Cutting a Grid Column v2

Sharpening the Saw

In between designing the new layout, we’ve been tuning up the ShopBot. A quick fix was replacing some hardware store L brackets that held the dust hose with actual 80/20 Series 15 parts.

Before

L-Brackets

Now

80/20 Series 15: 2x 6” T-Slotted Extrusions, 2x Corner Gussets

We also upgraded the ShopBot Control computer to a quick solid state mini-ITX and loaded the latest ShopBot Control firmware.

Lian Li Mini ITX case

Now that laptop is gone, we brought in a mobile workstation so the screen can be seen better around the shop.

Ziotek Mobile Workstation

And then to the cutting…

The new design was nested on two sheets of 0.75” plywood. We only had one false start. The material marking job was faulty. The ShopBot was supposed to move around the material sitting on the work surface and peck drill shallow holes to mark where our hold down polymer nails need placed. Instead the tool began cutting the parts on Sheet 2, not the marking of Sheet 1. We paused the job and went to inspect the Aspire 4.0 drawing file. Turns out that the full version of Aspire has a post processors for dozens of machines, where V-Carve Pro only had one for ShopBot.

Another setting that was missed was a “combining all tool paths” checkbox when saving to the .sbp file. I usually break each tooling step into it own path. When saving the cutting file, I combine similar steps. In this case, on Sheet 1 there are 3 tool paths that cut internal slots that get combined in to a “Sh1-01 Cut Slots.sbp” file which means Sheet 1 Step 1 Cut the internal pockets. Without the right checkbox checked, Aspire would only write the last selected visible toolpath leading to unexpected results.

The final new trick was trying out a new bit - an Onsrud 60-111, which is a 0.25” diameter compression spiral. A compression spiral is designed to upcut and downcut at the same time which is what you want for plywood or other laminates. This is a single flute.

Onsrud 60-111 Compression Spiral

The first rib on Sheet 2

Onsrud 60-111 Compression Spiral

Job almost completed.

Cutting part edges

Sheet 2 done - 2 Headers, 11 Ribs

Grid headers and ribs

Starting Sheet 1

Overall, I’m impressed with the compression spiral. The edges were very clean and we can probably move it faster than the 3.0 inches per second we used today.

These sheets were cut with a 0.02” onion skin instead of creating tabs to hold the parts in place. Looking back at how many parts there are to remove with the laminate router, this was probably a mistake.