Buying a K40 - Looking For Tips/Tricks/Suggestions

[kamon]

Hey Guys!

I've been doing a lot of research on different, entry-level lasers and I think I've finally decided on getting a K40 along with the X7 DSP upgrade and the z-axis bed(both of the latter, I'll be getting from here).

I'm new to lasers, but I'm stubborn and have tinkering experience .

I won't be doing the actual purchase until early next year, so hoping to aggregate as much info before then.

Can you guys give me any tips/tricks, suggestions(I'm open to anything!), and things to look out for?

Thank you all so much!

-kamon

[kamon]

Also, a lot of the K40's come with a water pump/exhaust pump, are these sufficient?
And, is it a good idea to upgrade my mirrors as well -- if so, which size should I use?

[coherent]

Not sure there are really any tips or tricks. Especially if you are going to upgrade. In that case most of the differences between sellers/versions will be pretty much irrelevant. Even the software that comes with your original machine will be upgraded. The mirrors that come with the unit are fine to start with. You may see some slightly better results with better quality mirrors but nothing earth shattering. Some folks even make their own from hard drive disks and report they cut a little better than the original, but I've no experience with that. They have a couple different grades of mirrors and lens here though and when you need to replace them due to wear, there are better than the original options. The original pump, hoses and exhaust work... kinda, but are lacking in quality and efficiency. Both should be upgraded fairly soon in my opinion. There are a few choices/options for these so research on the web is your best bet. Things like a flow switch that shuts off the laser if the cooling water flow stops is also a smart upgrade. Other than these and what you're already planning it should become a usable machine.
Have fun!

[kamon]

Hello,

Thanks for that info .

I'm looking to get the K40 by itself first and playing with it, then getting the air assisted head, then later doing the DSP upgrade followed by the z-bed upgrade.

It may be a few months between each(though, I'll probably get the air assisted head right when I get the K40), will the K40 be acceptable to use once or twice a day before I get the DSP upgrade?

Or should I get the z-bed upgrade first?

Thanks for the help guys!

[kamon]

Also, do most of the K40's come with PWM power supplies, or should I expect to have to buy one?

Is there a good way to ask the seller if the model they carry uses the PWM?

Thanks!

[Tech_Marco]

Don't bother to ask because they don't know it.
Anyway, our DSP will work for most LPSU

Marco

[kamon]

Thanks for the info Marco!

That's really encouraging.

If I bought the K40 + the X7 DSP upgrade(the complete kit you have here) and the flow switch(http://www.lightobject.com/Water-flow-O ... -P680.aspx), would I be set?

What other upgrades should I look into?

I have tinkering experience, but I have little experience with lasers, how long should I expect to go from receiving the items, to being up and running?

Thanks guys!

[seeigecannon]

We had a K40 as our first laser. The big things I must recommend is an interlock switch of some kind (we used one of these: http://www.digikey.com/product-detail/e ... 0-ND/43964). Get a flow switch: http://www.amazon.com/White-Plastic-Mag ... low+switch, and buy a pack of beer for somebody who is good with electronics because the capacitors in the power supply are likely to explode at some point. It is better to replace the caps with properly de-rated ones with brand names on them before one fails.

We had a cap explode with enough force to stamp it within the first month, but after I replaced all of the caps as well as a few components that went with it I have not had a problem. Working well with heavy use even a year later. Let me know if you have questions about it. Materials should cost less than $20.

[geartech]

What were the ratings on the caps you replaced, I might just go ahead and replace mine.
Heck I might even have a few sitting around from some HF tube amps I built in the past.

[kamon]

We had a K40 as our first laser. The big things I must recommend is an interlock switch of some kind (we used one of these: http://www.digikey.com/product-detail/e ... 0-ND/43964). Get a flow switch: http://www.amazon.com/White-Plastic-Mag ... low+switch, and buy a pack of beer for somebody who is good with electronics because the capacitors in the power supply are likely to explode at some point. It is better to replace the caps with properly de-rated ones with brand names on them before one fails.

We had a cap explode with enough force to stamp it within the first month, but after I replaced all of the caps as well as a few components that went with it I have not had a problem. Working well with heavy use even a year later. Let me know if you have questions about it. Materials should cost less than $20.

Oh wow, that's all you added?
What about an air-assisted head and the DSP control board?
Or, do you think that's unnecessary?
And what do you do about materials with different heights?

I'm happy replacing the caps myself, shouldn't be too big of a deal.

How do you feel about the MoshiDraw software?
I'm a pretty tolerant person and I get used to things, so is it *that* noticeable?

With just those upgrades you mentioned, how is the quality of the cuts?

Thanks in advance, really appreciate it!

[seeigecannon]

I know it is pricy, but I recommend getting an AWC608 from LightObject. Moshidraw was giving us weird problems. The biggest is that we would sometimes hit start and then the laser would just turn on full blast and cut a -40 degree through whatever we were going to be working on with only the power switch fixing it. The worst thing about Moshidraw though is the fact that it uses a hardware dongle. This laser is used by a hackerspace, so a hardware key like that was horrible for us.

We use the air assist almost every time we do a vector cut of something, so it would be a good idea to have that. Something I forgot to mention is ventilation. You want to be able to clear out the smoke/fumes that the laser generates and the tiny bathroom fan thing will not cut it properly, so upgrade that if you can. For our laser I have an arduino checking for laser activation and turning on a fan when it is running and keeping it on for a period of time after the job is finished.

Unfortunatley, without a Z axis on the K-40 you will have a hard time doing anything thicker than about .75". For this I do the best I can with the stamp slot in the laser. When we are just doing flat things I had a cover I could stick in there to keep stuff from falling in.

We have just recently upgraded to a much larger laser with a Z-axis and we have not looked back yet (though the PSU exploded, so we had to get a new one from LightObject).

[seeigecannon]

What were the ratings on the caps you replaced, I might just go ahead and replace mine.
Heck I might even have a few sitting around from some HF tube amps I built in the past.

It is important to properly de-rate capacitors. If a cap says "10uF 50V 85C" the 50V means that if you put that much power into it that it will explode (more or less). The 85C means that it is only rated to a max temperature of 85 degrees C, which for an application like this is pretty piss poor. If a cap is under-rated for a temperature range and gets hot the electrolyte dries out, when this happens the resistance increases and it gets even hotter. When I am adding a capacitor to a project I typically use at least 2X the rating for the voltage, so if I had a 24V rail I would use at least a 50V cap that is rated to 105C. (The caps in the original PSU might have put a 30V 85C no-name cap on the 24V rail, this is almost guaranteed to fail).

To replace the caps look at the original value and keep that. My preferred manufacturer is Nichicon, they are top of the line, but expensive (like $2/ea for the medium size ones). Much more information can be found here: https://www.youtube.com/watch?v=xlvqUts9H9c

[SScnc]

I'll add my opinions and hopefully help a bit. I suggest that you don't waste a minute of your time with moshicrap ! Immediately order the DSP and drivers, etc from Marco, even before your machine arrives if possible. Throw the moshi board away ! And get corel draw if you don't already have it and install the LaserCAD plugin for Corel Draw.

I use air assist 100% of the time to help cutting but also to keep the smoke and grit off the lens. Also, make sure your mirrors are properly aligned right away then periodically, makes a huge difference if they aren't. And put a flow switch inline to protect the tube, if for no other reason, in case you forget to turn the pump on before hitting "start".

And get the original "Z" table out and replace it immediately with the one from Marco, I made mine but if I had seen Marco had it at the time I would have ordered it from him. And mine's only manual, not powered like Marco's is.

Here's a couple pics of mine, I have the AWC608 from Marco and it's awesome, love it !!! The round laser power scale, the switch labels and the DSP mounting plate were all laser engraved and cut on this machine.

HTH

[DonL]

This is what I want!!!

So I have been reading the thread and what I would like to do is upgrade the controller, add a z table ( I already ordered and should have today) Mirros and lense I ill do later, Fan and water pump, later,
now the Power Supply.... Is the power supply offered here better or does it too need upgrade work?

What would be cool is a list of what one should buy from here to get something close to what you have.

I ordered the Table and driver

LSR-PWRTB320
ECNC-2M415

Trying to decide between
LSR-DSPX7
or
LSR-DSPR5
Your thoughts?


What else would you suggest?

DonL

[seeigecannon]

I bought a replacement power supply from LO for my 60W laser. I opened it up before installing it to see what would fail early so I can fix it before it turned into a problem. I was quite impressed. The PSU was still a bit under built in my opinion, but they were using upper mid level capicitors as well as a two layer board design (copper on both the top and bottom sizes of the PCB). I ended up not needing to upgrade anything. I am actually wishing I would have taken pictures and done an EEV Blog style teardown and posted it here. I might do that later.

That said, if you upgrade the caps and add a fan to your PSU before anything fails then you should be fine. We used our K40 PSU for a year with no issues (after it exploded once). Let me know if you have any more questions.