Octavio's Metal CNC Machine
Octavio went out on a limb and created a metal machine with some very inventive components. Inspired by this website, he was able to get this design and construction going. The machine is truly an example of using components in the machine for efficiency and simplicity. The overall structure appears to be steel. He uses bearings with channels to serve as linear guides. The z-axis mechanism is reversed to enable longer travel. All of this is not the most interesting part. Octavio is a medical doctor. This goes to show that individuals of all backgrounds dabble with this technology. Take a close look at the bearings used to guide along the rail (U groove and V groove bearings work well for this type of linear rail mechanism). I know, you're saying that this method is used on other CNC machines. Sure, but he is positioning the bearings and using minimum hardware to serve multiple purposes. You can see that he is using the same shaft for each pair of bearings. The back bearings (the bearings to the right) glide horizontally along the y-axis and the front bearings serve the z-axis up and down movement. This linear motion mechanics for the y and z axes is very clever. Octavio is currently trying to reduce the gantry weight. He says that the z-axis alone is 50 pounds. He has a goal of 20 pounds by changing the metal to aluminum using stamped parts.
Octavio is providing the rigidity by using a chain drive with two lead screws for the x-axis. As you can see in the images, the chain is connected to a bearing that is driven by the motor on the other side. As I have said in many parts of the website, backlash can be introduced in a machine at various parts including the lead nut, couplings, clamps/nuts at the bearings, gears, and pulley mechanisms. With the use of a chain and a sprocket, the backlash is minimized as long as there is sufficient tension. Tension is only required in a chain drive to reduce the backlash in both directions.
Octavio feels that this machine should contain fewer special and machined parts. It is more economical to to go with off the shelf parts which reduces the maintenance. He has also managed to make this machine portable and he has the adapted his machine to hold a plasma cutter. His choice of the software tool chain is Mach3 and Vectic (3DCut, Vcarve, and PhotoCarve). Octavio is a very bright man with his view that every hobbyist should have at least one CNC machine. I raise my glass to that one.
Here are a few examples of the work he has done on the machine. Octavio uses The detail of the flower bas relief is very nice. You can see that there is no evidence of backlash. The lettering in this examples is 18 point size according to Octavio.