High Speed Precision CNC Milling
Super High-Quality Hand Finishing
Crystal Transparent PMMA Prototype
Diamond Cut Lamborghini Model
This is an old project we did for UN in 2013. In order to stay within budget, we made it using SLA (stereolithography) and painted it black. The result we got was OK, but not brilliant. This is due to the limitation of the SLA process: the visible layers of the build process is the main problem. Recently, we came up with the idea to make this prototype using 5 axis CNC milling. in order to find a better solution for similar kinds of projects, meanwhile test out the accuracy and stability of our new machine.
Check Out How We Made This Prototype
CNC Milling Machine: JDGR 200
Max RPM: 32,000
Finish Tool: R 0.25 sphere cutter
Surface Roughness: Ra 0.5
Programming: 2 days
Machining Hours: 58 hours in total
Hand Finishing: 4 days
Challenges of This Project
For this kind of model, it is very important to keep all the lines of the edges as sharp as possible. In some areas, the angle between two surfaces is very large, almost 170 degrees, which means the join line is almost flat. To maintain these fine details is a challenge for our machine as well as for the hand finishing process. To avoid using sand paper, the overall milling roughness should be under Ra 0.6, so that we can polish the surface directly with cloth.
The material connecting the rearview mirrors to the car body is extremely tiny, and will break easily during CNC machining or hand finishing. To remove plaster after machining the second surface is also a difficult job.
The air inlets are designed with undercuts, so we have to use a very long small cutter. And the edges as shown is very thin and sharp, so any vibration during milling will break those edges. Our machine and tool holder accuracy is +/-0.005 mm, but it is also important for CNC operators to keep the cutter accuracy around +/-0.005 mm at the same time.