Making “nylon-like” Resin

Most resins are hard and can crack when dropped. There are some great “tough” resins such as Siraya Blu and eSun Tough, but what if one doesn’t want clear? I needed a white. I tried adding white opaque pigment to Siraya Blu, and it was promising, but the blue color was evident and it was just not white enough.

Elegoo white is often on sale for $38 per KG at Amazon with an extra 5% off if you buy several, but it is a normal modeling resin, which is designed to be hard and detailed – and my part was cracking the first drop at one meter onto a hard floor. I decided to see if adding in Siraya Tenacious would solve that.

https://youtu.be/WXHNfCgrlHg

Tenacious is a clear and flexible resin that when used by itself, can form flexible rubber-like parts such as watch bands or tank treads. When used for thicker parts, it behaves more like a urethane from skate-board wheels and feels solid. The nice thing about mixing in Tenacious is that the exposure happens to be the same as Elegoo White, so the same settings work for any ratio – though optimally another second or two is best, and base-time can be lowered.

I tested Elegoo white dropped from 1 meter, and it failed first drop. I then repeated with another sample, and that also failed on the first drop. With 33% Tenacious, 10 drops were not a problem. Now we are getting somewhere.

https://youtu.be/W4UEm3Tuo0s

The color does turn into a warm/yellowish white, but I am happy enough with the look, and recommend 33% Tenacious mixed with a hard resin for an affordable nylon-like blend. This is a simple 2:1 ratio, so easy to mix up with whole bottles.

Networking with the EPAX X1 LCD-SLA Printer

The EPAX X1 is capable of networking using hardwired ethernet. To set this up, first install the latest firmware from here:

https://epax3d.com/pages/firmware-and-parameter-files

To install, put both files onto a USB memory stick, insert the stick into the printer, and power on the printer. You will hear a series of beeps. Wait until they finish, and then check the version using the Info screen to make sure that it updated.

Now unscrew the four screws on the back side of the enclosure, and plug in an ethernet cable (the green cable in the photo). Plug the other end into your router or switch.

Using the front panel control, enter the network setup area:

Now toggle the network type. While WiFi is shown as an option, there is no WiFi hardware inside the printer, so you must use a cable. Push the switch in the upper left of the touch-screen to enable the ethernet connection. If you see an IP address fill in, it is working. A green LED should now be illuminated where the cable plugged in.

Now load the latest version of ChiTuBox, version 1.4.0 or newer, and slice a file. You will be presented with the option to save the sliced file, or send it to the network.

Select “Network Sending,” and you should see all of the EPAX printers that you have connected to your network. If this is your first time, you may need to select the refresh icon.

Note that you can click on the pencil icon and rename what each IP address is called.

Now press the send button. You should see it showing the progress where it says “Send file to the printer…”

When the sending is complete, it will ask if you would like to print the file. If you say OK, then it will start printing. If you hit Cancel, then the it won’t print, but the file will now be on the printer’s SD USB memory card for you to later start it manually from the printer’s touch screen.

If you would like to make the machine wireless using WiFi, you can probably make it work using a wireless bridge. Here are some untested referral-link examples:

https://tinyurl.com/yy3nnd4e

https://amzn.to/2Gt5H4E

I hope that helps get you up and running without resorting to the sneaker net.

On the difference between DLP and LCD based SLA printers

Laser, LCD, and DLP are three distinct methods of exposing a light-sensitive resin in layers to cause a cross-linking of liquid polymers, curing the liquid into a solid object. All of these are used within SLA printers, a term used to refer to the stereolithography process. There has been a disturbing trend to refer to LCD printers are “DLP” printer that started when lower price-point manufactures began to use the already-taken “DLP” term for marketing purposes and claiming it was ok because their LCD does light processing using digital signals. Doing so, however, is like calling a gasoline-engine car an electric vehicle – something that it is not – just to confuse consumers into thinking that they are getting something often seen as more desirable but at a lower price.

Laser, (originally L.A.S.E.R as an acronym for Light Amplification by Stimulated Emission of Radiation) uses galvanometer scanners to direct a light beam via vector and raster scanning. The process is fast for smaller object, but get progressively slower when it must draw out more objects. The advantage is a smooth surface finish and compatibility with resins high in polymer content for the strongest resulting parts. An example of desktop laser-based SLAs are the Peopoly Moai and the Formlabs Form-2 printer.

LCD is a variation of SLA that uses a Liquid Crystal Diode display, the same as in most laptops and mobile phones, as a mask. It is also known as MSLA, or masked SLA. A light source is placed on one side, and the resin on the other. Because the entire layer can be exposed at the same time, they are generally faster for printing more or larger objects. Example of LCD-based SLA printers are the Anycubic Photon, Wanhao Duplicator 7, and the EPAX-3D 1X. One reason why LCD still remains on the low end, because the fact that they can simply be manufactured for less cost, is that there is a limited amount of light that can pass through the LCD panel before it overheats and self-destructs. This limits the speed at which printing can take place. To help make up for this lower amount of light exposure, the resin makers increase the monomers and photo-sensitive initiators, with a resulting increase in potential for shrinkage and weaker parts. In reality though, due to advances in resin such as Siraya Labs Blu (the strongest LCD resin I have tested) and eSun Bioresin (the strongest solid-color LCD resin I have tested), some very strong parts can be made – just as strong, if not stronger, than PLA and ABS parts on FDM printers.

DLP uses a digital micro-mirror device in which light is reflected through a projector lens and onto a tank of resin. Because this matrix of mirrors can be well cooled, a lot more light can be directed than with LCD, thus making it the choice of larger, faster, and more expensive printers that can still make use of less sensitive and stronger resins normally reserved for laser. The downside being a higher price point, taller printer size, and sometimes lower resolution because DLP chips tend to max out at 1080P.

But you may ask – why is it not ok to refer to my LCD-based printer as “DLP” when the manufacturer says it has light processing and is digital? The answer is because the term DLP was already taken for a digital micro-mirror projector device, and there would be no distinction between the technologies, both of which are used in resin printers, if you used the same term for both.

Here is a video showing a DLP chip in action:



This is TI explaining their DLP reference design. Notice how it does not make use of an LCD:

Examples of some DLP printers are:

Chimera:

https://www.instructables.com/id/Chimera-60-DLP-resin-3d-printer/

Ember:

https://www.fabbaloo.com/blog/2014/12/28/see-autodesks-ember-3d-printer-in-action

Milkshake 3D:

https://www.milkshake3d.com

Carbon-3D

Moonray

G3D T-1000

https://www.g3dsys.com/product/t-1000-dlp-3d-printer/

FlashForge Hunter:



References:

See https://en.wikipedia.org/wiki/Digital_micromirror_device

https://en.wikipedia.org/wiki/Digital_Light_Processing