IVI: The Closed-Loop 3D Printer

[Software] IVI's cloud-based auto-slicer
almost 5 years ago – Mon, May 06, 2019 at 07:37:50 AM

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[Announcement] IVI's cooling system
almost 5 years ago – Sat, May 04, 2019 at 01:58:55 PM

Dear all,

We notice that there have been many concerns and doubts about IVI’s cooling system. Regarding this issue, we would like to make the following clarifications.

1. IVI does have two turbofans with 7.7 CFM airflow for circulating the heat inside the printer from the very beginning. All of our presented models are printed with this cooling system. In the next few days, we will share a full view video of IVI printing without the shell so that you can see current fans working.

2. Reasons why we didn’t add fans on the print head.

• At the beginning of the design, we wanted to design a smaller and lighter print head. A smaller print head would allow IVI to achieve a larger print area in a limited enclosed space. A lighter weight design means smaller inertia, more stable movement and higher movement efficiency. Therefore, we did not add the fan on the print head. 
• On the other hand, we wanted to use the air circulation in the enclosed space to achieve forced cooling of the print head and the model. Based on our previous test results, the current cooling system can meet most of the printing needs when the overhang angle does not exceed 45 degrees.
• When printing smaller models (printing time per unit area < heat dissipation time per unit area), our solution is to print multiple pieces at the same time. This solution can extend the printing time per unit area. This is how we printed the little owl, the bolt and the nut. At present, the heat dissipation time per unit area with our current cooling system is about 3 seconds. So when the printing time per unit area is longer than 3 seconds, theoretically there is no problem. (Below is the thermal imaging test video.)

3. When Joel Telling was testing the prototype in January, the two fans were also there.

Regarding the failed models he printed, we think there were another two reasons besides the cooling problem.

• Joel was using a 0.2 mm layer height for the 0.3 mm nozzle. This was our fault. He didn’t know that it was a 0.3 mm nozzle.

Below is the comparison of the 0.15 mm & 0.2 mm layer height when the nozzle diameter is 0.3 mm and the model’s overhang is 45 degrees. 

When the layer height is 0.2 mm, the overhanging portion’s length is 0.2 mm, which is ⅔ of the nozzle diameter. This means that only ⅓ is connected with the previous printed part. Under this circumstance, there is stronger extrusion pressure. Even with the cooling system, the print quality cannot be guaranteed. 

When the layer height is 0.15 mm, the overhanging portion’s length is the same as the layer height, which is half of the nozzle diameter. Together with the cooling system, this kind of parameter largely eliminates the possibility of collapse.

Therefore, we strongly recommend that the layer height should not exceed half of the nozzle diameter. And when the model’s overhang is over 45 degrees, it is better to add support for better printing results. 

• When we shipped IVI from China to the U.S., we separated the upper part and the bottom part. They were not securely assembled after we took it to Joel’s house. When Joel was testing the closed-loop control, we believe it caused some kind of shifting.

We realized that the packaging and shipping will also have a great effect on IVI’s   functionality. The mechanical design company we are working with will also help with the package design and we will test the packaging and shipping to ensure that it will not affect IVI’s functionality when you receive yours.

4. Even so, we fully agree that there’s still a large space for the improvement of IVI’s cooling system and we already have a new design. We are having a new design produced. Once we receive the new print head from the manufacturer, we will test the new design with Autodesk FDM Test again and share with all of you.

We are sincerely sorry if we have let any backer down because of the cooling system. Since the very beginning of our journey, our goal is to make IVI a truly easy to use and beginner-friendly 3D Printer while keeping the high print quality. This is still and will continue to be what we are endeavored to achieve. 

[Testing] Comparison of IVI prints at 300 mm/s VS 30 mm/s
almost 5 years ago – Fri, May 03, 2019 at 07:49:20 PM

Dear all, 

Some of you may notice that we mentioned IVI’s repeatability is kept within 10 microns even when the print head is traveling at 300 mm/s (IVI's maximum travel speed can reach 345.5 mm/s theoretically). Common FDM 3D Printers usually print at 100 mm/s as the highest speed. Why IVI can print at 300 mm/s? How is the printing performance when IVI is printing at 300 mm/s? You will find answers to these questions through the test we just did. 

In this test, we printed 2 different models with 2 printing speeds, 30 mm/s and 300 mm/s. The elephant phone holder represents common models. The vase represents models with Spiral Vase Mode. 

Why IVI can print at 300 mm/s?

1. IVI has a closed-loop system which largely reduces the possibility of failed printing caused by layer shifting when the printing speed is very high. 
2. IVI uses a ring-shaped ceramic heater. It takes only about 40 seconds to warm up from 20 °C to 190 °C. This heater can provide enough and stable heating to meet the requirements of high-speed printing. 
3. IVI uses a 3:1 gear ratio extruder to provide greater extrusion pressure. 
4. IVI uses a 32-bit 100MHz ARM chip to ensure it is 10 times more powerful than typical 3D printers, providing faster computing power and processing speed. 

Images for the prints:

The print videos:
 

#1, Comparison video of the vase

#2, Video of printing at 30 mm/s

#3, Video of printing at 300 mm/s 

#4, Comparison video of the elephant phone holder

#5, Video of printing at 300 mm/s 

#6, Video of printing at 30 mm/s 

How is the printing performance when IVI is printing at 300 mm/s?
 

1. The total printing time is about 3 to 4 times faster compared with printing at 30 mm/s. 
2. The wall thickness and the dimensions of the model are almost the same. 
3. But the surface finish is less smooth compared with the model printed at 30 mm/s. There are some ringing (a wavy pattern) on the surface of the printed vase. This is caused by the speed change of the motor and the inertia of the print head. 
4. There are also some blobs on the surface of the elephant. This is because the firmware configuration for Gcode buffer is too small (IVI very quickly run out the Gcode in the buffer and wait for new commands to come in), this problem will be fixed in a later version of the firmware.

You may ask why the total printing time is only 3 to 4 times faster instead of 10 times faster. 

Below are some of the reasons we concluded. 

1. The retraction distance and retraction speed are the same at both printing speed. 
2. The acceleration of the printer is a fixed value. When the printing movement distance is short or the movement direction is changed, the printing speed will change, and the fastest speed may not be reached, so the average printing speed is less than 300 mm/s.
3. When printing at 300 mm/s, the travel speed is 300 mm/s. When printing at 30 mm/s, the travel speed is 100 mm/s. It means that there is only 3 times difference in terms of the travel speed. 

Based on this printing test, we recommend that if you want to achieve higher printing speed without sacrificing the print quality, you can print the outer wall, the top, and bottom at normal speed and print the infill and support at a high speed or set the travel speed at the highest.
  More printing settings about fast speed printing and normal speed printing will be shared after we have done more testing. Once you receive your IVI, you can always do your own experiment and surprise us all. Have fun 3d printing! 

Below are the printing parameters during this test.
High speed settings
     Nozzle diameter: 0.3 mm
     Printing temperature: 230℃
     Layer height: 0.15 mm
     Printing speed: 300 mm/s
     Travel speed: 300 mm/s
     Retraction speed: 65 mm/s
Normal speed settings
     Nozzle diameter: 0.3 mm
     Printing temperature: 200℃
     Layer height: 0.15 mm
     Printing speed: 30 mm/s
     Travel speed: 100 mm/s
     Retraction speed: 65 mm/s

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Stretch Goal No. 2 Unlocked
almost 5 years ago – Wed, May 01, 2019 at 10:35:33 AM

Hurray, thanks to every backer, Stretch Goal No. 2 is now unlocked. 

Everyone who backed $299 or more will get a compliment built-in camera for his/her IVI 3D Printer. This camera can be used for monitoring the printing process.

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