Like many, I'm fed up with the common MK2B heated bed. It has about 1.2 Ω when wired in 12 V configuration and 4.8 when wired in 24 V configuration. Both times it outputs about 120 W of heat when driven by the appropriate voltage, resulting heatup times to print temperature of 10 to 20 minutes.
Heatup time can be reduced to 2 minutes by simply driving it with 24 V while wiring it in 12 V configuration, but well, this almost max out a seperate 500 W 24 V power supply I dedicated to driving the heated bed. Additional requirements for this setup are at least AWG 15 wire and a high current MOSFET or SSR.
The additional cost of a 500W 24 V power supply, high current SSR and heavy wire is not neglectable at all, since the can easily be half of a printers price tag. Also, bulky power supplys and wires do not contribute to the overall design and weight aspects of a 3D printer.
There are many benefits of a mains voltage heated bed: I will be driven directly from mains, skips the need for an expensive power supply and can be driven by a cheap low current SSR without heatsink. It's also cheap and provides a structural support for your printing plate, be it glass, tufnol/garolite or PEI - which silicone heater pads do not do.
Thus, a mains voltage heated bed must exist, and this project is dedicated to make it real. Additionally, this is also an attempt in making this the safest heated bed available. If you have concerns with the design, please share your ideas in the comments.
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| Inductive distance sensor on the extruder paired to Marlin firmware constantly corrects the distance to print surface |
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| Diagram showing how to connect inductive distance sensor to control unit ie. Ramps |
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| Combined with Mk3 Alu heated bed gives much better ABS prints like in this example where you can see very strait walls |
Both Tekma3D and New Matter both came out with printers that use crossed splines to drive the x and y of their printers. They both are in the process of trying to acquire a patent on the technology.
Being the open source hippie that I am, here is a system that is functionally the same but should give a wide berth to the patents.
To be clear, I don't think this kind of system is very good. I think it is fun to watch.
If the system has opposing racks as shown, one screw should be left handed and the other should be right handed. If all the racks face the same way, like the MOD-T, then you can use two left handed screws. The system is driven just like a CoreXY system.
You will need to remove touch electronics and plastics which is simple to do.
- Thin, yet flexible tempered glass
- Scratch-proof (scratch-resistant, it can be scratched with diamond or tungsten carbide tip scribers)
- Great thermal conductivity (for uniform heat distribution)
- Very low thermal expansion/distortion (at the usual printing temperatures of 110-120C)
- Resistant to pretty much all solvents (Acetone safe)
- Pretty cheap (around $15 on Amazon)
- Not too hard to hack it into a build plate (see instructions)
Ideal build surface for FDM 3D printers using ABS and/or PLA.
Key Features:
- Installs much easier than masking tape or films typically used and with fewer chances of air bubbles
- Protects build plate
- Heat resistant and durable, can be reused for many consecutive builds and you can go from ABS to PLA without the need to change the printing surface
- Creates an optimal bond between the 3D printed object and build surface that maximizes the chances your object will be held in place for the duration of the print and then allow for clean and easy removal of the object from the build surface.
- Works great with ABS, PLA and more without the need to change the surface. And no more pretreatments such as hairspray or acetone slurry!
- Easy installation to the bare print bed and clean removal without adhesive residue.
- Durable and with optimal care can last for many hours of use while providing extended protection to the original print bed surface.
- Creates an optimal bond between the 3D printed object and the build surface for the duration of the print while preventing curling. When builds are complete, the 3D printed object can be cleanly removed with minimal prying or scraping.
- Patent-pending heat resistant composition, developed to withstand the typical temperatures used on heated print beds (i.e. 110-125C). With safety in mind, BuildTak is composed of raw materials that are UL flame rated.
- BuildTak sheets can feature custom graphics and branding.
This is a demonstration of how I apply PVA glue to my glass print surface on my Reprap MendelMax 3D printer for printing with PLA filament. I can print PLA on bare glass for many objects, but for ones that are prone to lifting from the glass I use a coating of PVA glue which completely eliminates any first layer adhesion problems for me. I use a 1:10 dilute solution of PVA glue and water applied to the heated glass so the water evaporates quickly and I can control the thickness of the coating I apply. I can usually go for several prints without reapplying, depending on what I print. I usually set the bed temperature to between 50C and 60C for the entire PLA print and use fans on the nozzle and also across the build area.
