A standard for connecting to 3D printers

Although it’s easy for your average maker to connect the Discov3ry to their existing 3D printer, there are benefits to developing a simple connection port.

This could serve as the beginning of a standard for connecting the Discov3ry, or another after market extruder to a 3D printer, similar to how peripherals are currently connected to a laptop.

One of our Kickstarter backers has proposed using a mini-din connector for this purpose. I’d like to use this thread to continue the discussion.

A mini-din


I’m “one of the backers” :smile:

The connector would make it easier to connect 3rd party accessories like the Discov3ry, but it’s worth checking if this is the best idea.
I once though of connecting the feeding motor side of a bowden extruder setup, as part of a rear addon for 3d printer that includes the filament roll holder, and integrated filament dust cleaner and monitor. It will be a wide box that should connect to the machine with pogo pins.

The other issue is that stepper drivers don’t like it when you disconnect the stepper while they’re running, so a security feature should be embedded. It might require some logic, maybe an ATiny to control it, and allow connections/disconnections only when the machine is off.

Very good point about the locking device Cohen!

What other “peripherals” are out there that you would want this to support as well?

For now I can only think of things that will otherwise be able to be controlled through the Discov3ry extruder

Apparently this young man is working on an add-on metal extruder. Though his project is very early on, he might have some interesting opinions on how to go about it

This is solder wire
I might be able to print at higher temperatures (500 deg Celsius) with the new all metal extruder

A laser cutter for papers and vinyl stickers!

Ah good thinking, instead of buying these everything/all-in-one machines that do laser cutting + cnc + printing, you could buy a machine that has the 3D robotics figured out, and buy the add-on tools you need.

Yepp :smile:

Though for CNC you need stiffer mechanics

1 Like

The mini-DIN did seem like a good choice due to its popularity and might still be…

As I was curious about using the mini-DIN, I did a quick check on Digi-key spec sheets which indicate that they were designed for a maximum of 2A. Should a connector with a higher current rating be considered?

When I select a connector I look at it what it is being used for, and balance the requirements based on them and cost. First thing I look at is the total current (,including start-up currents,) and how much current goes through the ground. Then I look at the voltage, signal type, noise, movement, IP, temperature range, etc.

Can we get the requirements so that we can discuss and select a standard connector?

I think 2A are okay for a single stepper
Since there’s no heating involved

Super cool to see you guys thinking about this. I’ll try to get you some clear requirements for the connector today.

1 Like

The requirements for the connector are just that it can transmit the power and control signals to a NEMA 17 motor. Exactly the same as what would be required for the motor on your current extruder. Our motors are rated to 2.3 A and 3.1 V.

Basically, the port needs to get this guy the information and power to do his job:

That said, if the aim is to create a port that is useful for a variety of extruders, it would be good to support a higher range of power, as well as a temperature signal.

I don’t think that printer manufacturers are going to add a connector for people to swap in Discov3ry, unless you do deals with them so that it’s in their interest to do so.

But perhaps you can introduce the connector so that it’s easy to add/remove the Discov3ry. I’d love to be able to use my printer for FDM printing, then plug in the Discov3ry to print specific things, then back. So if you guys came up with a module that I could wire into my current printer controller, allowing me to plug in the Discov3ry and have it take over, then unplug it and have the standard extruder take over, that would make it much easier than swapping wiring to the controller board each time.

As for what else might plug in, one thing I can think of is a laser. There are some kits for mounting a laser into a 3D printer as a low-powered cutter, or for resin printing.

Another possibility is something like a dremel, using the 3D printer for X/Y/Z motion, and using the port to power the drill. Of course, only for low powered applications, since the printers aren’t designed to move the mass of a real CNC milling head.

Potentially swapping in different extruders entirely, such as between different nozzle sizes or filament sizes?

@laird, I think you’re probably right about the difficult of convincing manufacturers to create a port just for our product.

I want to be sure that I do understand your suggestion though:

  1. We would provide the extruder with a male connection port
  2. We would also provide a female port that could be permanently wired into the your printers controller board.
  3. We optionally might also provide a couple extra male ports that could be wired onto other tools, including extruders, lazers, dremmels, etc.

I think that would be interesting, let me know if we’re on the same page.

Yes, that’s exactly what I was thinking! Thanks for expressing it more clearly than I did. :smile:

1 Like

The practice of paraphrasing and clarifying is among the more valuable instruments in my tool box. :smiley:

Have you polled or contacted the RepRap community? Standardizing amongst the community would be a good starting point, as it would not only help this project, but others as well?

No, we haven’t though that is a great idea. I’ll do that in short order.

I use PC psu 4pin molex connectors for some of my printer stuff, mainly hotbeds.
they work great, and since i use atx psu’s its plug and play.