K40 Laser Beginner Insights draft document from FB K40 group

I designed and built a K40 lift table controller that allows you to raise and lower the bed with a joystick. It also will allow you to switch between joystick control and Lightburn control.
I have a prototype running in my machine.
I am willing to share the design and software if you think it would make a nice addition to your controller project.
Perhaps I could trade it for one of your first production units :)!


We could always look at selling it on the Beam Buddy product site. Right now we are selling the high resolution heads we designed, and the safety sytem will be the next product. A z table would be great. We will also be carrying replacement optics soon.

1 Like

I’d say that a great way to to native web pages of this content here would be to create a post for each separate topic. That also gives starting points for conversations on different topics more naturally, and discourse makes it easy to break them out later into their own topics, keeping links to the new discussion, so we don’t have to be the “stay on topic police” about it. The sticky “New to K40: Start Here” post can link to non-sticky posts.

I’m happy to help with this, please let me know!

1 Like

@ mcdanlij: Good idea. What’s the simple, effective way to insert what amounts to a hyperlink from inside one post to another post. Libre and Open Office will both automate in-document links as will html editors. The links can then just be replaced with the post redirection. For a limited number issues those can be either manually replaced or hunted down.

This will probably spawn a spirited discussion:

None of the below intends to deter anyone from making improvements or building alternate approaches. Its just that in this discussion I have “been there done that” so I fill compelled to poke the beast…
First off, I’m fully prepared to learn from someone with a different background. I have an EE background, but only months of thinking about the K40, mostly on my own,

I would never endorse a laser or CNC machine in which main power is turned on any automated way. Once the machine is turned on and enabled by a human (after ensuring the machine and room is in a safe state) the software can control its job operation. It also must have an estop that is mechanical. The dangerous parts of these machines (laser and spindle) must not start without mechanical interlocks closed.

That’s reasonable. Electrical safety standards do require a manual disconnect as well. UL, IEC, and other country standards specify that this can be done by the electrical socket disconnect below X power (I’d have to look up X, but the K40 is less than that). I’ve always thought that was silly, and that “polite” design made this be at least a hard two-wires disconnect - a switch. But there are cases where once you have the machine enabled manually where it would be very nice to disable AC power to sections of the machine. Hence the second AC switch inside the manual disconnect.

EPO switches are a good idea, but putting them on the machine likely to generate the fire is something to be thought about. I come from a formerly major computer company, where the EPO is mounted hand-high next to the exit door, so you can slap it as you’re running from the roaring fire. In my mind, the EPO switch for the K40 might best be mounted from 3 to 10 feet away from the machine, perhaps right next to the fire extinguisher so your movement away from the fire leaves you an efficient way to both kill the electrical power while deciding on fight or flight as you flee the machine. I am by no means a safety expert.

The smoothie and Lightburn folks spent multiple years getting a controller and software combination that works for the K40. I tested and used all these configurations on the way to the current state. I think the K40 controller and associated software needs are solved!

May well be. As I said, I’m new at this. I will need some experience before any real discussion of those deeper issues.

What is the advantage of a PI when C3D and Lightburn already provide; control panel, Gcode machine & job control which includes camera & bed movement?

In my baby steps approach, wifi connection to the machine. Do C3D and Lightburn let you do that? If so, maybe none. I’m aware of the advantages of the software operation of the laser movement and so on that users have posted. Just haven’t tried them, so I’m ignorant of the details. I see the Pi as an overseer, that I can reach out for ready to burn jobs from the graphics machine.

External devices like air, evac and water pumps can also be controlled with the C3D although I do not want my water pump ever to be off. In my machine, an aux panel controls all AC to the air assist and evac pumps but its built from simple relays switches & LEDs.

I agree, the pumps and fans should not be off. It’s more like killing any possibility of the laser going on when a pump/fan/flow fail is sensed, a second level of stoppage for those times when for example, you told the pump to run, but it’s inlet hose is kinked, or the fan motor spins but the impeller spins on the shaft. It amounts to feedback on the desired result, not on starting the auxiliaries up.

The things I was thinking of kit-ing in my earlier post was about the simple, critical but illusive interlocks, tube protection etc. I doubt the newbies that we have been talking about would be that willing to spend the $$$ and time to install anything that requires much wiring and if they do the support is probably a nightmare.

No disagreement here. I’m still thinking my way through it.

I have thought many times that an add-on embedded monitor was essential and in fact, started down that road a few times. I stopped after I found easier, safer and cheaper ways to do each of them in turn. Then again I love building embedded controllers so I still think this would be a fun project if it included bed controls.

That’s another thing requiring thinking. A Pi suitable to the things that are needed for the K40 is $35, and you might well be able to use a Pi Zero W AT $10. A 5" Pi display that fits the existing control panel cutout is ~$40, and an old HDMI monitor might be less, although external. In the role of a com link and overseer, it might be a fit. K40 whisperer runs native on the Pi, although it brings its own limitations as a software package, probably much more limited than the more-extensive packages. But it might well be a usable cost point for people satisfied with the limitations of the M2 Nano controller. Think of this as one step up from the base system for the limited budget, with some added overseer/monitoring functions and native communications. Different price point.

I even got deep into the notion of just building a better machine from scratch but realized the world did not need another Full Spectrum or Glowforge and full safety compliance is expensive in design and approval. It also became clear that the folks that want these for hobbies do not want to pay much more than a K40.

Building a better machine from scratch? Not for me. And I totally agree that the hobbyist market is cost- and attention-limited. Hence the cheaper Pi package might hit a useful step up. Especially if you go for an low-end overseer role, leaving off the display.

All in all adding over-temp protection, DVM on the pot and interlocks to a stock machine gives the new K40 user most of the basics needed to get good to excellent results.

Agree. I originally just programmed a PIC to monitor that kind of thing. Left off when a nominal-price Pi offered both wireless communications and the possibility of expansion to higher function.

Doubtful??? Ask @NedMan what upgrades he has done enabling him to create his amazing work :). Last I checked he still has a nano!

Not doubtful. As I said, I started with a PIC, and was seduced by the Shiny Thing of comm, display, and expansion without having to write the detail code inside the PIC.

No argument, just a baby steps approach in the design space.

If you want to quote the beginning of the article, you just drop the whole link in, like this:

Note that this doesn’t really preserve much formatting, as see above.

If you want to link it in text, you can just say to start here with [start here](/t/new-to-k40-start-here/79751)

To make it possible to link to a heading inside a post:

<a name="the_id_you_choose"></a>

## [Name Of Your Section](#the_id_you_choose)

Then the link would be [text](/t/category/id#the_id_you_choose) and it will take the user directly to that heading. (The number of # characters determines the level of the heading.)

Sorry for the delay. Got the file updated, mildly reorganized, converted to PDF with links inside it. Here’s the next draft.

Additions and corrections solicited!

EDIT: apparently not. I’ve made three attempts to upload the file, and although it appears to be uploading, nothing appears in the upload. Help…

Wait, why PDF?

I think that maintaining it as searchable HTML by having the text in the posts is really important for making the information accessible. I thought that was the plan.

Like I said, draft. :slightly_smiling_face:

I have found that I can extract basic html from the document that made the PDF, so that conversion’s quick. I would have done the html directly, but I really have to go learn whatever to keep the fomatting reasonable.

I found out how to do cross links within the document again, so the cross references should be fine, excepting for being unfinished at the moment.

So give a read, make suggestions, and we can convert to final form.

er… if I could upload it, we could look…

I did a bunch of fixes from the automatic conversion process for the page. Trying to square those with a PDF sounds very painful. :grimacing:

I probably know too little about the prep process and the end result you are envisioning.

When I read “searchable html” I translated that as “simple, flat-structured document html”. That’s where I’m getting my idea that a simple movement from the source document ODT to PDF with internal links and a separate process to move ODT to text-style html is OK. Really, Open Office and LIbre Office produce the html form with “file, save as”. That’s why I was considering a PDF as an OK intermediary for reviewing the document.

I suspect that I don’t understand the fixes you’re having to apply. Help me here.

Sorry, so many other things popping up with COVID-19 I’m not able to respond as quickly.

I’m saying why not make it all posts on this site? Just breaking out what has already been converted into individual posts, rather than trying to build a static site. That means that people can comment on the contents of each section in a convenient place and changes can easily be incorporated.

(I’m totally happy to help with that conversion, I’m just putting family needs first and family has needed a bit more while adjusting to being in the same house pretty much 24/7 except for walks and groceries…)

1 Like

No need to apologize - we’re all dealing with the higher-order needs now.

Sure - I can simply post the document here, I’m mentally parsing this as “post each subtopic here as a separate post” so the topic links can serve the function of a clickable index." Is that closer?

1 Like

That’s definitely what I’m thinking of. (I ended up adding replacing my flaky internet connection to the pile of stuff I didn’t expect to be dealing with these days. First world problems and all that!)

Now looking into making a new category just for getting started documents, to help people find them more easily. It would be moderated and hand-picked. Your getting started document would link into it, and the bulk of the document content would move into separate topics. The new category would be strictly information. It wouldn’t include your ideas about how to make a new cooling system; that would go in the #k40:Mods category; though if it were tested to completion and described, a link might go out from the new information category to the description of how to make it. The goal would be for it to become a resource of which you could reasonably say “If you know, understand, and follow all this, you are ready for K40”. That means it has to be feasible to actually read and understand all the content, so it should be only core information, no noise, no conversation.

… ⇒ #intro exists now :slight_smile:

1 Like

I have now broken out the first two topics from Start here into Getting Started, leaving a few summary paragraphs in the former but moving the bulk of the material to topics in the latter and linking. I hope this makes it easier for new K40 folks to find and digest the information.

@donkjr I think it would be great to link out from these specific pages to specific blog posts on your site that are relevant to the topic under consideration, as the next level of information.


I could not find where this point is integrated?

I am starting to wonder if we aren’t repeating history with this getting started document?
No reflection on anyone’s work BTW.

I for one am finding it difficult to navigate.
Lots of comprehensive information but also overwhelming for the novice.

Could be that I suck at using this tool.

My blog experience and helping users tells me that they go through these phases:

  1. What to buy: For $400 I can do all that, I can cut a 2x4?
  2. Just getting my machine to do something useful: Seriously, It doesn’t work out of the box?
  3. Learning the software and doing cool stuff: Jese this software is awful!
  4. Adjusting and maintaining: Damn it used to do that job
  5. Troubleshooting and repairing: Shit now it’s broken, must be the tube died!
  6. Upgrading: What’s should I add to make this machine behave as I expected?

Note: users mostly focus on the information that is in the context of the phase they are in they don’t read ahead.

BTW: I never took the time to organize my blog this way although the tag cloud shows this phenomenon by usage.

Since the demise of G+ and my lack of participation in the FB group I mostly get users that are in phase 4-6.

(I hope you don’t mind I moved this into the thread for working on the document.)

It’s in Do’s and Don’ts. It said that the digital display wasn’t accurate; I added the power calculation. But that’s in a section I otherwise haven’t edited and separated into “start here” and the “For more information:” parts.

I’m only halfway — if that — through pulling apart the topics so that it’s not overwhelming to get started. I have cut it down from 100K of text to 57K [now 46K and shrinking] of text. 100K is overwhelming, which is why I’m editing, and putting only the key points in the “Start Here” document and all the rest in the Getting Started category.

I think your phases are fairly aligned with topics I’ve put into the Getting Started category.

I expect it to be another week or two before I’m done with my first pass; depends on how much time my family can spare me for on weekends. :slight_smile:

And I’d really love to add lots of links from these documents I’m assembling into your blog. I already started in one or two places, but I think it would be great to add more!

1 Like

@donkjr and @NedMan and anyone else with experience: Do you have specific recommendations for online resources, written or video, for each of these following areas?

  • how to adjust focus
  • how to adjust mirrors for proper light path
  • how to adjust the X-Y axes to be perpendicular
  • how to tension belts

This list is included in the draft document; I would like to turn it into a list of helpful links to information. @donkjr I expect at least some of that is links into your goldmine of a blog! :slight_smile:

@keen, at the end of your document you have this:

The trick is getting some control of the process. Most K40s already have a bucket of water for cooling. Put in a second bucket, fill it with ice and water, and selectively circulate the main K40 water through a copper pipe in the ice water bucket. Use something like an Arduino to measure temps and control how much of the K40 coolant gets pumped through the ice reservoir. Water running through a spiral copper tube in a water bath is a very efficient cooler. The Ice reservoir could profitably be a cylindrical drinking cooler - cheap, insulated, and easy to plumb.

I think this approach could handle holding the K40 water at optimum temperature constantly. One nice thing about an ice water reservoir is that the water temperature is CONSTANT at 0C as long as there is any ice at all. A second bucket, a second pump, and some electronics gives very good control over coolant temperature. And it can be automatic, functioning quietly until it runs out of ice and temperature rises. Then it can honk at you to feed it more ice.

I think that without code and plans a beginner could follow, this idea should live in the #k40:Mods category and be developed there. Do you mind if I delete it from the document as I edit, letting you carry the idea, and if/when it’s complete link to it? I’d like to do the same for the more speculative suggestions, leaving the more concrete suggestions in the document for beginners.