Physical Connection

   In order to harness the powers of a CNC Machine, you must first establish a physical connection between your project components and the CNC Machine. This tutorial focuses on constructing a CNC Mechanical Tester. If you have another type of project that you would like to interface with a CNC Machine, please visit our General Tutorial. Otherwise, you're in the right place.

    In the case of a mechanical tester, the movements of the device are done with respect to the load cell, so that a sample may be compressed and so that a force value may be measured. Thus, in establishing a physical connection between a mechanical testing unit and a CNC Machine, the subsequent design revolves around the load cell. The idea is to connect the load cell to the spindle of the CNC Machine. Based on the CNC Machine, the spindle may or may not move. In any case, motion is based around the spindle and the connection method is the same.

   The CNC Machine used in our project was Roland DGA's MDX-540 Milling Machine. To demonstrate how to establish a physical connection with a CNC Machine, this tutorial will use the CNC Machine used for our project as an example.

How To

   Most CNC Machine spindles are customizable based on a threaded hole through which tools are attached. Therefore all one needs to do is measure the dimensions of the spindle's tool exchanger, and then design a properly dimensioned screw attachment that connects the load cell with the spindle.

   For the Roland DGA MDX-540 Milling Machine, the radius of the spindle's tool exchanger was measured to be 0.125 inches. The load cell used in our project already had an threaded attachment with a radius of x inches. Thus, a double-sided screw was designed using Solidworks. The design was then manufactured through a machine shop. The double-sided screw was designed so that each side fit either the CNC Machine's spindle attachment or the load cell's threaded callout. The solidworks design may be found here .

   Based the manner in which your load cell is oriented, the double-sided screw attachment may either have a threaded hole or a potruding threaded cylindrical screw callout. In our case, our load cell already had a potruding threaded screw callout so the double-sided screw attachment was designed with a threaded hole to account for the design of the load cell. The same procedure applied for the spindle of the MDX-540, which also required a threaded hole callout for the double-sided screw attachment.