Minimum Tool Head Guidelines

Discussion in 'Tool heads & ToolChanger' started by Paul Arden, Sep 5, 2019.

  1. Paul Arden

    Paul Arden Well-Known Member

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    I'm just starting to think about a very simple tool head (yes, I haven't even built my machine yet but when I can't be building I want to be designing). There are a few things I have been wondering.

    - Is printing the receiver feasible? I purchased an extra tool plate to work on an extra tool but it does not come with a receiver, so I'll need to make one somehow. Obviously tolerances won't be as good on a printed receiver but hopefully it would still be possible. Some metal would need to be inserted for the magnetic pickup but that should be straight forward.

    - I haven't been able to find details of the clearance required for the shaft coming through the tool plate in the source files yet. I assume there should basically be a keep out zone around the ramp but I'm just trying to work out the needed extents.

    - Are there specs for the countersunk screws that go into the backside of the plate? I can obviously work this out from the STEP file but if someone knows offhand what they are that would be great.

    Would it be the case that this picture from the guide would represent the absolute minimal tool (assuming that both screws are inserted instead of just the one) that could be successfully docked and picked up.

    [​IMG]

    I see a few people have started looking at tools already so maybe someone here as already thought of these things.
     
  2. Spoon Unit

    Spoon Unit Well-Known Member

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    I believe you're correct on the absolutely bare minimum 'empty' tool.

    I can't see why the receiver can't be printed. The STP is there and tolerances for that print would probably be more tricks from internal circle perimeters than external X,Y,Z sizes. I haven't looked at the internal dimensions of the receiver holes yet for docking pins; so far I assume they're dead straight. For consistency, it might made sense to print with them going in the Z direction.

    Metal for the pickup could just be another 6mm grub screw.

    I suspect the clearance for the pin is not large. When the pin turns it must logically be directly connected to the backside of the plate. Will admit I haven't eyeballed this yet. We can see from https://github.com/e3donline/ToolChanger/blob/master/PDFs/TC-COUPLER-KIT v1.1.pdf that the clearance beyond the pin is about the same as the pin width again. There's a bit more detail on the shaft too - https://github.com/e3donline/ToolChanger/blob/master/PDFs/TC-SHAFT v1.5.pdf - but you still don't get the actual mesurement there from the furthest point forward on the shaft to the back of the locking pin. At a rough guess, at least 6mm clearance is required, maybe 8mm to be safe.

    I did create a basic 'pen' tool (untested)

    [​IMG]

    This was sized for some Berol BROAD pens I have in various colours.

    [​IMG]

    This was designed for 3mm threaded inserts, so would take the countersunk 3mm screws supplied, but could also take longer if the exact match wasn't available. Similarly on the other side, the pen would be trapped using a similar 3mm threaded insert and an available shortish 3mm screw.

    [​IMG]

    The main reason for not testing it is that I forgot about the need for clearance, and hadn't removed the material to permit the lock.
     
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