Close
0%
0%

Turning a Makibox into a PCB Mill

I bought one of the ill-fated Makibox 3D printer 4 years ago. Time to make it earn it's keep - but as something it was not intended to be.

Similar projects worth following
I've had a partially broken Makibox A6 sitting in my workshop for three years. I don't think it will ever work again as a 3D printer (even if I could be bothered putting it back together and trying to get the now-abandoned software to work, I'm now the proud owner of a Lulzbot Mini, so there is little point), I hate to see a couple of hundred dollars of hardware sitting with nothing to do.

I've always wanted a way to make my own PCBs at home, but I've never been a fan of using chemical etching (It's messy, and getting rid of the chemicals is not fun), so I've decided to see if I can cobble together a PCB mill.

I want to see how far I can get armed with the parts that I have (Motors, driver board, some of the mechanisms) and a 3D printer.

You might remember the Makibox A6 - it was a sub-$400 3D printer that, like a lot of cheap printers at the time, was crowd-funded. It took forever to deliver, and there were a lot of problems with it.

Personally, I managed to print a single cube on my first print. On my second print something went wrong and I blew up the control board. I suspect because of the stalled extruder motor. The extruder needed replacing, as did one of the plastic lead screws (that was my fault - I over tightened it).

In the process of trying to get the parts replaced, the delivery got lost - they claimed it had been delivered, but I hadn't received yet. While trying to work this out, I had to quickly move interstate for work. To make matters worse, the company that made the Makibox disappeared around the same time, so I resolved myself to writing off the printer.

I decided to move to Melbourne permanently, so I flew back to Perth to collect my belongings - included what was left of the Makibox - and jammed it into my car for long drive over the Nullarbor.

And there is sat almost three years - dejected, in a cardboard box in my workshop.

On a recent trip back to Perth, my mother handed me a package which a person I worked with have given her. Apparently. it was delivered to the office years ago - so I had no idea what it was.

Low and behold, It was the replacement parts from my Makibox! Well, this was a sign. I put the parts next to the printer, as I wasn't sure what I was going to do with it. I had an M3D printer which was pretty terrible - maybe I could frankenstein the two designs and get one printer out of them?

Fast forward a couple of months - I come in to a bit of spare cash after selling off my time tracking application, and I decide to bite the bullet and buy a real 3D printer - a Lulzbot Mini. After setting it up and kicking out a number of awesome prints, I placed the M3D next to the Makibox. I now had a collection of old, cheap and not very good printers. I had to do something about that.

The Makibox has some decent steppers and screws in it (the M3D really doesn't - half the problem really) so I started looking at the parts and wondering if I could convert it to a PCB mill. Ideally I'll eventually want a proper mill that can do aluminium and stuff, but I reckon I can cobbled together something good enough to grind a few hundred micros of copper off some fibre glass. Bonus points if it'll drill through holes.

What's the worst that can happen? I have a broken Makibox?

  • 3 × 285mm 40x40 Aluminium Extrusion
  • 4 × 260mm 40x40 Aluminium Extrusion
  • 2 × 401mm 40x40 Aluminium Extrusion
  • 1 × 205mm 40x40 Aluminium Extrusion
  • 16 × 8mm M8 Square Washer

View all 8 components

  • Building the X-axis

    Myles Eftosan hour ago 0 comments

    Re-designing the X-axis of my Makibox to PCB mill conversion has been a challenge in constraints. Due to an ordering mishap, and lack of engineering designs for the spindle I have been racking my brain to re-use the parts I have to create a workable X-axis.

    The three constraints I have to work with:

    • The spindle can’t be too low – I want at least 70mm of vertical travel
    • The spindle can’t be too high – The further the cutting tool is from the centre of the holder, the more torque it needs to deal with
    • The spindle can’t be too far forward – I’d like the cutting tool to sit as close to the centre of the frame, so it can reach the full range of motion. The shaft of the spindle sits around 40mm from it’s mounting plate, which puts it out nearly 80mm when you include the Z-axis linear driver.

    I looked at mounting the stepper motor on top of the vertical extrusion, but it failed constraint 3. It also gave me no where to mount the top steel rod. I toyed around with moving the steel rods but centred either side of the lead screw seems the best place for them.

    I settled on a design where the motor hangs off the side of the vertical extrusion, with the steel rods mounted either side.

    The test build

    After printing motor and bearing holders, and the carriage I put everything together. I held the spindle against the carriage to get an idea of placement, and it became clear that the 4mm steel rods were going to flex too much under load.

    They would be fine for a 3D printer or as a laser cutter, but even the small forces from a PCB mill bit would cause issues. It was time to replace the rods with something more robust.

    I jumped on Aliexpress and found these 200mm linear guides that have a 12mm steel rod, and support for the full length, so bending should not be an issue.

    I also decided to replace the Y-axis rods with the 400mm version of the linear guide. This will remove the flex in the bed and will make alignment easier (the three points of contact design I used was difficult to square).

    While I was at it I ordered some plain 12mm rod, and linear bearings for the Z-axis for good measure.

    A substantial redesign.

    I have one 205mm cross bar, which a perfect support for one of the linear rails – I’ll need another one. I’ll also need another two, taller vertical extrusions to hold the cross bars. The two shorter vertical extrusions will hold the motor.

    Here is a rough render without any joining hardware so you get the idea.

    I’ve had to move the vertical extrusions to the rear of the frame (which is fine, there are still two connection points there), giving the spindle plenty of room.

    I’m going to design and print some new motor and bearing mounts for the X and Y axis. They will be much simpler as they no longer need to support the steel rods.

    The rear support for the Z-axis will be 10mm aluminium, as I can get the supplier to cut it to the required 138mm length. The end caps – which act as a motor holder and rod support – will be plastic to start (I don’t have facilities to mill aluminum… yet). My intention is to mill replacements once the machine is complete.

  • X-axis. Sort of

    Myles Eftos6 days ago 0 comments

    Been experimenting with the X-axis.

    Probably not the way forward as the the 4mm linear rod are too small and flex too much. Will flesh these thoughts about further and blog about it properly soon.

  • Building the Y-axis

    Myles Eftos07/15/2018 at 23:58 0 comments

    I've now built the aluminium frame and completed the Y-axis. Of course, this was not without it's problems.

    Firstly, I misordered - I was one set of uprights short. This may not be a massive problem though, as I hadn't taken into account the size of the spindle when designing the X-axis, and it wouldn't have fitted in the configuration I had designed for - That's what you get for forging ahead with out good engineering drawings.

    Other minor issues were easily fixed by reprinting some parts - I added limit switches into the motor and bearing holders (though I haven't worked out how to make the switch on the bearing holder work yet), I made the driver carriage wider so the whole anti-backlash nut fitted completely and I changed the shape of the passenger carriage so it could slide over the entire stroke.

    Everything went together quite well - I did my best to square everything up, using a shim I printed - the holders may not be exactly in the middle, but they are all consistently out, which is the main thing.

    I was a little concerned that both carriages were rotating around the z-axis, but realised that was because they weren't joined yet, so there was only two points of contact, rather than four. 

    To fix that, I cut out a 205mm x 205mm MDF spoil board, and attached it using a 0.33mm feeler gauge squared it against one of the uprights.

    I'm not sure I can do more alignment without having a X-axis, which requires a redesign.

    See the video below for the test! (Excuse the upright video - I need to get an iPhone holder)

  • Waiting, waiting

    Myles Eftos06/26/2018 at 22:48 0 comments

    This is less of an update, more of a keep alive. I’m waiting on the last of the parts to arrive from China, so I can do final fit tests before drilling holes in frames, but I did try a quick fit test of the Y axis

    I suspect it is going to have way too much deflection in the Z-axis, which is disappointing, but not unexpected. I’ll looking into alternative linear rails options. That won’t be a blocker right now though, as I should get on to testing the control board.

  • Aluminium frame is done

    Myles Eftos06/02/2018 at 04:24 0 comments

    I’m pretty happy with how the aluminium frame has come together. I’ve kept the X-axis pretty simple, though I tried a few iterations before coming to this shape.

    Originally I had the vertical X-axis supports butted on the top of the horizontal Y axis base, but I was concerned with keeping the vertical… vertical. I could have used right angle brackets, but decided that by putting them in the inside of the base, I can add additional points of contact that would better support them. This configuration also gives a slightly larger base, so should make it slightly more stable. They are now attached in two dimensions which effectively works like a right-angle bracket.

    The motor mount and bearing mounts are pretty simple, bridging the two verticals on each side. I toyed with running the bolts in a horizontal extrusion that would stop them from slipping down, but that would stop me from adjusting the heights when tramming.

    On the topic of adjustments, I’m starting to regret the dual-carriage design, as there is an extra dimension that needs to be aligned – not only do I need to align the X, Y and Z axes, I need to make sure both slides are exactly parallel. I’ve bought a digital dial indicator which should help in squaring everything up – we’ll see how that goes.

    The order cost me just shy of $200, which already takes me over my $250 budget, but I’ve been reconsidering how much I’m spending, as I assumed I could use my Dremel 4300. After a bunch of reading, I think I’ll need to by a different spindle that has less runout.

  • Designing the Y-Axis

    Myles Eftos04/23/2018 at 23:38 0 comments

      I’ve been iterating the Y-axis in Fusion 360. A common design I have seen on other moving-bed designs is four linear bearings - one bearing at each corner of the bed. The problem with this design is you lose the distance between the bearings in travel. Since I have only have a maximum of 165mm on this axis, I didn’t want to lose too much to dead play.

      My first thought was use a single bearing on each side, introducing a minimum lost travel of 12mm (the width of the bearing). This looked like it would cause rotation problems, though - especially when dive cutting in the outer edges of the build area.

      I went back and looked the parts I could salvage from the Makibox, and it turns out I have four 170mm linear rods at my disposal. This means I can create a passenger carriage - one that isn’t driven by the lead screw, but instead is pushed along it’s rails by the bed itself. This design gives four points of contact, eliminating the radial moment of the two bearing design (Note: this doesn’t deal with linear rod or bed flex, just the rotation issue). The disadvantage is the base is now double the size, but as the bed would have moved outside of the frame envelope during operations, it’s not that big of a deal.

      Here is a render of the Y-axis. If you imagine a bed on top of it, attached to the two carriages - the left (driver) carriage is driven by the lead screw, while the right (passenger carriage is pushed by the bed. (I tried making a video, but the Fusion 360 animation workspace doesn’t support animating joints!)

      The Y-axis will have a 131mm travel - the loss is 7mm from the ball bearing, 7mm from the coupler and 20mm from the anti-backlash nut.

      A couple of side issues I still need to work out:

      1. The mount holes for the anti backlash nut are too close to the shaft, so I can’t heat fit brass inserts to screw in to - I may have to thread the plastic. I may be able to find some small nuts to secure it. Ideally once the mill is working I’ll be able to machine a bracket from a small plate of aluminium 
      2. I have brass inserts in the carriages because I initially thought I would screw the bed down from the top - making replacement of the spoil board easier. This may not be an actual problem though - I’m not sure how often the spoil board needs changing. I may just make them screw holes, and be done with it. I have to think about it a bit more.

      Next up: the X-axis

  • We are back on!

    Myles Eftos09/15/2016 at 11:12 0 comments

     Time to unshelve this project. 

    I have been doing some research into PCB mill designs over the past couple of weeks, and I've decided to move from a fixed bed, to a fixed gantry design (based heavily off the cheap Chinese machines). This means I only need three motors, and three lead screws rather than 4 of the original design.

    I'm giving myself a $250 budget for the conversion.

    Due to the existing hardware that I want to reuse, the actual build area for this machine will be relatively small, so I'm hoping that will help with the rigidity of the system (smaller builds should be stronger than larger ones). Given that this PCB millgets decent results with a wood base, I'm feeling pretty confident we can get some good results with this.

    So, a stock take of what I have from the Makibox:

    • 4 x NEMA 17 sized motors (Longs: 17HS 42BYGH 1.8°)
    • 1 x 218mm T8.8 (8mm diameter, 8mm travel per revolution) trapezoidal lead-screw
    • 1 x 165mm T8.8 trapezoidal lead-screw
    • 1 x 147mm T8.8 trapezoidal lead-screw
    • 2 x 226mm x 4mm steel rod
    • 1 x 170mm x 4mm steel rod
    • 1 x 164mm x 4mm steel rod
    • A bunch of cap hex screws
    • Plastic couplers
    • Plastic anti-backlash nuts

    The plastic anti-backlash nuts are surprisingly good - I can't detect any backlash (with the naked eye). The injected plastic piece has some thread that acts as a preloader - quite clever really. Regardless, I decided to order some metal anti-backlash nuts - I'm not sure how the plastic will hold up to the additional force of milling.

    I also ordered some aluminium couplers (to replace the plastic ones), LM4UU Linear bearings (to slide on the steel rods), and round bearings to hold the lead screws. Total cost so far: $79.68.

    Everything else looks useable (at this stage) - I'm a bit concerned that the steel rods aren't straight enough, but I'll run with them for the moment.

    I'm going with 4040 aluminium t-slot for the frame. I've found a Melbourne based supplier so I should be able to get high-quality stock quickly (and cut to size!). But before I order them, I'm going to design the mill in Fusion 360 so I can test for fit and size.

    You can see the render of the Y-axis here:

    The X-axis will be basically a copy, rotated 90 degrees. The Z-axis will still need some thinking.

    The motor bracket, bed and bearing holder will be 3D printed on my Lulzbot Mini. This is is the cause of the weird design - it needs to fit in the 150mm x 150mm build envelope of the 3D printer.

    The design should allow a Y-axis travel of around 156mm. I still have to work out the X-axis travel.

  • Inventory

    Myles Eftos09/12/2016 at 13:06 0 comments

    So I had a look at the parts I had tonight. Four steppers, three with screw attached. Three plastic lead screws, a Print5D D8 printer controller, a bunch of screws and metal rods, and a 3D printer.

    I've been amazed that the Lulzbot has so many 3D printed parts - this makes me far more confident that printed parts will hold up strength wise for what I need.

    I think I'll rip off the Z-axis design of using two steppers and screws for the X axis. That will need to be able to drive the Y-axis reliably, so having two motors doing that work sounds like a good idea.

    I have two motors and screws that are almost the same size, and two matching plastic lead screws. If I take out the metal rods that are and use the two larger rods to join them together, I'll get little gantry system going.

    It looks like it might work.

    The one in the foreground is longer than the one in the background, but that is ok - the travel will be limited by the shorter of the two (it's about 10mm shorter, so not a big deal).

    So now I guess I have to print some mounts for the motors and the rods... and formulate a plan for the Y and Z axis.

View all 8 project logs

Enjoy this project?

Share

Discussions

Myles Eftos wrote 12/06/2016 at 00:54 point

Thanks for the comments. This project is on hold at the moment, while I finish some other stuff.

Power supply and controllers aren't show, but they are there :)

I have similar concerns around the plastic - it might just end up being a pen plotter. We'll have to see!

  Are you sure? yes | no

agp.cooper wrote 12/05/2016 at 08:27 point

Hi Myles,

PCB Milling

==========

I have done it but not that keen anymore. With my eyesight and no solder mask, it makes PCB isolation a pain.

---
Software is no big deal, search for grbl and xLoader (you will need that to upload the hex file).
Search for GCodeSender (dead simple) or GrblController361Setup (or GrblController351Setup) for a grbl controller. There are others.
---
Creating gCode for the PCB Isolation will be a little harder. There is a plugin for Eagle PCB (http://www.pcbgcode.com/) that may work for you (there is a free version of Eagle Cad that is limited to 100mm x 80mm PCBs).

I wrote some code for DeltaCad that converts a BMP into a DXF to do my PCB isolation if your interested (DeltaCad costs about A$80). See https://hackaday.io/project/12900-pcb-isolation-macro-for-deltacad. But I have a Cut2D to convert the DXF into GCode.

---

As far as what I see in inventory, where is the rest of it? No power supply, spindle, stepper controllers, Z axis??!

---

Those plastic support look as if they may be too light to give much satisfaction with the mill that you plan to build (i.e. not rigid enough). I have a cheap Chinese 3040 and that is not rigid enough to do a good job with speed. The bed and the Z-axis needs to be spot on for PCB milling. At speed the machine flexes and can take out your tracks.

---

Hope this helps, AlanX

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates