Arduino- An open-source electronics controller platform based on easy-to-use hardware and software.

Backlash- The amount of clearance between the threaded surfaces of bolts, machine screws and nuts to facilitate tightening and loosening of the fastener. If there is too much clearance between the threads, the threaded rod will slide back and forth inside the nut which will affect the accuracy of the axis it is used on.

Ball Screw- A means of translating the rotational movement of a stepper or servo motor into linear movement with a minimum of friction and backlash. In simple ball screws, bearings are recirculated within the nut assembly through the use of deflectors that redirect the ball bearings from the end of their path back to the beginning with every rotation of the shaft.  The ball bearings are secured within the nut assembly by a wiper/shield.

Belt Stretch - The natural tendency of drive belts to stretch under load and/or over time which will lead to loss of cutting accuracy.

CAD – Design software used to create vector or 3D files.(What the Software!?! – BobsCNC)

CAM – Software that is used to create toolpaths from 2D or 3D designs.(What the Software!?! – BobsCNC)

Climb Cut -- Refers to the relationship of the bit rotation to the direction of feed. A climb cut deflects the cutting away from the cut, cutting in the same direction of the feed.

Collet​ – A metal collar that holds the router bit within a spindle nut.

Compression Bit​ – A cutting tool with a combination of up and down shear cutting edges. (What Kind of Bits to Use With BobsCNC Routers)

Conventional Cut​ – Refers to the relationship of the bit rotation to the direction of feed. A conventional cut deflects the cutting toward the cut, against the direction of the feed.

Deflection​ – Tool deflection occurs when the spindle speed and feed rate exert sufficient force to deflect the cutting tool. Deflection leads to excessive wear and chatter which can shorten tool life and will leave unwanted tooling marks on the material. Deflection most often occurs when the feed rate is too high for the router speed being used.

Depth Per Pass​ – The depth of which the tool will cut on each pass. If the depth per pass is set less than the material thickness, it will cut multiple passes to reach the final depth.

Down Cut Bit ​– A cutting tool whose edges carve downward on the face of the toolpath. (What Kind of Bits to Use With BobsCNC Routers)

Drag Knife​ – A cutting tool that holds a razor or knife blade used to cut and inscribe material. Used with spindle or router motors turned off, it freely spins as it follows the direction of the toolpath. Cut2D Pro, VCarve Pro, and Aspire can create toolpaths for this with the Drag Knife Gadget.

Dust Shoe​ – An accessory which aids in dust collection by limiting the spread of dust and debris by channeling the airflow through an attached dust collection system.

End Mill​ – A cutting tool with a straight end, typically with spiral flute(s). (What Kind of Bits to Use With BobsCNC Routers)

Feeds and Speeds​ – A combination of factors that must be set to control the work performed by the cutting tool. (See RPM, feed rate, plunge rate, and depth per pass.)(Shop Talk: Speeds and Feeds - YouTube)

Feed Rate​ – The speed at which the cutting tool moves along a work piece in the X and Y axis.

File Type​ - Format at which a file is saved as. See different types below.

2D/3D Formats:

CRV (.crv) is a CAD file created by Vetric software that saves the vector design geometry and includes toolpaths for machining the design.

CRV3D ​– CRV3D (.crv3d) is similar to CRV above but is used for Aspire software only to be able to retain all of the 3D data.

DWG​ – Drawing (.dwg) is a proprietary binary file format used for storing 2D and 3D design data and metadata. Typically used by AutoCAD software.

DXF​ – Drawing eXchange Format (.dxf) is a file extension for a graphic image format typically used with AutoCAD.

PDF​ – Portable Document Format (.pdf) is a file format developed by Adobe to present documents and vector graphics.

SVG​ – Scalable Vector Graphics (.svg) is a file extension for vector image format for two-dimensional graphics. 3D File Formats:

3DCLIP​ – 3D Clipart files are exported from Aspire. This format maintains the component structure of clipart pieces at the time of saving, so will import all the components comprising the clipart piece.

STL​ – Standard Triangle Language (.stl) is a fairly standard file extension for 3D objects. These models can be completely 3dimensional (i.e., have a front, back, etc.), this means that when this type of file is opened that it must first be sized and oriented before a Component can be created (Aspire only represents base-relief so cannot work with a completely 3D object). Once the file becomes a Component it will have the same name as the original STL file.

V3M​ – Vectric 3D Model (.v3m) is a proprietary file format developed by Vectric for Design and Make. Files in this format can be purchased from ​​www. and when imported into Aspire will create a new Component with the same name as the file. This will be imported at the size and position the part was saved in the original file.

Image File Formats:

BMP​ – Bitmap (.bmp) is a raster graphics image file format developed by Microsoft used to store bitmap digital images.

GIF​ – Graphics Interchange Format (.gif) is a bitmap image file format.

JPG/JPEG​ – Joint Photographic Experts Group (.jpg or .jpeg) is a commonly used image file for compressed digital images. Generally, a lower resolution quality than a PNG file format.

PNG​ – Portable Graphics Format (.png) is an uncompressed raster image file format. This is typically the highest quality image format and also has the ability to have transparent backgrounds.

TIF​/​TIFF​ – Tag Image File Format (.tif or .tiff) is a file format for storing raster graphics images. 

Finish Pass​ – A 3D toolpath that eliminates the irregular contours left by the rough cut.

Firmware- A software program or set of instructions programmed on a hardware device. It provides the necessary instructions for how the device communicates with the other computer hardware. Firmware is typically stored in the flash ROM of a hardware device. While ROM is "read-only memory," flash ROM can be erased and rewritten because it is actually a type of flash memory.

Fixture​ – A term given to the apparatus or structure that is holding your work which is often custom-made to hold your specific part.

Flat Depth​ – The final depth at which the toolpath will cut to. Usually used in a vcarve toolpath.

Flats - The hexagonal face of a nut or head of a bolt.

Flute Length​ –The length of the cutting portion on a router bit or cutting tool.

Flutes​ – The cutting edges or inserts of a router bit or cutting tool. Most common woodworking bits come with either 1 or 2 flutes.

Gantry ​– The frame structure that straddles the bed and carries the spindle. It moves on guide rails along the length of the bed and is driven by stepper or servo drive motors.

G-Code​ – A simple text based machine language that uses axis points and commands which the machine uses to move and perform functions. This code is autogenerated from your toolpaths and must be saved through a post processor specific to the machine. Think of g-code as the directions from a map route at which your machine will move.

G-Code Sender - A gcode sender takes gcode saved from the CAM software and sends it to the machine.(What the Software!?! – BobsCNC)

Hold-down​ – A clamp or other such device used to firmly hold a workpiece or fixture to the table. Includes cams, clamps, double-sided tape, vacuum table, vacuum pods and others.

Home Position​ – Mechanical position generally the location of home switches on the X, Y, and Z axis.

Kerf​ – The width of the cut left by the cutting bit.

Nesting ​– The process of laying out patterns of material to be cut so as to reduce the amount of waste in a project.

Node​ – A point at which lines or pathways intersect; a central or connecting point. In Vectric software, there are a few types of nodes - start point, endpoint, mid-point, smooth point(biezer), arc point, and line point.

Origin ​– User designated zero point for the work piece. From which the router will reference the positioning of all movements. This point must match what was set up in your CAM software.

Plunge​ – The distance on the Z axis that the spindle and cutting tool moves toward, into, or along the material.

Plunge Rate​ – The speed of descent of the spindle on the Z axis.

Pocket Toolpath​ – A toolpath that creates a cavity in the horizontal surface of a workpiece.

Polyline​ – A continuous line composed of one or more segments of a line.

Post Processor​ – A software function that enables the CAD/CAM application to format G-Code, enabling the control system of a CNC to follow the designated toolpaths. This is usually specific to each different CNC machine manufacturer and model.

Preload - To apply force in order to minimize the internal clearance designed into to the bearing so that it can be reliably manufactured to a specified tolerance.  Bearings must roll in such a way that they properly carry and distribute the carried load evenly. Preloading applies force needed to minimize the radial and axial play of the bearing.  This causes the bearing to roll more accurately.

Profile Toolpath​ – A toolpath that cuts along the profile of a set of vectors. Typically used to cut out the shape of a design.

Proximity Switch​ – A limit switch that is used to find the home position or movement limits of an axis.

Recutting​ – What happens to chips when they are not removed fast enough and the cutting tool hits them again. Recutting can result in a bad surface finish or excessive tool wear.

Resolution​ – Describes the accuracy at which a CNC machine or component can distinguish position. 

Restore Point​ –The point along a toolpath where the spindle will start to resume a toolpath following a break. Not all machines are capable of this.

Roughing Pass​ – A 3D toolpath where the initial cut is designed to remove unwanted material, leaving a rough contour.

RPM​ - Revolutions per minute that the spindle will spin when cutting.

Safe Z – The height above the workpiece (including hold-downs or clamps used to secure the workpiece to the spoilboard) at which it is safe to move the cutting bit at its maximum feed rate.

Shank ​- The solid, perfectly cylindrical part of a router bit. It's the part of the bit that goes into the collet of the spindle and is secured with the collet nut.

Soft Limits​ – The physical limit of movement in each axis required by the workspace envelope and based on controller settings and the location of home position. An “out of soft limits error” implies that based on the positioning of the workpiece, there is not enough distance available to move in a designated axis.

Spindle​ – A rotating motor that holds tools and is used to machine parts. Sometimes substituted for a router.

Spindle Speed​ – Rotational speed of cutting tool (RPM).

Step Down ​– Distance in Z-axis that the cutting tool plunges into the material.

Stepover​ – The amount the cutting tool moves away from the previous cutting path as it routes the new path.

Stepper Motor​ – DC motor that moves in very precise steps upon the receipt of “pulses,” which result in very accurate positioning and speed control.(The Stepper Motor for CNC machines – BobsCNC)

Surfacing​ – The process of leveling the surface of the spoil board or material so that they are perpendicular to the spindle.

Taper ​– A uniform increase or decrease in the size or diameter of a workpiece.

Toolpath​ – User defined route which the cutter follows to machine a workpiece. Think of this as the “map” that you give your CNC to travel.

Touch-Off Plate​ –A device used to set the zero point (Origin) for the Z axis and sometimes the X and Y axis.

Tramming - Adjusting the carriages of the machine so that the router bit is absolutely perpendicular with the spoilboard. Moving the router mount clockwise or counterclockwise to adjust the angle of the router shaft to the spoilboard is the most common form of tramming.

UpCut Bit​ – A cutting tool whose edges carve upward along the face of the toolpath. Increases The potential for tear-out on the top surface but allows for a slightly higher feed-rate because this clears the material chips out of the cut. (What Kind of Bits to Use With BobsCNC Routers)

V-Bit ​– A rotating cutting tool shaped as a "V" and defined by the angle of the cutter. Used for V-carving; common size angle v-bits used are 30°, 45°,60°, 90°, & 120°.(What Kind of Bits to Use With BobsCNC Routers)

Vector​ – Computer graphics images that are defined in terms of 2D points, which are connected by lines and curves to form polygons and other shapes.

VFD ​– Variable Frequency Drive which controls the speed (RPM) of the spindle. Enables the fine tuning of the spindle during the operation of a toolpath. (Not available on all machines.)

Working Envelope ​– The three-dimensional area that the spindle can travel within while cutting or milling.

Zero Point -- The Datum Position or reference point of the workpiece used for accurate and consistent alignment of the cutting bit to the workpiece. This point is either set at one of the four corners or in the center of the workpiece

December 16, 2021 — Jonathan Horn