Football theme stencil design using VCarve Pro and RDWorks

I made heavy use of the Mirror copy, Weld, Interactive trim and boundary based Trim tools in VCarve Pro in putting together the design.

I'm trying smaller circles than any of my previous designs at 0.15 inches diameter.

Always remember to zoom in on intersection points in VCarve Pro that have been manually connected using the Validity tool and look for the square with + icon at the intersection points as verification.

Important: If you are experiencing incorrect geometries from imports of DXF files into RDWorks, make sure you go to Main Menu: Config -> File Para Setting and fill in the check boxes for "Import DXF text info" and "Import dxf point". Otherwise, you may get a variety of issues; in this case independent arcs getting connected into closed shapes and a large scaling down occurred. You may also try exporting out of VCarve Pro as an .ai file, which RDWorks can import dependably.


RDWorks: Config -> File Para Setting: check both DXF boxes

Here is what my stylized football object is supposed to look like

and here is a markup of what RDWorks does if the DXF options for  import are not set. The highlighted area shows where RDWorks (upon import) adds a connecting segment between the three shapes at the four "edges".

This was a problem on the Build RVA computer's installation of RDWorks that I was NOT able to reproduce at home on my laptop running Windows 10 and RDWorks V8.01.28. Next week when I am at Build I'm update this post with the RDWorks version installed there.

Baseball

Here I show the early design, an intermediate stage and the final drawing of my latest stencil of SymArt.

I attempted to raise the complexity of the design (my first oval stencil) and introduce an even larger assortment of colors and pen tip sizes into the final drawing.

This was my first attempt using 130 lb cardstock, to help reduce any buckling or stretching of the paper from the very wet inks, especially the metallic inks. The backside of the paper is very dry and even/smooth. I will likely use 130 lb cardstock going forward, as it also had firmer and smoother feel while drawing than 65 lb cardstock.

This drawing was the most time consuming I tried to date with my stencils, as I added blocks manually outside of the stencil using a ruler - semi-freehanded if you will.

Sketch book - note the numerous details and color trials

Early Outlines

intermediate stage

Variety of pens 

Baseball final artwork

Baseball 

With MLB Spring training getting started and the opening day for the 2019 season only about 6 weeks away, I thought that a baseball themed design was in order.

I loaded the baseball theme design into the Boss laser LS2436 with the 4-inch focal length optics.

Here are some Lessons Learned:

To set up my standard 10 in by 12 in rectangular piece of plexiglass it's best to only remove the center eight blades.

I had to rerun the outermost oval (30 mm per second) for 15% power because at that speed my first try at 10% power did not cut all the way through. On the second run, the trick is to either set layers at 1% power, either on-board or in RDworks software, so that fall through layers do not get recut. Something very low say 1% power so the laser won't fire. Then only assign the higher power or the lower speed (or both) to the layer to be recut. In the future I'll avoid this problem and make sure my Concentric Circle test samples all of the head speeds that will actually be in the design run.

Note that we are no longer adjusting the compressor pressure away from the default set by the manager.

I am now deleting my files after I'm done. The on-board memory max's out at 99 files regardless of size.

The photos show that all the cuts are very clean. I report that there are essentially no cracks or divots on the back side, nor were there any burn or char marks (either on the backside tape or on the plexiglass). This is proof that the laser is well-aligned and has a good beam cross section. Additionally, there was very little rubbing alcohol & terry cloth cleaning that I needed to do on the surface of the plexiglass stencil parts; debris was kept to a minimum.

Design size is 8.8 inches by 6.3 inches

Outer oval and baseball, bat, field and scoreboard

middle and inner ovals

partial sampling of the small pieces

Standard Tests

Starting with my upcoming baseball themed Stencil run, I am now performing a standardized 20 second concentric 3 circle test to see what minimum power is need to cut through the 1/12th inch extruded plexiglass.

I tried 15%/20%25% power and all cut through evenly cleanly. Previously, powers as high as 30% were required in mid to late 2018. However, now that the laser is so well aligned and the beam cross section is nearly circular, I'm able to use half the power to achieve full cutting. You are all encouraged to run similar quick tests to find the minimum power needs; running at lower powers will length the tube life and minimize debris in the chamber.

Notice from the photos below how smooth and crisp the cut edges appear.

Well Aligned Laser

From now on, I will be running an alignment and beam quality check before all stencil cut jobs. This will give me some correlation between cut quality and laser status. If I see that the alignment and or beam quality is too low, then I will do a laser tune up before running a cut job.

The check will consist of a beam pulse on triple layered painter's tape on the gantry mirror opening. The positions will be each corner, the center and then again a second pass of left/right-back and left/right front. Those last two will keep the same tape target for two pulses to check beam spot overlap (the more overlap the better).

As you can see from the photos, the laser is in a very good status. Indeed, in the 15 months I've been using the 4 inch focal length laser, I've never seen such highly symmetric beam cross sections and so well aligned on each other (and relative to the center point of the mirror.)

Before running the laser status check test, I thoroughly vacuumed and wiped down the inside and outside surfaces of the laser system, including the surrounding floor, chiller, the accordian exhaust vent tubes and the compressor (the blades were not cleaned by me this time).

Here is what a clean laser system looks like:

Simulations in RDWorks out of order

In order to make sure that the priorities of your layers are correctly simulated, and therefore will be correctly saved to the laser readable g-code Ufile, go to the Main Menu -> Handle -> Cut Optimize menu dialog and set up the parameters as shown in the photo below. Otherwise, shapes will be cut simulated in a random order.

Also, go my VCarve Pro and RDWorks pages, accessible from this Blog's main mnee, to see useful practical ideas for saving time on layer management in RDWorks and a possible artifact upon creating some shapes on DXF export from VCarve Pro.

First VCarve Pro design

Last night I finished drawing my newest SymArt after cutting the stencil with the 4 inch focal length laser earlier in the week. VCarve Pro is proving to be a faster and more versatile tool for creating artistic geometries compared to Inkscape. Additionally, the Makerspace license is free to install as long as we do all exporting on one of the Build RVA Makerspace desktops (as enforced by the Vectric license). Finally, VCarve Pro is a more reliable exporter of DXF formats for the RDWorks laser preprocessing software.

Notice the blue Painter's masking tape remaining on the stylized tree cutouts. The Painter's tape prevents charring and cracking of the plexiglass at the laser cut edges (especially around the supporting bed blades).