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New Feature: Linear Advance

Here at re:3D, we are results driven and want to provide the best possible product for our customers. Before the release of the new Gigabot Firmware 4.2.0, we wanted to put the new feature, Linear Advance, to the test. Referenced from the Marlin website, Linear Advance allows users to print more dimensionally accurate parts. Under normal conditions, the extruder gear movement is a linear proportion to all other axes. However, the pressure buildup in the nozzle is not proportional to other axes and this leads to extra material being extruded at the end of each movement.

To solve this issue, linear advance changes the extrusion rate whenever the extruder slows down or speed up, creating an even extrusion line no matter the speed or change in direction. The K value has units of mm of filament compression needed per 1 mm/s extrusion speed [mm/(mm/s)]

The advantages of this feature are as follows:

Better dimensional precision.
Higher printing speeds are possible without any loss of print quality.
Visible and tangible print quality is increased even at lower printing speeds.
No need for high acceleration and jerk values to get sharp edges.

A total of 48 test specimens were printed at a different layer height, speed and K value. Each of the 25mm squares were printed individually to decrease the effects of other variables. A circular indentation was added to the middle of the model to increase the number of changes in travel direction, emphasizing the effects of Linear Advance. Shown in Figure 1, are a set of test pieces printed at 0.31 layer height, 120mm/s and a K value of 0.0, 0.05, 0.1, and 0.15 from left to right.

Each test specimen was measured with a caliper. In Table 1, the dimensions of all of the test squares are shown. The highlighted boxes show the test specimen that had the most accurate dimensional reading in its group. As linear advance decouples the extrusion motor from other axis, the print quality is visually and quantitatively improved. Shown in Figure 1, Linear Advance significantly reduces the extrusion of extra material on the outer edges at higher print speeds and larger layer heights. As print speed decreases, the addition of Linear Advance has less of an impact on the quality, however, it is still beneficial with a delta of 0.2 at 40mm/s and 0.15 layer height. These results showed to be consistent with expectations because as flow rate increases, the more buildup of pressure and potential for extra material to come out of the nozzle. With 8 test samples of 0.1 K value and 4 samples of 0.05 K value excelling in accuracy, a weighted average of K= 0.08 provides a good value to improve print quality across the board.

If you are interested in using this feature on your Gigabot, please visit the full feature list of the new Gigabot Firmware 4.2.0 here

Noah Pan

Blog Post Author

Gigabot 3+ Firmware 4.2.0

Introducing the new Gigabot Firmware 4.2.0. This new firmware release features the latest version of Marlin 1.1.8 and is packed with new features that will elevate the user’s experience with the Gigabot.

Notice: This Gigabot Firmware is only for users with the Azteeg X3 Pro (GB-371 and up) with the dual limit switch kit. This version will not work for bots with single Y limit switches.

Here are the links to purchase the upgrade kit, new Simplify3D profiles, and to Download the Firmware

Table of Contents:

A New Look

Dual Y Axis Homing Switch

Linear Advance

Ditto Printing

Filament Change Routine

Continuous Printing After Filament Change

Babystepping for Perfect 1st Layer

Other Links

A New Look

The changes in the new firmware can immediately be noticed on the main info screen of the Gigabot. The larger font makes it easier to read and navigate. (Figure 1.)

The contents and item order of the Prepare Menu have also changed to create an easier and more accessible experience. The preheat option is placed on the top so a target temperature can be set quickly. A new and improved Change Filament routine item is shown followed by the Move Axis menu plus three axis homing actions. (Figure 2.)

About Printer is the newest addition to the screen menu (Figure 3). This menu displays useful information about the printer, such as the model number, firmware upload date, prints completed/ failed, total print time and longest print job completed. This data can be used to keep track of a regular maintenance schedule for your Gigabot.

Dual Y Axis Homing Switch

A major feature of the new firmware is the support for dual Y-axis homing switches. This feature provides more consistent performance and a higher degree of dimensionally accurate printed parts out of the Gigabot.

Previously, a single homing switch existed on the left Y motor, resulting in a carriage that was not consistently parallel to the machine frame. During a filament change, it was possible for an accidental displacement of the carriage, losing positional accuracy (Figure 4).

With dual Y axis homing switches, the machine is guaranteed to be squared to the frame every time the machine is homed (Figure 5). This will provide more consistent performance and accuracy for all prints. Paired with the new filament change routine, the Gigabot will show precise repeatability.

Shown in Figure 6 is a print completed to torture test the dual homing switch feature. A line of gcode was inserted after each layer incrementation to move the extruder aside, disengage the stepper motors, rehome, and continue printing. The results show the consist carriage squaring that the dual homing switch provides. After over 1000 layers, the tower shows homogenous layer quality with no layer shifts.

Linear Advance

Do your prints ever look like the image in Figure 7? Linear Advance is a new feature that allows users to print more dimensionally accurate parts. Under normal conditions, the extruder gear moves linearly in proportion to all other axes. However, the pressure buildup in the nozzle is not proportional to other axes and this leads to extra material being extruded at the end of each movement.

To solve this issue, Linear Advance changes the extrusion rate whenever the extruder slows down or speeds up, creating an even extrusion line regardless of the speed or change in direction.

The advantages of this feature are listed on the Marlin website and are as follows:

Better dimensional precision due to reduced bleeding edges
Higher printing speeds are possible without any loss of print quality
Visible and tangible print quality is increased even at lower printing speeds
No need for high acceleration and jerk values to get sharp edges

re:3D performed an extensive test on this new feature to determine the optimal K value for different layer heights and printing speeds. Shown in Figure 8, is a set of test specimens printed with different K values. Figure 9. shows the improved dimensional accuracy from a specific K value.

A weighted average value of K= 0.08 was chosen, improving print quality for a number of different print settings.

Check the blog post for more information:

Ditto Printing

Duplicate nozzle printing (aka. Ditto Printing) allows the user to print with both nozzles at the same time. It can produce two identical parts with the only constraint that the X length of the object is smaller than the hotend offset (~55mm on the Gigabot). This feature is particularly useful when mass producing parts, cutting printing time in half which can be very beneficial. To enable this feature, download the new 4.3 Simplify Profile for Gigabot, choose PLA Duplicate Nozzle or PC-Max Duplicate Nozzle under the Auto-configure for Material tab and Duplicate Extruders under the Auto-Configure Extruders tab. In the slicer, place only one model on the build platform and start the print. The bot will produce two identical parts.

(Note that this feature works by mirroring the left extruder to the right. Only the left filament runout sensor will be active and the right will be inactive.)

re:3D uses this feature to increase the speed of printing in-house production parts (Figure 11,12).

This feature can also be used to infuse parts together! Like this crazy dual color infused Marvin or 3DBenchy boat shown in Figure 13 & 14.

Filament Change Routine

The new filament change routine provides a series of walk-through interfaces that guides the user through the entire process. The user first selects the extruder and material type that needs to be changed. (Figure 15)

Shown in Figure 16 are a series of walkthrough LCD screens. The Gigabot will first heat the desired nozzle, then automatically unload the filament. The LCD will then direct the user to unload the filament and insert new filament. The filament will automatically purge and ask the user if they want to purge more or continue printing. There are also added safety features that will unheat the nozzle if the machine has been idle for a minute.

Previously, filament changes were tedious with the cable chain obstructing the workspace. With the new firmware, the nozzle park position is on the right side, avoiding all obstructions and allowing for easier filament changes. (Figure 17.)

Please Note: For filament changes from high-temperature material to lower temperature materials (Ex. Polycarbonate to PLA), Please manually heat the nozzle up to the melting temperature of the higher temperature material, switch materials, then purge 200mm of filament and lower the temperature down for the second material. This will clear out the nozzle of any previous material to prevent jamming.

Continuous Printing After Filament Change

Continuous printing after filament change is a feature specifically designed for the long prints that the Gigabot produces. Often times, the Gigabot uses an entire spool of filament and upon filament runout, the machine pauses and waits for the user to change filament. Production time will dramatically increase if the user is unavailable.

With the new Continuous Printing feature, the user loads two spools of the same filament into both extruders. When the first spool runs out, the Gigabot will automatically unload the filament, load and prime the second nozzle, and continue printing. This feature is listed under Controls> Filament> Filament Runout (Figure 18). The user can choose between two filament runout features, pause for change or continuous printing. These options are also available during mid-print so the user can change settings as any given time.

For very long prints, once the second filament spool starts printing with the left nozzle, it is suggested to pause the print and load another spool of filament into the right nozzle.

Shown in Figure 19 & 20 are some of the largest prints that re3D has done. The print time could have been dramatically shortened with the use of continuous printing after filament runout.

Babystepping for Perfect 1st Layer

Babystepping allows the user to adjust the Z height at very small increments to achieve a higher quality first layer. To use this feature, double click the encoder during the first layer of your print until the LCD screen displays the Babystepping screen as shown in Figure 21. Scroll the knob to move the Z up or down (clockwise to move the nozzle away and counterclockwise to move the nozzle closer). Babystepping can also be activated through a M290 gcode. Look at that perfect first layer in Figure 22!

re:3D uses this feature to accommodate for the expansion of the heated bed during high temperature prints such as polycarbonate. A M290 Z0.25 moves the nozzle 0.25mm away from the bed and M290 Z-0.25 moves the nozzle 0.25mm towards the bed.

As seen in Figure 23, Babystepping can dramatically improve the first layer quality. At the start of this print, the nozzle was too far from the bed and the babystepping was adjusted to -0.217mm. After the adjustment, a perfect layer line was achieved.

GB3+ Introductions

Fall is in the air and re:3D is very excited to introduce you to the latest updates for Gigabot. Over the past year we have been working hard to provide you with enhancements for Gigabot to print at a higher resolution, faster, and with better quality. Additionally, we have improved the user interface, made it easier to change filament and level the print bed. Here are the upgrades you have been waiting for!

New bed side plates with two more guide wheels. Now with six wheels on each bed side plate the additional stability gives higher quality print throughout the Z axis travel.

re:Designed cold end extruder with thumb tab for easily filament loading and unloading. New extruder design is more simplified with reduced number of parts, as well as more open and accessible.

re:3D all metal hot end designed for reliability and quality
- Electroless nickel plating on the hot end nozzle and thermal tube offer higher lubricity and higher hardness over standard hot ends, giving smoother flow of plastic with less wear and maintenance.
- Screw-in thermocouple temperature sensors offer industrial reliability.
- Interchangeable nozzle for printing with 0.4mm or 0.8mm extrusion diameter.
- Heater cartridge is almost completely captured inside the heater block for better thermal efficiency in the hot end.

New filament tubes are lighter weight and more flexible while reducing the load on the print head.

New Viki enclosure allows more room for wires and connectors and presents itself ergonomically for the operator.
Filament Detection units have been revised for easier filament feeding/more reliable detection.
Easier to use filament spool holders on the back side of Gigabot are modular and now accommodate multiple 15lb spools for printing huge!

The new GB3+ is dressed up and looking sharp with a new Gigabot nameplate, engraved corner logo plate, and XL/XLT badge corner plate. The serial number plate also proudly displays the flag and Made in America tag.

LED lights on every Gigabot shine bright and will show off your latest print.

Updated bed leveling allows simple and easy adjustments for bed leveling with the new four point bed leveling.

Wow, I know that is quite a bit of upgrade for the new 3+ and I am super excited for all of you to see the REAL benefits! To make sure that none of our customers are being left out we are offering all the upgrades as a bolt-on package starting next month. Happy Printing!

Matthew Fiedler

Blog Post Author

Pitching for a Circular Economy Part 1: Why We Went to Aruba

As I sit on a plane flying in the opposite direction of Aruba I feel there is nothing more important than finding a way back. You see, Samantha & I spent the past three days as co-founders immersed in a new culture with new people and pitching an idea that is new and maybe just ahead of it’s time. The event that brought us all together is Atech2016. There exist in the paradise of an island nation of Aruba a group of inspiring founders who for the second year now have decided to put their money on the table. These visionaries invite tech savvy entrepreneurs and guest speakers to discuss thoughts and ideas on topics ranging from mobile banking & blockchain technology. I’m just glad we did research into sites like https://beincrypto.com/tag/coinbase/, as this meant that we were kept up to date with all things relating to the blockchain industry. We even looked into wearable tech & social inclusion from the perspective of Burning Man to inspire each other as well as the local Arubans how we as a society maintain relevance in the age of acceleration that we are living.

Gatherings like Atech2016 are really the nexus, bringing together in one place a group of young individuals with passion, focus, and hunger for change. With connections made, and new ideas formed we are all contemplating our next steps as we fly in the opposite direction of Aruba. We feel honored to have been part of such an event and encouraged by many Arubans who resonated with re:3D’s vision and our pitch for the Atech and Aruban communities. We were stoked to be named finalists in the pitch competition, and, while we didn’t win left more determined than when we arrived.

Several things became clear to us in the few short days we spent on the island:

Arubans are ready, in fact hungry, for greater technology. Meeting and talking to the young men and women volunteering at the conference we felt their excitement for 3D printing as well as other technology on display.
The island nation of Aruba is resource constrained and imports the vast majority of all their physical goods. There is very limited manufacturing on the island.
With an economy largely based on tourism and very little to nonexistent recycling program there is a growing problem with trash and landfill space.

Our goal and dream, that which we pitched to Aruba, was that re:3D would engineer and manufacture the prototype hardware needed to take the first step in 3D printing useful objects from plastic trash. During our few short days at the conference, we reached out to community leaders, local entrepreneurs, Aruban schools and universities and well as hotels to partner in the effort of recycling, re-using and re: imagining the possibilities to own their our factory as well as the supply chain. The response was super positive and affirmed for us first – hand there was a HUGE opportunity to leverage trash for a more circular economy.

Why is this important?

Sustainability goals are a priority in Aruba
Island communities are significantly dependent on imports
Arubas are actively innovating new solutions to reduce landfill size
Several groups all already considering 3D printing from reclaimed plastic (and we hope to someday partner with them!)

Where do we go next?

While we left Aruba affirmed that 3D printing from waste is inherently right, we unfortunately did not secure the resources we needed to complete a prototype to leverage reclaimed plastic using Gigabot. Stayed tuned to upcoming blogs in our series as we continue to share our vision in future competitions and pursue partners to donate post-manufacturing waste streams to test. With a little luck, we will raise enough support to partner with Aruba on a pilot!

~Happy Printing!

Matthew Fiedler

Blog Post Author

Stepper Motors vs Servo Motors

One question we sometimes get relates to our choice to use stepper motors over servos. We’d like to explain our rationale behind that, as well as why we personally prefer stepper motors to their servo counterpart.

I think the biggest advantage for servo systems is its ability to produce higher levels of torque at high RPM whereas stepper motors produce the most torque at low RPM. You might want to look into something similar to propshaft services for more information on what might be able to help. More torque at higher RPM means having a higher degree of certainty of achieving the desired position in high speed movements, i.e. accuracy and repeatability. If you have any more questions about servo motors or just need a repair check out the Servo Motor Repair Experts. In order to achieve potential benefits of closed loop control you must be willing to make some trade-offs:

Increased cost
More parts and more complicated system (ie more parts that can break)
Decreased low end torque and power

Stepper motors on the other hand give time-proven reliability at a lower cost and provide a more robust system with fewer moving and electromechanical parts that can break. Some will point to servo closed loop control as being superior to steppers because it can correct positional errors should they happen. This may be helpful in traditional manufacturing technologies, but I challenge that a great majority of print failures and positional inaccuracies are caused by the 3D printer operators’ (in)ability to anticipate and control the thermodynamics occurring during the additive manufacturing process.

All plastic shrinks as it cools. Parts that warp and curl can become dislodged from the print surface, cause interference with the print head, and result in a loss of positional accuracy. Here are two reasons it does not help to have closed loop servo control: 1) If the part is warped and dimensionally deformed then the part will be scrapped anyway 2) If the part comes loose from the print surface and effectively causes the print head to loose position relative to your part, then your part will be scrapped. In the majority of causes of print failure, servo control has not saved your part.

If the size of the stepper motor is correctly chosen based upon the loads of the system, and appropriate limits are placed on acceleration and velocity, you will have the same reliability as a closed loop system. I have two large CNC mills driven by stepper motors that will drive a 1/2″ EM through steel at amazing rates machining parts to greater than 0.001″ tolerance. Stepper motors – we went to the moon on this technology!

Matthew Fiedler

Blog Post Author

Musings From Our Amazing Experience at the ATECH* Conference

Why is this important?

Where do we go next?