Good news!! --> No one likes to read a ton of text so we've kept it essential in this campaign!
Even better news!!! ---> Expand your printing capability with Selectra, the multi channel filament feeder for all! No longer just for team orange°, now YOU can enjoy this capability too!
Selectra is a multi channel filament feeder system for typical 1.75mm FDM 3d printers and allows dynamic filament switching during a print. Users are able to combine any colour, any material or any colour and material. We refer to this capability as "Multichromat", multiple chroma + multiple material. All of this driven by only two stepper motors and your existing electronics!
Current consumer level 3d printing is essentially a monochrome process and although users are able to select any 3d printable material or colour variant to print with, the choice is locked until the print job completes. At the moment, the costs involved with printing multichromat is typically accepted as being high, not just in terms of price, but also retrofit limitations, complexity and space requirements for additional hardware.
Primarily designed for 1.75mm Bowden tube type printers, Selectra replaces your existing filament feeder and also adds a 5 to 1 splitter block in the flow path towards the hotend.
Selectra has also been tested with direct drive extrusion systems. Although a more advanced retrofit, this case sees Selectra feed the hotend mounted stepper its required material. An excellent solution for ultra-mega-flexible materials.
Functionality relies on either a second separate* extruder stepper driver port on your 3d printer’s control board OR an electronic switch expansion**. You are able to use Selectra if one of the above requirements are met.
Retrofit is pretty straight forward. Users are required to print a mount for their specific printer(s), hook-up the wires and tubes, and enable dual extrusion in their firmware.
"Extruder" is the name given a mechanical assembly consisting of a raw material feeder and an extrusion shape die. Within your 3d printer, these parts would consist of the filament feeder + hotend assembly.
Selectra can be thought of as a collection of filament feeders, stacked together into an compact package. Combined with its selection mechanism, a single feeder within this stack is referred to as a "channel". Due to the way Selectra works, there can theoretically be any number of channels beyond the 5 channels currently offered.
As mentioned, Selectra uses two stepper motors, they are employed as follows: The feeder stepper is connected to the control board’s primary extruder driver port in order to be driven like any monofilament system. The selection stepper is connected to any free stepper driver on the main board. The user must ensure that "Dual extrusion" is activated in the 3d printer’s firmware before attempting operation.
In case you are thinking of going the expansion board route: All steppers are connected to their particular output port on the expansion board. The board itself is connected to the specified auxiliary signal pins on your 3D printer's controller. Finally, the extruder stepper driver (typically labeled "E0") is connected to the input of the expansion board.
Within a channel, Selectra drives filament by means of a hybridized constant distance - constant pressure pinch wheel mechanism. The result allows for a firm grip on the filament when operating and a zero contact idle position.
At the heart of the selection mechanism is a linear cam, driven by the rotation of a threaded rod (selector shaft) as mounted on the selection stepper. Thus, depending on the selection stepper's direction of rotation, the selector shaft causes the cam to advance or retract.
Each one of Selectra's channels are comprised of:
- Idler block - The part that actually handles the filament
- Channel actuator block - The component that engages the idler.
- Transfer spring - Mounted between the Actuator and Idler.
- Return spring - Returning each channel to a rest position when idle.
Channels are engaged by means of the channel actuator block being displaced when the selection cam interferes with its resting position. This displacement causes the actuator to push on the transfer spring thereby causing any filament in a given channel to be pushed against the main filament drive shaft. The full displacement position from the cam results in a compression of the transfer spring, supplying constant force to the filament via the pinch wheel.
If you happen to select an empty channel, the idler block will NOT come in contact with the filament drive shaft at all. Awesome!
Each Selectra kit will at least include the following:
- Two nema 17 stepper motors
- All injection molded plastic parts
- All required screws and fasteners
- All required push fittings between Selectra and splitter end +1
- A length of PTFE tube (between Selectra and splitter)
- ***Expansion board (***if ordered)
User supplied parts must include:
- Screw drivers (Phillips and flat)
- Small Allen keys (1.5~4)
- A suitable length of PTFE tube for your specific printer (between splitter and hotend)
- 3d printed mount (basic STLs will be provided for modification)
- 3d printer meeting above mentioned requirements.
The name “Selectra” is derived from a combination of the English “select” (to carefully choose the best or most suitable) and the Italian “allegro” (a musical term to describe a brisk or quick pace). Together they describe the ability to choose the right thing, quickly.
Finally, we would like to mention that you can choose to grab some extra value ad libitum.
ADD-ON INSTRUCTIONS: To include an add-on with your pledge, follow these steps carefully:
1) Press the "Manage Your Pledge" button. If you have NOT pledged yet, this option will not be available.
2) Increase you pledge in the "Pledge Amount" box by adding the value of the selected add-on(s) to your current pledge amount.
3) When the campaign finishes successfully, you will receive a survey. This survey will confirm your add-on intent and collect your shipping details.
**** VERY IMPORTANT, please note: ****
A) Add-ons are NOT AVAILABLE FOR TIER 1 BACKERS.
B) WE WILL NOT BE ABLE TO COMPLETE YOUR SHIPMENT IF YOU CHOOSE AN ADD-ON TO A "Spread the love" OR A "No reward" PLEDGE.
Risks and challenges
The single biggest potential failure point with hardware campaigns is always manufacturing. When dealing with various sources, a performance delay from one has an impact on the entire process. Although we've made sure to secure commitments from our manufacturing partners, delays can happen for whatever natural or "un-natural" reason (eg. flooding vs. Zombie invasion).
Don't worry, we'll keep everyone updated as to what's going on with this and hope you'll enjoy following the progress. Clear communication is key!
Finally, it is our hope to belong to all of your base(s)!Learn about accountability on Kickstarter
- (30 days)