When I first backed the Carvera Air on Kickstarter, I was convinced that manual tool changes would be perfectly sufficient for my workflow. And to be fair — they are.

But I couldn’t help envying the automatic tool changer (ATC) of its bigger sibling, the Carvera. Once you’ve seen a machine swap tools on its own, it’s hard to ignore the convenience.

Fortunately, Makera had the foresight to prepare the AIR for exactly this kind of upgrade. The necessary wiring for an ATC stepper motor and the ATC limit switch is already integrated into the machine — just waiting to be used.

So this project was born.

In this guide, I’ll present my fully functional ATC mod for the Carvera AIR. I’ll walk you through the required parts, mechanical modifications, electronics integration, and firmware setup — step by step — so you can upgrade your own machine and bring true automatic tool changing to the AIR.

Let’s turn the little machine into its bigger brother.

Note:

Right now I have designed the magazine mounting to fit the SMW bed.

I have bought the wrong type of toolsensor and currently wait for a different one to arrive soon. I'll update this post, once it has arrive and I have installed it.

Bill of Materials (BOM)

For the ATC upgrade of the Carvera AIR

Mechanical Components

[1] HTD Timing Belt 425-5M – 9 mm width

(Note: Standard width is typically 10 mm, but 9 mm works perfectly.)

[2] 50:1 Geared Stepper Motor – rated torque approx. 10 Nm

[3] Neodymium Magnets – 3 pcs – 10×2 mm

[4] Compression Springs – 24 pcs

1. Wire diameter: 0.4 mm
2. Outer diameter: 4 mm
3. Uncompressed length: 17mm

[5] M3 Heat Inserts – 8 pcs

[6] Superglue

Fasteners

[7] M4×12 ISO 4762 Screws – 4 pcs

(Stepper motor mounting)

[8] M4×10 ISO 4762 Screws – 2 pcs

(ATC sensor bracket)

[9] M3×10 ISO 4762 Screws – 2 pcs

(ATC sensor)

[10] M3 Countersunk Screws – 16 pcs

(Length 10–16 mm, ATC assembly)

[11] M6×20 ISO 4762 Screws – 3 pcs

1. 1× pulley to lever cylinder
2. 2× ATC magazine to SMW bed

[12] (Optional) M3×12 Countersunk Screws – 4 pcs

(Front plate)

Electronics

[13] 3-Pin Microswitch with Roller Lever

1. Case dimensions: 20 × 10 × 6 mm
2. Hole spacing: 9.36 mm
3. Hole diameter: 2.25 mm

[14] 3-Wire Cable – approx. 0.5 meter

[15] JST 2.54 SM Connectors – 2-Pin and 4-Pin

1. (Recommended: buy a set including crimping pliers if you don't have one)

First you need to print all the parts that are needed for this mod.

These include:

1. Motor mount
2. ATC sensor mount
3. Bottom gear
4. Top gear (not affiliated with the tv show)
5. Magazine including the toolpods (2 parts per pod)
6. Cover
7. Frontplate (optional)

I have used Tinmorry PETG-CF for all parts, except the white parts within the atc magazine.

Supports are needed for the magazine itself and the motor mount (only on the bed for the counterbores for the m4 screws).

Dimensions are critical for the bores at the gears and the toolpods. It may be necessary to print more than once with different settings or scaling to get it right.

The frontplate is optional since it is intended to be individualized to mount additional things. Just edit the step file, position holes and put heat inserts in or just put screws in directly.

Put the 8 heat inserts into the motor mount.

If you've bought the same stepper that I did, you have to put a connector on it. There's two options:

1. Install a female JST-PH 6 pin connector on the stepper side
2. Replace the 6 pin JST-PH connector on the machine side with a different kind. I have bought a set of JST 2.54 SM connectors (needed for the ATC sensor) and have replaced the PH kind on the machine side with a SM type and did the same to the motor. Refer to the picture above

Once that is done you can screw it to the motor mount. I have oriented the wires to face the back of the machine.

Afterwards you can install the key on the motorshaft and press the top gear on the motor shaft. Make sure there gear doesn't grind on the motor mount but also doesn't have a bigger gap than 1mm.

Unscrew the set screw on the front and back of the lever and pull it out.

Make sure that the screw in the cylinder that goes into the spindle is tightened securely.

Press the bottom gear on the cylinder and orient it so that the cam points to the top right. Align the diagonal hole aswell with the hole in the cylinder where the lever was installed. Secure the gear with one M6x20 screw [11]

Unscrew the top cover of the spindle. It is held by 4 M3 countersunk screws. We will reuse these screw to hold the motor mount. Take out the cables that are labeled ATC sensor and ATC motor.

Put the motor mount inside the sheet metal housing of the spindle with the motor shaft pointing to the left. DO NOT put the screws in yet.

Next, put the belt around the bottom gear and press it on the top gear while tilting the motor mount in the way that the motor shaft now points more to the bottom and the motor itself is raised by a fair bit. That way you should be able to put the belt around the gear.

Now you can screw it in. This part might be a bit tricky because you actually have to put the base tension on the belt during this step. If you can't get it to work this way, you can try to install the screws (not tightened though) on the left side of the mount first before installing the belt. That way you can apply the tension on the belt by simply pressing on the motor until the threads match the holes of the spindle housing.

Tighten the screws and you are done.

You have to use a 3mm drill (or do it on the machine itself if you don't have a 3mm drill) and widen the screw holes of the sensor to fit a M3 screw.

Regarding wiring, refer to the picture above.

Solder one end to the N terminal and one end to the NC terminal. (We want to have it fail safe).

Install a male JST 2.54 SM connector on the end.

I'll post the ideal cable length soon.

Fix it with a cable tie to the sensor mount.

Afterwards screw the mount with the sensor on the spindle housing with 2x M4x10 [8] and first position it in the lowest position.

Insert the springs in the holes of the magazine as shown above. Next, install the toolpods by screwing them down with the ring clamps. Once one, tap on each toolpod first to check if it bounces back up freely. If it doesn't twist the pod sideways in both directions. This might free the spring. If it still sticks in the bottom position you have to find where it catches and maybe sand it there.

Install the magazine with 2x M6x20 [11]

Download both the community firmware and controller (> 2.1.0-RC1)

Firmware

Controller

Once the firmware has been installed, run this command:

"fset func 5"

This tells the machine that it has an atc now.

It is also handy to use the main button long press function to clamp and unclamp the current tool.

In the controller go to settings Machine - Basic -> Main button long press function -> ToolChange or run:

"config-set sd main_button_long_press_enable ToolChange" in the MDI.

Next put the custom_tool_slots.txt on the root of your sd card. These positions specify where the tools are located. It does fit my machine and you might need to adjust accordingly.

You can find the sd card on the controller board of the machine. You have to unscrew the 9 screws of the top back panel of the machine. Just pull the card out, you don't have to push!

Glue in the magnets as shown above. Also glue together the two pieces of the cover. The orientation should be self explanatory since they only fit in one way.

When the glue has dried you can just slap the cover on and it'll hold perfectly by the magnets. Use the 2 indexing pins to specify the position.

You should now have a fully working ATC on your Carvera AIR!

I just love working with it every day compared to the manual toolchanges.

I will update this manual step by step with more information but this is all I could do at first.

-- Warioo