This model / project will always hold a special place in my heart when it comes to design and 3D printing. It was a real game changer. After extensive testing with my first printer (with manual leveling!) I had to conclude that I needed a reliable and accurate printer for a repeatable and clear result. After purchasing my P1S it turned out that the right candidate had been found!If it hadn't been for this model, I would probably still be working with my old printer! I was able to create something unique which was endorsed by the many positive responses I received from leading professors and academics in the field of 4D printing on my publication in the Linkedin group [3D Printing Today]

Explore the world of 4D printing with your own printer!

 

 

INTRO

Every print we make is full of stress. Stretched plastic that would like to shrink a bit. It is why we heat our print bed, need cooling during printing and why our models shrink a little after they cool down and sometimes warp during printing.

How awesome would it be if we could deliberately use this induced stress to make models deform themselves, create a 4th dimension by heating them above the glass transition temperature (1) after printing?

Well, we can! All you need is a model and printing technique that has been fine-tuned for this. You can even do this without using highly engineered materials or the use of multi materials!

In this example, a Rose is made up of separate layers with Petals that are 3D printed on a normal 3D printer. The different layers of Petals are placed on top of each other and enclosed between the Stem and the Pistil of the Rose, also both 3D printed.

To make the Rose look as real as possible, the division of the Petals was designed to look as natural as possible. As a result, they are not evenly spaced and also rotated slightly for each layer and therefore never in the same place in the circle. In there is my own formula, created with help of some sites which explain mathematical petal arrangements in flowers. The different layers are aligned on a T-shaped bar.

As mentioned, the final assembled model needs to be heated. We can do this by pouring the assembled model with freshly boiled water. What happens then is absolutely magical. All the stress translates into what appears to be a natural deformation of each individual petal, transforming the apparently flat print into a complete 4D rose. No rose will be the same due to small differences in printing and heating.

To give this unique model as a gift, I also added a nice gift box.

First recording of the assembly and transformation with hot water. I forgot to remove all remnants of glue used on the printerbed, therefore the petals were sticking to each other and that's why I had to manually separate them from each other at the end of the video. See also the timelapse by using an oven.

PRINTING

For all settings below I used Bambu studio. I suspect other slicers have the same possibilities.

Use PLA! Be careful using PLA with fillers such as glitter, wood or metals. This is because large deformations occur, which can lead to cracks or breakage with such filling. (2)

The determining factor of how your model will ultimately look is mainly determined by the print settings used! There is of course some kind of optimal setting (which I will share), but there is also a lot of room to experiment with the settings.

The model is optimized for layer thicknesses of 0.2mm (first layer can deviate). You can deviate from this, but this can have major consequences for the end result!

The first layer is the most important one for deforming. Experiment with the layer thickness and other settings below to determine the degree of deformation. Print one Petal with several settings to experiment.. The degree of deformation to the 4th dimension when inducing enough stress with your printer settings for the Petals will be enormous!

Advice for printing:

• Nozzle: 0.4mm
• Layer thickness: 0.2mm (experiment with first layer height for the petals!)
• Top Solid Layers: 3
• Bottom Solid Layers: 4

Make sure that all layers are solid when printing the Petals! As said, experiment with the first layer height. It has a huge influence on the deformation of the Petals. I used 0.28mm for the first layer and 0.2 for the rest.

Perimeters

The number of perimeters in relation to the size of the Petals has also a huge influence on the deformation of them. With a larger number of perimeters, the Petals will bulge strongly. With a smaller number of perimeters, this bulge is less strong. I used below settings:

• Petal 1-3: 25 perimeters
• Petal 4-6: 20 perimeters
• Petal 7-10: 15 perimeters
• Stem, Pistil, T-bar, Stand, Box and Box Lid: 3 perimeters (or what you normal use)

Infill

Use concentric infill for all layers of the Petals! The other parts you can use what you normal use.

Printing speed

The printing speed can have an influence on the final deformation of the Petals, although I expect the effect is not that great. Below are the most important speeds I used.

First Layer: 50mm/s. First layer infill: 105mm/s. Other layers: Wall and top layers: 200mm/s. Solid infill 250mm/s. Inner wall 300mm/s.

I own a fast printer, but with lower speeds it also works! I did the initial tests with my CR10-V2 with maximum 60mm/s.

Printing temperatures

The printing temperatures (and brand of PLA) can have an influence on the final deformation of the Petals, although I expect the effect is not that great when using the prescribed temperature range. Below is what I used.

Printing temperature first layer: 225°C, other layers: 215°C – First layer NO part cooling!

Bed temp first layer: 55°C, other layers: 55°C

Colors

You are of course free to choose your own colors, but advise is red (or white) for the Petals, yellow for the Pistil and Green for the stem. The T-bar can be printed in any color since it is not visible after assembly. The Stand: the color you like.

Filaments I used:

• Prusament PLA Lipstick Red - Petals (red rose) – Rose engraving on box lid
• Prusament PLA Vanilla White - Petals and T-bar (white rose) – Rose box and lid
• Prusament PLA Blend Viva La Bronze - Pistil and T-bar (red rose) – Ring on the box lid.
• Prusament Premium PLA Mystic Green - Stem – Rose engraving on box lid

ASSEMBLY

After printing, the different layers of petals must be stacked on top of each other.

Place the T-bar in the recess of the Stem and glue it in place with super glue. Then place the stem in the also printed Stand and stack the printed Petals in the correct order, from largest to smallest. With heating, the Petals will tend to form a bowl shape with the top layer inside. So placing them with the top side up will normally result in Petals forming upward (red rose) and placing them upside down (in the same order) will normally result in Petals forming downwards (white rose). Now glue the Pistil to the other end of the T-bar and allow it to harden sufficiently! Check whether everything is properly secured.

Now comes the exciting part, to let your rose bloom in the 4th dimension!

Do this together with or have the recipient do it so that the magic is not missing from the gift!

We have to heat the model above ±80°C, the temperature PLA becomes soft, but not melts. We can do this by using boilded water or by heating it in the oven.

Using hot water:

Make sure you have a sufficiently large (glass) bowl to use with freshly boiled water.

Place the Rose with the Stem in the also printed Stand, on the bottom in the middle of an empty bowl and poor boiled water evenly over it. Make sure to fill the bowl till the Rose is completely submerged! Allow the Petals to form in time.

Then carefully scoop the Rose out of the hot water with, for example, a fork and let it cool. While cooling, you can remove the excess water, shape the Rose Petals a little further by hand (they cool slowly and tend to stick a bit to each other) and after fully cooling down your self-created 4D Rose is ready. Cooled down the Petals are strong and sturdy, but still with a little bit of movement around the T-bar.

Tip: you can use the force of gravity to make the Rose more open or closed: let it cool down with the top up or down. You can also use centrifugal power to shape: turn the Rose around while cooling..

Using the oven:

Preheat the oven to 100°C. Place the Rose with the Stem in the also printed Stand and place that on a plate. Now place the whole thing in the oven in the middle or at 1/3 height. Close the oven door and wait for the magic to unfold. Beware that there is enough room above the rose to prevent burning of the petals by the heating element in the oven!

Normally this takes about 5-8 minutes. After about 5 minutes you can increase the temperature a bit to 120°C to speed things up a bit or to allow it to deform a little more.
When the rose is fully formed, take it out of the oven and let it cool. While cooling you can make small (additional) deformations if you wish. After removing from the oven, the petals are still soft. So they can still sag a bit due to their weight.

Alternative you could also use a heat gun, but making uniform deformations is then harder due to the concentrated heatspot created.

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I hope you all read till this and are now intriged and determined to go on this adventure! I love to see your experience and makes of it!

For those interested in the techniques of 4D printing, see the WIKI about it.

The technique I used is know as: Stress relaxation

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1) Glass Transition Temperature

The glass transition temperature is the temperature range where the polymer (PLA) changes from a rigid glassy material to a soft (not melted) material.

2) This advise is based on previous use in thin layers. I have not tested this for this model. If you try, please let me know if it worked well.