X-Carve – CNC Mill

X-carve

October, 2015

I took the plunge and invested in my first CNC 3D carving tool – the X-Carve.  I chose this over the Shapeoko and other desktop CNC machines because the Shapeoko 3 was not yet released, and the X-Carve provided a great support community and seemed to be a good choice for a beginner like myself.  I also liked that it was built using open source hardware.  The main purpose for investing in this tool was so I could fabricate parts for projects including circuit boards, robot parts, and other things.

I opted for the 500mm x 500mm option since my workshop has limited space.  Looking back, I’m happy with my choice as most of my projects will be small.  I chose to supply my own router and invested in the Dewalt 611.  Online research indicated that the stock motor for the X-Carve was insufficient for jobs like cutting metal which is what I will eventually graduate to.  I also chose the more powerful NEMA 23 stepper motors and am happy I did since they provide fast, smooth control of the X,Y, and Z axis.

X-carve

Assembly

Following the online instructions, it took me 3 days (about 12 hours total) to fully assemble the kit.  I admit I made a few assembly mistakes along the way which requires some rework.  In order to save cost, I opted out of the toolkit – I figured that I had enough tools that I could do the assembly.  I did have all the tools required, but struggled to find the proper size metric hex tools to fit the varying size screws that came with the kit.  I think I appreciate the tool more since I had to assemble it, and feel confident that I can tune it and replace parts as needed in the future.

My main mistakes in assembling:

  • The first time I attempted to use the self-tapping screw, I attempted to do it “dry”.  Later, I applied some WD40 and used a power drill to make the job easier.  Cutting threads in aluminum is hard on the forearms!
  • I assembled the Y axis rails upside down which caused a problem later with mounting the set screws for the limit switch.  Swapping those out after assembling the belts was a major pain.
  • I followed the instructions and cut the wires to the recommended length.  I’m now wishing I had more slack on the X/Y/Z motor control wires since I am now required to keep my power supply very close to the gantry.
  • I struggled (as I have in the past) to properly crimp the pins in the end of the wires to attach to the G-Shield for limit switch control.  I own a crimping tool and know how to use it, but the results are always terrible.  I hate pin crimps and avoid them whenever possible.  There must be a better way!
  • Orientation of some parts was not clear in the written instructions. When in doubt, I found the video provided the context I needed.  A combination of the video and text is really required for assembly – neither has enough detail to stand alone.
  • Despite the content of the documentation, the slight overhang of the Dewalt 611 chassis in the provided cuff does interfere with the Z-homing cycle and caused lots of issues for me.  I took the advice of someone online and sanded down the plastic on the side of the Dewalt so it would not interfere with the movement of the Z-Axis.
  • The clamps that come with the X-Carve are really clever.  I briefly considered not buying the “waste board” since I could easily build my own.  However, the threaded holes in the waste board provide a clever clamping system that is low profile and effective.

First Cut

I used the “Intro to Easel” project for my first cut to carve my name in some wood.  I used a 1/16″ bit with a 1/8″ collet to cut into some nice red maple I had left over from another project.  I found Easel easy to use to design the pattern to be carved.  I especially like the “checklist” provided when getting ready to carve – it includes reminders on how to set up the X-Carve and make sure it’s ready to go.  Overall, my first cut was a success.

Some lessons learned from my first cut:

  • Holding the vacuum close to the cutter is important in order to avoid sawdust on the rails that could disrupt the movement of the device.  It’s not a lot of fun to hold the hose for so long, but it is important.  I really need a way to mount the hose onto the device so I don’t have to hold it.
  • I resurrected an old laptop that barely runs Windows and use it to run Easel – that prevents me from having to keep bringing my other laptop out to the workbench all the time
  • Ear and eye protection is important.  I ran the first cut wearing glasses, but no ear protection and it took a while for the ringing to go away.  The Dewalt is loud, and the wet/dry vacuum is even louder.  Together, they make a very loud environment.
  • Slow and steady – I was eager to have the bit cut deep into the wood on the first pass to move things along.  However, the approach of cutting thin layers
  • Not too deep – I found that carving more than 1/4″ was not really necessary.

Projects

Pretty soon, I had everyone in my family making requests for cut patterns.  I started a queue of small projects and was excited to try and build them all.  I visited my local Woodcraft store and invested in some nice wood for cutting.  They have a large variety of exotic wood.  I chose some Cherry, Walnut and Wenge.  All had pretty grain patterns.  I didn’t realize that the X-Carve came with a variety pack of cutting bits, so I ordered several sets of different size bits and now I have too many!  For each project I tried a different type of wood and a different bit to get a sense for what works well.  Here are the results of some of my first projects:

Robot Room Sign Star Wars Imperial Logo Team Fortress 2 Logo 5SOS logo

I quickly exceeded the limitations of the Easel software and reverted to InkScape to create the .SVG files that Easel can import.  I’ve used InkScape on several other projects, so felt comfortable with it.  I was able it import and trace pictures, and generally manipulate the shapes and text however I needed.  The import into Easel is quick and easy.  After importing, I just set info about the wood to be used and the depth of each “object” in the design.

The wood I placed onto the table for carving was intentionally over-sized so I had room to mount the clamps without risk of the cutter touching them.  After the carve was complete, I used my bandsaw to trim off the excess wood.  I used another router to finish the top edges of each piece and hand-sanded them (dry, wet, dry).  In addition to various grits of sandpaper, I also invested in a nice Riffler file set that let me get into the cuts and do precision filing.  Finally, I finished them with Mineral Oil.  Each project took about 4 hours.

I must say, this is an addictive hobby.  I’m looking forward to trying different wood and bits.  This could get expensive…

Fixing a vexing issue with the cut depth

In doing the project cuts, I noticed that the cut depth was not uniform across the X-axis.  As I moved from left to right, the cut depth decreased.  On some projects, the first pass of the cut did not even contact the wood on the far right side of the pattern.  For example, you may notice that the right side robot in the Robot Room project is about 1/8″ shallower than the robot on the right.

I triple checked the assembly, checked the level, measured the height and found nothing wrong!  After much tinkering, I finally found the problem.  The eccentric nuts on the x-axis gantry were loose.  By tightening them up, I was able to get a consistent cut depth across the X-Axis.  Not at all intuitive.  I’ve revisited these eccentric nuts many times since they tend to jiggle loose during the cutting process.  I think I need to put some Loctite on the screw threads to keep them from moving so much.

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