraded controller, inline LED position indicator, autofocus assembly, and an air blower for the cutting head. I purchased these from Cloudray Laser, along with a proper industral chiller.

Unfortunately the German supplier wouldn't ship to Northern Ireland, so decided to order direct from China using Alibaba.

I chose to use Shenhuilaser because they responded promptly and were willing to modify the machine to my requirements. They offered a choice of colours and fitted the upgraded controller, saving me from having to cut the metal work to fit, a 100 Watt laser, autofocus, included both a blade cutting deck and a honeycomb deck. As an extra I also purchased a rotary drive for engraving on circular objects at the same time.

The laser was built in under a week, but it took almost 7 weeks to delivered, and I had to pay import costs, (as I expected)

After I was helped by my local farmer with this fork lift to offload the laser from the flat bed lorry, and drive it up the narrow lane on which I live, the laser sat over Christmas unloved and untested, apart from changing some of the bolts to stainless steel allen bolts as the the originals were rusting.

Then the lock down arrived and we decided to design and build Rapidly manufactured Ventilator System (RMVS) and we need the laser to help make the prototype, so it was time to set up and test the Laser.

After filling the chiller with dilute glycol, and on connecting the laser to the Chiller, the chiller just sat beeping loudly, until I realised that it had 2 channels, and when I fitted a short loop of tubing on the second circuit so that it saw flow, it worked perfectly.

I then focussed the mirrors on the laser, a relatively simple, but essential process.

I then pressed autofocus on the controller, and watched as the cutter bed moved down, and down and down, and then a grinding noise ensued. I quickly turned the machine off and whatsapp'ed John Lui at the manufacturer (who never seems to sleep). The solution was to unbolt the bed, reverse the setting on the controller and then Autofocus works.

I then placed some 3mm perspex on the bed, and tried to cut a case for my son, and for a 100W laser it seemed awfully slow. The laser was drawing approx. 6mA on full power , always get an ammeter fitted, it is very useful. So it was back to Whatsapp and John. After a lengthy diagnositic process, it was agreed the laser was faulty, so they would send out a new one, but only I after I set photographic evidence that the Laser had been smashed.

nearly 7 days later a new laser arrived, and I fitted it but to my dismay behaved exactly the same as the one which was in pieces on my workshop floor.

After further diagnosis, it turned out to be a faulty 1 dollar potentiometer, which we bypassed, and lo and behold the ammeter slowed 18mA on 90% power.

I then added a Chinese extraction system, which makes a good pass of filtering the noxious gases produced when cutting acrylic.

The laser is now working perfectly, but there is still a few things I would like to do, add limit switches on the z axis, and connect up a camera for remote monitoring.

In future posts I will talk about building and commissioning our 1m x 1m Workbee CNC.

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