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reprap:anet:a8:improvements:understanding_my_heatbed [2018/12/30 09:57] – [Heat-bed Power] cj_elec_tech | reprap:anet:a8:improvements:understanding_my_heatbed [2018/12/30 10:10] – [Some research in the net] cj_elec_tech | ||
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- | Resistance is calculated by dividing | + | Resistance is calculated by dividing voltage by current |
This gradient nearly fits the gradient expected for copper with an temperature coefficient of approximately 0.0039 1/K | This gradient nearly fits the gradient expected for copper with an temperature coefficient of approximately 0.0039 1/K | ||
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This is probably the reason why there are values of 1.2 to 1.6 Ohms mentioned in some forums and sites for this heat-bed. | This is probably the reason why there are values of 1.2 to 1.6 Ohms mentioned in some forums and sites for this heat-bed. | ||
==== Simulating the heat bed ==== | ==== Simulating the heat bed ==== | ||
- | In order to undertstand | + | In order to understand |
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- | The cool thing about simulations is that you can evaluate heat fluxes which are difficult to measure and to make a serios | + | The cool thing about simulations is that you can evaluate heat fluxes which are difficult to measure and to make a series |
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- | When the steady state is nearly reached the initial 110W of electric power are reduced to 0 by the following contributions (for a heat bed without insulation). It can be seen that a large portion of the heat is irradieted | + | When the steady state is nearly reached the initial 110W of electric power are reduced to 0 by the following contributions (for a heat bed without insulation). It can be seen that a large portion of the heat is radiated |
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==== Analysis with the simulator==== | ==== Analysis with the simulator==== | ||
- | It can be seen with these curves that a quite thick insulation is nescessary | + | It can be seen with these curves that quite thick insulation is necessary |
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- | Nearly half of the of the heat is lost by infrared | + | Nearly half of the of the heat is lost by infrared radiation. Therefore aluminum foil on the bottom is more effective than 6mm of cork. To reduce the heat-loss |
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- | It can be seen with these curves that increasing the voltage on the heatbed | + | It can be seen with these curves that increasing the voltage on the heat-bed |
- | * Use thicker wires between | + | * Use thicker wires between |
- | * Solder | + | * Solder wires directly onto the heat-bed |
- | * increse | + | * Increase |
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- | ==== Some research | + | ==== Some research |
- | The heatbed | + | The heat-bed |
- | Some recomendation | + | Some recommendations |
==== The optimal wire ==== | ==== The optimal wire ==== | ||
The original wires from the Anet printer are thin and therefore have an resistance which lead to an power reduction of the heat bed. If you use extremly thick wires you it will be a mechanical issue for the Y-axis stepper and as cables are made of very good thermal conductors it will remove heat from your heatbed by conduction. This rough estimation shows that AWG 9 would be an Optimum from the thermal point but the difference from an AWG 14 is minimal and AWG14 is conciderable more flexible and can be crimped with blue pre insulated crimps. Also the 1 W more for AWG16 would be ok as this as 1W would increase the max heat bed temperature by only 0.5K. | The original wires from the Anet printer are thin and therefore have an resistance which lead to an power reduction of the heat bed. If you use extremly thick wires you it will be a mechanical issue for the Y-axis stepper and as cables are made of very good thermal conductors it will remove heat from your heatbed by conduction. This rough estimation shows that AWG 9 would be an Optimum from the thermal point but the difference from an AWG 14 is minimal and AWG14 is conciderable more flexible and can be crimped with blue pre insulated crimps. Also the 1 W more for AWG16 would be ok as this as 1W would increase the max heat bed temperature by only 0.5K. |