Doing some very early testing of my new K40 and I heard some squeaking

Doing some very early testing of my new K40 and I heard some squeaking noise start a few seconds after I start a job that sounds suspiciously like my laser might be arcing.

Give it a listen and let me know what you think? Normal, or do I have another fun project on my hands?

My makes a similar noise when the laser is powered, at times. I’ve never seen any ill-effects so I’ve always just attributed it to the cheap high frequency power supply.

@Gee_Willikers well, that’s a relief. Thanks. With everything that can go sideways with these, especially when you’re still learning, I just wanted to get opinions and make sure.

What coolant are you guys using.

Even though they are cheap they should not squeal.

RV antifreeze and RO/DI water. Which have both actually wreaked havoc on my pump.

And now that you mention it that issue is ringing a bell…

Just purified water for me so far. But then it’s only been a couple weeks. Best long term option I’ve seen so far is just a capfull of bleach and regular water changes.

I suggest you change your coolant using distilled water and 6ml (.2oz) of Clorox and lets go from there.

If you have a conductivity meter I would be interested in the reading before and after changing it.

Anything else is highly suspect to be too conductive for healthy coolant.

Purified water and distilled water are widely different in terms of conductivity?

I have a multimeter. Would that do?

Also, since we’re on the subject, I’ve struggled to design a reservoir system that can be sealed to avoid contamination and evaporation. I was thinking of using a 5 gallon bucket with a standard lid and installing two bulkhead fittings with barb fittings for the in and out flows, but then the submersible pump power cord needs a way out and I’d rather not make anything permanent so I can swap parts etc which makes sealing that hole a challenge. So I thought next about using an external pump instead… and on down the rabbit hole I go.

@donkjr ​ what is your setup like?

@Bob_Buechler like many others I have a 5 gallon HD bucket (orange).
Nothing special I hang my water flow switch tubes and cables through a slot I cut in the lid. The cover is not air tight but keeps the BIG stuff out. My future plan is to a fix fittings to the lid.

Prior to this discovery I was using tap water and not doing anything about algae growth.

Pictures under: flow sensor in this post.

Thanks, @donkjr ​. I’d be curious to know the uS difference between purified water + 6mL of Clorox and distilled + the same. I don’t have a conductivity meter to test this myself, unfortunately. Reason being that purified (highly filtered) water is much easier to get and less expensive than distilled (evaporated and recondensed) water.

@Bob_Buechler what exactly do you mean by purified? What would you buy?

These are pretty common in my area (for example):

I noticed a funny click from mine, poor cutting. Changed the distilled water and seems fine.

@BeenThere_DoneThat the distilled water stopped the clicking and improved the cut???


@BeenThere_DoneThat Sweet yet another proof point! Thanks.

Yours sounded like a whine, mine sounded like a crackle.

Quick update. I’ve moved to a 5 gallon bucket and some bulkhead mounts with hose barb fittings, distilled water and 1/4 teaspoon of bleach per gallon of water, per @donkjr ​’s recommendations. I flushed the tube for about 15 mins so far.

I’ll do a few more test jobs and see if the sounds change.