Alternative materials for heater block

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stew4t2
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Alternative materials for heater block

Post by stew4t2 »

Has anyone tried using other metals beside aluminum with success? Fail?

Cost aside, what would retain heat the best? I'm probably over complicating things, as I tend to do.. I was thinking like a threaded copper insert pressed into a cast iron ring (or block) that is then heated vs. the aluminum head that is common today

Any thoughts?
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Captain Starfish
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Re: Alternative materials for heater block

Post by Captain Starfish »

You're not looking to retain the heat. You're looking to transfer it as smoothly, quickly and evenly as possible from the heater elements to the nozzle and thermistor. Although a material with higher thermal mass than Al will smooth out the highs and lows of the PID loop, it will also result in inaccurate readings of the "nozzle" temperature. Aluminium does this job beautifully and, fortunately, it's pretty cheap.

If you wanted to add bling, copper would probably do a similar job.
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DavidF
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Re: Alternative materials for heater block

Post by DavidF »

Captain Starfish wrote:You're not looking to retain the heat. You're looking to transfer it as smoothly, quickly and evenly as possible from the heater elements to the nozzle and thermistor. Although a material with higher thermal mass than Al will smooth out the highs and lows of the PID loop, it will also result in inaccurate readings of the "nozzle" temperature. Aluminium does this job beautifully and, fortunately, it's pretty cheap.

If you wanted to add bling, copper would probably do a similar job.
If you want bling, silver is the way to go!!
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1ggy
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Re: Alternative materials for heater block

Post by 1ggy »

Aluminum is where it's at for heater blocks. You want something with high thermal conductivity so that the temperature across the whole block is as even as possible, and low mass to reduce the weight of the effector. Aluminum fits the bill for this perfectly. Copper would be a good alternative except for the weight. Cast iron has a much lower thermal conductivity than aluminum so that could run into issues, ie the side of the nozzle away from the heater cartridge/nichrome/resistors/whatever is at a significantly lower temperature than the near side, and it also weighs a lot.
stew4t2
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Re: Alternative materials for heater block

Post by stew4t2 »

Hmm. Yeah, what I was going for was a smooth temp range, and willing to sacrifice a little heat up time.

I'd like to get my hands on "pro" grade (like one from 3DS) head, just to see what theirs looks like.

Thanks for the info :)
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Generic Default
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Re: Alternative materials for heater block

Post by Generic Default »

I haven't seen the newest Stratasys machines, but ones from ~2005 had a HUGE heater block made out of aluminum, it took a long time to heat up, and with the heated build chamber the entire thing wouldn't start printing for over an hour after you sent the print job to it.

Also remember that there are different alloys of aluminum. Thermal conductivity is what you want the most of in this application, and you can get twice as much or half as much depending on which alloy you pick.

They will all work, but overall it's good to keep the heater block as small as possible and as thermally conductive as possible. I tried to keep the hex block on my Tri hotend as small as possible but with enough room for the thermistor and 40w heater cartridge. The heat up time is really fast, but it's tricky to PID tune it. I can't use the dead time algorithm anymore since I have a smoothieboard. Dead time is the best!
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Re: Alternative materials for heater block

Post by Polygonhell »

Thermal Conductivity is one part of it.
All JHeads for example use a brass block, that's machined as part of the nozzle. While brass is heavier, it retains heat better than aluminum, so the block ends up being smaller than the AL blocks. It also has the advantage of being easier to maintain at constant temperature, though these days that's less of an issue.
I know that Brian Reifsneider has built JHeads with aluminium nozzles and heater blocks, he has just never sold them.
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