Hobbyist CNC Machine

In this case study, a hypothetical client contacted us for a design of a hobbyist CNC machine that is suitable for household use. The machine must be small enough to be put on a 1.5 x 1.5 m platform and must be a 5-axis CNC Machine. Our team went through more than 5 design drafts to reach the final desired design.

Project Highlights

• Designed more than 7 mechanisms including the ball-screw tracks, the tower swivel, and the XZ movement of the spindle

• Achieved feed rate of 0.3 mm/rev by specifying spindle speed, motor torque, and spindle shape

• Optimizing the case’s weight so that the whole system would weigh less than 30 kg. Chose Aluminum as case’s material.

Lessons Learned

• In a complicated system, the system’s accuracy is determined by the least reliable mechanism. We have to weigh the tradeoffs between performance, cost, and reliability to build the system for our needs.

• The ball-screw mechanism has the advantage over other rotational-to-linear motion converter because of its high accuracy and low backlash. Since the ball bearings are contained within the nuts, they are self-lubricating and no debris can enter, making them low maintenance.

• Ball-screw has the disadvantage of being prone to buckle under vertical loads, unlike rack-and-pinion mechanism.

Tools Used

SolidWorks | Pen and Paper