RepRap Interface Standard

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Revision as of 00:08, 12 April 2014 by Buback (talk | contribs) (electrical interface)
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RepRap Interface Standard defines interfaces between the various components of a printer. Like an interface between carriage and extruder, between extruder and hotend, between bed base and heated bed and so on. Effectively we have such standard interfaces already, but they're neither discussed nor defined.

With interfaces defined, components become exchangeable. If an extruder complies with extruder-hotend interface standard and a hotend does as well, a user can rely on both of them fitting and working together. No longer guessing by blurred pictures or even buying many versions just to find one that fits.


Discussion Thread in the RepRap forum


Intentions

  • Easily port new features implemented in one printer to another printer.
  • Ease the enhancement of printers by changing only one module and not having to invent/build/maintain a new printer thereby lowering the entry bar for new developers.
  • Not to invent new interfaces, instead document those interfaces that are commonly used.
  • Standard interfaces come with a price. So 100% compatible is not as important as new functionality. If a module needs to break the interface then that should be clearly stated. Best possible compability is still the target.

Module Types

This section describes the Functionality and the Interfaces of the different module typess.


Electronics

The electronic module provides the home for the fimrware that drived the printer. The CPU and Motor driver ICs are part of the electronics package.

mechanical interface

size of box?

electrical interface

  • Power Supply for all other Modules.
  • connectors for Stepper Motors
  • connectors for Fans
  • connector for end stops
  • connector for temperature sensor
  • connector for heating elements
  • UART/RS232 Serial Interface (optional)
  • USB interface to controlling PC. (optional)
  • SD Card Slot for printing without PC.(optional)


Print head

This Module transforms the raw material(PLA, ABS,..) so that is can be deposited on the printbed to from the print. If the intention is not to create a 3d printer but a CNC mill then the milling head will be a print head module.

mechanical interface

mounting holes?

  • Groovemount

This is a standard for many Hot end designs such as the Jhead. 4.64 mm wide with an OD of 12mm, using 5/8" stock

Jhn nozzle holder v1.jpg

electrical interface

  • Heating element

A through hole wire wound resistor is traditionally used as the heating element in the hot end. enamel coated resistors are rarely used in electronics today and can be difficult to source, but are often best as a heater element because they can withstand very high temperatures. Look for shiny British-Racing-Green colored resistors. Many other resistors are silicon coated and will have a significantly shorter usable life, as they are often operated way outside of their spec.

  • temperature sensor

thermistors, are the most widely used temperature sensor for printing because of their simplicity, cost, and relative accuracy at the working temperatures of common printing thermoplastics.

nominal thermistor specifications is as follows:

  • 100k thermistor
  • Tolerance: 1-4%
  • Diameter of Glass Bead: 1.35-2.3mm
  • Length of Glass Bead: 3-4.1mm
  • Lead Length: 45-67mm
  • Lead Diameter: 0.15-0.3mm

(Heated)Printbed

The print bed is the platform that the printer uses to create the print on.

mechanical interface

For a carteasean bot like a mendel-derivitive, the standard is the Prusa PCb Heatbed.

PCB Heatbed MK1 is developed by Josef Průša

  • 200 mm x 200 mm active heated area
  • 209 mm center-to-center mounting holes (outside the active area). The holes are M3, usually using standoffs to mount to the Y carraige, such as you would use when attaching a motherboard to a PC case.
  • 214 mm x 214 mm total PCB size

electrical interface

  • temperature sensor (heated only)
  • heating element (heated only)

Mechanic

The big parts of the rinter that allos the print head to move in 3 dimensions relatively to the printbed.

mechanical interface

so that the others can be mounted into it?

electrical interface

  • (Stepper) Motors


Existing Modules

In this section all existing Modules can be listed.

Electronics

Extruder

(Heated)Printbed

Mechanic