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HERE IS SOME INSIGHT AS TO HOW WE QUOTE A CNC ROUTING OR MACHINING JOB USING YOUR CAD DRAWINGS

THE SAME BASIC PRINCIPLE APPLIES TO CNC PROTOTYPING, ALTHOUGH WE CONSIDER PROTOTYPING A MORE INVOLVED PROCESS BECAUSE IT IS TYPICALLY EXPERIMENTAL 

In order to make CNC routing and machining possible, we use CAD design when applying toolpaths to cut the parts.

We often receive CAD drawings or files that have to be modified in order to be toolpathed.  These toolpaths are used to machine your part but are also needed for generating time and cost estimation.  Precision Fablab relies on you to convey all details related to what you are wanting to machine. 

Preferably this information will be in the form of a layered CAD file.  Files would need to be correct with layers showing basic geometry and any miscellaneous information about material to be used.  Below are some illustrations of different layers of a drawing, that has been imported into our CAM software.

We do different types of toolpaths on the CNC Router. Depending on the diameter of the CNC cut we will use an end mill, a dril, a v-groove bit or a surface paner bit.
CAD Drawing for CNC routing pocket fill for door hinge

The layers in your file should be titled with, for example: depth of cut, “pocket fill” to remove, or a groove.  Each layer is supposed to indicate proposed tool diameter and whether the tool would be inside or outside the geometry.  Anything that is the same for all entities should be in the same layer.  We also ask that the illustrations in your file appear as closed entities without overlapping duplicates on or around the lines.

Written information pertaining to the image shown is used on this CAD to provide more detail
This cad drawing includes information about drill holes to be CNC routed with the correct depth

Organizing the content of your CAD file helps speed up the process.  When we receive an organized drawing, we can use it to generate toolpaths sometimes with just a couple of clicks.  Once we have our toolpaths, we can then run a simulation to arrive at an estimated time of machining.  Because we base our cost on time, deriving a cost without a completed file would be a wild guess.  However, we can complete your files for an additional cost. 

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Either way, we have to have a clean, completed CAD file, in order to give you an upfront cost.  We understand CAD design may not always be possible for every client.  If computer designing is not within your reach, no worries we may be able to draw it for you.  Creating a CAD file that is ready to be imported into CAM software will require your specific information and often your direct involvement in the process.  Your physical presence may be needed depending on the level of difficulty of your idea.  Any drawing of parts to be machined will need to be approved by you before machining.  This type of work will take time and will constitute a designer-client agreement to be invoiced as design or art work.

This layer of the CAD drawing illustrates the outline to be CNC cut and the thickness of the material
Here we can see how the CAD drawing's layers are turned on all at the same time to see particular information on a layer and how it relates to the drawing as a whole

These are the CAD files you may send:

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  • For Autocad users, DXF/DWG files will work phenomenal in fact these are preferred 

  • If you use SolidWorks, please send: SLDPRT (.sldprt) for a single part and SLDASM (.sldasm) for an assembly of parts.  Generic parasolid documents X_B (.x_b) or X_T (.x_t) will also work just fine

  • If you are an Inventor user, please send an IPT (.ipt) when sending a single part and an IAM (.iam) when sending an assembly of parts.  Generic parasolid documents X_B (.x_b) or X_T (.x_t) will also work fine

  • STEP (.step) or STP (.stp) formats are substandard compared the format types above but those are ok too

  • IGES (.iges) and IGS (.igs) are ok but inferior to all the formats above  

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Tooling is a key factor in relation to how we quote as it will directly impact toolpaths.  We will be  putting together a description of the tools most frequently used in our machine shop shortly.  In the meantime you may email us at: precisionfablab@gmail.com or call: (404) 850-3155

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