X-Carve CNC Router

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Bloominglabs has an Inventables X-Carve 2015 750mm CNC router. This is a machine which can carve, cut, drill, and engrave sheets and pieces of wood, plastic, soft metals (like aluminum), and other materials.

After several months of on-again, off-again tinkering, the X-Carve made its first cuts on 31 January 2022. Although there are many improvements to be made, it can now be used as a tool.

Contents

Specifications

  • cut area of 750mm x 750mm (29.5 inches square)
  • Z-axis range of 65mm (2.5 inches of up-down movement)
  • gshield with three 1.5A stepper drivers, PWM spindle control, and grbl firmware
  • 300W 24V air-cooled spindle with ER11 collet
  • 400W 24V power supply

Assembly and Maintenance Instructions

This is a pretty old model, so the relevant instructions seem to be a hybrid of 2015 and 750mm.

Software

Easel

Inventables's official software for the X-Carve is Easel, a cloud-based CAM program. An account is required. It starts with a 30-day free preview of "Easel Pro", which offers desirable features for a subscription price of $156 $233 per year, and falls back to the more limited free tier.

Alex tried to get Easel to work, but was unsuccessful. Getting Easel to work seems to require installing the drivers, changing the laptop's DNS, networking, and browser settings, and possibly also changing the router's and modem's firewall and port-forwarding settings. Everything in that very tall stack of software standing between the X-Carve's microcontroller, plugged in on a USB serial connection, up through the browser to "the cloud", has to work perfectly, and Easel doesn't seem to provide any error codes. Many people online use Easel, but no one else at Bloominglabs has tried and succeeded in getting it to work. With these problems in mind, it seems worthwhile to get alternative software working:

Alternatives

At present, the laptop has Universal G-Code Sender, Blender with BlenderCAM, FreeCAD, Solvespace, and F-Engrave. Some other (mostly F/LOSS) programs below have been tried (and notes added), but these currently seem most promising.

Proprietary

Alex has experience with V-Carve; it would definitely work for this machine. However, the current consensus has been to try to find a good F/LOSS solution, and only buy proprietary software if none can be found.

Most of these programs require Windows. Also, most have system requirements that far exceed the laptop currently assigned to the X-Carve; a new computer would have to be found or purchased.

F/LOSS

Machine Control
G-Code Generation
  • BlenderCAM
  • dxf2gcode (Opaque user interface requires specific names for layers to make it do things. Has a bug where sometimes it commands straight paths right across shapes. As of June 2023, instead of launching, it errors: ImportError: DLL load failed while importing QtCore: The specified module could not be found.)
  • F-Engrave (Only for engraving and v-carving. Imports CXF or TTF fonts, and JPG, PNG, and DXF bitmaps.)
  • FreeCAD's Path Workbench (Seems viable for sophisticated parts, but complex. Laptop has FreeCAD 0.19.1)
  • Kiri:Moto (Browser-based. Imports STL, OBJ, 3MF, SVG, PNG, and JPG.)
  • KrabzCAM (Browser-based. Imports SVG, DXF, PNG, and JPG.)
  • Solvespace "is capable of exporting simple G code for 2d parts"
Both

Future Plans and Upgrades

The following members have pledged a total of $300 (as of Sunday, 21 November 2021) in donations to improve the X-Carve and make it a good machine for people to use at Bloominglabs. Thank you all!

  • Adam Stitcher (contributed shielded endstop wires)
  • jpt4
  • dosman (contributed Wide Makerslide for X-Axis upgrade)
  • Kyle
  • Christopher Tiwari

So far, $54 (not including shipping) have been spent on the X-Carve.

How the remaining funds will be used needs to be decided. Below is a list of ideas on how to improve the X-Carve, many (but not all) of which require, or will be much easier by, spending money.

Reinforce Table

The (large, and generously donated by Jason Brown) table is very stable across its long dimension, but rocks along its short direction. This happens to be the same direction that the X-Carve's heaviest moving assembly (the gantry) moves. This will probably cause the table to visibly shake when the machine makes aggressive cuts.

Adding some diagonal braces under the table (especially to the center two legs) should fix this.

More Tooling

The machine came with a few end mills. Bloominglabs also received, in a previous donation to the Electronics room, a collection of very small end mills and drills, suitable for milling and drilling custom circuit boards. Lastly, the spindle can accept 1/8" tooling meant for Dremels and the ShapeOko 2 CNC.

All that said, these are tools we don't have and might want, depending on what people want to do with the X-Carve:

  • ball-end mills (for making contoured surfaces)
  • V-nose end mills (for v-groove engraving)
  • 1/4" shank tooling (much sturdier than the 1/8" tooling we have, for removing material fast or just resisting mis-use)
  • downcut end mills (for milling thin or flexible material)
  • compression end mills (for producing a nice finish on both sides of plywood)
  • surfacing/facing mills (for making large, flat surfaces)

Also, tooling will wear out be broken, so we will want to have extras, and known-good places to buy more.

Compatible tooling can be purchased from many sites and stores, but Inventables is a good place to start.

Dust and Chip Collection

Right now, the X-Carve has no dust collection. Sawdust (or fine chips of whatever material is being cut) either get packed into the cuts, or they get scattered into the air, settling in a fine layer all over the machine and surrounding area.

The previous owner 3D printed a mount to hold a vacuum cleaner hose right up to the spindle. Completing this would allow the machine's waste to be captured while it operates. It needs:

  • a plastic disc (which could be made on the laser cutter) to cover the top of the vacuum adapter, and
  • a shop vac (ideally with a cyclone separator) and hose.

It would be nice if it also had:

  • a nice home for these things to stay in:
    • a stand to support the hose above the work, or a hose that follows the cable chains, or a hose that is stretchy enough that it can go from a mount to the spindle without excess length dragging all over the work
    • a shelf under the table for the shop vac, with a hole in the table for the hose
    • or even better, a soundproofed box under the table for the shop vac, with muffled exhaust
  • a convenient way to turn the shop vac on or off, either
    • locate the shop vac in a place where it's just easy to turn it on and off with its own switch
    • a power strip (like on the laser cutter) with a switch for each thing plugged in to it
    • electronics that detect when the spindle is running and turn the shop vac on, and leave it running for some seconds after the spindle stops
    • electronics on the controller board, and custom g-code, that allow the machine to control when the shop vac runs

A slightly more expensive but much quieter alternative to the shop vac is a dedicated dust collector unit, which could have a hose going right to the spindle, or ventilate the enclosure or area around the machine, or maybe both. A dust collector could also be homemade; Matthias Wandel has loads of examples of these.

Upgraded Spindle

The machine came with a very basic air-cooled brushed DC spindle. While functional, it is noisy, not very powerful, probably can't take much cutting load, and offers poor control over its speed.

Trim Router

It is common for these machines to use a handheld trim router. At 1 to 1.25 horsepower (750 to 900 watts), these routers are 2.5x to 3x more powerful than the 300 watt spindle that came with the machine, and also probably have much more durable and truer-running bearings. The current X-Carve is offered with a $99 30,000 rpm Makita router; for older machines like ours, the mount is available for $35. Another good option is the $99 Bosch Colt, which is slightly less powerful but claims 35,000 rpm and the same electronic soft-start and constant-speed features. I'm pretty sure it'd fit the $35 DeWalt 611 mount.

In general, these machines only take 1/4" and 1/8" collets, so they can only use tools with shanks in those diameters. An exception is the $150 Carbide ER11 Compact Router, which can use any ER11 collet (which covers a lot of other sizes, especially metric ones). Whether or not this is desirable depends on how exotic of tooling people want to use.

Electronically, the router would just plug in to one of the AC outlets, right next to the laptop and the 24V power supply. The hacker/maker would have to manually turn the router on and set the speed dial before starting the cut, and turn it off after. It would be possible to wire a relay into the existing spindle control circuit, which would allow the machine to turn the spindle on and off, but not to control the speed.

Water-Cooled VFD Spindle

A router would be a substantial performance improvement over the existing 300W hobby-motor spindle, but they are very loud. Most of the noise comes from the fan that keeps the motor cool.

Enter water-cooled spindles. Similar to the laser, these have a jacket around the motor, through which water is pumped. The water gets circulated into a tank or bucket, and keeps the spindle cool due to its thermal mass and, if necessary, evaporation. This eliminates the >20,000 RPM fan, making these spindles much quieter (and more tolerable to share a room with). Here is a video comparison of the noise.

There are many near-identical water-cooled spindles available from China.

Most-Common Chinese Water-Cooled Spindle Sizes
Power (kW) Diameter (mm) Length (mm) Weight (kg) Collet Size
0.8 65 195 3 ER11
1.5 80 188 4.1 ER11
2.2 80 213 5.5 ER20

Although the more powerful spindles are more popular and only slightly more expensive, anything more than 800 watts is probably overkill for the X-Carve, both in terms of cutting power, and in terms of size under an enclosure and weight to swing around. A 800W spindle like the GDZ-65-800A can be bought for around $90-$140.

These spindles require 3-phase electricity, at a variable frequency so that their speed can be controlled. This would be produced by a Variable Frequency Drive. Cheap ones cost ~$100 and, like the spindles, are available in a range of power outputs, with much more powerful units costing only a little more than less-powerful ones. It would probably be sensible to overspec the VFD to 1kW or 1.5kW so that it will never be overloaded by the spindle.

These spindles usually require 220V. Some are available at 110V, but their specified current draw (usually 4 or 5 amps) doesn't make sense for their claimed power output (110V × 5A < 800W). It would be safest to get a 220V motor and ensure it will get that much power. There are definitely VFDs which flat-out claim to be able to provide 220V from 120V, but they seem to cost more like $500. The inexpensive ones might be able to do it, but it's hard to tell for sure, given the range of models and poor documentation. It would be safest, then, to get a 220V VFD, and an inexpensive (~$55) 120V-220V 1kW or 1.5kW step-up transformer to power it.

Besides the spindle motor, VFD, and transformer, this setup would also require a water pump, supply and return hoses, reservoir, and a cable with a 4-pin aviation plug to connect everything together. These can be purchased all together in kits. For larger spindles, the kits appear to be cost-effective, but for 0.8kW spindles the kits appear to cost more than the sum of the parts (>$300).

The 69mm mount we got with the X-Carve could hold one of the smaller spindles with a spacer. A (simple) mount would need to be purchased or made to hold one of the larger spindles.

Polycarbonate Enclosure

The machine needs a permanent enclosure to keep sawdust from the woodshop out, and chips, noise, and broken tools inside. The best material for this would be 1/16" or 1/8" thick polycarbonate on a square-tube aluminum frame. Ideally, the enclosure would be tall enough to accommodate the water-cooled spindle mounted on the post-update Z-axis. The enclosure should also be designed to be compatible with whatever the #Dust and Chip Collection solution is.

X-Carve Upgrade Kit Bundle

Inventables sells 2 upgrade kits for the X-Carve, and also a bundle that has both kits for a discounted price of $499.

Z-Axis Kit

The Z-axis upgrade kit costs $360 on its own. It:

  • stiffens the Z-axis (which reduces chatter, making clean cuts easier),
  • substantially increases the maximum Z-height (from 2.5" to 4.5"!),
  • increases the stepper motor torque by 50% (to 212 ounce-inches), and
  • adds better dust guards.

This kit does increase the height of the machine to 21.25", so affects the requirements for the enclosure.

9 mm Belt and Motor Kit

The 9mm belt and motor kit costs $190 on its own. It:

  • replaces the 6mm wide 2GT belts with stronger 9mm wide 3GT belts, and
  • replaces the X- and Y-axis stepper motors with ones that have 50% more torque (212 ounce-inches).

These replacements allow the X- and Y-axes to move with much greater force, enabling faster cutting speeds.

Unlike the Z-axis upgrade, this upgrade has very little impact on the overall dimensions of the machine. The replacement stepper motors are maybe 0.5" longer than the stock ones.

Z-Probe

A Z-probe makes it much easier to establish how much the tool sticks out of the spindle, which makes it much easier to consistently engrave 2D designs, or to precisely mill 3D parts. Inventables sells one for only $29, but it is designed for the X-Controller electronics, which is not what our X-Carve has, so it may require modification. (Our X-Carve has the older gShield electronics, with an Arduino Uno.) We could also make one ourselves, or buy one from somewhere else.

Shapeoko sells a really cool one for $120 that can do 3-axis tool alignment.

Smarter and Safer Endstop Mounting

With both the stock and new endstop mounting, the machine runs directly into the microswitch. If for some reason the machine does not detect that it has hit the endstop (for example, if one of the wires is broken), it will keep running into the microswitch and crush it. The microswitches, have lever arms with wheels on them, and are meant to be used differently: mounted off to the side, so that the machine will move over them, never actually hitting the switch but passing close enough to depress the lever. This way, even if the machine fails, it will not create more problems.

This mostly requires coming up with mounts (probably 3D printed) to hold the microswitches in the right places.

Gamepad Controller

Universal Gcode Sender has all of the controls necessary to move the machine around, but it's tedious. It also supports using a gamepad to move the machine around. This is much more convenient, and could be done with an inexpensive controller like the Logitech F310.

Modifications and Upgrades

Endstop mounting and wiring

For some reason, the endstops for the Y and X axes were mounted on the moving parts, requiring that their wires run through a lot of cable chain. Alex made simple laser-cut mounts for the microswitches, and mounted them on the non-moing parts of the machine. This substantially reduced the amount of wire needed for the endstops.

In between the Y and X cable chains, and after the X cable chain, Alex and Josh Giem connected all of the endstop wires with DuPont connectors. This should mean nobody has to fish endstop wires through the cable chain in the future, and the microswitches can easily be removed and replaced.

To dampen vibration from the spindle, the Z-axis endstop is mounted on a bandsawed-off slice of a cork.

Fix Mis-Triggering Endstop

During the first tests of the machine, the most serious problem was that the Z-axis endstop would very often trigger when the spindle was started, causing the machine to panic and halt. The likely cause of this was electromagnetic interference between the spindle power wires and the endstop wires. Both were very long, unshielded and unfiltered, and ran parallel to each other for several feet.

Vibration was also suspected, but Josh Giem replaced the Z-axis endstop with a similar one salvaged from a board in the electronics room, and the issue persisted.

Adam Stitcher purchased 9 feet of shielded two-conductor wire. This, along with an extra 4-conducter stepper motor cable in the box, was used to replace the wiring to the X- and Z-axis endstops.

Even with the shielded cable, the Z-axis endstop still sometimes triggered when the spindle started. To settle that forever, Alex cut a slice off a cork and used it as a vibration-absorbing washer for the microswitch, and wired a big capacitor into the spindle motor. This seems to have settled the problem.

More Rigid X-Axis

Dosman contributed a 1000mm piece of Wide MakerSlide. Besides being a single wide piece instead of two thinner pieces, the Wide MakerSlide's walls are also thicker than the original MakerSlide rails. The upgrade was done during public hours on 13 July 2022. Should have measured how much twist the old gantry had, but just pressing on it by hand makes it clear the new gantry is far stiffer.

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