|
Work Examples
The
tables offer
a range of speed and accuracy. These pieces were routed with the small leadscrew tables unless noted otherwise. All of the small leadscrew tables use inexpensive threaded rods for leadscrews, so their quality of work is similar. The 13 x 13 Fixed Gantry table performs similarly, but it cannot cut as aggressively. The Rack and Leadscrew machine was designed to use a variety of components; its quality of work will depend on the chosen options.  The software's backlash compensation was turned Off in all of these examples. Turning it On can improve quality.   The above photo is an outline cut of the logo on the right; it was cut in aluminum with a 0.0098" diameter bit. The results of backlash can be seen in the retort's spout and in the bottom of the circles near the plant. Threaded rods and nuts are used as the leadscrews-leadnuts. Antibacklash nuts will improve performance, and increase the price.  The logo above is the same size as the cut shown previously but carved with a larger diameter bit; it was photographed with the dime to show the scale. |
 The pattern above was cut into a 6 inch long piece of oak with a Vee bit in a trim router. |
 |
| The aluminum piece above was
made with the belt drive table, which can
work with more speed
and accuracy
than the small leadscrew tables. The work is magnified to show detail. The ruler on the left is marked in 1/16 inch (1.5875 mm) increments; the dime is also shown for scale. Both of the rows of text are double line fonts; the bit diameter, tiny as it is, is as wide as the spaces in the letters in the second line of text; therefore resolution is lost. A 0.011 inch diameter bit was used and the router moved at 20 ipm for this work. This speed was set to match the rpm of the router-spindle. The cut was made in five passes; this shows that the table's repeatability is quite good. Evidence of chatter can be seen in the "O" in "One" in the top line. This is the result of the rubber belts which will rebound as the axes move. It is also the result of the table being made of inexpensive 1/8 and 1/4 inch thick aluminum rather than steel or thicker aluminum. Also, the Z axis was at the end of its 7 inch travel; this too allows for more flex in the table's components. ......................
|
| This is an 8 x 10-1/4 inch
letter cut from 1/4 inch birch plywood.
It was cut with a 1/8 straight router bit in the 5 amp trim
router. The feed rate was 36 ipm and the time for the cut was under 3 minutes; it was done in one pass. The edges are straight and the curves are smooth. This was cut on the small dual leadscrew table. |
 |
 Note: CNC
is addictive; you will find excuses to use your machine for all
sorts of projects. This is a box for an electric fence control. The routed piece is made of 3/4 inch pressure treated southern yellow pine and is approx. 20 inches long. It was cut in four passes with a 1/4 inch straight bit; cutting speed was 30 ipm with the 25 x 37 router. |
|
The 25 x 37 inch router cutting a sign. The feed rate was 30 ipm and a Vee bit was used. Carving five is as easy as carving one. |
| The PC board
on
the right was cut with the 25 x
37 inch router using a 0.03 inch diameter
bit. The holes are 0.1 inch apart and an IC is in the top row of holes to show the scale. The traces are 0.028 inch wide and 0.072 inch apart; they are 0.045 inch apart at the diagonals. The holes are 0.03 inch in diameter and the pads are 0.07 inch in diameter. This was done at one depth of cut for the outline pass and then a second pass was run for the drilling. The speed was 12 ipm to protect the tiny bit from breaking. There is evidence of backlash at the diagonals and the pads are not all perfectly round. |
 |
This PC board was cut with the belt drive table. There is less evidence of backlash in this piece.Not all of the holes are perfectly centered, but otherwise the blemishes have more to do with bit tear than backlash. |
 |
This four inch diameter gear was cut from 1/2 inch thick acrylic on the 25 x 37 table. It was cut in five passes of 0.1 inch each with a double flute straight bit in a trim router. The trim router's RPM had to be slowed to prevent the plastic from melting. Determining the correct feed and RPM is a trial and error process; expect to make a few mistakes before finding the best settings. |
|
The tables of course have full 3D capability; the carving on the right is a set of shapes routed into a southern yellow pine 2 x 10. A 1/4 inch round bit was used and the piece was not sanded before varnishing. The chatter marks on the lower edge are on the original surface of the 2 x 10; the section cut with the router is smooth as evidenced by the clean reflections. This was cut on the 25 x 37 machine. The software used to draw and generate the code was Rhino3D and RhinoCAM. This 3D software package is over $1000. |
 |
This is a 3D cut that used MeshCAM for the G-code generation. An image was imported into MeshCAM and MeshCAM interpreted the dark and light as depth and height. MeshCAM is a relatively inexpensive 3D program, but it is more suited to art pieces such as this, rather than pieces that require specific dimensioning. For the most part, it only dimensions height, depth, and width of the entire piece; everything else is relative to this. Mach3 now includes a CAM product that works similarly. The work is a four inch square piece of MDF trim that is one of a pair of blocks for the top corners of a door casing. The parallel path cuts were 0.005 inch apart, so it took over 3 hours to carve at 30 ipm. A Dremel Vee bit was used with an 1/8 inch adapter in the trim router. The cut is quite intricate; the paint's gloss enhanced some of the detail. |
  |