New Coupler, Rod Caps

Last night I had some time on the lathe and made a new 8mm-5mm coupler because my first one was just stupid big. I also made two rod caps with set screws to hold the end of the steel rod in the carriage mount. I still need two more of them, as well as two more for a smaller rod in the pulley mechanism.

You can also see where I cut a rectangle out of the carriage mount front and back, and CA-glued in 1/4″ delrin rod to protect the enamel wire as it feeds through. Next step is to figure out how I’m mounting the limit switches to control back-and-forth motion, then it’s assembly time!

Another Iteration

I have made another change to the slide carriage mount. I left out the part that actually lets the wire through. Originally the mount didn’t have a front and back, so it wasn’t a problem. Later I added them for stability, they helped a lot, but they still need a way for the magnet wire to pass through. So I cut slots out, and will put 1/4″ delrin rods at the top of the slot to protect the wire as it is pulled through. I should have a picture later today or tomorrow.

Slide Carriage Mechanism

So I glued up the parts I just cut out, and fit them to the mount templates I’ve been making so it wouldn’t glue up crooked and not fit right. Here’s a pic. I’m really fond of this design, and it looks cool with my maker mark. I may still add the OLED screen to the front. Also, still need to make the wire feeder, and the left and right limit switches.slide-carriage

Astute observers will notice a difference between yesterday’s picture of cut-out pieces and today’s pic. That’s because the part was re-re-designed and cut out again. It’s nice that prototyping is so quick with the laser…

Getting Closer

Last night I cut out all the new wooden parts, and a hunk of delrin off my big (2 x 2.5 x 12″) block. I also used the lathe to make an aluminum coupler to go from the NEMA17’s 5mm shaft to my 8mm carbon steel rod. I also tried out an idea for my “maker mark” by scanning my chop in and burning its imprint with the laser. Here are some pictures.

More CAD Work

Last night I did some more CAD work, drawing up v2.0 of some of my coiler machine pieces. I think the spool motor mount is good to go, but I modified the pulley mount, the carriage mount, and the carriage motor mount files. The magnet wire spindle mount was updated too, since I have two different magnet wire spool sizes (the larger has a 5/8″ center hole and the smaller has a 1″ center hole—don’t ask me why though.

I also did some measuring and drew up the profile for the carriage, which rides over two linear bearings (these, specifically). The last part I have to design now is the wire guide that will sit on the carriage. It will be machined from delrin, probably with a small-diameter hole going through it with a countersink on one side to guide the magnet wire through.

I also still need a coupler to go between the NEMA17 motor shaft and my 8mm steel rod. The ones I found are used in 3D printers and would be great except they’re built with some cuts so they flex (to prevent binding when things aren’t perfectly aligned I guess), but the flex is a non-starter for me. As soon as I installed one I saw how bad it was going to be for my purpose. However, this part will be easy to freehand on the lathe from some aluminum rod stock I have sitting around.

Tonight I hope to cut the pieces out on the laser and glue things up, and if I have enough time to also make the coupler on the lathe.

Electronics Ahoy

Last night I was given an unpopulated stepper motor board, so I soldered a bunch of headers on it, attached my “Plan B” DRV8825 stepper controllers to it, and crimped up some custom cables. “Plan A” was to use Adafruit’s Stepper Shield to run two NEMA17 stepper motors, but after one caught on fire and a second just not seeming to pass enough current to the motor, I’m giving up on it and switching to the 8825 chips. The 8825s are sensitive to LC (inductive capacitive) voltage spikes  from power leads longer than a couple of inches, and it’s strongly recommended to put a capacitor between VCC and ground as close to the 8825 as possible. This board neatly solves that problem by putting the capacitor right under the 8825 between the headers. I even color-coded the header pins for the different stepper motors and the inputs.