For us, we simply attach a thin Teflon film to protect the silicone from contacting the resin directly so as to extend the lifetime of resin container. You might think that Teflon is a non-stick material. In general, it is true, but some cured resin materials can stick on the Teflon film firmly and are very hard to separate. The followings are the reasons why a cured layer could be hard to separate.

1. Some cured resin has a strong Van Der Waals’ force with Teflon. When the cured area is large, the separation force is high.
2. Over-cured resins tend to have a much higher adhesion to Teflon.
3. Hollowed model without vent holes could introduce tremendous suction force.
   
4. Bulk shrinkage in a tapered solid region could turn a flat layer into a bowl like shape that could also introduce tremendous suction force. A thin cone shape is more likely to happen. This phenomenon often happens when:
   • a. Material itself has a high native shrinkage
   • b. Fast curing ( < 1 second) due to strong light intensity or more photoinitiator concentration could introduce higher shrinkage for the same material
   • c. For a fast resin, low separation speed introduce more on-going curing after the light is turned off. Low separation height does not mix the resin near the curing area with fresh resin outside the curing area well enough so the viscosity becomes higher in the curing area gradually. The combination of the above two could introduce differential shrinkage between layers and across the layer and form a strong suction effect. The situation is more severe when printing repeated patterns. This suction force may result in a phenomenon where the cured layer suddenly sticks to the Teflon and does not come apart (as shown in the photo). To provide an example, suppose a certain resin has a normal exposure time of 1 second. During the printing process, the resin has absorbed photons from both background and scattering exposure near the exposed area. Please note that the resin in the build area close to the vat floor tends to have higher viscosity when partially cured and tends to stay near where it is. If the accumulated absorbed dosage is equivalent to 0.5s of normal exposure, the next print layer will technically be over cured for 1.5 seconds (1 second for the exposure time + 0.5 second from already being cured due to background and scattering exposure). During the buildup of the partially cured resin, the effective over-curing will keep increasing the adhesion between the cured layer and the Teflon film. If you cannot use another slow resin instead, you would need to increase the lifting speed and lifting height to slow down the buildup.
     

How will the above affect your print? They will significantly affect the consistency of the separation force and increase the failure rate. Even if the print survives, the surface quality may be deteriorated. They will affect both the Teflon film lifetime (please refer to the PSP resin container blog ) and the printing quality.

Knowing the reasons as to why high adhesion occurs and the solution to it will greatly smooth out your printing process. Even if your print did not come out the way you expected, it is important to understand why it happened. This way, you know what the cause of the problem is and learn to avoid it next time. Learning from failed print is perhaps one of the best way to quickly learn and understand more about SLA printing!

Many of the consumer level printers were FDM (Fused Deposition Modeling) 3D printers. This involved a spool of filament to be heated to a high temperature and deposited into the shape that the user wishes to create via an extrusion head. With this type of printer, users only get the shape or form of the print but will not get details nor reach surface smoothness. In addition, the printing speed is relatively low.

Apart from the FDM technology, some 3D printers adopts the stereolithography (SLA) technology. Some SLA 3D printers use laser galvanometer to create patterns. This type of printer usually has laser stability and reliability problems.

How about the Titan 1 and Titan 2? Instead of the laser-based SLA technology, we use Kudo3D uses a highly reliable DLP technology developed by Texas Instrument to generate digital light patterns in a two dimensional fashion rather than scanning with a laser diode which is susceptible to ambient temperature, dusts and mechanical failure. DLP can also provide a resolution that laser galvanometer is impossible to match.

Using a better digital light pattern generator improves the resolution of the printers but it is not the main factor that attributes to our success in the last two years. So what exactly set our 3D printer apart from the other SLA 3D printers out in the market? The answer lies within the layer separation technology of the printer.

Most low cost SLA printers incorporate a bottom up light source and a transparent resin container. The challenge to these SLA printers is to separate the cured layer from the resin container floor. The separation force is proportional to the area of the cured layer. That is why most of the low cost SLA is not able to print big models.

To overcome this challenge, we have developed a patent pending passive self-peeling (PSP) technology that greatly reduces the separation force that others are hard to match by using both flexible and elastic materials for the resin container. PSP not only enables large area printing but also increases the speed and resolution of the prints. Since the peeling is passive, there are no motors involved. The printer’s structure is simplified. With less moving parts, the Titan 1 and Titan 2 are very reliable.

We understands that the lifetime of the consumables is a main concern for consumers while resin container is definitely a critical part for low cost SLA printers. Because of the low separation force, our container is less stressed and the lifetime is much longer. Besides, there is a protective film on the vat floor of Kudo3D’s containers to prevent the attack from the resin. As a result, our printers are compatible with more materials and relax the constraint for material developers.

With the PSP technology, Titan 1, our first generation printer, proved its worth when Kudo3D showed off a biomedical tissue scaffold research model printed at 37 micron XY resolution and 20 micron Z layer thickness. The beams have a diameter of 0.18mm (next to the print is a coffee bean for scale).

Pushing the printer to the extreme, we proved once more that our printers can print fine features that other low cost SLA printers cannot achieve. In the image below, a 45 micron thin needle was printed with the Titan 1. This needle is less than half the diameter of a hair. No other low cost printer can achieve this resolution.

Now in June 2016, we have launched its second-generation 3D printer, the Titan 2.

The new Titan 2 features:

• WiFi enabled.
  – There is no need to connect the printer to the computer after uploading the data.
• Allows web-based controlling.
  – Users can use any device (PC, Mac, smartphones, or tablet) to control the printer. Once the printing starts, the control device can be used for other purposes.
• One device can be used to command and control multiple Titan 2 3D printers.
  – This is especially helpful for those who would like to use the printer to setup a production line.
• Has a built-in computer.
  – The Titan 2 will be independent from the user’s computer.
• Has a shutter to reduce background exposure during prints.
  – This can ensure high quality prints.
  Additionally, the new Titan 2 will be assembled and calibrated before shipping, making the startup process even easier for first time users.

It is definite that 3D printer will keep evolving in technological advancement. Users are now able to print high quality things that they design or even better than they could ever imagined.

After 16 months of development, Kudo3D is proud to announce the launch of Titan 1, a DLP SLA 3D desktop printer, which represents a major breakthrough in printing speed, size, and resolution. The launch, which took place at 8:30am PST, was met with a great deal of enthusiasm, reaching its funding goal of $50,000 within 2 minutes. In 12 minutes, they had received $100,000 in pledges. Within 10 hours, that had more than doubled. Their Kickstarter campaign ended on June 26th and they managed to raise an impressive $687,116 to begin setting up production for the Titan 1.

The Titan 1 was well received due to its unique position in the market. Personal 3D printing has been limited by slow printing speeds, small sizes, surface smoothness and constraints on the resolution of the finished product. The industry, which did not exist just a few years ago, has already shown its great potential; Fabricators and designers alike currently use 3D printing for a variety of products and functions. However, industry growth has been limited due to the sheer cost of acquiring and maintaining the existing 3D printing systems.

Kudo3D’s innovation addresses all these problems by incorporating a unique technology on a modularized system. “In order to differentiate our product from the other 3D printers on the market, we had to invest in some practical as well as technological innovations,” Tedd Syao, Ph.D., founder, explained. To address cost concerns, as well as reliability, Syao also took a page from the book of Henry Ford. “It was crazy to me that all of these expensive systems were being built without modularized components.” Key components of Titan 1 include a HD 1080p DLP projector, an industrial grade linear stage module, open-source controlling circuits, a stepping motor, a fast leveling build platform, and Kudo3D’s patent-pending flexible passive self-peeling (PSP) resin container.

The printer can accommodate projects up to 9½ inches in height, making it the most accommodating unit on the personal SLA 3D printing market. Beyond the impressive size of the print envelope, Titan 1 uses a patent-pending technology to permit a level of detail unavailable on most 3D printing systems while still maintaining the flexibility to print large objects. The flexible PSP resin container comprised of 6 different materials was devised to minimize the separation force of a cured layer so that fine features, even those as delicate as a strand of hair, can survive the printing process.

Currently Kudo3D is solidifying relationships with suppliers, locating space to set up assembly, and continuously testing resins to increase their product offerings to backers and future customers. They are planning to begin taking pre-orders for the Titan 1 via their website in the near future.

San Francisco, California- After 16 months of development, Kudo3D is proud to announce the launch of Titan 1, a DLP SLA 3D desktop printer, which represents a major breakthrough in printing speed, size, and resolution. The launch, which took place at 8:30am PST, was met with a great deal of enthusiasm, reaching its funding goal of $50,000 within 2 minutes. After 12 minutes, it had reached over $100,000 in pledges. Within 10 hours, it doubled to over $200,000. The success of Titan 1’s launch can be attributed to its competitive advantage over its competitors.

Personal 3D printing has been limited by slow printing speeds, small sizes, surface smoothness and constraints on the resolution of the finished product. The industry, which did not exist just a few years ago, has already shown its great potential; Fabricators and designers alike currently use 3D printing for a variety of products and functions. However, industry growth has been limited due to the sheer cost of acquiring and maintaining the existing 3D printing systems.

Kudo3D’s innovation addresses all these problems by incorporating a unique technology on a modularized system. “In order to differentiate our product from the other 3D printers on the market, we had to invest in some practical as well as technological innovations,” Tedd Syao, Ph.D., founder, explained. To address cost concerns, as well as reliability, Syao also took a page from the book of Henry Ford. “It was crazy to me that all of these expensive systems were being built without modularized components.” Key components of Titan 1 include a HD 1080p DLP projector, an industrial grade linear stage module, open-source controlling circuits, a stepping motor, a fast leveling build platform, and Kudo3D’s patent-pending flexible passive self-peeling (PSP) resin container.

The printer can accommodate projects up to 9½ inches in height, making it the most accommodating unit on the personal SLA 3D printing market. Beyond the impressive size of the print envelope, Titan 1 uses a patent-pending technology to permit a level of detail unavailable on most 3D printing systems while still maintaining the flexibility to print large objects. The flexible PSP resin container comprised of 6 different materials was devised to minimize the separation force of a cured layer so that fine features, even those as delicate as a strand of hair, can survive the printing process.
Titan 1 is a completed invention, and Syao hopes to use the funds from Kickstarter to open an assembling line in California. The Kickstarter campaign launched on May 27th 2014, and can be viewed at: kck.st/1h9gFwZ.

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Ref.
Tradition Chinese Version PR (329K, pdf)
Simplified Chinese Version PR (287K, pdf)
Korean Version PR (250K, pdf)

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Special thanks to these media outlets for featuring the Titan 1!

1. Locate 3D models online

There are many websites providing a variety of 3D files you can download for free. If the file extension is not ‘stl’, you would need a 3D software to convert the model to stl format. “Thingiverse” is our most favorite site, because most of the files contributed are in stl format for free. We look for 3D models with higher resolutions to avoid limitations posed by the image itself. We use 3D Eiffel Tower as our main testing model for tuning printing parameters of our machine and our PSP (Passive Self-Peeling) mechanism. We have printed more than 80 of them with different sizes. The tallest one is about 9.4 inches, whereas the smallest one is 3.5 inches tall with pillars as tiny as a strand of hair.

2. Check and fix files

All downloaded 3D files need to be checked before slicing and printing. A lot of them may even require repairs. Check your STL files to ensure:

• all objects maintain “outside” orientation.
• the surface of all objects is closed and there are no overlapped faces.

We use “Netfabb basic” to repair models. If the number of shells is too high or “Netfabb basic” fails to fix the model, you would need to upload the stl file to “Netfabb cloud” for further repair.
Sometimes, multiple shells could get you a problematic hollowed model in the following step.

3. Hollow 3D models if necessary
Most of the models require hollowing to save printing materials. In addition, hollowing minimizes light exposure area and greatly reduces layer separation force. The printing time is thus shortened and the printing quality is enhanced.

We use “Meshlab” to hollow our 3D models by building a smaller offset model with inverted surface.
(To Be Continued….)