Become warped edge
The hot bed is a special accessory for FDM printers, the main purpose is to prevent edge warping. So what's the reason for the edge warping? Edge warping is caused by material cooling shrinkage. The shrinkage rate of different materials is different, so the degree of warping is different, but one thing is certain, warping is inevitable, is inevitable, can only reduce the influence of warping. So some brothers said: "I print PLA so I don't need a hot bed". This sentence is wrong. Printing PLA from different manufacturers has different effects. Some of the warping edges are not obvious, and some of them will be very serious.
Why can the hot bed reduce the warping edge
The hot bed cannot eradicate the warping, only attenuate it. The main principle is to maintain the print at a high temperature (PLA 60 ° C ABS100 ° C) by heating the hot bed to prevent material cooling and model edge warping during the printing process.
Performance analysis of hot bed
1, polyimide heating sheet (yellow soft, you can add tape), uneven heating, easy to damage, need to add 3M tape fixed to the aluminum plate, need to be customized
2, heating rod & aluminum plate heating is not uniform, aluminum plate needs to be very thick
3, PCB hot bed, is the best hot bed at present, heating evenly, can not add aluminum plate, can add manual leveling, stable work, not easy to damage.
PCB hot bed principle
The PCB hot bed is mainly heated by the thermal effect of resistance. When the current passes through the resistance, it will heat up, P=(U*U)/R, usually the heating power is 120W. Under the condition of 12V voltage, the resistance is about 1 ohm and the current is 10A. According to the formula, point increase will greatly increase the heating power. Therefore, do not increase the power supply voltage at will when using, so as to avoid danger.
Hot bed usage guide
1 Power supply voltage should be consistent with the rated voltage of the hot bed, or slightly higher, not too much higher, voltage increases one times, hot bed power will become 4 times the original, dangerous oh.
2 To use the hot bed in a closed loop, it is necessary to have temperature measurement + feedback + temperature control. The main board is generally equipped with temperature control, so rest assured that the thermistor has been welded on the hot bed
3. How to do if the temperature of hot bed rises too slowly? You can increase the power supply voltage a little bit, for example, 12v hot bed, with 15V power, the power will be 1.5 times the original.
4. The wiring must be thick enough, 10A current, 2.5 mm square wire diameter is recommended.
When the electricity is off, the hot bed will still be hot. Please take care not to touch them
When you have young children, you should not use the hot beds.