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, Candle, PyCAM, FreeCAD, Inkscape, and dxf2gcode on it. Other F/LOSS programs 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.

None of these programs work on Linux, so a Windows license would have to be purchased. 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
  • PyCAM (Development has slowed but not completely stopped. Lots of features, but doesn't look overwhelming.)
  • Aptos
  • BlenderCAM (Even the oldest supported version of Blender (2.83) is unusably slow on the available laptop. This might be a good solution if a more powerful computer is assigned to the X-Carve, or for people that want to plan toolpaths on their own computers.)
  • CAMmill
  • HeeksCAD
  • gcodetools (Inkscape extension) (abandoned since 2016, doesn't let you adjust the cutting depth)
  • FreeCAD's Path Workbench (Seems viable for sophisticated parts, but complex. Laptop has FreeCAD 0.19.1)
  • Solvespace's basic g-code export
  • KrabzCAM
  • Millcrum
  • dxf2gcode
    • DXF files can be exported by Inkscape, Solvespace, LibreCAD, and most other vector drawing programs.
  • dmap2gcode
  • gcodeplot (appears to be intended only for pen plotters)
  • OpenBuilds CAM
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!

So far, $4 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.

Fix Broken Endstops

The X-Carve has three microswitches that allow it to home itself in the near-top-left corner of the work area. Two of these microswitches (the X and Y axes) were broken when the machine was donated. (Their plastic bodies cracked open and their lever arms fell out.)

This seems like the right replacement part, and costs $2.86 each.

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

The previous owner 3D printed a mount for brushes and a vacuum cleaner. Completing this would allow the machine's waste to be captured and removed while it operates. It needs:

  • a plastic disc (which could be made on the laser cutter) to cover the top of the vacuum adapter
  • a shop vac (ideally with a cyclone separator) and hose
    • a nice home for these things to stay in
    • 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

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

Ebay is fat with inexpensive water-cooled VFD spindles that support ER11 collets, and only cost a couple hundred dollars. We received a mount for this type of spindle with the X-Carve when it was donated. They are available in 0.8kW and 1.5kW models; 0.8kW would probably be plenty. This style of spindle might be substantially quieter, and could also offer automatic control over the spindle speed.

I'm not yet sure how one of these would be controlled by the machine. It might be that it could be set to be fully controlled by the electronics, or it might need to be manually controlled.

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.

More Rigid X-Axis

Our 2015-era X-Carve's X-axis is made of two parallel pieces of 40mm x 20mm MakerSlide. This makes the axis unfortunately easy to twist, which severely limits how aggressively the machine can cut. Since 2016, X-Carves have used a single piece of Wide MakerSlide, which is much more rigid. I'm pretty sure the $39.00 750mm piece would fit our machine.

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.

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