Replacing Crap Water Flow Sensor

CO2 lasers are water cooled.  If the cool water stops flowing the laser tube will die.  That’s all there is to it.   To prevent the laser from firing when there is no water flowing most lasers incorporate some kind of switch that chops power to the laser circuit when no water flow is detected.  We need a good quality water flow sensor.

My new 50 watt laser has such a switch but forums are FULL of reports of failures and especially the fact that the switch will begin leaking.

Crap Water Flow Sensor

While this may not be the exact switch, it is darn similar. There is no outlet port on these things.  The switch is hooked to a Y valve.  One side is inlet, the other is inlet flow and the top opening goes to the switch.

In my mind that doesn’t really measure “Flow”, rather the fact there is water pressure present on the switch.

Let’s say you had a fancy water chiller and the chiller was setting up higher than the laser.   Gravity and shit, would put head pressure on the switch allowing it to fire EVEN WHEN THERE WAS NO FLOW.  I’ve seen several reports of this already.  That renders this switch USELESS.  And again, even if it is working right I’ve also read MANY reports of “this failed after a month” or “this started leaking right away”.

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There seems to be an epidemic in LaserLand™ where people buy really expensive, and large CO2 lasers for their home business and experience component failures and become frustrated with the re-seller for selling crap.  I’m sorry to keep harping on this but it’s like watching a car crash, paint dry, and grass grow all at the same time.

These lasers are so capable, and so fun and provide the ability to make the owner some money.  But they are not without issues.

Let’s be clear about these CO2 lasers.   They come from CHINA.  That is about all one really needs to know as it relates to product reliability.

The blue power supplies in these lasers = Crap that will fail

The Water Flow Sensors = Crap that will leak

The Air Assist pump is in a special category of crap = Crap that crap calls crap.

Look.  I dig laser etching and cutting.  It’s fun and its a great way to make continuous $20 bills.

But I spent a career in the US Navy and as a Gov’t Employee fixing equipment that costs a lot of money.  I’m an Electronics Tech Rep for DOD that supports the Navy and Marine Corps.   I know how to fix broken things and I can smell a crap component a 100 yards away with the wind blowing away from me.

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I’m not sure what is going on in the world of Home/Small Business Lasers.  Just a couple of months ago they were relatively easy to get, and now suddenly they are nearly unobtanium.  Kind of like last year when Coronavirus hit and you couldn’t buy a bicycle to save your life.  Everyone all at once decided to buy bicycles.  So it goes with the larger CO2 lasers right now.  I think a lot of folks have decided to do the side hustle thing and laser engraving from home is a viable and sometimes profitable endeavor.  I refer to my lasers as “$20 bill vacuums”.

I belong to several forums regarding lasers, and software and they are filled with first time users who have no idea at all what they are doing.  And, let’s be clear……..there is nothing wrong with that.  That’s what forums are for………helping each other and learning.  When I bought my first laser I had no idea what I was doing either.

If you buy a Chinese Laser …… YOU ARE ESSENTIALLY ON YOUR OWN.  You might get some limited support, but you better be able to be self-sufficient.

Laser engravers and cutters are pretty complex systems that require at least some technical skill.  Larger CO2 lasers consist of a few different subsystems such as:

• High powered laser
• Precise Optical Alignment system with mirrors
• Water cooling system
• Air Assist system
• Electronics – power supply, controller, switches
• Machine settings in firmware and software
• G-Code – you may just have to pass some G-Code settings to your machine manually

And I’m really oversimplifying things here.    Once you ship a machine half way around the world, it may or may not have problems upon arrival.  Your choices are then:

• Send the Machine back and wait for the reseller to fix it or provide another machine, which by the way is unobtanium at the moment.
• Deal with the problem, whatever it is.

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OMTech Preenex K40

I cut my teeth in the CO2 laser world the same way most other people do……..with a Chinese eBay K40 laser.  Hobbyists love them because they cost next to nothing (about $350 and up) and they are pretty powerful devices.

That being said they are Chinese, are cheaply built, with not the highest quality parts.

Much of the allure here is in the hacker installing upgrades and building it into a much more capable machine.   At the end of the day though the machine has some serious limitations.  Here are some that got my attention:

• Very small work area – 12 x 8 at best.
• Doesn’t interpret g-code which means you can’t use some of the better software out there for it (i.e. Lightburn).  You must upgrade the controller card.
• Upgrading the controller card renders the control panel basically useless.  All controls are now software controlled.
• The z axis (up and down) is fixed.  The machines are basically configured to cut or etch 3mm materials.  There are things that can be done to provide some z lift capability but I don’t think it is worth the time, effort, or money to do.
• The machine I own isn’t really a 40 watt.  Probably more like 30.  It is a “Mini” with a shorter tube.  Essentially, the longer the tube, the more powerful it is.

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Laser + Poodle

Got my new OMTech 50 Watt Laser today.

I also own 2 Ortur Laser Master 2 – 20 watt diode lasers and a K40 Laser also from OMTech.

After tons of research I have decided that your best bet on buying a Chinese laser system is to buy it from OMTech.  Your mileage may vary and in fact some people’s mileage DOES vary.   That has NOT been my experience.

The K40 I bought from them and now this 50 watt machine………JUST WORKS. Right out of the box. No damage.  Not one scratch.  Not one dent.   The machines both came aligned right out of the box.

Shipping was fast,  the price was competitive albeit you could save a few dollars by buying from other dealers.  I don’t recommend it unless you are prepared to take a machine out of the box and spend time aligning it and making it right.  If you posses those skills then by all means…….save some money.  Me. I posses those skills but it isn’t worth $50 or $100 to me to do all that quality assurance and work.

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Well the unthinkable happened.  My K40 fouled up.  I’m not sure what happened but my working theory is that my accidentally dropping the laser tube door really hard caused a retainer to fall out, which in turn released spring tension on mirror #1.

Retainer and Spring on Mirror Assembly

Laser beams were firing all over the place.   The dreaded realization came to me that I had to do a mirror alignment on the K40.

Okay, I removed the #1 mirror and reinstalled the spring and retainer and remounted it.

To my surprise I got it back real close to where it was just by using a sharpie to locate orientation.

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Here is a common occurrence on laser forums and groups.  Post a picture of something cool and within about 4.1643 seconds someone will ask, “What Are Your Settings?”

Unquestionably a valid thought from someone who saw what you did and seeks to emulate it.   And most of us want to help answer that question.  We really do.

But there are a LOT of variables involved in a burn.  My settings could produce great results but could start a fire at your house.  Here’s an example worth noting that happened to me just today.  I have a K40 laser and have settings saved for Baltic Birch Plywood.  I bought a new lens and cleaned all the mirrors and ran a job.  That which was supposed to etch my plywood burned slap through it.   New lens was a heck of an improvement, I guess.

Here are some variables:

1. The type of wood or material you are burning on.  I may have 3 layer Baltic Birch and you may have 7 layer.  My plywood may have glue made by virgins with harps and your glue may have been produced by the Communist Chinese.
2. The direction of the grain.  Lasers etch and burn better in some directions than others.
3. Air Assist.  If I have an air assist and you don’t then my settings may not be relevant to your setup.
4. Focus.  I may be focused using a microscope and you may have no idea of what the actual state of your focus is.
5. Temperature.  If using a CO2 laser, cooler water temps can produce more efficient burns.
6. Lens cleanliness.  If my lens is clean and yours is dirty my settings are useless to you.
7. Diode intensity.  I may have a brand new diode laser and you may have been burning at 100% power for 6 months.  Diode lasers wear out.  CO2 in a laser tube depletes.  Also you might have a 4.5 watt output and I might have a 5.5 watt output laser.

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I have an Ortur Laser Master 2.

I have determined that it is now an essential piece of equipment that must have minimum downtime.

That lead me to purchase a new Laser module and a new Motherboard.  These two items and associated parts are the lions share of the machine.

Ortur seems to be really trying to be open about issues and also seems to have pretty great customer service.  And they’ve done something that I think is remarkable.  They have created a Product Advisories web page.

One of these advisories is about a batch of defective motherboards.  My Ortur Laser Master 2 is working perfectly but I was concerned about my spare board that I just received.  They specifically said if your board failed some previous tests to look for the markings OLM-MAX-V10

Ortur Product Advisory

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OMTech K40 Laser

The Chinese laser often referred to as the K40 (40 watt) is an entry level CO2 laser at a magnificent price point.  They can be had for around $350 to $450 dollars depending on where you get them and how you get them configured.

I got mine from a place called OMTech for about $420.  It is also were well configured and has many upgrades already included.

Right out of the chute these things engrave and cut well although the 40 in K40 seems to be a bit of a gimmick.  A lot of the included laser tubes are actually 30 to 35 watts.  It’s really not enough to kick a fuss up over.   It’s just the way it is.  So that kicks off the upgrade discussion.  You can buy larger and more powerful laser tubes.

Once you use one of these things a bit and learn your way around one you’re going to want to upgrade some things.  While they do indeed come at a magnificent price point the old adage applies.  You get what you pay for.

Let’s go over a quick list of things you are going to want to upgrade.

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I have an Ortur Laser Master 2.  Very, very nice low powered diode laser rig capable of making some great craft items.  I also have a larger K40 Laser however sometimes it is like trying to use a sledgehammer to drive a nail.   The Ortur has great flexibility because of how open it is and the fact it can be set on any surface or pass materials through it or raise it way up high.

Make no mistake though, the Ortur Laser Master 2 is NOT a production machine.  It was not meant to be run full power, all day, every day.  It is a hobby device for hobbyists.  If you push it beyond that…….well…….good on ya.

There do seem to be some issues with the laser though.  Some users report 100% laser power 100% of the time and frequent disconnects, not to mention the fact they can’t connect at all to the computer.  So there are issues going in……………

It CAN be a production device though with some pre-planning and regular maintenance.

Let me tell a somewhat unrelated story.  I like solar power and solar powered generators such as the company Jackery makes.  Every time they release a new one about 50 clowns on the internet say “This is bullshit. This will only run a refrigerator for 14 hours and my heart transplant kit needs to run for 15 hours.”

My response to that is always this:  “So buy two of them!”

Do you see where I am going with this?

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