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There are many different RepRap configurations and some work better as RepRaps and others are easier to use for a RepStrap when fabricating parts with other tools.
Many people would like to compare machines that share the same basic structure to see if there are ideas and improvements they can incorporate on their own machine. There has been no way to guess what the arrangement of a machine has been by just following the ancestors.
Basically there is no way to make an elegant symmetrical 3 axis Cartesian configuration. (Why? Is this because of category: DriveTrains#binding ?) Most of the compromise configurations have been tried. Some favour mechanical simplicity at the expense of moving the build platform while others attempt to minimise head inertia by using fixed motors and complex belt actuation. A symmetrical system that has a lot of elegance and is gaining popularity is the Delta Bot configuration that converts the Cartesian coordinates onto a different coordinate system that controls 3 identical actuators, either linear or angular to achieve movement in 3 dimensions. The higher speed SCARA style jointed 2 axis systems are gaining favour as designs with parts that can be largely printed and use very few vitamins. The robot arm style requires a lot of precision joints that are not easy to print and are not often seen. A compliant arm system has been proposed that uses flexural members. Polar designs have been proposed and fall between the SCARA and robot arm in complexity
Some RepRap machines types do not use a traditional single nozzle melted plastic extruder so are listed on their own by technology type. There is still overlap in the mechanical arrangement and the technology type categories list and incremental clean up will formalise the categories further.
The arrangement of some of the popular types is as follows, not all are derived from the RepRap project and not all are open source.
- Cartesian-XY-head: Darwin, RapMan, Ultimaker
- Dualwire-Gantry (DW-G) New fishing line wireing method that seperates X and Y motion and does not suffer the wobble problems of the h-bot.
- Is there a name for the mechanism that uses 2 stationary motors to drive 2 toothed belts with Cartesian positioning? Used by Cartesio; for more details see ; ; etc. Edit: Thats the Dualwire-Gantry_(DW-G) method (look above)
- The CoreXY mechanism ( http://www.corexy.com/theory.html ), a two-axis XY CNC stage with a drafting-table-type stabilizer, does not use any smooth rod, using 2 motors (both are stationary) to drive a single (!) toothed belt to move a head with Cartesian XY positioning.
- At the moment, H-bot and CoreXY mechanism printers (Uconduit, FoldaRap2, Create, etc.) are lumped into the Cartesian-XY-head category. Perhaps later we may split them out into one more category. (Is there any difference between H-bot and CoreXY printers? If so, what is that difference, and is it significant enough that they need 2 more completely separate categories?)
- "H-bot and CoreXY 3d printers" mailing list / google group.
- Is there a RepRap wiki article specifically about H-bots or more generally about Cartesian-XY-head arrangements, analogous to the "Polar" RepRap wiki article specifically about polar arrangements?
- Cartesian-XZ-head: Mendel, Huxley, Prusa i3, and most (all?) printers that use the Vertical X Axis Standard
- CoreXZ: just like the CoreXY, except rotated so that mechanism controls the X and Z axis. For example, "Youtube: RepRap CoreXZ"
- Cartesian-X-head: Up!,
- Cartesian-Z-head: Makerbot, Bamboo Printer
- Cartesian-XYZ-head: QU-BD
- Delta: Rostock, Kossel, Cerberus, Delta-Pi, TRap
- Polar: RepOlaRap
- Scara: RepRap Morgan, Wally, Helium Frog Scara
- Robot-Arm: Robot Arm
- Powder: CandyFab, MetalicRap
- Laser Cutter: LAOSlaser, LaserSaur
- UVResin: Lemon Curry
- Compliant: Bamboo
- Other arrangement: (perhaps should be renamed to mixed)
If a machine development page is not listed in one of the sub categories here you can add it. The discussion page has instructions and examples on what to add to the machine page source to list it in one of these sub-category pages. Sometimes simple errors in the category tags may prevent inclusion.
- General FAQ#Mechanical 3D robot
- RepRap Family Tree has a somewhat dated but very illuminating run-down and graphic of the different arrangements and their evolution. There are still machines listed on that page that do not have a category specified and they may be hard to find.
- DriveTrains which has some overlap in specifying machines but contains a lot of other information
- Parallel Mic a site with lots of interesting news on parallel kinematic platforms
- "Parallel kinematics machine tools: history, present, future". Z.Pandilov and K. Rall. It describes "Delta 3-DOF" (the same configuration as the Rostock) and many other parallel mechanisms and compares them to serial mechanisms.
This category has the following 14 subcategories, out of 14 total.