Computer Numerical Control (CNC) Madness

Right now, I am sitting in the office, waiting for some well information to come up on the computer.  Unfortunately, the website for the Office of the State Engineer is going extremely slow. 

I am reflecting on today and earlier, I had shown a property to a really great family.  We were downstairs in a basement and the father told his son, this room would be a great place for our X-Carve.

I thought it was so cool to hear that.  Not many people know what CNC is, let alone have a CNC controlled machine.  CNC stands for computer numerically controlled and it is a technology that can be implemented into any number of things that many people use on a daily basis.... they just don't know they are using it.  In a simple sense, things like elevators, printers, scanners, and copy machines use CNC.  In a more complex nature, things like metal CNC machining centers, plotters, vinyl cutters, 3D printers, CNC plasma cutters, and CNC routers use the technology.  

In a nutshell, CNC uses a programming language called g code.  It stands for general code.  The g code is interpreted by a controller which tells a motor how many revolutions to make.  Some things like CNC machining centers, routers, and plasma cutters typically have 3 axis, an X, Y, and Z.  Everyday things like copy machines, printers, scanners, and elevators don't necessarily have axis, but they have motors that receive a bit of code from the press of a button and a controller tells the motor in the machine how long or how far to go.  For example, if you are on the ground floor in an elevator and your press the button to go to the third floor, the elevator knows exactly how many revolutions on the motor shaft are necessary to get you to the third floor.

When I started building my CNC router, it was all a bit overwhelming at times but I just took it one step at a time and learnt as I went.  Honestly, I'm still learning.  Fortunately, I started with a kit and that greatly reduced the learning curve.  Here's a picture of the machine when I started putting it together.

I bought the kit from a company called cncrouterparts.  It is a 5' X 10' CNC kit with a 2.2kw spindle.  Everyone asked me what it was, then they asked me how much it cost.  When I told them it was about 22K, everyone, including my wife thought I was insane. It took a couple of days to put it together and when I finally got the first movement out of it, I was elated.  Really, I couldn't hardly wait to put it to use.  Here is the first project I did with it, I table for my drill press.  It had replaceable inserts.

The masking tape on the front of it was there because I bedded the T Track in epoxy and it was in place to keep it from spilling out before it set up.  I cut this project out before I even had a spoilboard on my CNC router.  The spoilboard is a sacrificial surface used for holding work pieces while you are cutting.

For the spoilboard, I first used 3/4" birch plywood and mounted it to the extruded aluminum frame of the CNC.  Then I glued 1" MDF to the top of the birch plywood and used epoxy to fill the joints where there was a seam in the MDF.  The MDF came in 4' X 8' sheets and my table size is about 61" X 124".  Once I got everything glued in place and the epoxy set in the seams, I skimmed the top off the MDF with a 2-1/2" surfacing bit like this.

Once I had this surfaced, I cut out cut out 8 pockets to mount some flanges so I could create a plenum with 8 vacuum zones.  Here's what it looked like.

After this step was complete, I cut out a grid with a 1/2" ball nose end mill to make a grid for the vacuum plenum just like this.

The purpose of this was so that I could have 8 different zones of vacuum hold down suction on my cnc.  Once I had the plenum cut, I sealed it thouroughly.  I had heard that a mixture of Titebond III and water was the thing to use, and I used that for 4 sections of the plenum, but I eventually ran out of what I had on hand.  I did, however, have some Redguard and found that worked extremely well. So half my plenum is Redguard and th eother half is Titebond III.  Here's a picture that also shows the dust collection I rigged up for this project.

Once I got the plenum complete, the next step was to glue the spoilboard on.  For this step, I used 3/4" ULDF which is ultra low density fiber board.  It is similar to medium density fiberboard (MDF) but much more porous.  I don't have a picture of the spoilboard, but here's a picture of the first project I cut with vacuum hold down, a test cabinet.

The coolest thing about making cabinets with a CNC router is the efficiency.  There is barely any waste at all.  Here is what was left of the sheet of plywood when I was finished.

And here's the finished product.

This was just a test cabinet to see how exact everything was.  The machine still needed some tweaks and adjustments but eventually I got it cutting pretty good.  Here's a picture of the first kitchen I made with my CNC router.

Interestingly, I also cut those countertops out on my CNC router.  I will go more into details of how I did that later.  Meanwhile, stay tuned for a continuation of this series on CNC.

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