Inventables Community Forum

Building B-Carve

short version:

My X-Carve asked for a big brother. I think I will call him B-Carve.

long version:

I was initially planning to upgrade my 500mm X-Carve to 750mm to gain footprint. Then I thought I would also like a T slot bed. And maybe something stiffer than V wheels and belts.

So after spending a year with the X-Carve making dust and experimenting and upgrading the machine itself I thought to take the challenge to design and build something bigger. V wheels & GT3 belting have performed just fine, but now let's try HGR15 & 1605.

The main goal is to go heavier and stiffer... and therefore faster... and therefore sleep more. Carving is a hobby for me (at least for the time being). It takes place after my girls go to bed. So, any gain in machining time translates to more hours of sleep.

Also, I want to see if I can build a 5k machine myself within a 1.5k budget. Also, to have fun tinkering and problem-solving and failing and trying again and learn some lessons along the way.

In terms of logistics, long parts (extrusions, guides, drives) will be sourced locally to avoid surprises with customs. All smaller parts (guide blocks, ballnuts & mounts, bearing blocks, motor mounts, couplers, brackets, z axis) are coming straight from Chinese sources. This is going to take some time.

The picture above is a render from v58 ...and this is still not final :slight_smile:

PS. This is not a guide, it's kind of a personal journey. Of all the posts in this forum, what I have enjoyed reading the most were other people's custom builds. I thought to share as well.

24 Likes

Your story sounds just like mine :slight_smile: CNC time = when the girls go to bed. Although I just got my X Carve a few months ago, I am very interested in following this. Looking forward to seeing how it comes out! Good Luck!

Look fab! I am also doing something very similar based on SBR16 rails and ACME T8 lead screws. (would love BB'd lead screws but that will need to wait!) Nema23's and dual Y's. Wood torsion box with 4" fence around the table perimeter.
My aim is also to achieve a more rigid setup (currently running a diy-CNC on the cheap) :smiley:

Looks like a great project. You might could save some money by using a single Y motor and ball screw.

Most machines in this class seem to have a single screw drive under the table with linear drive guides on the side.

I wonder if the quality of the chinese railblocks will be adequate. But my linear Z axis is pretty good so I guess it's worth a try.

This is a bucket list project for me too, but probably a couple of years down the line.
I'd be very interested in seeing any kind of plan, or even just a parts list.

@AllenMassey
I did check out some single Y setups like this one and this one apart from the double ones like this one and this one while researching.

I settled with the dual Y since
- with a single Y I wouldn't be able to cut my own (wider than my machine's cutting width) Y end plates
- I like the idea of having the drive(s) close to the guide(s)
- I already have an X-Controller (i.e. dual slaved Y 3Amp drives)
- I have no problem with my existing belt-driven dual Y setup (the ballscrew-driven setup is expected to have even less -virtually zero- backlash)

Btw, by no means do I claim that this design is the best homegrown CNC out there. It's meant to serve a purpose within certain limitations in a certain confined space.

@xfredericox
I'm not making any quality discounts on the guides. They are the cornerstone of the build. I'm getting original Hiwins. 15mm is the smallest rail size, but more than enough for my application. Btw, this is by far the most expensive component of the build. I got the rails locally for 88EUR/m (approx 30$/ft). I got a sweet deal for the blocks though, for around 120$ for all 6 ( >300$ locally).

There will be snippets of plans along the way. As for the part list, it's essentially:
- guides: Hiwin HGR15 rails & HGL15CA blocks
- drives: OEM 1605 ballscrews & ballnuts & ballnut mounts
- bearing blocks: FF12 (floating sides) & FK12 (fixed sides)
- z axis: 1605 ballscrew & 12mm rod kit
- gantry: 60x30 extrusions
- base: 90x30 & 60x30 & 30x30 extrusions
- bed: 120x15 extrusions

(all sizes in mm)

Those are legitimate reasons, you have done your homework!.

My new machine has ballscrews and it makes all the difference in the world.

What spindle are you planning to use?

Sticking with the Makita currently. I am open to a VFD upgrade at some point, but there is no time for researching this right now.

...and here's batch A. 30kg of metal is not your ideal broom, but still nice to ride.

3 Likes

thats what I was hoping you'd say :slight_smile:
Thanks and looking forward to your build

Sibling rivalry already. B is pushing X to the corner.

The extrusions are just piled up. T nuts & brackets are on their way. You also get an idea of what confined space meant earlier.

This was the status since mid December. Then Santa came yesterday.

He brought the Z axis.

and ballnut mounts

and -my precious- guide blocks (still in factory oil). This is when I decided to start posting. I wouldn't dare to do so before getting a hold of them out of fear that they would be turned to paperweight by customs officers. Or be abducted by aliens.

Then Santa came today too. These are 269oz.in . I already happen to have a 4th one (345oz.in) for the X axis.

And this brings us up to date.

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I'm thinking a soundtrack of cnc machines needs laid down for all the cnc children who sleep better to the sounds of their father's cnc buzzing away in the garage...

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T nuts. Lots of them. Time to install the guides

...and calibrate them.

A couple of hours later.

I also cut a mock-up spindle mount (seen in the background) with the X-Carve. We'll see if we're happy with it.

2 Likes

That looks like a really compact Z-axis, can you tell us where you sourced it? I like the way you designed the machine by using ready made parts combined with what you can build yourself on your improved X-Carve.

Thanks. Now I have the Dirty Dancing soundtrack stuck in my head.

The Z axis kit is this one. I asked them not to include the motor, to make it lighter and cheaper to ship.

My criteria for the Z axis were
- stiff => ballscrew and rods
- no sacrifice in X travel => compact in X
- careful with torquing => compact in Y
- easy fit for the X-Carriage => 8020 based (*)

(*) I initially thought to get it as an X-Carve upgrade before deciding to build a machine from scratch.

Now here's the challenge:

compact kit => compact carrier => narrow spindle mount hole spacing

This results in the spindle mount cylinder covering the mount holes.

These are my spindle mount options:

Option A: use Inventables' spindle mount and cut an interfacing plate. I will leave this for last if nothing else works. The order of installation will be challenging. The only solution I can imagine involves cutting a stub allen key.

Option B1: new ( ) shaped spindle mount. This is shown just for reference. It will not work, as a minimum 18mm screw (DIN933, for side fastening) cannot clear the outer diameter to align with the mounting hole.

Option B2: new ( ) shaped spindle mount + slots. One idea to fit the mount screw.

Option B3: new ( ) shaped spindle mount + cut outs. If the slots of B2 are not enough. I am a bit sceptical about the cut out, but on the other hand, this design allows for the rear part to be thicker.

Option C: new [ ) shaped spindle mount. Needs mount holes for DIN912 screws. Beefier, but challenging to drill the outer pocket for the screw head.

Here's a detail of the pocket.

The carrier has 2 pairs of mounting holes, so all the options discussed above refer to spindle mount pairs (as also shown in the render of the original post).

i did it on my custom mounts with a crappy drill press, and it ended up being easier than anticipated.

http://www.manmademayhem.com/?p=2325

But I drilled at a 90 degree angle. I fear drilling a slope like that will be a pain, unless you drill before milling the shape

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Challenge but the best looking option. In this case I would suggest you take two blocks of aluminium, drill the fixing holes and mount them together with a 1mm sheet metal spacer before the router mills out the spindle mount. In that case there is no slope to worry about.

@xfredericox @ErikJanssen Thanks for the feedback. I like the idea of drilling square then milling. Then all the focus moves to correctly position/fix the drilled pieces before milling.

As I am writing this I am thinking
- cut the (rear) part minus the half-circle (i.e. rectangular profile + ears)
- mark and drill in drill press
- cut a pocket on same thickness scrap material along the same contour (plus a hair for good fitting) to use as a fixture with same X0Y0Z0 set with G10 L20 (as opposed to G92, just in case something happens and I need to home/reset)
- place the part in the fixture
- mill the half-circle

Should work, for making the bottom of the bolt holes flat you can use this special drill.

no idea what the formal name for it is, it came with some tools I bought.

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yeah sounds like a plan.

I also did the first few mms of the drilling operation on the cnc, as explained in my blog. Just so that spacing is perfect. Because I feel like centerpunching and manual drilling isn't exact enough. This is especially important at the back side where the bolt protrudes the piece. If the front (wider) hole is off by 0.1mm, it doesn't really matter all that much.