Ramps 12V to 24V DC step-up transformer for only hot end

I am running the typical 12V all around Ramps 1.4 setup. All my parts are rated for 12V, except my heater resistor is rated for 24V. I want to slap on a 12V to 24V DC Step-up after D10 output.... so ONLY the heater resistor recieves the 24V boost. Anyone tried this? Thoughts?

Is the heater element replaceable? If so, might be easier to get a 12v version instead.

... I'm sometimes driving the heaters and/or the heated beds with industrial temperature controllers and SSR's - then the voltage can be anything, as it's complete separate from the other electronics ...

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Viktor
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No such thing as a DC transformer, and I doubt that many DC to DC switching converters will tolerate PWM temp control . . . maybe if you can use bang bang, and accept looser temp tolerances. . . all in all, not a good situation . . . Maybe a DC solid state relay and external 24v power (or 12v upconverted *prior* to the relay), driven by D10.

- Tim

... im using simple 12V or 24V AC-transformers and AC SSR's - the PWM will 'interfere' with the 50Hzz from the line, but it works ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Thanks for all the suggestions.
Elmo c - yeah I tried my best to get around to using a 12v but the hot end is an ultimaker knock off and has a 4mm resistor hole. All I can find is the 24v heater that is a m4.

Tim- thanks for the vocabulary lesson. Converter not transformer. Yeah I didn't think of the slight difference that the converter may play in the switching. Since it will charge and discharge a capacitor and inductor it seems I will be sending the hot end l "packets" of electricity. So the hot end current may switch off but that capacitor may go ahead and send what it's got.

Victor- I am going with you on this. I don't think this will play much difference and I believe the limiting factor to accuracy of temperature remains with the tolerance of the thermistor and sensor electronics.

I got the converter in yesterday. Will wire up this weekend. Thanks

Use a 12 volt relay?

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Follow my Mendel Prusa build here: [julianh72.blogspot.com]

I would use a 12V relay, but my goal is to build the most inexpensive printer I can without sacrificing quality... that being said a 24V power supply that also supports 12V for the ramps will cost me more than a DC-DC step up. However, I will look into that if this does not work.

I have an all acrylic printer down to 450$ cost. So far, it looks commercial. CNC Acrylic cut frame, X-Y core, with LED and all that stuff. This issue with the hot end will probably be changed to accommodate more inexpensive heater resistors.

If you are designing your own printer, why not use a different hotend that can accommodate the standard heating element, like a J-head or E3Dv6?

Good point. Right now the highest quality hot end I can get for the money is a 60$ ultimaker hot end... not OEM but the highest quality for the price. This includes the attachments for the x-y carriage and not just the hot end itself.

After I get this together, and it prints good quality parts I am going to start the long design process of developing my own x-y carriage and seeing what hot end will give good quality. The cost of development is slowing me down and I must start with cost effective parts to gain funds. Right now the people that are interested are a few people in my city.

I did try a J-head once... but after designing the shields and fan mounts and x-y carriage. I realized I would need to injection mold these parts. AND after the prototype assembly was still disappointed with the low quality of the hot end itself. So this is the long term goal, however, not feasible at the moment.