Silver Heat Block August 13, 2021 06:56PM |
Registered: 4 years ago Posts: 285 |
Re: Silver Heat Block August 14, 2021 05:05AM |
Admin Registered: 16 years ago Posts: 13,891 |
Re: Silver Heat Block August 14, 2021 06:36AM |
Registered: 12 years ago Posts: 1,450 |
Aluminium 237 Copper 386 Silver 420 Brass 115 Bronze 26 Tellurium Copper 360 - my favorite on thermal conductivity and machinability but hard to get
Re: Silver Heat Block August 14, 2021 11:24AM |
Admin Registered: 16 years ago Posts: 13,891 |
Re: Silver Heat Block August 14, 2021 01:12PM |
Registered: 4 years ago Posts: 285 |
Quote
leadinglights
I would be interested to see what your results are as I looked in some depth at various materials and geometries for hotends and came to the conclusion that the race is a lot closer than you might think.
One starting assumption that I used is that having a high specific heat is a good thingas it acts a a heat store while the heater is trying to catch up. From this point of view, while Silver has a specific heat of 0.233 J/g.K and Aluminium has a specific heat of 0.900 J/g.K, both have the same specific heat per unit volume at 2.43J/cm³.K. Again, in terms of conductivity, the conductivity and area where the heat transfer from metal block to plastic takes place is much more important than the conductivity of the bulk of the metal: If this is through a stainless steel tube having a 1mm wall thickness and with a contact area area of 220mm² then the difference between the ability of Copper to deliver the heat is less than 5% better than Aluminium.
Having said that, I use Copper as other considerations make my hotend uncomfortably small, having a 3W wirewound resistor for a heater - no cartridge is available in the size I need.
I have to (as I very seldom do) disagree with VDX as Brass and Bronze both have fairly horrible conductivities and are not even particularly easy to machine.
Edit:
A late edit to put this into perspective.Thermal conductivities in W/m°C
Aluminium 237 Copper 386 Silver 420 Brass 115 Bronze 26 Tellurium Copper 360 - my favorite on thermal conductivity and machinability but hard to get
Mike
Re: Silver Heat Block August 14, 2021 04:11PM |
Registered: 12 years ago Posts: 1,450 |
J/g.K g/cm3 J/cm3.K Aluminium 0.900 2.7 2.4300 Silver 0.233 10.5 2.4465 Copper 0.386 8.9 3.4354
Quote
Linus Pauling
Satisfaction of one’s curiosity is one of the greatest sources of happiness in life.
Re: Silver Heat Block August 14, 2021 05:16PM |
Registered: 4 years ago Posts: 285 |
Quote
leadinglights
The figures I get for volumetric heat capacity are from [www.tibtech.com] and I get
J/g.K g/cm3 J/cm3.K Aluminium 0.900 2.7 2.4300 Silver 0.233 10.5 2.4465 Copper 0.386 8.9 3.4354
The thermal conductivity of Aluminium alloys is significantly worse than pure Aluminium, but compared with Copper alloys it still remains in the usable range. For example, 6082T6 Aluminium is about 180W/m.K but 75% Cu 25% Sn Bronze is only 26W/m.K. Intrigueing bit of info is that isotopically pure C12 Diamond has a thermal conductivity up to 41,000W/m.K [en.wikipedia.org]
Quote
Linus Pauling
Satisfaction of one’s curiosity is one of the greatest sources of happiness in life.
Mike