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  1. #21
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    I did find one YouTube reference that explained that borosilicate glass at 120*C (250*F) would take and hold ABS without anything.

    I'm aiming for that. But I have a glass plate that is full size to the stock plate and I have a alumina thin plate that is about 10mm smaller.

    But I have one stick with the heater, and the glass is the only confirmed method. But I really want to use the alumina if I can confirm the parameters.

    I ordered a 120W power supply today. Now to find a read-back from the thermocouple. And a laser thermometer.

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    I ordered another b-glass plate. I'll start there.
    I need to know my 120W heater will raise the temp to 120*C.

  2. #22
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    consider that you can also add laser for your cube 3 and convert it into engraving and cutting machine.

    Gave a look at this tool http://endurancelasers.com/diode-lasers/5-watt/ or this: http://endurancelasers.com/diode-las...e-diode-laser/
    ENDURANCE ROBOTS

    We love everything that can be 3D printed!
    -------------------------
    EnduranceRobots.com
    EnduranceLasers.com

  3. #23
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    Lasers still scare me. My eyesight is poor enough already.

  4. #24
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    Google Goggle

  5. #25
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    It is the innocent bystanders that typically pay the highest price.

  6. #26
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    Sharing an approach to implement a heated bed on our beloved cube 3...

    Have to keep the added weight low, manage the extra heat, transfer the rigidity and remove mechanical interference from the movement.

    Flip the stock build plate over on a diagonal with the build sheet peeled away and the magnets removed.
    Magnets do not like heat. Just try one in a toaster oven. Well don't do that.

    Cut a 40mm hole or rectangle in the center of the build plate to pass the body of the original y axis mount preserving the height and lowering the weight. I did not enjoy destroying the nice build plate but I have been using glass and 3m adhesive attached magnets for several years on all my cubes and needed a rigid flat base. The magnets had been convenient and released on head crashes but are now removed.

    Drill three M3 pass holes in the center of each of the machined magnet recesses.

    Mount the old build plate inverted and under the mount with three M3 button head screws in the magnet recesses with steel washers and a silicone washer as a low profile spring for levelling pointing up.

    A M3 countersunk pass hole in each corner of the build plate has a spacer to another corner countersunk 1/64inch thick aluminum heat spreader.

    WP_20181206_03_39_35_Pro.jpg

    Silicone heater pad to this aluminum with glass on top.

    WP_20190125_06_07_03_Pro.jpg

    Secure the glass with clips to the aluminum next to the spacers to float the glass and aluminum.
    I tin snip the excess off one side of cheap binder clips to lower the profile.

    Check that the old build plate and screws clear the y axis hardware and the z axis hardware on both sides for all movements.
    I typically had been removing the y axis fashionable plastic box enclosure from all my cubes.
    If you think about it, that box looks very much like an acoustic guitar and does nothing for keeping it all quiet.

    Now this extra heat has to be kept out of the cube so two fans are added under the y axis frame.
    But this associated extraneous fan wind has to be shielded from the build with a clear plastic heat formed shield on the front and rear of the build plate.

    Add your favorite heat insulation between the silicone heater and old build plate.

    WP_20181206_03_36_49_Pro.jpg

    There is now much more heat near the nozzle.
    This may make the x nozzle carriage weaken at the mounting screws.
    I had already reinforced most of my ten cubes with metal plates and expect to have to modify them all.

    Please be cautious and careful with all the additional heat carefully watching any potential safety issues.
    The cube was never designed for a heated build plate.

    ...


    Last edited by Kame808; 02-12-2019 at 12:43 AM.

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  8. #27
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    Excellent Build! ..and welcome to the forum.

    What glass are you using? If you are interested, I found some really nice flat borosilicate glass perfectly sized on eBay.
    That shouldn't chip.
    I can see why you needed some heat on the bed with those large contact areas.

    Is this a 12/24V heater or a 120/230VAC heater?

    Good call on the magnets. That is what's been holding me off from this upgrade. I've got a silicon heating pad for mine.

    Thanks for posting!

  9. #28
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    After 70Kg of filament through the cubes, the parts all had well chosen contact with the build plate to handle shrink.
    I had a few kilograms now on the heated build plate with flat large bottoms but they had occasionally chipped ten surfaces of glass along the way.

    WP_20190121_06_21_18_Pro.jpg


    The solution was to keep the bed temperature high with no substances, just bare glass, and let it cool only about 30'c to let the shrink safely release the part.

    WP_20181210_20_48_20_Pro.jpg

    Now.

    WP_20190122_09_00_16_Pro.jpg



    Christmas 2018.

    WP_20181215_03_38_10_Pro.jpg

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  11. #29
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    Now I can see your build pix... thanks.

    I was going in a similar direction but you've certainly improved on it. I was going for a similar double decker but leaving the build plate alone with fixing collars to keep the magnets from having to maintain position. The magnets would just be for tip-control. My silicon pad can go directly to glass, but the 4 corner mounting is not quiet worked out yet. Now I see I can just use a generic "tab" mounted to the standoff for the clips. I'm trying not to transfer the heat through the posts which this will do.

    I do have a spare build plate if I can ever get to that printer. Need it for flex-plate tests too!

    How hot does the bottom plate get during your prints?

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    D'oh! Of course, heatshield! Very effective.

  12. #30
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    Thank you and Thank you, again.

    I am pretty sure I have the same quality boro glass from eBay. 170mm square. I can not complain about the quality, but I did wonder how many more would have to be bought to find the trick. I got very good at getting prints to stick. They just could not reliably be removed without sometimes damaging the glass. After minor chips, I would keep using them and both surfaces until the increasing divots could not be avoided. Always with the usual adhesives. The process finally settled on hairspray. The snaps on cooling were incredible to hear with the accompanying excitement to see if there was damaged glass. Plenty more heat to keep the plastic like taffy was the trick on bare glass. Cool about 30'c and never force the part off. It slides off. I know it is hard to believe and I feel foolish for all the time I spent trying to find the magic stick material to use. This seems to be cooking and not chemistry.

    Use your preferred heat barrier on the opposite side of the heater. I do not think what you do there matters much. It probably needs to be passive to keep the heat bed thermally stable. I thought of all the usual solutions and have the exotic materials too. The fans below are very effective at removing the extra heat and the y axis movement while printing also changes where the fan airflow is directed. This air flow only has to be kept from getting above the table. The difficult to see clear plastic pictured in front and back does that. I can always continually hold my fingers on the cube frame and old build plate without pain. I had much worry about this for a few kilograms of filament over the past three months.

    The heat source... I think significantly more resistance than the source leads is best for electrical heating. Nichrome wire is easiest with mechanically crimped connections to source leads. Choose the voltage and ac/dc you like. I prefer a dedicated power supply for the temperature controller with a separate supply for the heater. I do not like on/off control. The resistance is going to stay mostly stable over temperature so I want to control the voltage or current to hold the temperature. I am now using the ubiquitous ebay 24v dc power supplies modified by me to adjust down to 9v. I got the 24v model to have 35v capacitors rather than the identical 12v unit. This took a deep dive into the circuitry. I am using a 12v rated silicone heat pad. One pad burned out after a few months. I used to lay it on the unheated build plate to preheat the platform. The hours and hours of time to degas the pad was not fun. After I get many more kilograms on this or there is a failure I will build a nichrome heat pad on the upper aluminum plate and isolate it with Kapton and 3m adhesive layers. The goal will be to make it even more thin.

    All that said, I did not see it all matter too much. I wanted to get that 100feet of track printed so it was ample time to also play with temperatures. For a long time I would adjust the voltage to hold the temperature. Now I have an on/off controlled scheme. You can start with any rudimentary arrangement.

    I struggled with how to arrange all this. I think you always want glass that can be easily changed out. The aluminum flattens the silicone heater pad and keeps it near the glass. It can gap under heat but it still radiates the heat to the glass. Just don't clip the two in the unsupported middle. Float it.

    At the moment I level with a heated painted glass and swap to the print glass to gap and print.

    Yes, these are threaded brass spacers milled to 17mm to not sacrifice build height with stainless flat head screws. I wanted stainless spacers or Teflon but settled on the easily machined and available brass ones. After it all seemed to be viable, I check the heat passing thorough the brass and it was minimal. There is a small cross-section of brass in contact with the heated aluminum because of the counter sink and the screw is stainless. I can always retrofit that too. I wanted to quickly access whether this would work. I was very worried about adding all this heat to the cube. I can iterate on the design and will on building another but really wanted to just print now and make sure the cube is stable.

    I think that is all.

 

 

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