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ayahoo

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Posts posted by ayahoo

  1. While my printer is printing I have too much time to think :), and lately it is printing all the time :-P .

    Did anybody tried to connect the 3D printer to a Pantograph? (for anyone who doesn't know what it is, it is a simple set of arms that allows you to scale up or down 2D movement).

    Since the biggest "price" of the system is the drive system, if we leave the X-Y build area the same, and just move the Z platform out, we can get a GIANT, build platform... I guess the accuracy will be less, but still it can be a very nice try...

     

  2. Great link! this is the same idea :) now it is hard to assemble because he is not using any parts to allow easy assembly, but if we use some printed parts like the plastic part that i showed, it will help with the wrapping & we need just a simple part to connect the ends :), I think I'll try it since the accuracy of the pulley is not high, and using this system will greatly improve the accuracy.

    Nice to know somebody already tried it :)

     

  3. Hi All, again with some crazy idea, in my line of work, we are using a drive system that uses friction to move many shafts over large distance.

    The idea is simple, taking the two 8mm shafts, wrapping few wraps of cable (in our systems it is steel cable) then going to the second shaft, wrapping few wraps of cable and then connecting them in the middle with a tensioner.

    the only thing that is needed to adopt the system is just to find the correct material (steel cable wire plastic nylon what ever) to use.

    then we get cheaper system with less parts & much more accuracy.

    I'm attaching some photos :)

    Screen

    System with plastic cable arrange

     

    Untitled 1

    just few wraps around the shaft.

    waiting to hear what you think.

     

  4. Thanks for the info :) it was interesting to see his try at this, but his design has many flaws... my idea is not using a motor at all! just using magnets :) today we are using circular motion (motor) to get linear motion (filament), I would like to stay at the linear motion without using the motor and the gears :) (fyi a solenoid weights around 25gr which is MUCH less than the motor & gear).

     

  5. Hi Guys, I have an Idea I would like to hear your comments :).

    We all know that having the feeder next to the extruder is the best design regarding the clogging and jammed extruders... BUT the problem is the size and weight,,, so I have an Idea to make is VERY SMALL & VERY LIGHT.

    How? well using a solenoid! i'm an ENG in a factory that we are using many kinds of feeder system to our machines, one type of a feeder system is Pneumatic like this one:

    You can see in the video that there are few steps for each cycle:

    Hold the strip

    Advance fix distance

    Hold the end of the strip (so it wont come back)

    Release the first gripper

    Move back

    and again...

    Now I think we can make something similar to this to advance lets say 1mm every time, and the using pulses we can control the speed of feeding per second.

    it would be possible to use solenoid with a brass collet of 3mm (Like this - http://i326.photobucket.com/albums/k418/scdscd8/cute/04/0402/04020115/04020115cute_w4_a.jpg) that would once the solenoid is moving forward it would mechanically lock on the filament and move it forward, once going back (with a spring) it would release the grip.

    What do you think? is it possible?

     

  6. Ok, So I promised to update, so it took some time for the items to arrive, but now that I finished making the hotend, I must say it is working GREAT!, I'm uploading a video & a photo, that shows the hotend, I'm pushing the filament with my hand with very little force, and the top side of the hotend is cold... no modification is needed for the ultimaker, not even to recalibrate the platform, total assemble time is about 5 min :)

    so bye bye plastic parts!! :)

    Final design

     

     

     

  7. I dont think Calcium Silicate has useful mechanical properties, and I would be very surprise if you could clamp into lathe jaws without crushing it like chalk (EDIT, yes Calcium Silicate has a compressive strength of about 600kPa....so thats about 100x less than ABS plastic and in fact slightly LOWER than chalk)

    MACOR (developed as a machinable ceramic) is a much better material if you want a high temp insulator, its a little more conductive - but

    its not really expensive, its machinable and quite strong. Its also stable to extreme temperatures

    far higher than you would ever need to print any thermoplastic.

    C.

     

    Thanks for the input, you are right, I went and check and this material is not suitable for hot end, and after many simulations & designs, I manage to choose the one I think will be simple & effective.

    I'm using aircraft grade titanium (grade 5) M6 bolt, it has very low heat conductivity, and should be easy to use & make, I believe the whole cost will be lower than 50$ material & manufacturing, so I've ordered the bolts, and I'm waiting for them to arrive to check.

    thanks for all the inputs :)

     

  8. I'm using Solidworks to model & simulate it.

    Not to think less of your efforts. But remember there is more in play here then meets the eye and the simulations. You won't know how your hotend really works with PLA in it, and how it responds to retractions and backflow, until you test it.

    I know, but like anything else in life, you try to think about the problems before making the final product, and simulating & thinking about potential problems is better than just making the part & than thinking about the solution :).

     

  9. Ok, I would like to hear you thought about this design, I'm thinking about using calcium silicate as a connector between the hot end and the tube, according to the simulation and the datasheet (0.058 W/m/Deg K) it should be great material with melting point over 1000 deg C.

    the material is cheap and I need to get a sample to check if I can work with the lathe on it.

    any thoughts?

    HotEndV3

    HotEndV3.1

     

  10. I wonder if a stronger design from a cost+effort perspective might be to ditch the titanium for SS and instead just add a small fan to the heatsink? I'd be interested to see that simulation.

     

    Using a fan will help alot, but I'm looking for a design that will be problems proof, and fan is alway a point for problems.

    Anyway i managed to burn the peek... so I will make the hotend today or tomorrow, I desided to change the desing, go with SS 303 and make it much longer, and by this desing I solve 3 problems, first. All metal no problem of burning plastics, second is the bowden tube, I make the hotend go all the way up to the top of the head, 90mm so I can connect an industrial grade connector to the end of it and never have the problem of disconneced tube. And last is the leakage at the top of the aluminium block. this is the answer to snowygrouch.

    I'll post a pic of the simulation & the real part tomorrow :-)

  11. Hi snowygrouch, You are right, I played with so many simulations that I uploaded the wrong one :shock:.

    Regarding your comment on stainless steel vs titanium, if I use 6Al-4V, it is 6.7 W/m/Deg K, b which is much better than the 303 stainless steel.

    Although you can see that the temp in my design is higher than the peek (70 vs 28) the heat goes up gradually down the tube vs the design in the peek which is jumping from 28 to 200 when the material goes from the peek to the brass connector, and I think 70 C should be OK to work with, with no problem of peek melting at 320 deg (and the simulation is on a "stationary" state, when there is no air flowing, while using the heatsink you get much bigger surface area so when the head is moving i should get better results).

    what do you think?

    HotEnd2

     

  12. Hi All, I started to think about redesigning my hotend, the main Idea was easy to replace V2 hot end, I wanted to stay as close as I can to the current design, without modification to the head \ nozzle, and to try and make "simple" parts to manufacture to lower the cost of the design.

     

    My Idea was using Titanium "Core" to replace the current brass connector & the peek, and to use aluminum hotsink to cool it.

     

    I must say the according to the computer the results are very good, about 100deg C less than the peek at the end of the hotend.

     

    What do you think about the design?

    HotEnd

     

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