I use NX7 for my modeling and CAM software and like most software, there is not necessarily an easy way to add tabs to hold work pieces in place as you are cutting them out. One of the options that is commonly used is to make the tabs part of the actual model itself or profile of curves. This can be time consuming some times and/or not really allow you to view your 3D model as it was meant to be, without tabs.

I came up with another option and that is when you are working in the context of an assembly in NX7, you can actually create a “tab” part (i.e. a 1/2″ x 1/2″ x 1/2″ block) and align it with your 3D model where you want the tab to be located. And you can even instance it multiple times to add as many tabs as you want.

Here is a picture of my layout assembly in NX7 of the top and bottom portion of my dust shoe. The green blocks are the tabs I added to the assembly:

The intention of these tabs is to interfere with the cuts along the perimeters of the parts. When you go to create the CAM operation in NX7 that cut the perimeters of the parts, you need to specify faces from the tab components in the “Check Boundaries” options so that when the tooling paths are created, it will jump over (avoid) those tabs. Here is an example tooling path resulting from this:

I decided to create a new dust shoe to replace the one I was currently using. I wanted to use a split shoe design where the bottom strip brush could be removed from the the rest of the dust shoe. This split shoe design would allow me a couple advantages:

  • Allow me to remove the strip brush to allow for visual alignment of the Z-axis with the workpiece
  • Allow me to create bottom rings with various strip brush lengths for different job types (i.e. where I may need to use longer bits)
  • Allow me to easily replace just the strip brush portion of the dust shoe when the strip brushes wear out (i.e. are too bent and don’t return to their normal form)

The top and bottom pieces of the dust shoe will be held together by rare earth magnets which I acquired very cheaply on E-bay and have several pounds of pulling force a piece.

Here is the 3D model of the top and bottom pieces of the dust shoe based on using 1/2″ MDF:

The final assembly was composed of the following:

  • Top and bottom pieces cut out of 1/2″ MDF
  • Conveyor strip brush from McMaster Carr
  • 3/8″ magnetic discs acquired on E-bay
  • 2.5″ dust port adapter
  • 1/2″ threaded rod and nuts

I think one day I will make a version out of cast acrylic but for now this will do.

Here are pictures of the finished shoe:

(Notice I did not put magnets in ALL the holes. The magnets are very strong and I did not want to have problems pulling the top and bottom pieces apart.)

Well up until now I have been using my computer running the router with the CRT monitor, keyboard, and mouse on the bottom shelf of the router. This was not very convenient so I set out on figuring out how to fix this.

The first thing I wanted to do was to replace my bulky 15″ CRT monitor with a flat screen LCD monitor. I scoured online stores and E-bay finally ended up snagging a 15″ LCD monitor on E-bay for $17 USD.

Then I was trying to figure out how to mount the monitor to the machine, a custom made LCD arm? A pre-made monitor arm from E-bay or other source? Then I came up with an idea of making a drawer mounted under my router that would hold the monitor, keyboard, and mouse, and the monitor would flip up. Here is the design I came up with:

Note that this design is based on 3/4″ plywood with finger joints interlocking all the pieces. OK, a glorified drawer! I then used my 3D model to layout the cuts for the drawer for my CNC and cut them:

I assembled the drawer using wood glue and mounted it under my router table using 24″ full extension drawer slides. Here is the result:

I think I’m going to make the drawer look more sleek and finish it with a nice coat of flat black paint.

One thing I did learn doing this project is that when cutting finger joints on a CNC router, you should probably do pass with a smaller bit into the insider corners to square up the corners so the pieces can slide all the way together. The alternative is what I did was lots of filing and sanding to square up the corners.

Another thing I wanted to do was to build an enclosure to organize all my electronic components and help clean up the wiring. First thing I did was looked around CNCZone.com for ideas. I came upon the following thread:

http://www.cnczone.com/forums/gecko_drives/108326-my_g540_controller.html

I was very inspired by this thread so I set out on looking for an equivalent enclosure. I finally settled on the EM-04 enclosure at Web-tronics available here:

http://www.web-tronics.com/emsermulstee.html

Here is a picture of it before I made any modifications:

I then began to design a 3D model of the enclosure with my various components arranged in it, here is a rough model of it. I did not model everything, only those things that I thought would impact the layout. Here is a rendering of the 3D model:

In my design, I included three fans, two exhausting from the front and one pulling in air from the rear. I plan on filtering the air coming in using a simple filter fitted over top of the fan inlet. I’m also concerned with any dust getting into the enclosure.

After I completed my design, I used my router to make my first ever aluminum cuts and cut out the holes from the front and rear panels. Here is the result:

Once I cut out the front and rear panels, it was just a matter of assembling the pieces. Here is what I have done so far.

As part of my efforts to reduce the amount of airborne dust created from the routing process, I decided to look at my options for dust collection.

I seriously looked at the Harbor Freight 2HP dust collector which is very popular amongst woodworkers and fellow CNCZoners but the cost was prohibitive at the moment. I especially considered it because I could purchase it for a great price at $139 using a coupon from the latest WOOD magazine located here WOOD Magazine – December 2010/January 2011. Maybe in the future.

But with the budget in mind and the need for an additional circuit for it, I decided on using my existing shop-vac. Certainly it doesn’t provide the amount of dust collection power a dedicated dust collector would provide but it’s the most budget friendly option and requires less power. All I had to purchase was an additional 7 feet of shop-vac hose for another $15.

I created a “swing arm” using some existing aluminum rod and bar I had laying around. I created a bracket from the aluminum bar, bent the aluminum rod into a little arm and mounted it to the bracket, and mounted the bracket on a pole in the middle of my shop right by my router. The shop-vac hose is mounted to the swing arm using a caribiner and is allowed to slide along the arm as the arm swings left or right based on the movement of the router.

Here are some pictures of it all:

So far this works out great!

Realizing now how much saw dust my CNC router creates in my little workshop, I decided it was a top priority create a dust shoe to capture the sawdust and limit the amount of clean up I would have to do afterwards. I could probably buy one, I really like the split shoe design at http://www.kentcnc.net/nc/ but cost was definitely prohibitive. So I decided to make my own.

The first thing I did was design the shoe using NX7, taking into account the material I was going to use (1/2″ MDF) and the relationship of hole needed for the router collet, the location of the already existing 1/2″ hole on my spindle mount for mounting dust shoes, and size of the hole needed for mounting my shop vac adapter. Here is my 3D design with the generated toolpaths:

Dust Shoe Design

I acquired some 1/2″ MDF, some rubber stripping (I think used for tiling), some 1/2″ acme rod, and proceeded to build the first revision of my dust shoe. I cut the dust shoe from the 1/2″ MDF and mounted the rubber stripping to the outside using screws, and then caulked between the MDF and rubber (to help seal in the dust). My first tests of the dust shoe, it worked really well, collecting almost all the dust I saw but after a few uses, the rubber fingers began to catch and break off. I think either the rubber was too stiff or I left it too long or a combination of both.

So I decided I need to use a different material for the dust shoe skirting so I bit the bullet and ordered some conveyor strip brush from McMaster-Carr along with the corresponding PVC strip brush holder. I ordered the PVC strip brush holder because it could bend around the contours of my dust shoe. When the strip brush arrived I cut another dust shoe from the 1/2″ MDF, mounted the strip brush in the PVC, and mounted the PVC to the MDF. One nice difference is that the strip brush is only 2″ long so it has less to compress than my original rubber stripping and also it is more flexible. So far the results have been great!

Here you can see pictures of my original dust shoe and my latest revision:

One thing I might do differently is use a rectangular shoe design. The PVC strip holder would definitely mount more flush to it instead of having to contour it around the rounded edges of the current design.

Well just to test out the router, I created my first 3d wood puzzle of a spider using 1/4″ MDF.

I obtained a DXF file from http://cnczone.com, imported the DXF into NX7, scaled it for the 1/4″ MDF, generated the tool paths and the corresponding G-code, and sent the G-code to the router using Mach3. Here is a YouTube video of it in action:

Here is the final result of the 3d puzzle put together:

My 5 year old son and 1 year old son both love the spider!

It’s alive!!! I’ve got the router running and making cuts. Still not going full throttle yet but I’m slowly working up to it. Obviously I have made made significant progress since my last update. Here is what I did to get it this far:

  • Wired the Y axis including homing switch
  • Wired the Z axis including homing switch
  • Installed the spindle relay on the back of the Z axis
  • Installed the router on the Z axis using a spindle mount I purchased from K2CNC
  • Installed 1/2″ MDF for the router table (and bottom shelf)
  • Made my first test cuts!!! It’s alive!!!

Here are some pictures of the router:


Note the spindle relay installed (but no control wiring is present yet)


One advantage of using 80/20 extrusions, just bolt on limit switches using a simple bracket.


Another advantage of using 80/20 extrusions, you can run the wiring through the empty cavities of the extrusion. In this case, this is the wiring for the Y axis home switch running from one side of the gantry to the other.

I’ve been learning more and more about how to use the NX7 Manufacturing application. I created a simple model which consisted of some writing carved into a 0.5″ thick piece of wood. I was able to easily create multi-pass toolpaths for this. Here is a video of the simulation of the cutting in NX7:


Simulating toolpaths in NX7

I’ve been looking around for a DC controlled relay to turn my spindle on/off. Since the router I have has variable speed control built into it, I did not need a speed control, just something to turn the router on/off. I looked at various sites that offer relays but for higher amp applications, they seemed to be very pricey. I looked on and E-bay and found the following, and for the price, it was worth a chance:

Spindle Relay

I hope that it will be up to the task and won’t wear out.