Football Field design complete

Today I finished the drawing of the football themed design. For this project I kept track of the hours involved in each stage of the process.

Software design in VCarve Pro: 4 hours
Laser file preparation in RDWorks: 2 hours
Laser prep, alignment check, test run and design run: 5 hours
Stencil cleaning, tape removal and review: 1 hour
Sketch book color planning; 1 hour
Drawing: 3.5 hours
Blogging at various stages: 2.5 hours
Total: 19 hours

9 pens for the drawing

sketch book

Football Field and Stadium

Football themed Stencil

Before starting, I did a thorough vacuum and wipe cleaning of the 4 inch focal length laser and the supporting components.

Then I ran my standard beam quality and alignment check. The operating condition at the moment is nearly perfect. The beam cross section is nearly circular at 12% power and even the beam halo is uniform. The beam is hitting center in a left to right sense, and slightly high of center in an up to down sense. This is the case for all 4 corners and the center of bed test points. The slightly high of center is actually preferred, as when the beam is reflected down from the 3rd mirror of the head into the focusing lens, it will be more centered (given the beam width).

Excellent laser alignment results

L: left, R: right, F: front, B: back

notice the uniform yellow halo around the burn spot

I ran a small 2 inch test file that represents the range of shape size/ head speed combinations to make sure I get clean cuts, but without using too power. Everything was good except the larger shapes with a 30 mm/sec speed needed a 7% increase in power to get a cut-through.

As a reminder when working with plexiglass, make sure the exhaust fan on the other laser is ON to prevent any odors of burnt plexiglass from seeping into the workspace.

I am extremely pleased with the overall results, especially considering that this was my most challenging design to date. I used a large number of very small circles and closely adjacent ovals to test the laser precision. The football helmet face-guard also has very thin lines criss-crossing that retained their shapes with cracking or splitting.

The major stencil parts

8.8 inches high. 6.3 inches wide.

Ellipses in VCarve Pro

Be careful when creating ellipses in VCarve Pro and then exporting as dxf, ai or eps. VCarve Pro will make two identically sized ellipses superimposed exactly on top of each other. This creates havoc when you import into RDWorks and run a simulation, as the apparent priority layer order set by you may not be respected because of the double ellipses. Black is set as the default priority 1st color for layers, and the hidden layers will be colored black. Since you could not see them to color them anything else, the simulation will then do all the visually hidden ellipses as priority 1 ... and then go to your priority 2.

I even tried exporting out of VCarve Pro as a PDF which Inkscape can read, then exporting as dxf out of Inkscape. The problem of double ellipses still holds, but now the redundant ellipse has jagged edges and is merged with the true intended ellipse.

The work around without going back to VCarve Pro is to set the layer property for the ellipse to "hide yes" by double clicking on it in the Work Tabsheet. This will reveal the hidden ellipse as colored black; delete it. Then unhide (set "Hide = no") on the actual ellipse that is colored and you want to keep. Remember to File -> Save the changes before running a simulation.

You can see the issues with the images below. If the outlines in the image are dim on your view screen, just click on it to enlargen and darken.

There is an ellipse underneath the red inner ellipse.

The hidden ellipse is revealed.

See the hidden ellipse now has jagged edges after using Inkscape as an intermediate DXF creator.