Creating a ShopBot Custom Cut File with a Menu Shortcut

Where is that zero?

A while ago, we did a project based on the Fibonacci Series that involved cutting a few dozen cedar boards into parts to make a modular decking system. On our ShopBot, it doesn’t keep track of the motor movements so it often to be re-zeroed when you change a tool or material. It is not a difficult process, but it is very repetitive and a key to your machine’s accuracy. Originally, our ShopBot came with a standard z-zero plate that is mounted in a holder on the gantry. You attach the ground wire to the router, remove the plate, place it on the material, and run a z-zero routine which is saved as C2 in the control software.

While researching better solutions, we stumbled across Morris Dovey’s SuperZero. The device is basically a block of billet aluminum with a large hole through it and rails along two sides.

Combined with the part files that ship with it, this device let’s you zero all three axes from anywhere on the work table surface, in about 30 seconds. This makes it very easy to place material anywhere instead of always starting jobs at (0,0) which causes a lot of wear on that corner of the table.

Today we were able to improve the zeroing process a little bit more. Until today, we would place the SuperZero, align the router, then go into the control software. In the ShopBot Control, hitting [F] opens the file dialog. Then you click through the Windows directory structure to C:/SBParts where the SuperZero part files are installed. We use the XYZ CRNR part file that is used when the short side is aligned to the positive X-axis and the long side is aligned to the positive Y-axis. Once you run the part file, the router determines z-height first, then moves back and forth inside the open circle to calculate the x and y values.

The first improvement was the simplest. Since we are cutting multiple sheets of plywood, it aligns with the work table, so the job zero is at (0, 0). This means the location of the SuperZero will be standard. After measuring the SuperZero, we can send the router to 1.25” X and 1.25” Y instead of attempting to line up the router bit over the opening by eye. Not sure why that hadn’t been done before.

The next optimization is in the Control Software. Since C2 used to run a z-zero routine, is there a way to change it to handle the SuperZero? Yes. The software supports Custom ShopBot Part files. In the C:/SBParts/Custom there is a template for creating special files that can be included in the [C]ut Menu. We simply added the content of the SuperZero XYZ CRNR part file into a custom part file and updated the file description. After restarting the Control soft are, our new SuperZero menu option appears at C4.

As soon as you key in C4, the routine starts running, saving a number of steps.

Continuous Improvement

The next tweak should be launching a modal dialog reminding the operator to place the SuperZero plate and attach the ground wire before executing the zeroing process.