Since their introduction by the United States Air Force in the 1950's, CNC routers have been a useful tool in the aerospace industry. It was in the mid 1990's that we saw the potential for the equipment in the architectural world.
First, what is a CNC? A CNC router (Computer Numerically Controlled) is a computer numerically controlled cutting machine similar to a hand held router but much larger. Routers are primarily used for cutting various materials, such as wood, composites, plastics, solid surface (such as Corian®, Krion® or Hi-Macs®) and high density foams. Omega has 3-Axis machines - which route X, Y & Z Axis. Omega also has a 5-Axis machine that is a great tool for doing complex, curved surfaces. Our 5-Axis machine, with the addition of the B-axis and C-axis, has great 3D capabilities and has opened up an entire new realm of cool stuff that we get the privilege to produce.
3-Dimensional CNC (Computer Numerically Controlled) modeling is the process of routing physical objects from 2-D or 3-D digital information, commonly referred to as CAD (Computer Aided Design) files. The process of CNC routing involves two main steps – tool path generation and actual routing.
How the Process Works…
An idea is brought to the table in either a digital or non-digital format. Omega employs creative design and fabrication professionals that can assist in questions ranging from how to integrate the machine process into your design plans and the manufacturability of your idea.
CAD (Computer-Aided Design) Drawing
If the idea has not been rendered in a digital format then this is the time for that. The CAD file can be a simple 2-dimensional drawing or a full 3-D model. Our staff is experienced in CAD drafting and can assist in this process as well.
CAM (Computer-Aided Manufacturing) Package
The CAM Package is the process of taking the CAD data and converting it into coordinates that the machine understands. It is also the process of adding stock, flanges, run-out, and other necessary machine information to the model. In this step, cutters are chosen and the finished machined information is created.
Create a Toolpath
Once the proper parameters are set in the CAM program, the next step is to create the toolpath program. Creating the toolpath is the actual act of converting the geometry into X,Y, and Z coordinates for 3-Axis and X, Y, Z, B and C coordinates for 5-Axis that the CNC machine can understand.
Post processing the toolpath is the last step that is done to the program before it goes to the machine controller. The post process customizes the program to the specific machine that the toolpath will run on. Just like on a car, you have to use the correct type of gasoline to make the car run; the CNC needs to have the correct style of program language to understand it.
On a CNC machine there is an attached machine controller which houses the user interface. The post processed program is entered into the machine controller. Other data is added including where the stock that is to be machined is located on the machine, the speed and feed rate that the machine is to run at, the length of the cutter, etc.
CNC Machine Part Model
Once setup correctly, the machine is told to run the program and the part will be machined to shape and size per the original CAD drawing.
Make Part Mold (if needed)
Often times, CNC machining is used to create thermoforming or fiberglass mold instead of cutting a part or design out directly.
Materials that Can Be Processed with a CNC Machine
-Corian® Solid Surface by Dupont
-Krion® Solid Surface by Porcelanosa
-Hi-Macs® Solid Surface by LG Hausys
-Staron® Solid Surface
-Other modeling materials
-Epoxy Prepreg Lay-ups
Plastics and Other Sheet Materials
-And many more
A Note about Surface and Edge Finish
Depending on the application and the customer’s needs, we can create a surface that is free from machine marks or scallops. Our machining techniques are used in tandem with our fabrication department to provide a completed product with the desire surface finish. If the 3-D Model is being used as a mold, then we can post process the model after it has been machined to knock off any of the scallops, adding a priming agent such as Duratec, and sand the surface to whatever grit necessary. Also, using state of the art cutters, our edge finish can appear to be polished should the project necessitate it.
Benefits of CNC Fabrication: Repeat-ability and High Volume