Low Cost PCB BED Heater for 3D Printer (No Toner Transfering/No Paint Burning)

Recently I'm changing my cartesian 3D printer to Ender 5 type cartesian printer due to its large bed. For this i'm making 430mmx430mm bed area and need to make a multi zone heater for this to save energy. This is a trial i have done for making 9 zone heating element. I did not had previous experiences in ferric chloride etching and pcb trace width calculations. I did this to check the behaviour of trace width calculator. Many attempts i made for toner transfer mathod did not worked for me. I used different type of paper and some heat transfer papers but couldn't get shop owner to print due to low gsm in paper. I saw someone on youtube makes copper paths by covering copper area masking by insulaton tapes and i tried and it wass far beyond succesful. So I thought about cutting sticker paper whiles it is attched to copper board. If you have any suggestions and tips please leave them below.

1. Copper clad board 1.2mm (FR4 preffered)
2. Ferric chloride
3. Sticker paper
4. Laser cutting service
5. Soldering equipments
6. Thermister
7. Thermal fuse

This is a small video i created about the process. Hope you enjoy. If you like the content give a thumbs up and subscribe to my channel.

I used 4pcb trace width calculator. I haven't used these calculators before. You need to play around with this software to get voltage drop to match your power supply and your desired power of heat bed. My bed is 450mmx450mm and i'm going to divide it into 9 zone. Then size of a single zone is 150mmx150mm. Don't make too small trace width. I started at 2mm width and 2mm gap between each line. You need to give the temperature rise. I gave it 90 degrees of celcius. I made a mistake when adding copper layer thickness. i thought i was 35um which is very common but i was actually 18um when i checked for resistance after etching. I used solidworks to design the layout.

Use output data in internal layer section.

I attached sticker paper avoid having air bubles. Its better if you can get a sticker that does not drench in water. Because it will make outlines much sharper and able to achieve closer resistance values. I got laser cutting service from a local shop. It is a big CO2 laser machine. Using very light power of laser beam you can cut the sticker without even making marks on copper layer. Laser head in that machine was heavy so it could make small movements accurately. This was the first time i got a laser cutting service. After cutting you can easily peel off unwanted sticker parts.

For etching i used Ferric Chloride. You can get ferric chloride in solid form. Time for etching depends on the concentration of ferric chloride. Don't add too much. For me i took around 10 to 15 minutes i think. You neet to stir the board and chemical from time to time. After etching wash it with water and remove the sticker. I was able to get very good results. This method is much easier than using clothing iron on laser printer paper to toner transfer.

Measure the resistance of the copper line to validate results. Unfortunately, i got 4.6ohm due to the wrong copper thickes i added into calculator. There are standard thicknes levels and when i added 18um into calculator results matched very closely.

I mounted pcb board onto a 3mm glass which i was going to use as build plate. I hoping to drill the glass as shown in picture to attach large 45cmx45cm pcb board. Screw isez is m3. But for this test i using aluminium tubes covered with insulation tape, where its going to touch copper layer. I placed a thermoster on top time of glass to get actual surface temperature. This varies how good you have place thermoster. I just added some thermal paste to get good thermal contact. I using SKR 1.4 tubo controller for measuring.

Because of the unexpected resistance value i had to divide the copper line into two sides and joined them parallel. This makes resistance reduced by 4 times and total resisitance is around 1ohm. This values is not exactly correct because of the measuring error for low resistance in the multimeter. So, i can't supply power using my 12v computer PSU. Then i used old UPS transformer to get lower voltage. It gives around 8V between center of the secondary winding and end of secondary winding.

When you are making one for actual bed make sure to add a thermal fuse just in case thermistor does not work. I will prevent going to high temperatures. You can get these for different cutoff values.

At begin 6amps are drawn by heated. As per results it took aroung 6:30 minutes to reach 70°C which was OK by me because it was the actual surface temperature. My prusa MK2 heat bed provide around 0.21W/sqcm and this pcb i created provide 0.2W/sqcm. 6x8=48W which was close to my orignally expected values of power loss in trace width calculator. My trial was far bayod succesfull by me. Now, i'm going to make bigger pcb heater using actuall 35um copper board.

Your suggesions and tips for making a better pcb heater are kindly welcome.

Check my other instructables, you may find something relavant to you.

Thanks for reading.