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'''Discoveries:''' (by Yngve:) After leaving the ABS-like material (RGD 515+535) in a 5% caustic solution over the week end, the outer layer of the models became so soft that fingernails will scratch the material through that layer entirely. That is, one can remove about 0.5 mm of the walls in the model with the fingernails after the support is washed away with water jet.
'''Discoveries:''' (by Yngve:) After leaving the ABS-like material (RGD 515+535) in a 5% caustic solution over the week end, the outer layer of the models became so soft that fingernails will scratch the material through that layer entirely. That is, one can remove about 0.5 mm of the walls in the model with the fingernails after the support is washed away with water jet.
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== ==
 
=== iDings ===
=== iDings ===

Revision as of 09:08, 19 September 2011

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>]]

Printer: <SST 768/ Connex 500 /??>

Post-processing: <...>

Discoveries: <your discoveries>


Ultrasound Mounting brackets in ABS-like material

By: Kim Mathiassen (Design), test of material by Yngve

Purpose: Mount for an ultrasound probe

Fil:IMG 1200 small ABS caustic soda.jpg

Printer: Connex 500, ABS-like material (RGD 515+535)

Post-processing: Waterjet+ 5% Caustic solution + Waterjet

Discoveries: (by Yngve:) After leaving the ABS-like material (RGD 515+535) in a 5% caustic solution over the week end, the outer layer of the models became so soft that fingernails will scratch the material through that layer entirely. That is, one can remove about 0.5 mm of the walls in the model with the fingernails after the support is washed away with water jet.


iDings

By: Yngve Hafting


422px Fil:Iphone4holder..jpg


Purpose:

Make a box that can hold an iphone4, arduino board and some connectors

Description:

The model was designed as 2 parts, one for holding the iphone, one for holding the arduino and its connectors. Each part was designed as one or more parts in solidworks before assembeled. For example was the 3.5mm jack panel mount fitting made in one part, duplicated 16 times for the box. The distance added for the slider between the iphone compartment and the arduino compartment was 0.25mm on each side. This provided the ability to slide easily.

400px 400px


Printer: Connex 500.

Material: Vero White and/or Fullcure 720

Post-processing:

Washed in waterjet + 20 min in a solution with 5% caustic soda.

Discoveries:

0.25mm distance on each side makes sliding tracks wide enough that models can slide with little resistance. In order to stop the arduino and the iphone compartment from sliding apart when held vertically, adding a paper folded once in one of the track sides will be enough. The paper thickness was measured to about 0.10mm, thus one can suggest that a tolerance of merely 0.15mm on each side may allow the slider to work with (high) resistance.

There were some differences in in the sliding friction between the models made in Vero White VS fullcure. The all-fullcure version showed greatest resistance.

Manipulator

By: Magnus Lange

Fil:robot_v3_cad.jpg

Purpose: Master thesis prototype

Description: Industrial manipulator for educational purposes with modular parts for several configurations

Fil:robotv3-print.jpg

Printer: SST 768

Discoveries: When printing the parts in spars the mounting of screws are more difficult then with solid physical models. Also experiencing issues with fitting the part for mounting on motor axle perfectly. It seems that the dimensions on the abs model always is too large for the motor axle. This causes wiggling when mounted on motor axle and can make the motor position inaccurate when controlling the joint.

Cable holders for INF 5460

By: Yngve Hafting

Fil:kabelh_ytre.jpg Fil:kabelh_indre.jpg

Purpose: to hold a primary and a secondary coil in fixed position for testing magnetic pickup in cables using different shielding and termination.

Description: Each ring consists of four equal quarters that has a snap fit connection.

Fil:kabelholdere_bilde.jpg

Discoveries:

  • The snap fit mechanism worked well. At approximately 10cm radius, tolerances of .2 degree worked very well for the snap fit mechanism (0.35mm). The screw holes i made were not needed, but they did align well having 0.1mm difference in radius
  • 1.5 mm deep knob on the snap fit is enough, it works, but wider will probably break the 9.8 degrees long leg it is resting on. 1mm should be sufficient in this configuration.
  • 2mm out of a 10cm radius is much more tolerance than i need for this build. If i make a version 2, i will go down to 0.5mm or less difference between the inner radius of the outer ring and the outer radius of the inner ring.

Snapfit fail after one day:

  • Made one sample of the primary coil holder using duruswhite. Unfortunately it was put together before it was completely washed. Thus for 16 hours (next day) the parts were put together without snapping perfectly. When they were taken apart for further cleaning the next day, it was evident that the snap fit mechanism was damaged permanently.

Fil:snapfitfaildurus.jpg

The picture shows how the "legs" that were intended to be straight never curled back in position. Thus this mechanism will never be able to "snap" or hold on to anything ever again. Fortunately, this will not become a problem in this project.

Box for electronics

By: Yngve Hafting

Fil:eske_liten.jpg Fil:lokk_liten.jpg

Purpose: To build a box that should contain a PCB and some connectors. To test a snap-fit design with fullcure.

Description: A box that can fit an XLR-connector in one end, and a BNC-connector in the other.

For the snap fit design, i used a

1 mm thick, 
10 mm deep, 
3.8mm high foot, 
with a ball at the end having 0.6mm radius. 

It was supposed to fit a carved slot that hat 1mm radius. (All tolerances was set to 0.2 mm at each side)


Fil:eske_bilde.jpg

Discoveries:

  • The lid fit very tightly at the first attempt.
  • One leg broke when i tried to re-open the box.

This box is not meant to be opened many times, thus for its purpose, the lid behaved as intended. I would expect the lid to come off more easily, but i did also anticipate that the leg might break as it did. To ensure that it doesnt break, i think the leg should be longer, or the ball need a smaller radius.

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)
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.

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.

1. Oct. results (all mm):

HQG length: 100,2 max width: 6,1

HSG length: 100,2 max width: 6,8

HQM length: 100,0 max width: 7,1

HSM length: 99,7 max width: 8,6

It seems that water absorption continues for all models, although slower for the glossy ones, 
and somewhat slower on the HQ models with respect to the HS models.

Note that the length of the HSM model has decreased by almost 0.5% from the first measurment of length.

8. Oct results (all mm):

HQG length: 100,1 max width: 7,4

HSG length: 100,2 max width: 7,6

HQM length: 99,8 max width: 8,9

HSM length: 99,5 max width: 10,5

To test if water is absorbed in between layers only, or if it is just so that 
the walls expand due to the weak force from the water inside the tray--
i would guess printing the tray-only sideways (having one side down, rather than the bottom)
will give a clue..

13.10. Two sideways printed tray-only models was added to the collection. (HSLG- High-Speed-Laying-Glossy [only one side being glossy], and HSLM- High-Speed-Laying-Matte). Initial measurments were done right after cleaning:

HSLG length 100,0 width 5,0

HSLM length 100,0 width 5,0

Fil:Tray-only.jpg

Both trays were filled with water after the initial measurment, along with the other models that had dried up.



22.10:

The HSM tray printed along with the HSL's were filled a few days later (5 or 6). Its initial measurment were lost, however build accuracy has not been the issue, so we can assume that its initial measurments would have been (width) w:5 (length) l:100.

Measurments mm only:

HQG       w: 7,3   l: 100,2
HSM (new) w: 7,3   l: 100,1  
HSG       w: 7,7   l: 100,0
HSLM      w: 8,0   l: 100,2
HSLG      w: 8,1   l: 100,2
HQM       w: 10,1: l: 99,5
HSM       w: 11,7  l: 99,2

At this point it seems pretty evident that the glossy models are maintaining shape much better than the matte ones, as long as the sides being in contact with water is glossy. The trays that were built on their side, does not maintain shape anywhere near as good as the glossy models, thus it seems that limited UV transparency in fullcure720 was not the big issue. (ie the difference between HQ and HS is negligible in comparison with glossy surface vs matte) It does however seem like the material softens quite a lot when in contact with water- in particular on the sides that have been coated with support material. Weather this is a chemical issue or an issue with UV being blocked by support material remains to be determined...

25.10: Added a tray made glossy with duruswhite/high speed/normal alignment. Initial measurments DWHSG w: 5,0 l:100,1

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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