• 04/19/22 - Hot End Board, Space Savings, Print Bed

    Daniel Grace • 04/20/2022 at 00:05 • 1 comment

    Hot End Board

    I went ahead and made a project for the hot end board that will be a key part of this printer. There's not much there yet, but I'm waiting on parts to be delivered, and to see if anyone is actually interested in the project. So far I have zero interactions, including views. I'm not sure what I did with my first project to get my first few viewers, but maybe linking it here will help. I can't really tell if the project is interesting if literally nobody has even seen it!

    https://hackaday.io/project/184838-hot-end-board

    Space Savings

    One of the things I've wanted from the beginning was three point bed leveling. As soon as I first saw it on the HevORT, I knew it was "the" solution in my mind. But putting the stepper motors in the bottom directly attached to the lead screws means that you're eating into your X and Y dimensions by the size of your motor. And if you leave yourself just enough room for the motor you chose, you are limited in ever making that motor bigger. That has never sat right with me, and it's been a sticking point in me wanting to move forward with that part of the design.

    Somehow I wound up accidentally reading the build guide for a Voron 0 rather than a 0.1, and they had an ingenious solution to this problem back then -- attach the lead screw to the motor via a belt rather than directly. Yes, there are downsides to that, but I like decoupling the physical size of the motor from where it is mounted. I'm going to sit on it for a bit, but at first blush, I might steal that old design element from the Voron team. I assume they abandoned that for a reason, but our design goals aren't exactly the same, so maybe it won't matter to me as much. Or maybe I'll find out the hard way.

    I could probably find public statements about why the change was made if I put some effort into it...

    Print Bed

    One of the things I did recently was join a local maker space. I have to get trained on some of the machines before I am allowed to use them (fair enough) but they have a lot of cool machines. Such as a forge to do metal working. I am strongly considering CNCing my own build plate, and possibly even casting my own. Depends on how quickly I get trained on the machines, how slowly I do everything else, and if that cool factor still seems cool when the rubber meets the road.

  • 4/11/22 - Big Ol' Dump

    Daniel Grace • 04/11/2022 at 16:23 • 1 comment

    I haven't written anything here in a while, but that's not because I haven't been working on this at all. I've just been working more slowly than I wanted to, and no single day feels like I wanted to write an update. But cumulatively it might be enough now, and I can also go over what the delays have been and what the future looks like. First, a spoiler list.

    • My 10-year old daughter is now my "boss."
    • There is (probably) a commercial product coming out of this.
    • I am making a reflow oven. It should be done shortly.
    • I am designing some custom boards. The RP2040 board is the next to be sent off/tested.
    • I am going to build a Voron 0.1 as part of the commercial stuff.
    • I am considering more projects on here.

    10 Year Old Boss

    I have been trying to teach my 10 year old daughter responsibility. At the same time, I am bad about starting 20 projects and finishing none of them. So I've started a thing where every Friday, I give my daughter a list of my deadlines for the week, and list of things I want to eventually work on but aren't deadlined. She's enjoying holding me to task, and it's probably good for me, too. They aren't all work-or-project related. The first one was cleaning my work area. I call her my boss to make it more fun for her, and because it amuses me, too.

    Commercial Product

    I don't know if I've said this before, but this project actually started in part because I'm itching to create a commercial product. I ran my own business many years ago, have been in the corporate world again for a while, and am looking to dip my toes back into being a business. My wife and I technically co-own a business (it's my old company name, she's using it to do consulting), but I wasn't doing anything in the business.

    3d printing being one of my hobbies, I immediately went about trying to solve a problem that is being inadequately solved in 3d printers. There's a lot, honestly. The biggest trick is finding a good balance of price and quality. I do not want to put out a shoddy product, but 3d printer people seem to be very price-conscious. And the pandemic isn't really helping that.

    I am not ready yet to 100% lock in what parts will be commercial, even though I have an idea at this point.

    Reflow Oven

    I am making a reflow oven. Getting basic functionality is on my list for this week, so my daughter will yell at me if I don't. It has been taking a decent amount of time, but isn't special or unique enough for me to want to spin up a project page for it.

    Custom Boards

    I really want to make custom control boards for my 3d printer. Doing so requires working with no-lead SMD components and SMD components with pitches < 0.5mm. It's a hassle, hence the reflow oven. I should be sending off one of the most important prototype boards to be manufactured this week if I follow my schedule. I have already purchased the hard-to-find components to insulate myself from the chip shortage in the short term. This is what I expect this log to be mostly about in the short term.

    Voron 0.1

    While I still want a fully-custom 3d printer, and this project isn't dead, there are three reasons to build a not-designed-by-me printer. In no particular order: The only printer I have right now is an Ender 3 v2 which I am tired of fixing. I can take design ideas from the other printers more easily if I am more intimately familiar with them (cad drawings are nice, but don't give you everything). And the commercial product will likely mostly be used by people upgrading their own printers, and I would be served well by designing for that purpose.

    More Projects

    One of the people I follow the closest on here has a lot of projects. I follow a number of them, and I honestly don't even notice when/if one of the projects doesn't get that many updates because they are always updating some project. I am considering doing something similar so I don't go silent when my interest is on something else....

    Read more »

  • 03/09/22 - Odds and Ends

    Daniel Grace • 03/09/2022 at 14:52 • 0 comments

    I figured out the trigonometry to calculate most of the stuff I needed to know with the interactions between rail sizes. Enough to rule out a big chunk of them. There are some potential clearance issues I didn't math out, but I'm taking the remaining combinations (only like 10 passed the math test) and mocking them up in CAD. Any clearance issues should be obvious there. And in fact, the only combination that looks like it MIGHT work is 20mm unit vertical rails and 30mm unit horizontal. There MIGHT not be enough space for the acrylic sheet then. I will look a little further later, but I'm kinda disappointed that it seems like it may not work exactly how I want. Am I going to wind up going to the boring fully-boxed design?

    In other news, I started the process of joining a makerspace. I have the keyfob that will eventually let me in, but I have to attend an orientation first (which is scheduled for early next month) and then I have to get training on the machines that interest me before I can use them. I want to eventually start machining my own aluminum parts. Being able to make custom parts out of something that isn't plastic seems awesome. The makerspace has a forge, and I kinda want to see if I can make a custom build plate out of recycled aluminum cans that I melt down, cast, and then plane all myself. We'll see. That's a lot of work for little reward aside from satisfaction.

    DigiKey had TMC2209s in stock for the first time in a LONG time. I immediately bought almost 1% of their stock. Probably overkill, but that's the last electronic component that had been hard to find.

  • 03/06/2022 - Rail and Enclosure Design

    Daniel Grace • 03/06/2022 at 17:55 • 3 comments

    I haven't been as productive as I would have liked. For reasons that aren't important to this build, I have to shift focus away from what I have been working on and go to more theoretical stuff temporarily. Given where I am in the project, that means mechanics. I said before that I had an idea on how to make that part somewhat unique. In this post I am going to attempt to explain it.

    There are quite a number of variations of aluminum extrusion that are all vaguely similar.

    Here you can see two that are on my radar, though I am aware that many other places have their own variation. The top one is from misumi and is showing both the 30x30 and the 30x60 (which is basically two 30x30 side by side). The bottom shows a 20x20 from open builds. Both places sell variations on the size.

    Here is how I hope to arrange some rails (note: this was done with open build rails because they were the easiest to get the CAD models for, not necessarily because I am going to use them):

    The rail in blue is the vertical support rail. It will be oriented "normally." The rail in red is at exactly 45 degrees in the image, but there is some wiggle room here (there likely will HAVE to be to make the math work). If you notice on the left side of that red rail there's what looks like a perfect slot for some acrylic paneling to go. In fact, with some open builds rail I have in hand I have tested it and it works just fine.

    Right now though I have a trig problem I am trying to solve. This is going to be hard to explain for anyone who hasn't used so-called "blind joints" in extruded aluminum before (I was exposed to the idea from the Voron design, though I'm sure it's used elsewhere, too). I want to find a complementary set of rails where I can blind joint the red rail with the blue rail and the angle works out such that acrylic can comfortably fit in there. With open build rails and exactly 45 degrees, there is some wiggle room. I will need that for some weather sealing, but I can probably work with less. And if another rail design has a larger opening, that means more wiggle room on angle.

    It's just a LOT of dependent numbers, and I haven't done trig in a LONG time.

    (Note: ignore the silver/white parts in the above. It's from the most recent design I have done in CAD, but there are problems I want to fix.)

    (Oh, and I've made progress on the reflow oven, which again is related because I will use it to help make this project, but it's not this project.)

  • 03/02/2022 - USB Hub Discovery, Mechanics Decisions

    Daniel Grace • 03/02/2022 at 15:45 • 1 comment

    After looking over my USB Hub schematic, I found the likely culprit:

    The USB Hub chip has an NRESET pin. It's expected to be low during startup, and then go high when the power is stable (and for the rest of the runtime). It also has some requirements for how long it has to be low for. I googled this sort of pin setup and got a lot of info about how a simple RC network isn't ideal, how it doesn't handle short blips in the power supply as well as it should, etc. so I put off designing that circuit. I meant to investigate whether there was a cheap and simple IC I could use that handled all the edge cases.

    Then I forgot.

    So on my actual board, that pin is just floating.

    I told my daughter that the next round of boards would be for a thing I'm making for her. So I need to update this schematic, but it'll be a bit before I can order a new board. I will probably try to solder some wires to pins and see if I can bodge a test out of this. I'm annoyed, but at least it's not a mystery anymore. If the failure was unknown, I would have no way to move forward!

    As part of hooking this board up I discovered how much I hate crimping my own cables. Realistically, it's going to happen, but I might change the type of connectors based entirely on which ones are less annoying to crimp. We'll have to revisit that later.

    What I want to do is move forward on the mechanical aspects. The problem is I can't commit to a size. I have an Ender 3 v2 right now. It's this weird middle ground. It's not big enough to print everything I've ever wanted to print (but it prints 90% of things just fine size-size). It's too big to be all that fast (especially as a bed slinger). But do I go small and ultra-fast or big for my custom-built one?

    I think the right answer is big for the first one, then make another to be small and fast. My reasoning is that the big one opens up new possibilities, the fast one just makes the same kind of things faster.

    I have what I think is an innovative idea for the walls of the printer and the enclosure. The math hasn't worked out yet, I need to figure out how to make it work. That's my goal for today: make the math work for my walls. And start uploading some pictures to this project. And ideally even start publishing info on the wall thing. Depends on if I manage to figure it out.

  • USB Hub Setback -02/28/2022

    Daniel Grace • 03/01/2022 at 07:10 • 0 comments

    The hub components and board arrived and it was the hardest soldering job I've done yet. No obvious flaws, though I wouldn't say that I was proud of every joint. Most testing went well, but a small part but important part doesn't quite work. 

    My oven that is destined to be a reflow oven is being borrowed for my brother in law's school project. Eventually I want to try reflow soldering this board to see if that fixes some bad joint.

    In the next few days I may try some more debugging of the board, but I expect I will take a detour to more mechanics or aesthetics until I have the reflow oven working. 

    I will gather my thoughts and make another post soon.

  • USB Hub Idea - 02/28/2022

    Daniel Grace • 02/28/2022 at 16:24 • 0 comments

    This is my second custom board, and it's supposed to be delivered today! What is it?

    Most projects I've seen that have something like a dedicated hot-end circuit board use what's called CANBus. CANBus is a protocol designed for use in cars, where it's electrically noisy, and you have multiple microcontrollers talking to eachother. It's actually a pretty good match for what a 3d printer with multiple control boards is doing. I see why they do it!

    But it does have downsides.

    For one, you have to use a "CANBus hat" to make your Raspberry Pi talk via CANBus, so there's extra hardware required right at the Pi. And if you're like me and are just using your computer instead of a Pi, you're out of luck. You also cannot use CANBus for everything you use USB for (like updating the firmware on the control boards), so you have to still use USB sometimes in addition to CANBus, and it just seems like a kinda janky solution. And since there isn't any microcontroller that can update its firmware via CANBus, it's not a problem that can be easily worked around.

    But what if we could just use USB directly? Low speed USB is not that sensitive. I am going to try connecting everything with just four wires: +24V, Gnd, USB+, USB-. I will derive any other voltages I need on the board on that actual board, and I will use high quality wires to try and shield the USB signals.

    Today I will have the board that first tests this idea. If it's a complete abject failure, I will likely know today. If it works today, there's no guarantee that it will be fit for purpose -- adding in the noise of actually using motors might be too much for it.

    But let's talk about this board I'm building today. It's basically just a custom USB hub. It takes USB in (from the Pi), ignores the 5V line, sends the USB+ and USB- into a USB hub IC, takes the USB+ and USB- signal(s) from the hub, adds those to a 24V line, and spits it out three custom connectors.

    If this were ever a commercial product, this would be the one board everyone would require. It is the heart and soul of the custom parts of these electronics.

    The USB hub chip only comes in SMD. Its pin pitch is 0.5mm, which I have done before. The new thing I'm testing on this board is SMD capacitors and resistors (who don't have a pin pitch, and it's hard to find what their "equivalent" is). I am going to try and hand solder those.

    But in the future, I want to be working with chips that have pads on the bottom, and pads that aren't visible from the side, and pads with a pitch of less than 0.5. I am going to need something "better" than hand soldering. So I'm also currently working on a reflow oven. I likely won't make a project for that since I am not going to do anything all that custom there. But details of that work likely will leak over into here.

    I will likely make one more post here later today, after my package comes in, and I have preliminary results. It might even be pushed into tomorrow. But after that, the speed will slow down quite a bit, because I will have to design, order, and receive custom boards for a lot of these tests. And as I said in the first of these initial posts, I am taking things slow and testing everything.

  • Power Rail - 02/28/2022

    Daniel Grace • 02/28/2022 at 16:10 • 0 comments

    The first component I tackled won't be used directly in the printer at all. It's a basic power rail that takes the 24V from a Meanwell power supply and turns it into 12V, 5V and 3.3V.

    For this I used through-hole power conversion chips, and through-hole capacitors that were recommended on the data sheets. I could easily have breadboarded this, but decided to use this as an opportunity to test doing things "right." So I designed the circuit in KiCad, did the routing, and ordered boards from Osh Park.

    Osh Park surprised me! I hear all the ads for JLCPCB, and it's China, so I expected it to be way cheaper than anything in America. But (without getting too political) I'd rather not work with China any more than necessary, so I decided to see just how much of a tax I would pay to work with Osh Park. It's virtually the same price for my specific use, once you factor everything in. JLCPCB was something like $5 for the board, and like $10 for shipping. Osh Park was something like $15 for the board and free shipping. For a $0 tax, I will gladly take the American option.

    So the boards arrived, I wired everything up, did the very basic soldering of through hole components. So far so good. I turned on the Meanwell, and started to plug the board in and got a very small spark. Eeks! Gathered my breath, started to plug it in again and got another small spark. After some careful investigation, the power converters weren't getting hot, the sparks were very small, I decided to see how bad it really was. Plugged it in all the way, no continuous sparking or anything. Nothing was getting hot. Broke out the multimeter and everything is at the right voltages.

    After some investigation, it all makes sense. The data sheet for the power converters want capacitors from in to ground and from out to ground to filter noise. Makes sense. But capacitors start off as basically as short when they are empty. So for a fraction of a second, when I plug it in, I'm shorting my Meanwell's +24 directly to ground, then the cap charges quickly!

    It shouldn't harm anything, but it's a bad experience for the user, so in future designs there will be a resistor in series. A small resistor should be enough to not spark, and it won't meaningfully affect the power circuit, especially if my first drop is from 24V to 12V. At least that's the theory. Future boards will test that theory!

  • First Update - Basic Info - 02/28/2022

    Daniel Grace • 02/28/2022 at 16:02 • 0 comments

    Today is not the first day I have worked on this project, just my first log. This will be stream of consciousness and as-best-I-remember-it. I will forget things. I will get minor details wrong.

    I am approaching this project slowly. I have a lot to learn, and I want to double check my assumptions as I go. Because of this, there's a lot of basics that are going to be done before it feels like I'm making progress on this one directly. I will try to explain how each thing is relevant so that the connection is made.

    This log is only about the big picture. I have decided to make separate logs for the bits that I have done and have started working on/designing just to make organization easier.

    So why the name Alice? I have two daughters. One of my projects not relevant for this channel is making my own computer language. Alice is already the name of a computer language, so I named it after my younger daughter. So now my older daughter gets the 3d printer. It's as simple as that!

    What is different about Alice vs the other 3d printers? The kinematics and aesthetics aren't 100% unique. I will likely go with core xy, probably 3-point bed leveling. I am not going to go with a direct copy of voron or hevort or anything like that, but I will be taking heavy inspiration from them until I have some idea on how to make a fairly large modification.

    The main modification idea I have had so far is in the electronics realm: many, custom-purpose control boards.

    Klipper allows you to have multiple control boards, but that's rarely used, and when it is it's for things like adding 1-2 more z motors to your janky default control board. Hardly a shining example.

    I want to have a control board for the hotend/carriage, another for the z motors, etc. This won't be the first ever printer to have separate control boards, not even the first with those specific ones, but that idea is certainly less explored.

    Aside from that, I also have an interesting idea when it comes to wiring that I want to try out, but I'll leave details of that for when I have made progress there. (It shouldn't be long, I have parts coming for the first sanity-check of the idea literally today.)