Hello, I am in the process of developing a large desktop CNC mill for prototype work with some friends with the hopes to sell and I would like some feedback on the design. We’re hoping to target the makerspace, hobbyist, and prototype shops.
The CNC mill features a gantry style structure that is made from fully cast gray iron with all axis’s using linear guides and ball screws with hybrid stepper motors (steppers with encoders) with a target weight of approximately 350 lbs. It will use a bt30 spindle with power draw bar, and be offered with a 110V AC spindle motor capable of 6k rpm and an upgraded bt30 spindle, 220V AC spindle motor capable of about 12k rpm that will not trip and breakers. We are considering dropping the 110V option. We are attempting to minimize the machine’s weight by using FEA to selectively remove material while maximizing rigidity. The machine will be just narrow enough to fit through a standard single width door.
For electronics, we are planning to use a FPGA motion controller capable of S-curve acceleration (higher order motion planning). User interface will be through a 24” touchscreen LCD monitor. We are also planning on creating an optional enclosure to sell with it also. Tool height setting will be made easier with an integrated tool height setter.
We believe that quality control is essential and plan to assembly the entire unit in the United States. Spindles will be tested on a dyno and motion systems will be tested with a Renishaw ball bar to ensure performance. What do you think? We are also considering selling the machine just as a kit only, basically all the parts but unassembled. What would you be willing to pay for a machine such as this if you were considering purchasing one?
We’re also considering a lower cost option using an ER20 spindle but would not have a power draw bar and would require you to change tools manually and set the tool height each time.
Here is a picture of an earlier iteration for reference. The newer iteration has a different gantry/ z-axis profile that is still being developed.
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