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(Fullcure 720 water absorption test)
(Fullcure 720 water absorption test)
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Now the trays has been filled with water again to see if they will absorb more after being moist over a longer period of time.
Now the trays has been filled with water again to see if they will absorb more after being moist over a longer period of time.
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  Although this has only been a single test, it seems that printing in HQ mode will protect the models from water absorption
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  Although this has only been a single test, it seems that printing in High-Quality mode will better protect the models  
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much more than High speed orn digital mode printing. The tests indicates that it may be because UV does not fully penetrate
+
from water absorption compared to High-Speed or Digital mode printing. The tests indicates that it may be because UV  
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the photopolymer in which the model is built from, thus only partially curing the bottom of each layer.
+
does not fully cure the photopolymer that is on the bottom of each layer.
=== Hingetest ===
=== Hingetest ===

Revision as of 09:58, 24 September 2010

Contents

The 3D-printing log

In this page we would like all that has made a 3D-print to add a few lines about their 3D-printing project.

What we would like to have covered is at least, but not limited to

The name of the design or project
Your name and position
A picture of the CAD model
A short description of the purpose of the design
One or more pictures of the design, preferably in use.
Interesting discoveries or aspects with this model

Feel free to add links to project websites or your own homepage.

Please insert your entry above the entries that have already been made.

Log entries

Copy the sample text below and fill in:

<design name>

By: <your name>

[[Fil:<your_design_picture>]]

Purpose: <your purpose>

Description: <describe the design/model>

[[Fil:<your physical model>]]

Discoveries: <your discoveries>


Fullcure 720 water absorption test

By: Yngve Hafting

Fil:vannres.jpgFil:vannres2.jpg

Purpose: To test whether water absorption will make models made with Fullcure 720 will make the material expand or shrink

Description: The model was made with a narrow tray for depositing water, lbh: 100x5x10 (measured on the outside), combined with a 1mm thick bar (not to be in contact with water), and 2 legs, 100mm long- as shown above. The hypothesis to be tested was that the legs would visibly move together or apart if the tray shrunk or expanded. One model was made as glossy (support only below), and the other was made matte (support all around). For the first test, water was filled into the trays, and they were left in an airconditioned room (20 degrees Celcius), only lit by fluorescent light (no direct sun). The first model was made in high speed mode. A second model has been made, but not tested, using high-quality mode.

Fil:matte.jpgFil:glossy.jpg

Discoveries: The first test was examined after 4 days. At that point the water had dried up completely from both models.

  • At first sight the glossy model appeared normal...
  • The matte model had opened its tray (which originally was only 5mm wide) to past 8mm width.
    • Most of the deforming happened within 15mm form both sides
    • A rough calculation shows that the expansion of each side was about 0,15% ( side length = 70 + 2*sqrt( 15^2 + (1.5)^2 ) = 100.15 mm)
    • The shape of the model does not return to its original state.
  • The legs of the model did not move as predicted, since the tray rather increased width more than length.

A second attempt was made to fill the glossy tray with water. I measured the width the day after.

  • The width of the glossy model had expanded its width to about 6mm. Most if it within the first 15mm.
    • A rough calculation shows that the expansion was slightly less than 0.02% (side length = 70 + 2*sqrt( 15^2 + (0.5)^2 ) = 100.016 mm).
  • The length of the trays were measured to be about 100.2 (matte) and 100,3 mm long (glossy). (After the tests).
    • (Thus the full length of the sides should not be 100.15 and 100.02, but 100,35 and 100.22 however the difference in rate of expansion is negligible.
    • The tray length is measured to be 100,2 mm for models that has not been tested with water yet (HQ-test)
Even an expansion of 0,15% due may be devastating for a design. 
Moist has to be avoided in order to avoid serious mechanical defects in models made with Fullcure 720.

Questions remaining:

  • Why didn't the bottom expand as much as the sides?
    • is it possible that the layers doesn't completely cure?, (making water absorption through the sides easier than through the top of a model)
      • Is it possible to further cure a model using a strong UV lamp?

Third test, using the same cad, only difference is that the print was made using High-Quality mode (reduced layer thickness). The lenght and width of the trays were measured before filling the tray with water, and a couple of days after all water had evaporated. Results were as follows:

  • HQ Glossy, before water test: length: 100.2mm width(top) 5.0mm
  • HQ Glossy, after water test: length: 100.2mm width(top) 5.2mm ( corresponds to 0,003% expansion in length)
  • HQ Matte, before water test: length: 100.2mm width(top) 5.2mm
  • HQ Matte, after water test: length: 100.2mm width(top) 5.6mm (corresponds to 0,01 % length expansion compared to 5.2 mm, or 0,02% lenght expansion compared to 5.0mm)

Now the trays has been filled with water again to see if they will absorb more after being moist over a longer period of time.

Although this has only been a single test, it seems that printing in High-Quality mode will better protect the models 
from water absorption compared to High-Speed or Digital mode printing. The tests indicates that it may be because UV 
does not fully cure the photopolymer that is on the bottom of each layer.

Hingetest

By: Yngve Hafting

Fil:Mattest2.jpg Fil:hengslesketch2.jpg Fil:hengslesketch3.jpg


Purpose: To test if tango+ can be used in a hinge, as a sort of spring

Fil:hengsler2.jpg

Discoveries:

  • 0.25mm gap using glossy will fuse in glossy vertical gaps => use matte option to cover with support and avoid fusing (middle model)
  • 5mm radius 2x30 degree overlap, 0.25mm gap hinge will work as a not too tight snap-fit (the model at the top)
  • Tango+ blob, detached in one end will not be able to push back the hinge in position (top, middle model)
  • Tango+ will straighten the hinge when attached to both parts (bottom model). It does have a weak fully dampened pull-back.
  • Tango+ tore near, but not at edge (where it is thinnest) during manipulation when waterjetting. (bottom model)

FlexiFoot

By: Yngve Hafting

Fil:Foot_E.jpgFil:Fot_sketch.jpg

Purpose: To test how flexible 1mmx10mm thick fullcure 720 is, and see if a surrounding blob of tango+ makes the foot stronger or flex differently.

Fil:Foot_picture.jpg

Discoveries:

  • 1mm Fullcure 720 appears to be quite firm.
  • The fullcure 720 properties dominates when it comes to rigidness, although it is flexible.
  • Model D and B is only slightly easier to bend than C because of the different Tango+ configurations.
  • Model A broke violently close to the center when its legs were bent too much (was not able to bend the ends so they touched each other.).
  • I was able to put the legs that were closest to each other- together- with B, while A broke on the same manouver.
    • B did not go back to its original shape after that
    • B broke on the third attempt to squeeze the closest legs together
  • Model C also broke on that manoever. It didnt break in the center, but in one of the legs, just where fullcure reached 1mm thickness.


Ball joint material test

By: Yngve Hafting

Fil:Mattest1.jpg Fil:Mattest2.jpg

Purpose: To test some of the material properties for both Tango+ and Fullcure720

Fil:Mattest3.jpg Fil:Mattest4.jpg

Discoveries:

  • The inner blob was made in Tango+ to push the balljoint back in position. Being attached to the cup and free from the balljoint, it did push back the joint some, but not nearly 100%. After some manipulation, the inner blob in one of the joints got detached from the cup. To have better spring effects the ball must be attached to both the balljoint and the cup, if it will survive the physical manipulation.
  • 0.25mm works for clearance
  • At first, the whole joint was rigid due to the support material. removing support without "breaking" it up is impossible when using only 0.25mm gap.
  • Breaking loose the parts is somewhat violent and possibly harmful to the inner blob in this case.


Tango+ disk test

By: Yngve Hafting

Fil:tangopdisktest1.jpg

Purpose: To test the properties of tango+ for use in joints.

  • Models were made in three sizes and three configurations:
    • h/d = 0.5, 0.25, 0.1
    • d= 5, 10, 15mm

Fil:tangopdisktest2.jpg

Discoveries:

  • h/d = 0.1 (smallest disk) feels almost rigid.
  • twisting tango+ is easier than bending, thus twisting is the easiest way to tear the material.
  • small models are easy to manipulate, and "invites" you to play too harsh => tango+ breaks.
  • Volume seems constant on the tango+ material (streching makes thinner, compressing makes thicker)
  • Tearing the material by compressing (straight) is nearly impossible by hand
  • Tearing by stretching is possible, but quite hard with the large models
  • Tearing by bending is easy to achieve
  • Tearing by twisting is very easy
  • When stretching only, tango+ tears near the edge of fullcure 720
  • When bending/ stretching, the displacement is visibly largest near the edges. Design precautions need to be made in order to make reliable stretchy objects.
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