SD3D is changing the desktop 3d printing market with our innovative technology. All of the above technologies are currently in alpha testing and can be explained further below:
1. Filament monitor: Precision tracking of filament position and diameter providing closed loop extrusion control.
Detailed description – The filament monitor provides a solution for filament jams, material shearing and under/over extrusion. Precision optical diameter monitoring is provided with enhanced signal filtering onboard. This allows for continuous filament diameter measurements with a resolution of 100 microns. These measurements are used to automate extrusion flow rate changes throughout the print to provide extremely tight print tolerances and enhanced surface quality.
The filament monitor also senses the physical position of the filament to provide closed loop motion control for the extrusion axis when used with our encoded stepper motors. This monitor also provides feedback for automated inventory control systems, including our RFID material tracking module.
2. Dual geared extruder drive: Enhanced traction for reliable high speed material extrusion.
Detailed description – SD3D’s dual geared extruder drive is the world’s first variable axis multi-geared extruder drive running off a single stepper motor. The extruder is configured to run 3.0mm filaments through nozzle diameters ranging from 0.25mm through 1.2mm. To achieve this, we use an encoded NEMA 11 stepper with a 22:1 gear reduction.
This extruder is a drop-in replacement for any existing extruder assembly mounted to the standardized Greg Wade’s adapter plate. The form factor is significantly smaller than most NEMA 17 direct drive configurations while providing a similar torque to weight ratio. Most importantly, the dual gear configuration provides twice the surface area distribution leading to a drastic reduction in filament stripping and material slippage.
The integrated encoder on the extruder drive, along with the filament monitor, provides closed loop feedback for the extrusion axis throughout the print. This also allows printer manufacturers to configure their builds with slave assist drives on the extrusion axis. This is particularly helpful for printers with bottom loading, asymetric, or extra long filament feeding configurations. A second slave drive set up in a static location in-line to the main extruder drive will provide continuous “slack”, drastically reducing hysteresis on large format prints.
3. High precision auto leveling: Automated mechanical four-point leveling of the build platform to within five microns.
Proper leveling of the build plate is extremely important to increasing printer success rates and can decrease print warping drastically. The common method of auto-leveling uses an inductive or capacitive probe to determine the level of the build plate prior to the print and continuously augment the z-height of the hotend throughout the print to account for the variance. There are several problems with relying on this method alone to provide reliable and autonomous bed leveling. It prematurely wears the z-axis components, requiring an increase in maintenance frequency and increases the processing load on the print processor. Furthermore, most probe configurations lack the resolution required to adequately level the heated build plate.
Extensive testing has shown that an optimally leveled build plate will be leveled to within 4% of the initial layer height. Most printers lay down an initial layer height between 150-250 micron depending on the nozzle diameter being used. This means that the bed must be level to within 6-10 micron to ensure reliable extrusion and minimize internally built up stresses that lead to premature part warping. Probe configurations typically provide a limited resolution of >100 microns which is grossly inadequate for typical initial layer heights. SD3D’s mechanical bed leveling module utilizes a high precision analog hall effect sensor to provide leveling resolution down to 5 microns providing reliable extrusion on even the most demanding printer configurations.
4. Non-destructive autoejection: Automatic non-destructive ejection of completed prints enabling continuous 24/7 production printing.
SD3D’s heated build platform is modular and can be configured to most standardized configurations. It includes a proprietary gradient free heated build plate which also contributes to lower surface level warping forces. Combining the precision bed leveling and advanced HBP stack make it possible to non-destructively auto-eject printed parts reliably. This means new prints can be started without requiring a technician to return to the printer, drastically reducing the labor intensity involved with 3D printing.
Printers can now be configured to run continuously without needing to be monitored or serviced by technicians between prints. This drastically lowers the costs involved with production 3D printing while increasing print reliability. Surface quality is maintained by ejecting the prints through a non-destructive sequence utilizing the hotend nozzle as a two axis pick-and-place. This method allows for extremely high precision placement of the finished parts for additional automated post processing.
5. Closed loop motion control: Modular closed loop control system provides industrial level 3D printer reliability.
Most 3D printers operate under open loop controls. These systems assume that the each printer move is executed exactly as it is commanded. If the hardware fails to execute the command, the control system is left unaware of the error and continues the print without any corrective action. Over long multi-hour prints, these errors can stack up quickly, leading to print failures and in some cases, severe printer damage.
SD3D’s closed loop motion control system solves this problem by providing precision feedback from each motor responsible for for hotend positioning and extrusion. Additional sensors are used to provide feedback regarding the effectiveness of the mechanical transmission. This allows the control system to monitor for failures such as belt or filament slippage in addition to motor positioning errors, fully closing the loop on 3D printer motion control.
6. Adaptive Build Environment (ABE): Modular environmental control system adapts to internal and external influences to optimize the build chamber for warp free printing.
Engineering grade materials require environmental control systems to print reliably. Materials with high glass transition temperatures such ABS and polycarbonate also tend to have very high shrinkage rates, leading to part deformation when printed without environmental control systems. These deformations can take the form of warping the entire print if the shrinkage forces overcome the adherence to the bed. If bed adherence is maintained but shrinkage forces are significant, parts can also suffer from interlayer delamination.
SD3D’s solution to part warping and delamination is an Adaptive Build Environment (ABE). ABE includes a set of modular panels with variable insulation properties which allows it to adapt to both internal and external influences to the build environment simultaneously. Each ABE panel is capable of absorbing up to 80W of transient thermal energy. Multiple panel sets can be configured to reduce temperature gradients across the build chamber to within 2C.
ABE is a much more efficient solution for managing high temperature build chambers than the conventional method of differential resistive heating elements. ABE simply contains and redirects the latent thermal energy output from the heated build plate (HPB), hotends and stepper motors while providing a completely sealed build environment from the outside world. This allows for elevated internal ambient temperatures of up to 80C while using less than 160W of dedicated power. Printing engineering grade materials just got cheaper and easier.
7. Material detection & inventory management: factory level material detection, tracking and ERP system for lean FDM manufacturing and JIT inventory control.
SD3D offers an RFID based automatic material detection system. When this module is used along with closed loop motion control on each extruder, inventory status is constantly logged and can be viewed from a single web based application. This system is used to track how much material is remaining on each spool and automatically renew filament inventory once a minimum threshold is met. The user will be alerted if there is not enough material to complete a pending print so that it can be changed before the print starts. Previously used settings for that particular machine-material combination will be automatically retrieved, drastically reducing user error. This is extremely convenient when running multiple machines and/or material types during a production run.