Connex500

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Connex 500

Intro

Just before easter 2010 we installed a brand new 3D-printer, a connex 500 machine delivered by Signcom and manufactured by Objet Geometries. The printer itself is using polyjet technology, which means that it builds the model by applying layer by layer of thin liquid photopolymer on top of each other. Each layer is cured instantly by the use of UV lamps.

FAQ

Know-how

Material costs

  • 1cmm -> ~1g material
  • Support material cost us slightly more than 1-2NOK/g
  • Build material costs us around 5 NOK/g
  • This machine builds solid blocks (no air gaps at all)
  • Support structures always contain a mixture of build and support material, hence the "support" cost will be higher than 1 NOK/ccm.


Design consciderations

  • Multi coloured parts:
    • Parts can be assembled inside each other in Solidworks for adding text etc, even though this is bad practice. They can also be made into one single STL file, and broken into shells by Objet studio.
    • Using a mixture of VW+ (Model1) and TB+ (Model2), the Tango material in Model compartment 2 will take precedence. That is, with this placement, you get the darkest combination chosen, never the lightest.
    • It is possible to place models on top of each other using Objet studio, but that is even worse practice.
    • Best practice is to have no overlapping structures using boolean operations (cut out embedded parts before inserting them), then making one STL which may be broken into shells in objet studio. This way you will have all possible colours available, and less risk of errors.
    • UiO logo Suitable colours for the 2012 logo "UiO:University of Oslo" may be:
      • background: DM8515 Grey 35 (or brighter)
      • letters: DM9885_Shore85 (or softer/darker)
      • colon: DM8530 Grey 60. (+-1 level may be OK if the background is lighter than Grey35)
      • inverting the colours requires non-overlapping structures.
  • Tolerance:
    • Parts that should fit inside each other should have at least 0.1mm clearance on each side. Note that ehan building things inside each other, 0.1mm clearance may still fuse the parts together, thus when printing parts together, attempt to have 0.2mm clearance or more, non glossy surfaces.
  • Material economy
    • When making boxes etc, you may save a lot of material by having a separate lid and printing with the hollow side up.

Printing specific

  • To avoid uneven vertical surfaces: do not print glossy, as some material may slide down the side.
    • This effect may also cause surfaces that are close to connect, fixing structures that should be able to move in relation to each other.
      • This effect has been demonstrated with 10mm high walls separated by 0.25mm. They adhered at the bottom, causing cracks in fullcure720 when forced to move.
  • (Probably obsolete after sw update: When using tango+ material (might be related to changing a material) the "light-support" option should be chosen before assigning material, otherwise the option will be unreachable in objet studio.)

Build material

  • Fullcure 720 is cheaper and more sturdy than the Vero materials. The downside by using this material is that is cannot be mixed with tango materials to obtain semi-softness.
  • Tango materials will break if stretched more a few times. The 40% stretch limit indicated in the brochures is not something that can be obtained multiple times without tearing.
  • Tango plus is more flexible than Tango materials, however stretching it to 200% multiple times will result in tearing.
  • Tango plus material will go back to its initial state very slowly, and is not suited to use as a rubber band.
  • Tango materals are suited for making coatings, and perhaps to be used for shock absorbing.
  • Tango materials are not suited for vibration dampening.
  • Some materials are more slippery than others
    • Objet states wall thicknesses can be down to .6mm
      • We have built successfully wall thicknesses specified to .3mm (glossy, VeroClear)
      • .2mm wall thickness fails (breaks)
      • Walls at .x mm will be sligthly thicker than specified. (+.05 -ish)

Support material

  • Support material is cheaper than any build material. The machine has options for filling solid blocks with support rather than build-material. Normally, printing thinner walls is more desirable than filling them with support.
  • The machine does not build air gaps, all caveties in a model will be filled with support material.
  • The support material can generally be removed with the Krumm water-jet.
  • Persistent support material can be softened by putting the model into water. The support material will absorb water and break or loosen up somewhat after a few hours has passed, then it can be removed much easier using the waterjet or a brush.
  • The water jet is generally the best way of removing support
  • The support material can consist of build-material as well as fullcure 705. This amount of build material in the support can be adjusted in objet studio.
  • Note that the border between material and support will be a mix of the two components, as they mix somewhat before curing.
  • To achieve completely smooth surfaces in a model where there used to be support material- sanding will be needed.
  • At 1mm thickness, the vero materials may break easily- they will probably withstand the use of the waterjet, but they may also break thus caution is needed when removing support.

Post processing

  • Sanding surfaces with P320 paper will give a smooth surface that normally will suffice
  • Apply water when sanding to flush away excess support material.

Links

The manufacturers link: Connex500

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