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CNC machines are used to mill block and flat stock materials. The RPC runs two primary 3-axis mills: the Bridgeport and the Komo. Each machine has unique abilities and limitations in regard to material type and size that need to be taken into account when preparing a model for CNC machining.
Follow the links below to find tutorials on how to prepare your files for our respective machines.
Key Machine Differences
||Bridgeport Machining Center
|required file type
||IGES (preferred) or STL
||IGES (preferred) or STL
|max workpiece configuration A
||33.00(X) x 18.00(Y) x 10.00(Z)in
||120.00(X) x 60.00(Y) x 6.00(Z)
|max workpiece configuration B
||36.00(X) x 15.00(Y) x 10.00(Z)in
|tools in carousel
|programming cost per minute*
|machining cost per minute**
|g code output file
*This is in addition to a programming base charge of $10.00.
**This is in addition to a machining base charge of $8.00 (Bridgeport) or $10.00 (Komo).
Follow the links below to find information on how to get started with CNC machining.
As soon as you have a design that you believe you will use, please consult with Scott Lincoln regarding strategies for Rapid Prototyping. Bring in images on paper or screen to show us what your finished shapes and functions will be. Even if you are already confident in what model making techniques you will use, we may have some helpful suggestions and will also get a sense of how much demand you plan to put on the RPCenter resources.
Sections of your model that are best accomplished without using RPCenter operations should be directed appropriately. This includes:
- Flat-panels or other shapes which could be accomplished by manual means
- Parts that could be easily purchased ready-made
- Parts that cannot be machined due to material limitations
CAD files for CNC-milling should have all parts arranged for cutting in the 3-axis machine. Here is a quick review; appropriate preparation includes:
- A good strategy for separating pieces of your product to facilitate tool-approach issues, including considerations for re-assembly after cutting, if needed.
- The CAD model arranged for milling, showing exactly (and only) the parts as you want them cut, including space between the parts for the cutters to work and the foot-print of the block of material modeled in wire-frame ( see maximum milling size)
- The material prepared as directed. Most parts will require that the material is mounted on 0.75" foam. Please be sure to use ONLY foam that is in good condition. The success of your parts depends on this foam during cutting (to hold the parts).
- For parts which cannot be split and must be cut from multiple sides, special programming is required.
Ensuring a Successful Result
Checklist before exporting CAD model:
- Position your CAD object so that the origin for X, Y and Z is the lower left corner of the material-block.
- Position parts at Z: 0
- Minimum of 0.125" between parts and outside edge of block
- Minimum of 0.050" between top of part and top of block.
- If you have several objects in one file, create at least 0.625" space in between.
- Make sure the scale is correct.
- No undercuts (split parts if needed to avoid undercuts).
- Layers in your program will be exported which can be useful with understandable naming conventions.
- Show a representation of the footprint of the block on separate layer.
Acceptable File Format
The RPC accepts the file format *.IGES (or *.IGS) for milling. Proven programs that export *.iges files are:
- Alias Studio