Pins are marked in terms of how they
may be used with a breakout board:
Pins are marked in terms of how they may be used with a breakout board:
- Input: Pin can bring data from machine back to
PC, for example status of home or limit switches or encoder pulses.
- Input: Pin can bring data from machine back to PC, for example status of home or limit switches or encoder pulses.
- Output: Pin can bring data from PC out to machine,
perhaps to trigger a relay (for coolant or spindle motor control) or to
drive a step motor.
- Output: Pin can bring data from PC out to machine, perhaps to trigger a relay (for coolant or spindle motor control) or to drive a step motor.
- Input/Output: Pin can serve as either input or
- Input/Output: Pin can serve as either input or output.
In using parallel ports, there are a few things to keep in mind. First, most PC's only have 1 parallel port (some newer models and especially laptops don't have any). You can use up to 2 parallel ports with Mach 3 to get more connections, but you'll need a parallel port card for the second port. Mach 3 gives you a lot of flexibility in how to use the connections provided by a parallel port. Lastly, some newer parallel ports operate at a lower voltage than the originals--about 3.3 volts instead of the normal 5 volts. This can be a problem if all of your components are not expecting the lower voltages.
In CNC, the term Parameters generally refers to settings
that are made in the machine's controller outside the part program.
Parameters can include many things necessary to tune or configure the
machine for proper operation. Examples include the maximum speed an axis
can travel or the maximum following error before a servo fault occurs.
Parameters can include many things necessary to tune or configure the machine for proper operation. Examples include the maximum speed an axis can travel or the maximum following error before a servo fault occurs.
Parametric drawing refers to a feature of CAD programs that allows the dimensions of the parts to act as parameters. One can change a dimension and the part will adjust its size accordingly. This is very convenient for revising drawings. The feature does not exist in all CAD programs. SolidWorks and Alibre 3D have it, while Rhino 3D does not.
Parametric programming is the practice of designing a part program so that it has parameters that may be varied without having to rewrite the program. This is useful, for example, when a single part program is used for families of parts, or when some characteristics of a part must change from time to time on different production runs.
Parametric programming tends to be a proprietary feature that differs from one CNC controller to the next.
A part chute is a component of a CNC lathe that provides a convenient way to gather parts as they are sliced off and place them in a bin.
What you’d call a G-Code program. Part Program is a more proper and less confusing term than “G-Code” because G-Codes are only one type of word that can appear in a part program.
A word that indicates the name of a subprogram to execute.
A type of drilling or canned cycle (See Also Canned Cycle) in which the bit is advanced into the hole a short distance and then withdrawn repeatedly to facilitate chip evacuation.
A handheld control for a machine tool.
Any milling that uses the edge of the milling cutter that is parallel to the axis of rotation instead of the end of the cutter, as in Face Milling (See Also Face Milling).
PID is a type of servo or feedback tuning system which stands for Proportional, Integral, and Derivative.
Pinch Turning (Also Called "Balanced Turning")Like Follow Turning, Pinch Turning is a way to employ 2 independent tool turrets on a CNC lathe to cut more quickly. When pinch turning one tool follows behind the other. The first tool cuts a spiral swatch (not unlike threading) and the second tool cleans up the spiral of uncut material left by the first tool.
Pitch or Leadscrew Pitch
Usually, the number of turns the leadscrew must make to travel a standard distance. For Imperial screws, the standard distance will be an inch and the unit of measure would be TPI or Turns Per Inch.
A more accurate and technical definition is the
axial distance between threads, which will be equal to the lead in a single
start screw. See Also Lead and Screw Starts.
A more accurate and technical definition is the axial distance between threads, which will be equal to the lead in a single start screw. See Also Lead and Screw Starts.
A gantry style (See Also Gantry) machine used to move a plasma cutting torch over sheets of metal under CNC control.
To cut straight down, similar to drilling with a twist bit.
An interior recess that is cut into a part.
Rake is the angle from the workpiece wall to the cutting tool at the cutting edge. If it is 90 degrees, the edge is perpendicular to the workpiece. Angles less than 90 degrees are negative rake angles. Angles greater than 90 degrees are positive rake angles. Positive rake is generally preferable to negative rake because it requires less pressure to cut. Negative rake has the advantage that it provides more edges on a carbide insert (See Also Carbide Insert) that may be used, and may be more economical.
Post or Post Processor
The “Post” is the set of G-Codes or part program generated
The act of sending the G-Code program to the CNC machine,
usually from a
A powered drawbar typically uses an air or electric impact wrench to operate the drawscrew mechanism under power. It’s advantages over a manual drawbar include much faster operation together with more repeatable torque on the drawbar.
A powered drawbar is a much simpler way to speed up tool changes than an automatic toolchanger (See also Toolchanger)
Preload (Bearings and Leadscrews)
Preload is a mechanism used to eliminate backlash by tensioning a bearing or leadscrew to take up the slack that causes backlash. Some typically ways in which preload can be achieved include using a threaded screw that is torqued down to create a load, using spacers or shims, using springs, wavy (Belleville) washers, or using oversized balls in a ballnut.
As in "blueprint" or drawing. Refers to the drawings that define what the part should be. Once upon a time all prints were "blueprints", which were made with a photo-chemical process. They smelled strongly of ammonia and were a deep purple blue in color with white lines. This was before laser printers and the like, and the blueprint process was a fast way to copy hand drawn prints of any size.
Sliding ways are used by many machine tools so that their axes may slide against one another. There are four prominent designs:
- Dovetail Ways: Very common on mills, dovetail ways look like the dovetails used in wood joinery.
- Box Ways: Box Ways are rectangular cross section, as opposed to the angular shape of dovetail ways. Box ways are very strong, but they suffer from two shortcomings. First, they involve a lot of surface contact area, so managing friction is key. Second, in order to slide at all, some clearance is required, which results in some slop in their travel. They are the strongest and most rigid design, but they are difficult and expensive to manufacture.
Probe: See "Touch Probe”
Profiling: See “Contour Turning”
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