I had obtained a few pieces of phenolic boards that was discarded from a switchboard maker. As they were quite stiff I thought I could make use of them to make some clamps for my movable gantry cnc machine.
I really needed to replace the wooden clamps that I had because one by one they were getting damaged. Somehow the wooden ones tend to split when shear forces acted on them when clamping. Sometimes this was unavoidable.
I would rather cut these phenolic boards because they did not contain fiberglass. If they had they would quickly dull my cutting tools if I were to fabricate the clamps out of them.
The fabrication of the clamps were easy with my movable gantry cnc milling machine. All I had to do was to make a drawing of the outline, slot in autocad, saved it as a .dxf file, and then open this file with dxf2gcode software. I could program the tool to move in a tool offset path or in a direct path and obtain the g-code files from the software. After that, I just open the g-code file on LinuxCNC which was then able to operate my movable gantry cnc milling machine.
Moving in a tool offset path was useful when I wanted to move the tool to cut to the actual designed shapes. The software would do all the calculations with regards to the diameter of the tool so that it would move the tool to cut away the work piece material leaving behind the required designed shape. From my previous experiences, the designed shape was cut accurately as required.
When selecting the feed and speeds to run the g-code, I had to rely on my past experiences with the settings. My spindle was rotating at a fixed speed of 6000 rpm because I could only have a 24 VDC supply available. Working around this, I found that I could have quite satisfactory results with speeds of 800 mm/min without the tool getting dull.
