3mm Brass Heat Spreader?



  • Has anyone tried this?

    Why?

    • Increase inductive probe trigger height.
    • Saves need for packing pieces to get swiss clips to work better with glass bed + alloy mk3 bed.
    • Potentially helps heat uniformity.

    I'm thinking it may increase the trigger height of the 8mm inductive sensors. They currently trigger at ~4.5mm which doesn't give much print clearance with a 3mm glass plate! It may benefit the uniformity of a heat distribution compared to a plane mk3 alloy heatbed. Down side will be a longer warm up.


  • Moderator

    @DocTrucker said in 3mm Brass Heat Spreader?:

    Down side will be a longer warm up.

    And weight.



  • @Phaedrux yes, thought that not much longer after posting. Could go nema 23, wider belts etc but a bed slinger isn't worth that effort in my mind. That said this could still apply to static beds.

    The brass coloured stick on shielding may have a posative effect on my trigger height. I'll try sandwiching various materials between the bed and glass. It's been a while since I did any inductance calculations, and I've forgot which material property comes into play. I think it's something to do with the density of free electrons, which is likely a relation between valence and material density. Physics was about 20 years ago though...



  • @DocTrucker Oxidisation might be a factor which comes into play over time? Dunno, just hypothesis ....



  • I'm using 2mm aluminium plates on some printers as heat spreader ... I don't see benefit of brass over aluminium, it's too heavy, alu vs pure copper plate heat uniformity after 3-5 minutes is same



  • @arhi said in 3mm Brass Heat Spreader?:

    I don't see benefit of brass over aluminium, it's too heavy, alu vs pure copper plate heat uniformity after 3-5 minutes is same

    From experience or from guestimates? What is your z-level probe?



  • @arhi forgot to ask if you are using a mk2 polymer PCB or a mk3 alloy PCB? I stopped using Al alloy heat spreaders with the Mk3 PCB heaters. The loss of the 3mm caused issues with the swiss clips.



  • @DocTrucker said in 3mm Brass Heat Spreader?:

    From experience or from guestimates?

    As I wrote I tried copper (that is way better conductor than brass) and thermal uniformity ove glass heater (waaaaaaaaaay worse scenario than pcb heater) was identical to 2mm alu sheet after 3-5 minutes (it uniforms faster with copper and then after 3-5 minutes thermal images are identical). Brass can only be worse than copper

    @DocTrucker said in 3mm Brass Heat Spreader?:

    What is your z-level probe?

    depends on the printer

    • precision piezo orion (so I probe with hotend tip - e3d in this case)
    • precision piezo old version (again probing with the tip - hexagon in this case)
    • precision piezo old version with 3 sensors in the bed plate (probing with tip - hexagon 3mm hotend)
    • precision piezo andromeda (again probing with the tip - hotend of my one design)
    • bl-touch v3
    • bl-touch v2
    • bl-touch vAliExpressClone x2

    so as you can see not a single printer 🙂



  • @DocTrucker said in 3mm Brass Heat Spreader?:

    @arhi forgot to ask if you are using a mk2 polymer PCB or a mk3 alloy PCB?

    I don't 😄

    I'm not using any mk2/mk3/prusa stuff at all

    heaters I have are 3 categories

    1. pcb heater (on ender 5 only, that's 3mm aluminium pcb)
    2. 4mm window glass with silicone mat heater (only one, serious mistake to make, that's where I was testing heat spreaders as when you image top of that glass it is very uneven)
    3. alu plate with silicone mat heater (using 2mm, 3mm and 6mm plates)
      3.1 alu plate with embedded heater cartridge

    on top of the heater I have either a 2mm aluminium sheet or 4mm glass sheet and on top of that sheet I have printbite print surface (IMHO much better than PEI coated board from prusa but I tested pei coated board from prusa only for 2 weeks and use printbite for many years so I might be biased by knowing how to use printbite good and had no experience with PEI before I tested prusa's sheet ... but I wanted to have one printer with PEI flexible mat so I tested)

    important thing to note, that is important IMO for "nozzle probing" is that printbite uses some special double sided tape that turns "solid" when it cures so it's not like your standard 2 side tape, it is not removable and it is like rock so there's no flex... very important when printing materials that will bend the PEI sheet and unglue it from the surface (happened to me), and also, there is no flex with probing due to soft glue sheet (I did not notice any of that flexing with prusa pei coated flex surface but I did with what for e.g. originally came with ender 5 - some magnetic buildtak like surface)

    hope this answers some questions

    so to summarize

    • I have one printer where 230x230 bed is a piece of glass with 500W silicone heater (or 750W I don't remember) and that thing has very uneven surface temp so I use heat spreader on top of it
    • I tried copper and aluminium, copper is better for first 3-5 minutes and after that they are identical, while copper is waaaaaaaaaaaay heavier and on that printer bed iz moving in Y


  • ah and to be clear - I don't use inductive sensors, found them to be too unreliable many years ago so no clue how they react brass vs copper vs aluminium, I'm just talking about heat spreading



  • @arhi cheers, so thats ruled the potential head spreader benefit out then. To be honest if I was gong down that route I would need a thermal camera to check results which isn't happening any time soon.

    Regards mk2/mk3 I was only using the terms to distinguish between Polymer and Al alloy substrate PCB heaters.

    Yeah, and the reason I was asking about the probe was due to my interest in increasing inductive trigger height closer to the (ideal conditions) specified 8mm. I've my machines set to do multiple probes with max range set to 0.03, not had that fault out for a long time and not fussed about getting a more consistent first layer than that right now.

    I've got a genuine BLTouch to try at some point soon.



  • @DocTrucker said in 3mm Brass Heat Spreader?:

    @arhi cheers, so thats ruled the potential head spreader benefit out then. To be honest if I was gong down that route I would need a thermal camera to check results which isn't happening any time soon.

    I have two SEEK THERMAL cameras (first original, and the one that came second, they have some new stuff now I see so price and features will probbly vary) and it is very useful for this 3d printing stuff and it was $199 IIRC each so not in the thousands range as thermal cameras usually are 😄

    Yeah, and the reason I was asking about the probe was due to my interest in increasing inductive trigger height closer to the (ideal conditions) specified 8mm. I've my machines set to do multiple probes with max range set to 0.03, not had that fault out for a long time and not fussed about getting a more consistent first layer than that right now.

    I am using inductive probes in the industry for 3 decades and they are never made to be "sub mm" precise. The way we are using them in 3D printing world is not really the intended usage. Distance measurement is done usually very different. Anyhow I do have a "bag of probes" (I think for e.g. "today" I have at least 30) and did bunch of tests with different materials, they can be very consistent in short period but "today vs 5 days ago" difference can be over 1mm due to changes in humidity, temperature and whatnot .. still way better than capacitive probes that can have 2mm drift inside 10min 😞 ...

    I don't know many ppl that use inductive probes in real life, the one I know that does cannot hit print, he needs to babystep each first layer every time, the bed is leveled the measurements during mesh measurement are consistent so the shape of the bed is ok but the actual distance - z-home drifts a lot and babystepping is a must .. I did hear from a guy who purchased ezabl or something like that called (usa company, they tweak prc stuff and sell them improved if I figured them correctly, I might be wrong) and with their sensor he has precision and no drift so probbly it can be made good..

    I've got a genuine BLTouch to try at some point soon.

    I have few originals and whole bunch of clones. I took clones to use for some other non 3d printing project but gave up as none of them will work reliably if not probing Z (graviti needs to be pulling pin down, in other orientations they behave weird and unpredictable) but for mesh leveling they all, originals and clones, work awesome. I still prefer piezo as I don't need to have additional piece of hw on the nozzle as I often run dual hotends and thing get busy there and with piezo things are simpler, only, this last electronics for piezo comes without schematic and the digital output is not very useful in my case, luckily analog output works good with duet so I'm ok with it.



  • @DocTrucker I found the video of that "heater on glass" thermal camera view
    https://youtu.be/NSo4Dus8VVY
    (when you put 2mm alu on top after 5min it is consistent temp all around)



  • @arhi Thanks. My main issues with the inductive sensor for me are size and weight. The BLTouch with lead to a significant reduction in probe offset, will make more of the bed probable, and lead to less exaggeration of the deviation of the carriage from ideal alignment. Ulimate for me will be nozzle probing with precision microswitch triggering on movement, and a servo lock down to prevent extra unintentional movement. After a more rigid x-axis.

    According to the following site both copper and brass are little to no better than Al alloy.

    I have greater issues with my IR z probes than inductive, bit to be fair that is in part aspects of the Ormerod design causing more issues than the sensor.

    https://fargocontrols.com/sensors/inductive_op.html



  • @DocTrucker well in that case precision piezo is the right move for you 😄 what hotend you have?


Log in to reply