CNC Router Build

[DDY]

Big project time!

I’ve been thinking about building one of these for years. Yes, I could buy a CNC router with comparable capabilities for £150 delivered but I quite enjoyed building my first 3D printer kit back in 2014. As I’ve retired that exact 3D printer from 2014, I figured this would be great opportunity to take it apart and use the broken down bits to build, almost from scratch, a CNC router.

The 3D printer I built in 2014 was a Velleman K8200, quite bulky by today’s standards and lacks the capabilities of its contemporaries. Performance was suffering and it needed to be rebuilt due to age and use related wear-and-tear, I thought about upgrading it while rebuilding e.g. new extruder and hot-end, and new controller and drivers, but figured to make the most out of an upgrade I’d need a 3D printer to print the parts!

One way or another, I’d needed a new 3D printer. Well, when I say need… You know what I mean! Ended up replacing the K8200 with a Creality Ender 3 V2, nice bit of kit – almost a third of the price and took about 2% of the time to get up and running to the first good print compared to the K8200!

I mulled over how I could convert the K8200 to a CNC router, but as my conceptual designs progressed, it ended up being more than a just conversion. This was mostly down to the difficulty of adapting the belt-pulled XY bed and the low strength of the Z axis – it all needed to be changed.

So, from this:
https://forums.hexus.net/general-dis...adventure.html


I’m planning this:


That's my initial concept sketch to figure out how it will all go together. I have 95% of the materials needed and I’ve already started to 3D print a few prototype components for the Y axis - the easiest axis...

Updates to follow soon!

[g8ina]

Nice. Its the one bit of kit Ive always fancied but cant really justify. Yes, I have a table saw, pillar drill (new, Titan 700 watter !), lathe etc, but there are some parts I can't make unless I go 3D one way or another

I may have some things for you to make soon !

[Kovoet]

A mate of mine built and he does a lot of car modding with it. Envy you guys using these. So much you can do with them

[kompukare]

I once had a bunch of old printers and someone remarked how the stepper motors in some of them are really sought after for DIY CNC routers. Aside from not having a shed - and lets be honest, for this kind of thing you'd really want a Mathias Wandel (woodgears.ca) sized shed/workshop, I always though building one was way beyond me. I'm okay at DIY and woodworking but this kind of thing requires a lot more engineering than I am used to.

@DDY, will be interested to see the final results!

[DDY]

Quick update.

The 3D printer has been running since Sunday during the day-hours, here's a collection of the prototype 3D prints I produced to test the fitment.





I haven't done any more design since yesterday, currently waiting for the 3D printer to churn out a few-days worth of parts.

Once I'm happy with the fitment of the 3D printed parts, I will commit to cutting the aluminium profile extrusions to size. The annoying thing is that the K8200 uses an uncommon aluminium profile size of 27.5mm and replacements need to be sourced from Germany, hence wanting to be sure before chopping them up!

[jimborae]

Oh crap, now you've got me wanting one of these, especially as there's been a couple of situations recently where I need to print some 3d stuff. Also that Creality Ender 3 V2 looks sweet as it seems you can really customise it, some great vids on youtube.

[DDY]

The motor speed controller arrived today, a Velleman Kit K2636, which I suppose leads me to a quick explanation of the plan for the electronics.

The controller board that came with the K8200 is a Marlin derived design, basically an ATMega 2560 with four slots for the common A4988-type stepper driver modules.

I could in practice use the same board and flash it to GRBL but I figured the time and effort needed to reverse engineer the K8200 controller, e.g. to figure out the pinout, would be more than say buying a CNC shield for a regular Arduino, and simply using a reference setup with GRBL.

GRBL is a firmware for the ATMega 328 (e.g. the Arduino Uno) and the latest version also adds supports the ATMega 2560 (e.g. Arduino Mega).

The CNC shield I bought is also takes common A4988-type stepper driver modules, so pulled the drivers off the old K8200 board and popped them on to the CNC shield. I have a few TMC2208 stepper driver modules on order, I’m using the A4988 simply because I have them to hand – I was intending to upgrade them on the K8200 anyway but never got around to it.

I can also reuse same 15V power supply, which I upgraded on the K8200, should be more than OK for this build since there’s one less stepper, no heated bed and no hot end now. The router will be powered from the mains via the speed controller.

The CNC shield doesn’t have any baked in support for spindle speed, just the signal to enable and disable – a relay signal in my case, hence my need for a separate speed controller, or a router/spindle with its own speed controller - although the £30 router I bought from Aldi is single speed 30k RPM job. Secondly, it should be fairly easy to adapt GRBL to control spindle speed off the K2636 which is a triac AC wave chopper circuit controlled with a potentiometer, can't do this as easily with a router with built-in speed control.

As for pushing GCode to the GRBL controller? While I haven’t got a solid plan on that yet, I’m going to play around with Fusion 360 and decide if I want to separate the GCode sending task to something else, like a Raspberry Pi or spare regular x86 machine I have lying around.

That’s it for this update, the 3D printer still churning out parts!

Velleman K2636:


CNC shield with the K8200's A4988 drivers fitted


Bottom of the machine table, a 15180 aluminium T-slot profile, with a pair of 3D printed linear bearing brackets.


A common sight over the last few days

[DDY]

Progress!

Now that the physical design and all the significant 3D printing is done, and most of the additional parts needed are now to hand, I've started putting it together!

It hasn't taken me half-a-year to 3D print or order stuff, that was actually done in January. I just needed a dedicated space to put this together and I only just got around to completing all my other projects in the shed-workshop, so now the workbench is free.

I started with the base and the Y-axis, that's all gone smoothly. Next is the Z axis.