A prototype is a preliminary model of something. Projects that offer physical products need to show backers documentation of a working prototype. This gallery features photos, videos, and other visual documentation that will give backers a sense of what’s been accomplished so far and what’s left to do. Though the development process can vary for each project, these are the stages we typically see:
Proof of Concept
Explorations that test ideas and functionality.
Demonstrates the functionality of the final product, but looks different.
Looks like the final product, but is not functional.
Appearance and function match the final product, but is made with different manufacturing methods.
Appearance, function, and manufacturing methods match the final product.
Who are we?
CALT stands for computer aided life technology, we want to focus our efforts on the core areas of a persons life that can benefit from computer aided devices. We have plans for devices in areas such as education and food production but we're kicking things off with a tool for the makers.
Why a tool for the makers?
We've been interested in additive manufacturing for a long time and we've built a lot of printers so it seemed natural. We've had a lot of printers over the years and we've always been frustrated with either the device quality or the print quality or some other sacrifice we had to make so we thought we would do something about it. These devices can be used for education, prototyping and even casting production parts so they can have a real impact on communities and businesses.
What did we come up with?
FDM printers can be great fun but there are inherent issues that prevent them from reaching the same quality as photo lithography based systems so we began developing a photo lithography based printer.
We needed it to be robust, reliable, cost effective to run, high resolution with a large build volume and have low maintenance costs. We built lots of designs and pitted them against each other and it became clear that a top down orientation was the way to go and we wanted to avoid PDMS because its messy, expensive and prone to sudden failures.
Also for a large build volume bottom up print detachments can damage the machine.
With this in mind our final branch of iterations were focused on a top down non PDMS/oxygen inhibition based system. Simply leaving the vat open and dropping the bed into the vat comes with its own problems.
Firstly, the device would need to be precisely level or else the resin will sit at a slant in the container and prevent us from printing a flat layer.
Secondly, we would need to build in some sort of overflow tank to account for the bed lowering into the fluid since we would need the surface to stay at a constant height.
Finally, we would need a way to tackle the large settling time of some resins. Since the resins are quite viscous they take time to settle into a flat layer.Sometimes a really long time, sometimes they just don't and you end up with a pitted print or you'll find layers bulging from one another. This would limit the printer to very low viscosity resins.
The gull wing vat.
By partially submerging the window it no longer matters what angle the surface of the resin is at once the band of resin is in contact with the window. Once the print bed is parallel to the window the device can print.The device has adjustable legs so you can quickly get the band in contact with the window
The gull wing shape means that the window frame can sit into the tank and allow the offset volume from the bed to raise up around it. No need for extra tanks or overflows. We've included a saline pump so you can easily adjust the resin height.
As the window is below the surface and the resin is sandwiched between it and the last cured layer you don't need to wait for the top surface to flatten so the settling time brought on by the surface tension and viscosity of the resin is solved.
There are further advantages such as it being passive. This makes it more reliable because there are fewer moving parts and it lowers the overall cost of the machine. There are no wipers or further mechanisms.
The flexible window can contour to the shape of the cured layer minimizing the separation force. During separation the area at the edge of the cured layer becomes a threshold region where the vacuum force will be broken first. Its flexibility reduces the pull on the print during this separation.
The rigid gull wing window frame means new windows can be easily bolted in using basic tools so you don't need to buy a new vat, just the low cost window. The built in tension adjustment allows you to plan for maintenance so no more sudden failures. These windows are remarkably strong and I've printed on a single window for months and never had one suddenly burst.
We're really happy with the core printing method. Its incredibly reliable and achieves all the goals we had laid out.
To make the large build area more flexible we've included a projector stage so you can adjust its distance from the build plate within the UI. The unmodified projector is mounted on a quick release so you can easily remove it for access or if your in the mood for a film
Now when printing smaller areas you can get the best possible resolution
We modified our circuit board to utilize NanoDLP so the L2S is networked. This way you can use a phone or laptop and not have to worry about installing software or your operating system.
We think its the perfect interface to have out of the box and it lets kit builders work with familiar electronics. It has a whole host of features such as pixel dimming & slicing. It can store your plates for printing again later and allows advanced functionality through gcode equations. We'll be backing you up with NanoDLP updates specifically for your L2S
All we need is your backing
Risks and challenges
Any project like this involves risks but we have done everything possible to mitigate them.
We are working with a local manufacturer to ensure the parts are high quality and correct but we need your support to be able to produce the L2S at this price point. Without your backing , the cost is too great per machine.
We have done long term testing of our prototype and produced hundreds of test prints to ensure the design is robust.
Your backing will also help us to complete any remaining safety tests for the device to be compliant in Europe and the USA