I purchased the Mars 2 alongside some further relevant materials. When a print is made it first needs to be cleaned off the excess resin with a relevant liquid (in the case of the water based resin I have purchased this is water), after that the print needs to be cured under ultraviolet light. Some people leave their prints outside to cure in the sun but with the current unpredictable weather and a need for the prints I create to be consistent across a range of prints I opted for a machine that will wash the print as well as cure it.
Tinkercad
While waiting for the order to arrive I endeavoured to learn more about the 3d design process but setting myself a series of tasks to complete in tinkercad, this was a method I utilised in the Digital Media unit and I found it very helpful to progress through the relevant tasks.
The tasks I set my self to complete were
- Draw a square
- Draw a cube
- Set cube to 1inch x 1inch x 0.918inch (Type Height for letterpress printing)
- Add letter to cube
- Hollow cube
- Support cube
- Add drainage holes
Mars 2 3D Printer Calibration and Tests
Once the printer arrived there were various assembling and calibrations to be done. Much of this is documented very well in the materials that come with the machine and after levelling the print bed I attempted my first print with the test model provided, a chess piece. While printing this piece I kept the space well ventilated and used gloves while handling resin. After a roughly 2 hours the piece had finished printing successfully and I washed and cured it using the wash/cure unit.
Testing the Test print
Structurally the piece is very solid, the resin doesn’t feel brittle and the surface feels relatively smooth to the touch. With being in lock down I have limited tools to test the durability of the print, however it withstood multiple drops onto a concrete floor without shattering which is important for a printing block as they can easily be knocked off a table in a print space.
Print Angles
The test piece was printed flat on the print bed but a technique that is often used for more complex prints is to angle them off the print with a series of thing supports holding the piece in the air. In his video “My favorite way to 3D print perfect resin bases for my minis. Something I discovered printing dice?” (2020), maker 3dprintedpro shows that the reason for this is that apparently when things are printed directly on the print bed they can be hard to remove, with so much of the print being in direct contact with the print bed. When the initial layers are attached to the bed they are intentionally overexposed to create a good adhesion to the print bed, this overexposure can cause a slight variation at the base of the print where the overexposed resin expands slightly. This is colloquially called “elephants foot”. Also for complex prints with overhanging parts when printed flat you run the risk of not it printing incorrectly if not angled and supported in the right manner.
With the print process taking a while and me not having any blocks designed for print yet, I downloaded a selection of coins/tokens/model bases (essentially flat objects with a design on one surface) with which I can experiment with print angles to see which method of printing will work best – flat on the bed or at an angle with supports.
Initial Tests
Angled Designs
I placed a selection of designs on the print bed and varied their angle of elevation, then placed supports around them to connect them to the bed. The prints were successful and similar to the eye, but when viewed closely you could see and feel a stepped pattern across the top surface of the token caused by the angle of the layers being printed. Interestingly prints that were only angled slightly from the print bed had the worst examples of stepping, with it be very pronounced even to the eye.
Flat Designs
Using the same token designs as the last experiment, I printed a selection flat on the print bed. With printing something so shallow the print was completed very quickly (around 25 minutes). However I found that when placed in the wash/cure unit to wash the prints that there was a lot of excess resin. The wash/cure unit cleans the print via creating a whirlpool of water that the print is placed into. Evidently, this doesn’t clean a print sufficiently when the design is shallow and on the print bed. For the next prints I will try cleaning the prints by hand in water with a small scrubbing brush. The quality of the prints was very good but they were very hard to remove from the print bed, to remove a print you lever it off with a metal tool much like a paint scraper. With so much force being exerted upon them, when they did separate from the bed they ricocheted off the cleaning surface and onto the floor, so some means of removing them from the bed needs to be considered if this is the way I choose to print future print.
Printing a Design as Veneers
With the flat design taking so little time to print, and my skills in Tinkercad progressing, I also experimented with printing a selection of thin designs that could be mounted onto a block of material (for instance mdf) to bring them to type height. My research shows that this is something that other printers have done, as shown in the previous post.
Though the print was ready very quicky the resulting prints were so thin that once cured and dry they have warped and curled. I tried heating them in warm water and clamping them to correct this but the prints remained unsuitable for printing.
It is my hope with this project that I can devise a method of production that minimises the amount of post production needed before printing with the blocks. Printing a design as a veneer in this way and then mounting it was always going to have involved accurately cutting and mounting them on to wood. Something that in the current lockdown with minimal access to tools will be very difficult so I will progress with my aims of accurately printing a type height block.
References
- 3DPRINTINGPRO, 2020. My favorite way to 3D print perfect resin bases for my minis. Something I discovered printing dice? [viewed March 7, 2021].
- ELEGOO, 2021. Mars Series LCD Printers 2021]. Available from: https://www.elegoo.com/collections/mars-series