TUKI17 - Heated Chamber Part2

Heated chamber.

As you may be aware I like 3d printing in ABS. It makes some wonderfully durable parts and its easy to rework. I also like recycling ABS left overs and failed prints into ABS goop. With that said here are the recent upgrades to the printer.

DC-DC Boost converter.

The heated bed on this printer takes about 20 minutes to reach 90c, and close to 30 minutes to reach 100c. With the losses of the glass and the fact that the bed is undersized for a 330mm chunk of mirror adding aluminum plate to spread the heat it takes forever.

I decided to install a DC-DC boost converter. Using ohms law I was able to calculate my bed wattage. The bed is 1.0-1.1 OHMS and my PSU provides roughly 12.3V, with cable losses of about .2v the bed puts out about 133-146w of power. Not bad but could use some help. However increasing the voltage will increase the power of the bed by a square. The DC-DC boost converter outputs about ~14v. To put this into perspective, the bed now puts out about 178-196w. This is a bump of 46-50W of power. Here is the unit I purchased. If memory serves correctly it cost me about 20USD shipped to my door. It has a range of 12-80v output and can handle supposedly about 10A output. This has been verified that it does much more than that. It does need a fuse replacement. The 15A fuse provided is not a very good fuse. I replaced it with a 15A automotive fuse. The unit does get warm when in use but never too hot.

The result? 24-90c in less than 7 minutes. 24-100c in about 10minutes. Big change.

Here is a temporary volt meter plugged in to show the output voltage from the buck converter, it is occupying my thermometer hole for now until I 3d print a small case for it. It will most likely reside inside the 3d printer as I do not plan on reprinting the front panel.

I may as well explain the panel.

  • Top left is the 4 line LCD.
  • Top middle is the control knob with the bottom hole not yet filled by the kill button (this will be printed in RED)
  • Top right is the voltmeter to keep an eye on the PSU health. -Mid right are the 4 control switches that control power, inner halogen light, exhaust fan, and the 3 leds on the print head.
  • Bottom right where the hole is will reside a thermometer to measure the temp in the ramps case.
  • Bottom mid is the hour counter
  • bottom left is the temperature controller for the heated chamber.

The bottom of the printer.

I have not shown many pictures of this part of the printer. However I have to show you guys this. I will give you a recap of the components.

  • 1300w server PSU (Has been rock stable)
  • Ramps 1.4 inside 3d printed enclosure with 80mm fan blowing across it and the PSU fan sucking the air out.
  • DC-DC boost converter.
  • Front panel enclosure and LCD, various knobs and switches.

If you made it this far I can say that the wiring needs a bit of zip tying but generally it is out of the way. One more thing is that the sides of the printer will eventually get some 3d printed sides to keep everything in this compartment sealed and well ventilated. There is a plan to add one more 80mm fan on the side to help ingest air and the other two fans will eject the hot air.

Inner chamber parts

The inner chamber got self-designed carriages, and effector. With IGUS bearings and CF rods. All the plastic parts were 3d printed in ABS so they can withstand the heated chamber temperatures with no warping or melting. Planning on starting with a ~40c heated chamber and possibly working my way to 70C depending on what I need to print. Pardon the first picture but all the green and red parts are new parts.

The heated chamber also needs a separate heater. This is an automotive 150W heater that has been modified a small amount. It will also run from the controller in the panel quite happily. The main modification is the replacement of the power socket plug to a XT60 Plug. It is a ceramic heater for cars. Its cost was less than 16USD shipped. Its not of the best quality but it is rated for 150w. That may be enough to heat the chamber comfortably….. Maybe not. The halogen light also has the advantage of providing heat to the chamber.

Now speaking of the chamber. it is 1/2 done as of now. However this is how it looks from outside.

Left side.

Right side.

Now among the people who have sharp eyes. They will notice in the heater pic they see a brown wall. That is in fact cork insulator. The chamber walls are made of Aluminum sheet and as such aluminum is a good conductor of temperature, we need to keep heat in the chamber. As such we need to insulate. I like the cork product I used on the bottom of the printer so much that I picked up two more rolls. As of now the chamber only has 1 layer of cork. If necessary I will add a second layer down the line.

ABS goop?

Well I use different formulations of ABS goop for different things. First and foremost ABS goop is my adhesion method. I like this as it provides a stable surface to print on and is easily cleaned up from the bed.

The main reasons for ABS goop for me are these for 3D printing.

  • Thick layer of ABS goop is good for larger prints. It reduces warp.
  • Thin layers are good for smaller prints and is easily sanded.
  • It is very useful to make water or air tight prints.
  • It’s good to wipe on to printed parts to get a semi-gloss surface.

Other uses?

  • Its a decent thread locker replacement. It leaves a clean thread if you need to remove the fasteners afterward and its a good thread lubricant when torqueing down the fastener.
  • Its a very good wood sealer. Its not pretty but costs me practically nothing. In thicker concentrations I was able to seal the wooden platforms of my printer. Its durable and does penetrate the wood.
  • It is a good glue for ABS part repair. It practically replaces crazy glue or such alternatives. Leaves behind a part that is basically as strong as the base material, no more no less.

Final thoughts.

Preparing to enclose a printer is definitely not trivial. Your parts need to be able to survive the elevated temperatures. You need to have some safety margin in there. This part of my build has been very time consuming and thought provoking. However I feel comfortable with the materials chosen, especially cork material which is not exactly fire proof but a good fire retardant. I only run the printer in a room that has not one but two smoke detectors and never leave the printer printing at home when I am not at home. This is a fairly complex machine and deserves respect.

At this point I feel like I am about 3/4 the way done with this project. It’s been nearly a year since I started building this machine with the hopes of turning it into something very functional as well as very special. The virtual list of wants and must haves is slowly getting crossed out. As of now I feel like I need to do my final push and finally put in the door and start 3d printing the hinges as well as the belt covers.

Bruno M.

Engineer, Tinkerer, Technologist, Maker.

New York

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