Desktop electric kiln

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A desktop electric kiln is a kiln that can be used on a desktop in a makerspace, workshop or other environment that is heated using an electric heating element. Kilns provide many opportunities to expand and compliment 3D printing.

Desktop kilns exist but are expensive for the components used and are proprietary designs. The only open source designs and free but restrictive license designs are all large kilns for outdoor use. RepRap printers have sophisticated heating, timing and safety features which could be useful.

There is potential for an open source kiln to be able to create its own refactory brick, allowing it to be partly self replicating.


Uses

There are many uses for kilns in relation to the RepRap project 3D printers which rely on different temperatures, meaning even a relatively low temperature kiln would be useful.

  • Lost PLA casting, could be used to simply create the moulds and used in combination with pouring aluminium or other metals from a furnace. Or by creating custom metal parts using moulds that have a reservoir for the metal included. This could be used for mechical parts and jewellery making.
  • Firing cermaics, very useful in combination with 3d printing paste extrusion. This can include metal clays, porcelain, earthenware and other materials.
  • Sintering parts that are created using an metal powder and an adhesive e.g HP Metaljet
  • Annealing PLA prints
  • Dehumidifing nylon filament

Temperatures

  • 50℃/122°F drying plaster for lost PLA moulds
  • 55℃/131°F annealing PLA
  • 70℃/158°F dehumidifing nylon filament
  • 250℃/482°F melting the filament out of lost PLA moulds
  • 660℃/1220°F melting aluminium for lost PLA casting (pouring molten metal indoors is a terrible idea, please don't do it), one possible option could be to create a mould with a resevoir for the aluminium to sit and then travel into the mould using gravity.
  • 900℃/1652°F metal clays (a wide range of temperatures)
  • 950℃/1742°F - 1100℃ firing earthwnware pottery
  • 960°C/1760°F Melting silver (e.g for jewellery)
  • 1162℃/2123°F-1240℃ firing industrial cermamics
  • 1263℃/2305°F to 1326℃ firing high fire stoneware
  • 1305℃/2381°F firing porcelain
  • 1300-1500℃/2372-2732°F Melting glass
  • ? Sintering parts that are created using an metal powder and an adhesive e.g HP Metaljet

Useful features

Operational features

  • Accurate temperature control
  • Timed programs for annealing PLA, firing cermaics etc allowing the community to build functions and processes through shared knowledge and experiments

Sensors

  • Logs to record heating records, useful for experimenting with new processes and diagnosing issues
  • Temperature sensors for outside of kiln
  • Door open sensor
  • Active cooling for kiln exterior? Useful for safety features and possibly active cooling during regular operation, also cooling of electronics

Safety features

  • Very well insulated, given the environement heat leaking is bad
  • A door lock that doesn't all the door to open above a certain temperature
  • Automatic shut off for unsafe operation e.g external temperature or door is opened
  • Non damaging materials including biosoluble cermaic blanket

Design ethos

  • As safe as possible including construction, operation and materials used (e.g biosoluble ceramic fiber blanket)
  • Simple to construct with realistic minimal tools
  • Cheap to construct to improve accessibility
  • Scalable size to allow different uses
  • To be useful to both the 3D printing community and the ceramics community
  • Partially self replicating if possible

Parts

The main components of a kiln are readily available and inexpensive:

Controller

Could we bring across functionality from 3D printers to have things like programmed heating routines, timers, controller logs safety features like case temperature detection, open door heater shutoff etc?

  • A Thermocouple amplifier may be needed.
  • 3D printed buttons and other controls will allow experimentation of kiln control interface

Display

Used to display temperature. Could a standard 3D printer screen be used? What other information could be displayed?

Heating element

Heat sensor

Insulation

Possible materials

  • Refactory bricks, there is potential for an open source kiln to be able to create its own refactory brick, allowing it to be partly self replicating. A 3D printer could be used to create a mould for bricks allowing novel shapes.
  • Biosoluble ceramic fiber insulation (cheaper than brick but potentially less efficient insulator)
  • Vermiculite pebbles: So much cheaper than the board

Structure

Existing related projects

Further reading

Commericially availble electric desktop kilns

Microwave kilns

Related pages on the RepRap wiki

Ceramics firing

Metal clays