Glossary

The Polar3D printer melts plastic filament and deposits in layers or “slices” to additively build up a solid, three-dimensional object. More generally, there are a variety of forms of “3D printing”; see http://www.3dhubs.com/what-is-3d-printing for an overview.

Plastic filament 3D printers are relatively inexpensive, and accessible to students. Students may find it interesting to consider how the sorts of thinking and skills developed using a plastic filament 3D printer could transfer to alternate forms of 3D printing.

ABS (Acrylonitrile-Butadiene Styrene) is an oil-based plastic. If not quite as environmentally friendly as PLA, it is a bit tougher material, and besides its use as 3D printer filament, it is also used in making plastic objects for everyday use, including Lego bricks. 434, 436–438, 445, See also filament & PLA

To promote adhesion of the object being printed, sometimes an extra ring of material may be printed encircling the object; this is referred to as a “brim”.

For 3D printers in general, the build plate is the platform on which objects are printed. For the Polar3D printer, the build plate is a round mirror with a toothed gear on the underside, that meshes with a gear on the build plate shuttle. 1, 4, 57, 411, 412, 436, 441, 460, 462–464, 466, 477, 493, See also build plate shuttle

For the Polar3D printer, the build plate shuttle consists of the carriage underneath the build plate: the shuttle arms and pads, and the gear, on which the build plate rests. The build plate shuttle slides along two support rods (in the x axis of movement) and rotates (the θ polar coordinate) the build plate via its gear. See Figure B.1. 4, 5, 381, 383, 384, 435, 461, 463, 464, 466, 474, 489, 494, See also build plate & polar coordinates

Computer Aided Design is the use of computer systems to aid in design. CAD output is often in the form of electronic files; for 3D printing, the industry de-facto standard is .stl files. 65, 67, 175, 418, See also .stl file

A captive portal is a “landing” web page that a user must view, and at which a user typically must accept prescribed conditions for access, before access is permitted. Free WiFi hotspots at business centers, airports, coffee shops, etc., typically permit access by means of a captive portal, where after a user accepts the conditions, the MAC address of the user’s device is permitted access for some period of time. In the context of Polar3D printers, note that a Polar3D printer cannot navigate itself through a captive portal; so for a Polar3D printer to get on a local network, the local network must allow access to the Polar3D printer (perhaps involving local network configuration to recognize the printer’s MAC address) without requiring the Polar3D printer to do an extra step of “viewing” or “agreeing to” some access agreement. This is the same sort of situation for any hardware device that needs to get on a local network. 8, 20, See also MAC address

Cartesian coordinates are rectilinear coordinates, describing the position of a point in two-dimensional space via x and y coordinates, or in three-dimensional space via x, y, and z coordinates. Cartesian coordinates are named after the 17th century mathematician René Descartes who developed them; compare with polar coordinates. 418, See also polar coordinates

In the context of 3D printing, combing contrasts to performing retraction and a Z hop: combing is when a non-extrusion move is performed without retracting the filament and without raising the print head, but ensuring that the extruder only moves over extrusion areas of the prior layer. With combing enabled, non-extrusion moves don’t bother to lift up the filament but rather try to keep any resulting “ooze” or smearing only over infill areas by constraining movement paths so as to avoid crossing over edges (and hence unextruded areas) of the prior layer; movement (without extrusion) takes the “long way round”, if necessary, in order to stay inside the currently printed island of extruded material. If printing via the Polar Cloud, see the “PRINT SETTINGS”, “ADVANCED”, “Enable Combing” option. 314, See also filament, infill, print head, retraction & Z hop

This is a type of print defect characterized by a ripple pattern which quickly dampens and is seen on the vertical faces of prints, particularly after a direction change in the surface.

Cylindrical coordinates are one way of extending polar coordinates to three-dimensional space: cylindrical coordinates use the r and θ of polar coordinates, plus a z height. See polar coordinates

DHCP (Dynamic Host Configuration Protocol) is a client/server protocol that automatically provides an IP host (such as your 3D printer) with its IP address and other related networking parameters such as the IP subnet mask and default gateway IP address. In the absence of a DHCP server on a local network, each network device (such as your 3D printer) will need to have a statically (i.e., manually) assigned IP address.

DWG is a proprietary, binary file format for storing 2D and 3D design data, used by a number of CAD packages, including for instance by Autodesk. There are a number of variants of DWG format. The Polar Cloud does not act on such files itself – but in case you have an object originally designed in a CAD package that generated such a file, and you would like to store an object’s DWG design file in the Polar Cloud along with its .stl or OBJ model file, the Polar Cloud does support uploading and storing DWG files as object subsidiary files. 148, See also DXF file

DXF (Drawing eXchange Format) is a CAD file format developed by Autodesk, intended to enable interoperability between Autodesk’s DWG files and other CAD programs. Although the Polar Cloud does not act on such files itself, in case you have a DXF file that you would like to store along with an object, the Polar Cloud does support uploading and storing DXF files as object subsidiary files. 148, See also DWG file

The extruder, or extruder nozzle, of a 3D printer is the nozzle at the bottom of the print head; it extrudes the melted filament. 294, 305, 314, 328, 334–336, 443, 451, 462–466, 479, See filament & print head

In the 3D printing context, filament generally refers to the plastic filament that the printer melts and prints; PLA and ABS are two of the most common materials for 3D printer filament. 39, See also ABS & PLA

Gcode, sometimes written as “G-code”, is a numerical control programming language used to control the operation of machine tools such as 3D printers. While there is an international standard for Gcode, the 3D printing community loosely adheres to it. For example, different 3D printers accept different variations of Gcode. The specific Gcodes produced by different slicers and accepted by different printers are often not well specified. 106, 267, 272, 294, 319, 342, 344, 382, 410, 506, See also slicer

Each model to be printed is comprised of an exterior and an interior. While the exterior is typically printed solid with no holes or gaps, the interior may range anywhere from completely empty to completely solid. The plastic printed in the interior is known as “infill” and its solidity is the “infill percentage”. For example, 0% infill means the print is completely hollow and 100% infill means it is fully solid. Printing time is reduced and plastic is saved by printing with infill percentages significantly less than 100%. The amount of infill you should use depends upon the nature of the piece being printed and its intended usage. When printing via the Polar Cloud, see in particular the build plate “PRINT SETTINGS”, “ADVANCED”, “Fill”, setting for “Infill Amount”.

A MAC address (Media Access Control address) of a network device is a unique identifier assigned for network data layer communications purposes. MAC address are typically assigned by the manufacturer of a network device, encoding the manufacturer’s registered identification number, and are stored in the device’s read-only memory or other firmware. Among other uses, a device’s MAC address is a way of identifying the device for network access purposes.

Gcode can contain “miscellaneous” function codes known as “Mcodes” and which begin with the letter “M”. See Gcode

Material Safety Data Sheets are a widely used system for cataloging information on chemicals, chemical compounds, and chemical mixtures – so for instance, the plastic of 3D printing filament. Note that 3D printing filament, especially PLA filament, is about as safe as plastic can get; but for those who need an MSDS document in their environment, Polar 3D has MSDS sheets available for the printing filament available from Polar 3D; see the Polar 3D support document Polar Filament MSDS Sheet. See also filament & PLA

MTL (Material Library file) format is a companion format to OBJ file format. MTL files can store surface properties such as color and texture. 417, See CAD & OBJ file

Next Generation Science Standards, released in 2013, were developed by a consortium of 26 states, the National Science Teachers Association, the American Association for the Advancement of Science, the National Research Council, and the nonprofit organization Achieve. For details, see http://www.nextgenscience.org.

The OBJ file format is an open format for representing 3D geometry of objects. It does not include features such as color or texture, nor does it specify a fixed size; it solely represents the shape. However, OBJ files can have a companion MTL file, where the MTL file stores properties such as color and texture. OBJ file format is an open format, first developed by Wavefront Technologies, and now used by other 3D graphics applications, including 3D printing. OBJ files are very commonly used for 3D art, design, and graphics in general, but .stl files are more commonly used in the specific arena of 3D printing, as .stl files are somewhat simpler, and more easily correctable. Note that as OBJ files often were not created with 3D printing in mind, models in OBJ format frequently are less “ready to print” than a typical .stl file might be. Some lovely OBJ format models may not be suitable for 3D printing; others, though printable, may require some adjustment of orientation (ROTATE), size (SCALE), and position (MOVE) prior to printing. 67, 122, 127, 128, 139, 141, 146–148, 156, 157, 159, 171, 175, 178, 280, 282, 284, 287, 326, 382, 398, 399, 417, 418, 424, See also CAD, MTL file & .stl file

When the extruder outputs a surplus of plastic, over-extrusion results. Over and under-extrusion are caused by a mismatch between the slicer’s expectations and reality: the slicer expects that when a millimeter of raw filament is fed into the extruder, a specific volume Ve of plastic will then be extruded — output by the extruder. When the actual volume of plastic output, Va, exceeds Ve, over-extrusion results; when Va is less than Ve, under-extrusion results.

There are a number of causes of such a mismatch of plastic extruded, but it generally is the result of the input filament diameter not matching what the slicer expected, or the steps per mm for the extruder being incorrect. By carefully measuring your filament diameter, and then checking that that value is properly entered in the slicer – for a Polar3D printer, this means properly entered under the object’s “PRINT SETTINGS”, “BASIC”, “Filament Diameter” – you can generally prevent over- and under-extrusion from occurring. (But note that poor quality filament whose diameter varies can cause intermittent over-extrusion and under-extrusion.) 478, See also filament, slicer & under-extrusion

PLA (PolyLactic Acid) is a biodegradable plastic, typically made from renewable raw materials such as cornstarch or sugarcane. Besides 3D printing filament, other common uses are for plastic cups and plastic water bottles. 1, 45, 433, 436–438, 442, 443, See also filament

Polar coordinates describe two-dimensional location via radius, r, and angle, θ. Compare with Cartesian coordinates, which instead describe two-dimensional location via x and y coordinates. The Polar3D printer uses polar coordinates at the hardware level, which has several advantages; see the Polar 3D video “WWBD - Polar is Better”.

Does this mean that you or your students need to use or understand polar coordinates? No! The Polar3D printer expects industry-standard .stl files, which describe location in the more familiar Cartesian x, y, and z coordinates; the Polar3D printer’s firmware automatically converts from the Cartesian coordinates describing an object to the polar coordinates (technically, cylindrical coordinates) that the printer’s hardware uses.

However, if you have students who are learning about polar coordinates in their math class – see Common Core standard http://www.corestandards.org/Math/Content/HSN/CN/B/4/ – you may wish to draw such students’ attention to the underlying polar operation of the Polar3D printer, both to help motivate them as to why one might want to learn about polar coordinates, and to help them visualize the relationship between polar coordinates and Cartesian coordinates.

Also, a couple of printer operational tips will be more intuitive if you are conscious that the printer is operating, at the hardware level, in polar coordinates. 409, 410, 460, 462, see also Cartesian coordinates & cylindrical coordinates

The print head is the assembly including the heating element and the filament extruder. It moves up and down the Z rod. See Figure B.1. 1, 4, 5, 30, 294, 314, 381, 383, 441, 448, 451, 461, 466, 479, 486, 489, 493, 494, See also extruder & Z rod

To promote better build plate adhesion or to accommodate an uneven build surface, most slicers can add to your print a thick series of layers which can later be removed once the print is finished. These layers — referred to as a raft — are printed slowly so as to promote better adhesion to the build plate as well as to level out the printing surface. A raft usually has support material at its base, and a platform (smooth surface) at its top, to support the object’s base. 293, 294, 306, 309, 432, 437, 441, 481, See also slicer

In the context of 3D printing, retraction typically refers to the amount by which the filament is retracted back into the extruder nozzle to keep it from oozing out during non-extrusion moves between sections of the print. That is, during printing there are normally extrusion moves, during which filament is being extruded, and non-extrusion moves, during which the filament is retracted slightly back up into the extruder nozzle while the extruder is moved without extruding melted filament to some other portion of the build plate where extrusion will be resumed. Retracting the filament slightly up into the extruder nozzle for non-extrusion moves helps keep filament from oozing out while the extruder moves to a new position. 294, 312–314, 432, 479, See extruder, filament & Z hop

SCAD file format is a plain text format developed by OpenSCAD for storing their 2D and 3D designs. Although the Polar Cloud does not act on such files itself, the Polar Cloud does support uploading and storing such files as object subsidiary files.

An SD card is specific type of memory flash card and is used to convey print files to your printer without using a USB or network connection. SD cards come in a variety of sizes, ranging from a fraction of a gigabyte to upwards of 256 gigabytes or more. The term “SD” is an acronym for “Secure Digital”.

When a model is prepared for printing by a slicer, the slicer generates commands to print a solid exterior. The exterior is typically printed by following the model’s perimeter. The perimeter may be printed multiple times per layer, each time inset from the prior pass. The final result can be thought of as a series of nested shells, one inside the other, from which arises the term “shell”. With some slicers, you control the thickness of the solid exterior by specifying the number of shells to generate. When printing via the Polar Cloud, see in particular the build plate “PRINT SETTINGS”, “ADVANCED”, “Quality” settings, especially “Wall Thickness”. 314–316, 443, 478, See also slicer

A skirt is an extra outline of material surrounding, but not touching, the perimeter of a print object. A skirt is sometimes used to shield the main object from thermal drafts, especially when printing using ABS filament, or to establish a smooth flow of filament. 51, 293, 294, 309, 432, 437, 445, See also ABS

SKP files are created by SketchUp to store 3D models. Such files may be used as well in IMSI TurboCAD and Trimble 3D Warehouse. Although the Polar Cloud does not act on such files itself, the Polar Cloud does support uploading and storing such files as object subsidiary files.

The process of turning a 3D model into printing instructions — Gcode — is referred to as “slicing”. That name derives from the fact that the process takes slices of the model and determines the necessary “tool paths” (extruder paths) to print that slice. The slice is a “layer” of the print. As the process is referred to as slicing, the software which implements the process is often called a “slicer”. For a Polar3D printer, slicer settings are set in the Polar Cloud under “PRINT SETTINGS”. (If using a direct connection to the Polar3D printer via a cable, and hence third-party software to control the printer, then the slicer is controlled by that other software; for instance, Repetier-Host uses the CuraEngine slicer.) 293, 334, 478, 506, See also extruder, Gcode & tool

Most slicers have a mechanism whereby you collect together a number of configuration settings used by that slicer when preparing a model for printing. Such a collection of settings is here referred to as a “slicing profile”. A given slicer may use a different name (e.g., a “factory” in Simplify3D). Each print of an object – each print job – has an associated slicing configuration. In particular, the Polar Cloud provides two pre-defined slicing profiles suitable for the Polar3D printer, a “Draft Quality” profile and a “Medium Quality” profile. Or alternatively, a customized slicing configuration may be specified; see Section 12.2.2. 51, 81, 105, 160, 245, 267, 272, 291–293, 302–305, 307–309, 330, 344, 361, 362, 365, 366, 432, See slicer

A stepper motor is a brushless DC (direct current) electric motor that divides a full rotation into a number of equal steps. In a 3D printer, stepper motors are typically used to move the extruder and build plate. In particular, in a Polar3D printer, there are three stepper motors: one controls the movement of the print head up and down the Z rod (z axis), one controls the movement of the build plate shuttle (x axis), and one controls the rotation of the build plate (θ rotation). 381, 383, See also build plate shuttle, polar coordinates, print head & Z rod

STL originally stood for the STereo Lithography file format native to CAD software created by 3D Systems, describing the surface geometry of a three-dimensional object. It does not include features such as color or texture, nor does it specify a fixed size; it solely represents the shape. It has become the de-facto standard format used in 3D printing. 34, 38, 46, 65, 67, 70, 105, 119, 122, 126–128, 139, 141, 146–148, 156, 157, 159, 171, 175, 178, 182, 267, 272, 280, 282, 284, 286, 304, 326, 344, 381, 382, 398, 399, 417, 419, 497–499, 506, 512, See also CAD

SVG (Scalable Vector Graphics) file format is an open standard, XML-based vector image format for 2D graphics, developed by the World Wide Web Consortium. The Polar Cloud supports uploading and storing such files as object subsidiary files.

A print defect caused by too thin of an exterior shell through which interior printing penetrates leaving visible surface blemishes. 478, See also shell

In Gcode parlance, an extruder is a “tool” which is controlled by the printer. That is, a “tool” is another name for an extruder. If your printer has a single extruder, than that extruder may be referred to as “tool 0”. If your printer has two extruders, then the right extruder is “tool 0” and the left extruder is “tool 1”. To further confuse matters, in Gcode, motion commands for the right extruder may use the prefix “A” while commands for the left extruder use the prefix “B”. See also extruder & Gcode

When the extruder outputs a deficit of plastic, under-extrusion results. 318, 478, 481, See also over-extrusion

An XLSX file is an Microsoft Excel Open XML Format Spreadsheet file. The Polar Cloud supports uploading and storing such files as object subsidiary files.

In the context of 3D printing, a Z hop typically refers to the amount by which the extruder nozzle is raised when performing non-extrusion moves between sections of the print. That is, during printing there are normally extrusion moves, during which filament is being extruded, and non-extrusion moves, during which the filament is retracted (retraction) and the extruder nozzle may optionally be raised by a Z hop amount so that the extruder may be moved without extruding melted filament to some other portion of the build plate where extrusion will be resumed. Performing a Z hop, raising the extruder nozzle (in fact the entire print head) for non-extrusion moves, helps keep the extruder nozzle from dragging or smearing extruded material while it is being moved to its new position. 294, 312, 433, 479, See extruder, filament, print head & retraction

On a Polar3D printer, the Z rod or Z threaded rod is the tall, threaded rod towards the back of the printer on which the print head (the printer extruder assembly) moves up and down; see Figure B.1. 4, 381, 384, 461, 464, 493, See also extruder & print head