This router is inspired by the Openbuilds OX, but with a ground up design that improves upon the OX's weaknesses.
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My first CNC machine was a shapeoko and while it was pretty cool for what it was, my first mod was to make it bigger. Then I began to notice that it had serious rigidity issues especially when I got brave enough to tackle aluminum. So I designed a replacement for it, and while it was leaps and bounds above a shapeoko (the router mounts were the only remaining piece from the original machine), it still had some limits. With a maximum cut of 14x14, I decided I needed something bigger.
Design Considerations
When sat down to design this router, I did a lot of research as to what was out there and made a list of things that were important to me.
And of course, it must look tough and not like some cobbled frankenrouter. I managed to hit every one of those points except overall cost. In all it was not super expensive and for someone who works on a pretty tight budget that is important. Heads up though, the hardware alone is the biggest expense!
- Cut area
- Strength
- Rigidity
- Speed
- Ease of maintenance
- Overall Cost
Specs
- X axis: Misumi 4080 x 1000mm with openrail
- Y axis: Misumi 2060 x 1500mm with open rail
- Z axis: 2060 Vslot with 8 solid wheels, 8mm Acme rod, 3:1 ratio gearing through 2 threaded blocks
- 4 NEMA 23 steppers @ 269oz/in
- 15mm htd-3m belts
- 0.75" MDF open torsion box
- 5 axis parallel breakout ran on LinuxCNC
- Dual Y homing switches for auto squaring in LinuxCNC 2.8pre
- 4 TB6600 driver modules @3 amps (1 X, 2 Y, 1Z)
- 24v 30A power supply
- Aluminum plates 100% recycled from local scrap yard
Remember, Ebay is your friend!
So here are the pics...
This is the finished product looking pretty mean.
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(UPDATE)
This is my second version, Black Rabbit 750
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The Controller
The controller is designed to use a parallel breakout and separate stepper driver breakouts. I use linuxCNC as my main software because it gives me more control over the machining process than using a GRBL board. It incorporates separate drivers for the Y axis so that I can do tandem homing so that squaring the gantry can be done in software rather than the shim and measure method. (Being able to cut square every time over a large distance is amazing)
(UPDATE)
Some of the lessons learned from controller v1 to v1.5:
- Redesigned the side panels because as cool as it looks, it is also awesome to be able to get into your controller without having to dismantle the whole thing!
- Created modular rack system for the drivers which attach to the extrusions rather than the acrylic top plate.
- Used 7 pin aviation plug with common ground for limit cable rather than separate connections for each one.
- Added rocker power switch on back for power instead of key system. Will probably still use if for my laser though, but need to find a switch that captures the key when turned.
- Included 12v out to power laser guides and dust shoe lights
- Added 3rd fan on side panel to make sure airflow is spread evenly
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This is the building process of the controller.
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Test fitting the parts together
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The best investment I ever made was a cheap harbor freight powder coating gun and a pizza sized toaster oven from walmart. So much better and easier than painting, but if you blow it, that stuff is HARD to get off!
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1500 Build
The original design was to be able to use a limited number of unique parts and create a design that is modular and can be nearly whatever size you need it to be.
I built this one around a 1500x1000mm design and another one to be 750x750mm. The original design is built like a tank, but at the same time very fast. I learned a lot from this build and incorporated those lessons in the 750 build and then retrofitted those lessons learned on the 1500
Some notable improvements:
- Designed spacer block on top and bottom of X axis plates to ensure rigidity and consistent spacing
- when with 3 wheels on top of y plates rather than 4. the gantry is heavy, but not that heavy.
- Modified the belt clamps, and will still do one more iteration with a screw drive for tensioning the belt
- minor tweaks to the torsion box
- Flanged bearings are the greatest thing ever created and I now use them on the belt roller bars
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The Torsion Box
The torsion box is made of 3/4 MDF with M6 threaded inserts in the deck. For the 1500, I glued the deck and all of the ribs down, and for the 750, I decided to glue the bottom and ribs of the box, but use countersunk screws for the deck just in case it gets damaged and I need to be able to replace it. It is still amazingly strong even not being glued.
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The Finished 750 and 1500!
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The Future:
Now that I have a working tabletop router and can cut again, some of the first projects are a lighted dust shoe with laser alignment guides and an enclosure to keep the mess and noise down.
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Black Rabbit 1500
Build in 'Cartesian Style CNC' published by Dexter Oddwick, Sep 2, 2016.
This is a router that I designed that is loosely based on the Openbuilds Ox, but designed to be heavy duty, rigid, and yet quick and agile.
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- Build Progress:
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- Build Complete!
Attached Files:
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Build Author Dexter Oddwick, Find all builds by Dexter Oddwick
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Build Details
- Build License:
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- CC - Attribution NonCommercial - CC BY NC
Reason for this Build
I needed a heavy duty, large format router, but at the same time cost effective and more agile than screw drives. Overall, I like the concept of the OX, but I feel that it has some limitations and weaknesses, so this was designed to correct those.Inspired by
OpenBuilds OX and Mark Carew