Parametric Filling System Model

Discussion in 'Sand Casting' started by Dean, Jun 19, 2022.

  1. FishbonzWV

    FishbonzWV Silver Banner Member

    Does the spin trap really fill before the gates get metal?
     
  2. Melterskelter

    Melterskelter Gold Banner Member

    I see that OIF used a direct right angle Tee intersection of gate runner to the main runner. But Dean’s model shows a recurved junction favoring flow down the runner to the trap. I would tend to think that would make a real difference. Maybe we can connive OIF to make up a new test with that configuration. It is instructive to see the mold cavity filling lag compared to the trap.

    Thanks to OIF for his excellent video and to you, Bonz, for reposting it.

    Denis
     
    Last edited: Jul 7, 2022
  3. Dean

    Dean Copper

    That's the intent but can be a bit hard to achieve in practice.

    One way is to have vertical gates like in OIF's video but at a cost of reduced head pressure. Also note that he has a tapered runner after the gate which I think caused the gate to fill before the trap was full.

    Another option is to have horizontal gates coming off the top of the runner ie. runner in the drag and gate in the cope. Campbell does talk about this and notes that the gate/runner intersection can catch debris which is then pushed into the casting. His solution is to install a filter in the gate entrance to act as a restriction. He talks about it in this video

    Something I thought of recently is having horizontal gates that are angled back towards the sprue. The idea is that the momentum of the flowing metal causes it to flow past the gate so that the gate only fills when the back pressure increases. This then opens up the possibility of some out of the box thinking about sprue, runner, gate and spin trap placement away from the contemporary linear arrangement.
     
    Tops likes this.
  4. Tops

    Tops Silver Banner Member

    filling_basin_180.png

    // Basin
    rotate([0,0,180])//added to spin basin from feeders

    Useful with larger basins and/or shorter runners and gates.I know this can be done upon assembly but I like the WYSIWYG (what you see is what you get) and it keeps the feeder from melding into the basin during the creation of the STL
    @Dean , is it worth a variable in the script? Maybe I can try to add that here too.
     
    Last edited: Jul 8, 2022
  5. Tops

    Tops Silver Banner Member

    34 //basin rotation
    35 rotate_basin =90;
    36
    285 // Basin
    286 rotate([0,0,rotate_basin])//added to spin basin from feeders

    filling_basin_90.png
     
  6. FishbonzWV

    FishbonzWV Silver Banner Member

    Gates on the same plane as the runner?
     
  7. Dean

    Dean Copper

    The gates can be in the drag with the runner, or above the runner in the cheek or cope.
     
    Tops likes this.
  8. Tops

    Tops Silver Banner Member

    filling_system_gates.png
     
  9. Dean

    Dean Copper

    I'm working on it with a few other enhancements.
     
    Tops likes this.
  10. Dean

    Dean Copper

    Tops likes this.
  11. Melterskelter

    Melterskelter Gold Banner Member

    Dean, from the standpoint of clean metal/late gate filling the lower drawing above seems like the ideal setup. But, I am having a hard time visualizing exactly how that system is molded into the sand and attached to a mold cavity. How is that to be done? I guess one could use a core print which would allow the vertical gate runner and mold cavity to be set in place as a bound core? I must be missing something…. Depending on the pattern to be molded, that core itself would often have to be an assembly of core sections.

    Denis (evidently, from the back of the class.)
     
  12. Tops

    Tops Silver Banner Member

    @Dean, thanks for the updates.

    @Melterskelter Denis, when the pieces are output for 3D printing, they can either be output as one co-joined piece (as shown above) or into logical pieces for laying out flat in a 3D printer. The logical pieces can then be assembled so as to be placed in the cope (red/pink) and the drag (blue/blue), and extracted with the pattern or from the top of the cope (basin and sprue).
    filling_system_assembly.png
     
  13. Melterskelter

    Melterskelter Gold Banner Member

    Yes, that one is pretty straight forward, though ramming sand under that broad flat-bottomed pouring basin will require close attention in order to get it solidly rammed. I was asking about the lower of the two drawings put up this morning. The angled more or less vertical runner/gates would be difficult to draw out of the sand.

    Denis
     
  14. Chazza

    Chazza Silver

    Nothing new in that; have a read of The Complete Handbook of Sand Casting by C. W. Ammen; Copyright 1979; pg 148, 149.

    Cheers Charlie
     
  15. Dean

    Dean Copper

    So similar to what Tops said, the gates are printed as separate pieces so you would put the runner in the drag, the vertical gates in the cheek, and the casting either in the top part of the cheek or in the cope.

    Or, if you wanted to go all fancy, you could use it in a vertical split flask.

    Filling System Pieces.png

    As for the basin, it is also a separate piece from the sprue and the dimensions aren't that critical. Nothing to say that you couldn't also just make a mound on top of the cope to hold the basin.

    In fact, the whole model is broken into pieces for printing and use. About the only thing I would stick together is the vent on top of the spin trap.

    And also, you don't have to use the actual model pieces - you can just use them as a guide to what the theoretical ideal sizes are for the different pieces and just cut them by hand as you normally would.
     
    Tops likes this.
  16. Dean

    Dean Copper

    "Gating and risering is by far the most controversial subject in the foundry and each expert comes up with his pet theory on the subject." - Not much has changed in the last 40 odd years then ;)
     
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  17. Melterskelter

    Melterskelter Gold Banner Member

    Dean,

    Have you molded and poured any of these proposed gating systems? Cope, cheek, and drag or vertical systems are all “possible” but add quite a bit of complexity. (I do use cope cheek and drag setups repeatedly on 3 castings that I pour in iron. But I resorted to such systems only because it is not possible to pour them otherwise.) Seeing substantial improvement in small-scale casting clearly linked to these system designs might provide motivation for adoption of these practices.

    Denis
     
    Last edited: Jul 12, 2022
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