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Release status: working

The RepRap Wiki PrismX page.
CAD Models
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The PrismX is elegant, strong, fast, and affordable. It's an open-source reprap 3D printer that traces its lineage back to Prism AliceBlue, Prism, and Mendel before it. Like its predecessors it prints 3D objects, can replicate itself, can be tuned, hacked, repaired, upgraded, and more. It's designed to be outfitted with deluxe components throughout, but can be downgraded and even rep-strapped from the ground-up. Its plastic parts can be manufactured for higher degrees of precision. Frame strength and alignment have been improved. As a result the machine's performance is outstanding.

The PrismX is an evolutionary open-source design. The PrismX keeps the spirit of its forefathers intact, being a true reprap that can replicate itself. However it is also designed to be manufactured with molded or machined parts, to be mass produced, and proposes several deluxe but affordable upgrades that provide significant return on investment.

To create PrismX I've taken the SCAD fork of the Prism (link) and started a long process of creating new parts, replacing and revising existing ones, refactoring the code to improve it, and so on. One of the primary milestones I reached in January, 2013 was to create a complete OpenSCAD model of the PrismX. This was inspired by Johan Rocholl's work on the Rostock Delta Robot (link), which is also 100% OpenSCAD and was published with a complete machine SCAD file. This took a long time to write and debug - but in the end the investment payed off immensely and we've never looked back.

The PrismX has been developed by focusing on each area of the printer and revising it. The revisions were tested on a prototype named AliceBlue. Both PrismX and the earlier AliceBlue have the same geometry as the original Prism. They both share some original parts from the original Prism. In the PrismX much has changed with respect to the original Prism. It still looks similar, but refined and evolved.

PrismX Specifications

Manufaturer Terawatt Industries
Model PrismX
Technology FFF/FDM
Size 440mm (W) x 440mm (L) x 410mm (H)
Weight ~8 kg (gantry only, not including motors, PSU, wiring, etc.)
Max Potential Build Envelope 215mm (W) x 210mm (L) x 200mm (H)
Cost to build $1295 US (complete w/original deluxe upgrades)

PrismX Features

  • Parts designed for molding or machining - can be printed also.
  • 4-motor design. Designed in OpenSCAD.
  • Belt-driven z-axis with GT2 belt and 36T pulleys. Motor has 36T pulley so entire z-drive is 1:1 ratio. This ratio was chosen to simplify things.
  • Belt-driven extruder - the 00str00der
  • Y-Axis completely redesigned. Universal y-axis plate, GT2 belts and pulleys, custom idler and motor mount. The y-axis belt is designed to loop around the bottom extrusion to maximize z-axis travel. With the universal plate this design is light, fast, and accurate.
  • Z-axis completely redesigned. Designed for acetal bushings, thrust bearings, and leadscrew nut. Acetal bushings work best because this is exactly the kind of motion (axial) they're design for - and they're affordable, precise, and durable. I've tried the original design and a couple variations on AliceBlue; this setup is the best so far. The precision leadscrews are optional but somebody will have to modify the SCADs for other leadscrews. I'd say a printed leadscrew nut works best because it can be printed slightly tighter than the threads but still be secured and adjusted. Delrin is next best, metal is OK and probably has the best aesthetic.
  • Z-axis rods moved 4mm outside of frame. This not only makes assembly easier - the original top-support is not needed (though I revised it) - the frame is actually stronger now.
  • X-axis completely redesigned. Sheliak x-ends and Sheliak X-carriage are designed to be printed for precise alignment.
  • Top-rod "armor" - supports that secure the top rod to the uprights. With four (4) of these the frame is very strong. I've had no problem holding the entire machine by the top bar and have traveled with it several times. It needs it own seat in the car though...
  • LM8UU bearing mounts -- Mounts are designed to be printed for precision. Instead of clamping we use steel bearing retaining rings. They're affordable, durable, and work so much better than clamping mounts - especially the printed clamping ones that always break. More importantly, the bearings are rock solid, align more precisely, and travel smoother.
  • Bottom-feet completely redesigned. Can be made in multiple materials such as soft rubber.
  • Frame can be resized. I don't see anything wrong with 800mm extrusion here - the T-6061 heatbed probably won't flex much, if anything...
  • GT2 belts and pulleys throughout.
  • Mounts for power switch and power supply on the frame.
  • Filament guidler (in development)
  • Filament spool holder (in development)

Prism AliceBlue

The PrismX is actually based on Prism AliceBlue. Thus AliceBlue can be considered an early PrismX prototype. It's somewhere halfway between the original Prism and the PrismX. I started revising the original Prism in early 2012. After a few detours in life Prism AliceBlue was commissioned in December, 2012. It has been running incredibly reliably ever since - even with further modifications made for proving PrismX.

AliceBlue Features

  • y-rods moved above frame ~3mm
  • Universal Y-Axis Plate with customized idler and y-motor support - however at first it had TommyC's y-plate
  • z-axis drive system upgraded to GT2 belt and pulleys (not printed), thrust bearings
  • x-ends with customized Kuehling's x-ends - the motor moved behind the bearing holders
  • power supply mount, RAMPS mount, ATX adapter board mount
  • other goodies like power switch, eventually

AliceBlue has become a proving ground for PrismX modifications; all sorts of mods, actually. It's extremely dependable.

Why a PrismX instead of a MendelMax?

The closed-triangle design on the Prism is inherently stronger than the open-triangle design, or T-frame. There is no need for a double-lower gantry like the Prusa and MendelMax - that never added any strength to their frames and was always there for the y-axis. The PrismX has a complete CAD model of the machine, does yours (or the one you want)? It should, otherwise the designer(s) is/are doing alot of guessing. The PrismX can achieve incredible alignment with printed parts, not to mention the tolerances that are feasible with molded or machined parts. Finally, the PrismX is based on a proven history that goes back to the original Prism Mendel. The design is based on proven revisions. There has never been a need to make radical design changes from one revision to the next - the design changes have been evolutionary. Apparently the original design was based on sound principles.

Printed Parts

We have a printed parts list. It will be conveyed once Terawatt Industries makes the PrismX available to the public. Probably no in this wiki...most likely Google Drive or the TW website.

Non-Printed Parts

The extrusion profile is the same as the original Prism.

The vitamins BOM has evolved and is slightly more complex. There is still only one type of hardware for the frame: M4. The 00str00der is being revised so it will work with M4; then the entire hardware/vitamin BOM will be for M4 hardware; currently the 00str00der introduced a few M3 parts into the BOM.

We will convey the entire vitamins and machine BOM once Terawatt Industries makes the PrismX available to the public.

Build Instructions

Terawatt will publish a complete full-color assembly guide for the PrismX when kits are made available to the public. In short, assembly is still similar to the original Prism - but the parts are revised, the rods have moved, and the z-axis supports are different; amongst other assembly variations such as split-parts.

Further Development

I'm going to stay mum about this for the moment. We have an entire roadmap planned for this machine that potentially extends beyond 2015, but I'm more interested to see what types of enhancements PrismX users will contribute and demand.