Independet Heated Bed for Easythreed X1

With the dissemination of 3d printing we got printers like easythreed X1 , simple , inexpensive , but , without any luxury .

The X1 does not have a heated bed , what give people who have it a closed range on what materials they can and cannot print , mostly with just pla and tpu , we sure have good pla brans and produtcs , but pla have some drawbacks that abs or pet does not have.

Thinking on it , i`ve made a heated bed for my x1, and I want were to explain how i made it for anyone who wanted to make it aswell.

For the supplies we gonna need:

-A simple heated bed(i`ve buyed this one;https://shopee.com.br/product/300999365/7460918534... , but it is small for the X1 , anyway i use it)

-A 12x12cm aluminium Plate (i´ve used a 3mm aluminium plate that i´ve funded in a junkyard , but i´ll recomend you, buy a new one with you can )

-A 12x12cm glass plate(you can , like me , buy a glass plate for ender 3 and go to a glass shop for people to cut it for you.)

-A simple termometer for you to see the temperature on the bed to control it

-some eletronic components(soo , that the complex part , i´ve made the bed controller independent from the printer , so we gonna need a circuit to control it , i´ve tried to made it the more analogic way possible , so we dont need to program and its less expensive them using a microcontroller)

The eletronic Components:

LM741

10k NTC 5mm Thermistor

10k Potentiometer

12v 10A relay

BD679

Leds(3)

3K resistor

1K resistors (3)

1M Photoresistor

So the circuit its a comparator , working using a signal input from the potentiometer , and a signal input from the thermistor in the bed.

The second circuit , i´ve made a optocupler from a photoresistor for separating circuits and making the low output current of the 741 drive a 10A relay, this optocupler is made putting together an led and the photoresistor and putting eletric tape around it to prevent ligth from the enviroment to trigger the transistor.(sorry by the bad image for the optocupler but my is already in the circut).

i´ve print a simple case for it but its optional.

the termistor and the probe needs to be on the glass bed to sense and control its temperature.

I´ve used an angle grinder to cut the aluminium sheet to the rough shape , i recommend to use the magnetic bed of the x1 and a permanent marker to draw on the sheet , and the cut it , make the four holes using a small 3 mm drill bit and chamfer it using a 6,8 and 10 mm drill bit to hide the heads of the screws , after it , grind the screws head to make it straight (the glass bed will go above it so it need to be quite smooth).

cut the rubber spacers , something like 8,5 mm or 10 mm will go well , but remember to mesure it , becouse it depends on the sheet you are using.

I´ve passed thermal paste on the heated bed , and the glued it on the aluminium sheet using high temperature silicon , after using it some days i saw that you need to cover the whole botton part in silicon to isolate it from giving heat to the enviroment and giving out a poor heat to the glass bed.

after a day drying it , you can screw it down on the bed , and them level it , remenber that the level has to be on the glass bed not on the aluminium sheet , so go using try and error , put the glass bed , try it , take it off , regulate it , its a pain but with patience you can make it .

its just turn the potentiometer to on position , the open led will pop on , and current will flow to the bed to heat it , so turn it all open , wait to get to the temperature that you want , them turn it until it pop off , leave it in between on/off , the circuit will work by comparing the voltages of the potentiometer, and the thermistor , when the thermistor heats up , its resistance gets lower , when the voltage in the gate gets higher them the potentiometer gate , it turn off , when the temperature gets lower the voltage gets higher on that gate , when it gets lower them the potentiometer voltage , it turns on again , controlling the temperature , i´ve see that the amplitude its like 4°C at maximum.

always clean up the glass bed using steel wool and make sure that the probe and the termistor always touch the glass bed and only it , using the claws its the best way , but make sure that nothing from the nozzle or the head touch it.

well thaks for reading it , its my first time posting something here , if i made any mistake (on the project or grammactaly since iam not a native speaker and its my first time making a long text in english aswell ) put it on the comments .