Page 4 of 5 FirstFirst ... 2345 LastLast
  1. #31
    Doddy's Avatar
    Lives in Preston, United Kingdom. Last Activity: 11 Hours Ago Has been a member for 4-5 years. Has a total post count of 297. Received thanks 34 times, giving thanks to others 10 times.
    Quote Originally Posted by Boyan Silyavski View Post

    Please correct me bellow if i am wrong before i burn sth:

    1.Now as i understand it the wire resists temperature 200C. Obviously if use 3 meters of wire at 33 ohm per meter i will achieve the desired result.

    2.They say :"The product can withstand the power of power: 25W/M" but thats for floor heating, so i assume if wire is connected to a temperature regulating device which does not permit it to go above 130C /+ the thermal and current fuses/ there will be no any problem????

    3. I understand that also i have to push fit the wire in the channel/ 3mm/ so there is not any air gap between plate and wire which could cause overheating due to incorrect temp measurement.

    I plan of: 6/8/mm plate=+ channel+tight fit wire+thermo conductive silicone flush with bottom surface. So no air there art all

    Apart from that i will use some insulator sheet from bellow, still not clear but most possibly Teflon, Silicone, Mica ???

    What do you think?

    I know i can buy 40 euro 500 W ready heater from China for 40-50 euro, stick it to the aluminum bed from below and thats it. But that is expensive compared to what i propose, Chinese will not care to make trace separation properly and so on. I mean its expensive and i dont find it more reliable than sth i could make. Plus machining all will cost only around 10 euros with the plate, which is 1.3 kg

    Calculation shows that 3000mm cable/400mm bed =7.5 which is roughly 7 channels on the long side. So ~200mm/7=~28mm separation between channels which seems quite right to me.
    Your figures are broadly correct, but there's a bunch of information missing from the cable spec - max current rating (you can guess at 0.8A given the 25W/M - but that's likely derated given the intended installation buried in a concrete scree) - to be honest, I'd just try it and see. Yes, you'll get a bit over 500W heating which should give a respectable amount of heat energy for the 1kg block of ali that you're using. Temperature control you've mentioned, and a thermal fuse (you mention) a necessity in this system; zero-crossing SSR also a good idea as well as a current protection device (fuse). All good stuff, but very little in the data on the cable to give support to your design simply because you're using it for a different purpose. Try it and see - my thoughts are that it should be workable.

    My only reservations are: No indication of the thermal expansion of the cable - if you bed this too tightly in the ali block you could sheer the cable strands - I'd look to a loose fit and infill with thermal paste when you look to productionise.

    Experiment, is the name of the game - you've nothing to lose (provided you keep a fire-extinguisher to hand :) ) In case the cable fails catastrophically I'd certainly use a test bed well away from anything flammable and be able to isolate the supply easily. Once you have your thermal control in place then test worst-case performance with it shoved in a cardboard box crammed full of thermal insulation (cloth sheets) to make sure that the control system still works.

    The one area I'd be concerned about with this cable is making the ends off correctly - looks like you are supplied with copper ferrules to crimp - that to me is the area that you're likely to see failure if not done properly.


    I'm not sure I'd agree that this is a cheap solution, though - in the UK I can source heated beds off ebay for 6 each (214mm x 214mm) and these will be being etched in their hundreds or thousands in china with the precision from decades of investment in PCB manufacture. Only 120W, but two in parallel for the 400mm bed and you're not a million miles from your solution.

  2. #32
    Doddy, many thanks!

    Quote Originally Posted by Doddy View Post
    Your figures are broadly correct, but there's a bunch of information missing from the cable spec - max current rating (you can guess at 0.8A given the 25W/M - but that's likely derated given the intended installation buried in a concrete scree) - to be honest, I'd just try it and see. Yes, you'll get a bit over 500W heating which should give a respectable amount of heat energy for the 1kg block of ali that you're using.
    My research on similar setups shows that in real life 500W non insulated bed this size will heat very fast, and insulated will heat probably under a minute, so no worry as you say.


    Quote Originally Posted by Doddy View Post
    Temperature control you've mentioned, and a thermal fuse (you mention) a necessity in this system; zero-crossing SSR also a good idea as well as a current protection device (fuse). All good stuff, but very little in the data on the cable to give support to your design simply because you're using it for a different purpose. Try it and see - my thoughts are that it should be workable.
    Good info for the zero crossing SSR, i did not know what that means. Learned something. So are the cheap Chinese SSR relays zero crossing? I have used them for my kiln but they just work, i did not have an idea that they are different types.


    Quote Originally Posted by Doddy View Post
    My only reservations are: No indication of the thermal expansion of the cable - if you bed this too tightly in the ali block you could sheer the cable strands - I'd look to a loose fit and infill with thermal paste when you look to productionise.
    I chose the carbon fiber cable exactly for that reason that the carbon fibre itself is very stable and does not expand or shrink. At least that is what they brag about it. But will look into further info about the whole cable.



    Quote Originally Posted by Doddy View Post
    Experiment, is the name of the game - you've nothing to lose (provided you keep a fire-extinguisher to hand :) ) In case the cable fails catastrophically I'd certainly use a test bed well away from anything flammable and be able to isolate the supply easily. Once you have your thermal control in place then test worst-case performance with it shoved in a cardboard box crammed full of thermal insulation (cloth sheets) to make sure that the control system still works.
    I will do exactly that.

    Quote Originally Posted by Doddy View Post
    The one area I'd be concerned about with this cable is making the ends off correctly - looks like you are supplied with copper ferrules to crimp - that to me is the area that you're likely to see failure if not done properly.
    I briefly looked into that and saw how people connect carbon fibre tape into clothes. More or less they use some kind of silver glue. So i am thinking i have to buy some ferules and test, if needed fit inside some extra silver compound for better conductivity. One thing is clear that everything should ve additionally fixed mechanically to the bed, meaning pressed between plates or sth, and from bed only 3 kevlar teflon double shielded thermo resistat wires will protrude.

    Quote Originally Posted by Doddy View Post
    I'm not sure I'd agree that this is a cheap solution, though - in the UK I can source heated beds off ebay for 6 each (214mm x 214mm) and these will be being etched in their hundreds or thousands in china with the precision from decades of investment in PCB manufacture. Only 120W, but two in parallel for the 400mm bed and you're not a million miles from your solution.
    I will explain why i like this solution below. Mind me that the actual bed in the drawing is 440x220mm, so it will take 2x MK2 heated beds 12/24VDC on top of it bolted, which 1 of these is 7 euro.

    1.The overall design of the machine.
    -The printer must be rigid, fast and able to Scale Up. From that the result will be precision, nice prints and easy to build a second one, which probably most of the people will do, once they have one and are serious into printing.

    I meditated long on the various possible designs and chose this one due to the simplicity to build and later adjust, compared to all of the other designs. Some of them are so ridiculous honestly, that even i can not imagine what hassle will be to straighten it to some acceptable precision. If i that build a 3m machine to some standard, can not be sure how to put together precisely a 50cm machine, then imagine what the result will be for a person that has no idea at all.

    When you start scaling the machine up, the so called Core designs start to loose in moving weight compared to this one, though i dont know why the guys are so confused and praise them so much.

    Thats another story but suffice to say that from what i see scaling the machine up, if i do the custom bed then the bed weight will keep in line with a Core XY design moving mass weight very simple. 20x20 beam is 0.45kg per meter even a 1000x1000mm bed could be done from same 6mm precision aluminum cast sheet and a simple beam bolted from below if it starts deflecting from heat. At the same time Core XY will have very serious lengths belts which will start back slashing/ from stretch/ on high accelerations, or motors have to be moved, which is additional mass...


    And anyway all other design suffer from the problem called twisting the machine out of precision when prying out a printed object from bed Or separate glass bed that is insulator, ... and so on.

    2. The lack of additional under bed carriage that is connected to the bearing blocks on which the bed lies, or whatever they call it. If that thing is made from plastic it bends, if its from aluminum it is heavy. In fact the aim here is to go without it.

    3. Eliminate adjusting the bed once its adjusted when building the machine.

    This practice is absolutely ridiculous to me. From day one i saw a 3d printer. Imagine having to do that on your mill or router every time you start a job

    4. Ability to bolt it and to make bolt holes from bellow where i like. You can not drill PCB heated bed. That will additionally provide support to bed against bending from temperature, though from reports 6mm bed is alright.

    5. If you glue additional silicone plate which is the only viable solution for big beds for now, first you can not drill it-means additional plate from below, second as i said its heavy, expensive and not any safer or cheaper.

    6. I found a nice 230V heated PCB project which also seems stack-able but it will suffer from need of additional glass on top, hence weight, low reliability, loss of precision surface etc.

    7. I think an additional sheet of thicker PEI on top of the aluminum bed will allow things to be removable and exchangeable, without f"""g the precision of bed and machine. Glass i dont like for 2 reasons- first its an insulator, second i dont like one shiny surface and all else different. Anyways i learned to print 100% with rafts.

    I am not in a hurry, i prefer the quality result.


    Here bellow is the latest update on the design. At the end when all is clear, printer will look very simple and clean. Bed will be thermo insulated from bellow. Electronics and motors will be below. Heat flow will be up , so all is ok. After long search at the end i found some people sharing that when bed temp 100C in enclosure temp is around 45C, which is ok for the plastic parts and the motors, so i dont believe they will need additional cooling.

    Meanwhile i looked most of the extruders and hotends. The way i see it- E3d6 plus E3d Titan extruder or i have to make sth similar, which i dont have the time to investigate. One company, great products. No super duper over complicated extruders that cost 200$. These days i printed 24h and many different things, and i found that the weakest place in the 3d printer is the extruder itself and the measurement of the heat in the block- hence the thermistor type, position and especially way of attaching it.


    All else could be Chinese or mediocre and will work more or less, but not feeding reliably the filament and not knowing reliably the temperature of the heating block= bad prints, unreliable prints, messing with adjustments that is not needed to mess with if these 2 are working right.

    And these 2 could make you crazy if they are not perfect.


    Click image for larger version. 

Name:	Tank3d 21.PNG 
Views:	54 
Size:	185.6 KB 
ID:	20028 Click image for larger version. 

Name:	Tank3d 22.PNG 
Views:	52 
Size:	72.7 KB 
ID:	20029 Click image for larger version. 

Name:	Tank3d  23.PNG 
Views:	66 
Size:	432.7 KB 
ID:	20030
    project 1 , 2, Dust Shoe ...

  3. #33
    Totally unsuitable. You need an electric element or elements.

    This was fun to CNC but probably overkill for your application

    Click image for larger version. 

Name:	cooker.jpg 
Views:	91 
Size:	125.0 KB 
ID:	20033

    Edit: Just ignore me, nothing works on this website, I can't see what you are typing, if I upload a picture the world goes away, famine and frustration.
    Last edited by Robin Hewitt; 18-12-2016 at 02:36 PM.

  4. #34
    Some electrical help here please.

    If the heated bed consuption will be 2.1A at 220V, and 500W, then what cutoff fuse should i choose? I am looking at 150C 2.5A and 150C 5A. Which one will be better? I assume the 5A? As it will cut off at 150C in both cases, i am not sure about the amps.
    project 1 , 2, Dust Shoe ...

  5. #35
    Doddy's Avatar
    Lives in Preston, United Kingdom. Last Activity: 11 Hours Ago Has been a member for 4-5 years. Has a total post count of 297. Received thanks 34 times, giving thanks to others 10 times.
    Quote Originally Posted by Boyan Silyavski View Post
    Some electrical help here please.

    If the heated bed consuption will be 2.1A at 220V, and 500W, then what cutoff fuse should i choose? I am looking at 150C 2.5A and 150C 5A. Which one will be better? I assume the 5A? As it will cut off at 150C in both cases, i am not sure about the amps.
    If this is a thermal cutoff that you're talking about then either is sufficient - either will handle the current draw, and disconnect. Of course, the over-current protection needs closer consideration; I'd not go as low as 2.1A, but 3A would be adequate (just make sure that all cabling and switchgear is rated at 3A).

  6. #36
    Doddy's Avatar
    Lives in Preston, United Kingdom. Last Activity: 11 Hours Ago Has been a member for 4-5 years. Has a total post count of 297. Received thanks 34 times, giving thanks to others 10 times.
    ...and if you want to know what pees me off about cheap 3D printers - I've just had to replace the x-axis cable form on a near-new QIDI; what an unnecessarily tedious faff! Boyan - get a decent energy chain in there and use silicone cable. The cable form should be designed never to need replacing.

  7. #37
    What i am looking is a thermal fuse, which apart the thermal protection, has Amp rating. So i thought before that i need 2 separate elements but it seems is 2 in 1. All cabling will be industrial servo cable rated for flex drag chain instalations. No crap stuff. I am just having also problems with the cables of the printer i borrowed.

    here is link to the cheapest best quality cables i have found after long sleepless nights searches. These are not for the printer, i will look further, but just to see prices. have bought from there flexible thermoresistant cable for soldering gun also, which is superb for the price.
    servos

    http://www.tme.eu/en/details/str-c-p...lukabel/49637/


    shielded cable for the proximity sensors:

    http://www.tme.eu/es/details/str-c-p...lukabel/49632/





    The cable chain is ready and tested. It had some final adjustments and i am 99% happy with it.. Its printed but i have designed it as a commercial quality chain. So its 2 in 1. What do you think? It seems to me bnetter than the one they use in the printer i have here





    here are the files http://www.thingiverse.com/thing:1963745

    Last edited by Boyan Silyavski; 19-12-2016 at 10:08 PM.
    project 1 , 2, Dust Shoe ...

  8. #38
    Lure's Avatar
    Lives in Alta, Norway. Last Activity: 29-06-2017 Has been a member for 0-1 years. Has a total post count of 3.
    Is there any progress om this project? Should be really intresting to see the final product, considering your great skills.

  9. #39
    Quote Originally Posted by Lure View Post
    Is there any progress om this project? Should be really intresting to see the final product, considering your great skills.
    Thanks,

    Yes, there is. But as it seemed that there is no interest here about the printer, i kept silent a bit. Also i am very short of time and had to design each element including the hotend assembly, blower fan, etc. I have already uploaded some of the designs http://www.thingiverse.com/silyavski/designs
    but still have not had the time for the separate assemblies.

    In short, i am putting all together 2 printers, while meanwhile revising the drawings and populating screws, nuts etc. Very soon will be more info on all with pictures

    All parts are here minus the controller, as i have still not clear which will be the controller.

    for now the final design :

    Click image for larger version. 

Name:	Tank3d  24.PNG 
Views:	92 
Size:	364.0 KB 
ID:	21154
    project 1 , 2, Dust Shoe ...

  10. The Following User Says Thank You to Boyan Silyavski For This Useful Post:


  11. #40
    Lure's Avatar
    Lives in Alta, Norway. Last Activity: 29-06-2017 Has been a member for 0-1 years. Has a total post count of 3.
    Looking nice. Can't wait to see the rest of the project. Hopefully there will be a detailed and educational build log like the others you have made.
    Last edited by Lure; 18-03-2017 at 09:18 PM.

Page 4 of 5 FirstFirst ... 2345 LastLast

Similar Threads

  1. Who is Denford 3D Printer?
    By g20hz in forum Denford 3D Printers
    Replies: 1
    Last Post: 25-09-2016, 09:33 AM
  2. A3 printer plotter
    By gatesy in forum Machine Discussion
    Replies: 4
    Last Post: 21-12-2015, 03:19 PM
  3. New toy, Afinia 3D printer
    By Robin Hewitt in forum 3D Printing Machines
    Replies: 34
    Last Post: 05-07-2014, 10:18 AM
  4. What's needed for a 3d printer build??
    By Davek0974 in forum 3D Printing Machines
    Replies: 26
    Last Post: 18-02-2014, 10:54 AM
  5. eBay: 3d Printer project!
    By andrewbond in forum Items On eBay UK
    Replies: 8
    Last Post: 11-05-2013, 07:07 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •