Replace extruder with a Spray Valve

Hello,

I am looking for a pre built printer that is easily modifable. I want to replace the extruder with a Spray Valve that I will control with the signal that usualy controls the extruder. The spray will be room temperture so I also need to modify the printer to not look at extruder temperature or advancment. Is there any recomendation for a very well documented eaisly modifable printer that people are hacking?

Alan

Quote
ajmartin
Hello,

I am looking for a pre built printer that is easily modifable. I want to replace the extruder with a Spray Valve that I will control with the signal that usualy controls the extruder. The spray will be room temperture so I also need to modify the printer to not look at extruder temperature or advancment. Is there any recomendation for a very well documented eaisly modifable printer that people are hacking?

Alan

first off what you trying to build a T-shirt printer not assembled you could use any of the mechanical kits without the electronics. And then use Mach 3 CNC software and buy drivers and set up a relay on off like the spindle would be on a milling machine or router. Or any of the cheap small CNC routers you see on eBay or whatever

Edited 2 time(s). Last edit at 02/05/2014 03:12PM by cnc dick.

Thanks for the reply, I will be spraying a "Gel" and I need XY and Z axis. So I was thinking I could just use a cheap 3D printer , replace the extruder with my valve , feed the machine an STL file and print it. We have a Cubify Cube here we would be OK converting but its a pretty "closed" machine. I would need to disable some sensors (heat, feed) and interoupt the "print signal" to send to my valve. So I was looking for something assembled that people knew how to Hack, for reasons of getting this idea done quickly?

Thanks,

Alan

Most of the "Hacking: you are talking about will be to the firmware. The firmware controls things like sensors and what the outputs are. I think most any reprap kit will fill the bill of what you want to start with. Figuring out how to make changes that will be appropriate to the firmware are out of my league and would for some part be virgin territory. Now people have already made things like chocolate extruders and they must disable the temp sensor for that, you might google that to get a head start.

The extruder is a stepper motor on 3-D printers not a simple on-off. And it's not like the qube you don't just put a STL in it has to be sliced in different software turning it into G code

AJ any reprap should be able to do what you want but you will have to do a few things. You are going to have to learn how to modify the firmware to ignore temps (pretty easy) and control your valve/nozzle (may be easy, may be hard). You didn't mention what build volume you need so just about anything should work. If you are looking for something prebuilt I would check out seemecnc and makerstool works. Personally I think you would be better off building your own and here is why. When you build your own you understand how it works inside and out. This will help you understand how the whole machine works and make it easier for you to integrate custom pieces.

If you don't know how to do any of this you may want to find someone who is in your area who can help you. This work is time consuming so be ready to pay for it.

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Thanks, I want to do this in hardware, so for instance on the Cubify I see the the temperture sensor , I can break the circuit and measure the current when the Cube is happy and starts to print. From this I can figure out what value resistor I will need to use to replace the sensor. I want to intercept the stepper motor signals and decode that into a control that will tunn my valve on and off. The printer *I think* also wants some kind of feed back so it thinks the filiment is moving, I could feed that back every time I open the valve. So I was just wondering if there was an inexpensive HACK freindly printer someone could reccomend. I have gotten some very good hints and suggestions already from these responces, THANK YOU! I would love to just build from scratch, but my "people" want to use something off the shelf. Oh and the reply about not being able to shove an STL file in the printer, yes, I know, my bad. Currently using the Cube SW to make the slicer , using Cube INVENT to do the 3D STL then sending that to the cube SW. The Cube is not HAck friendly though.

Thanks MUCH for all the advice.

ALan

You can try buying a 3d printer and doing what you want only through hardware but it really isn't going to work well. You might be able to use a resistor to bypass the thermistor but its way easier to modify the firmware. You are going to have to modify the firmware anyways to tune the printer to your nozzle unless your nozzle has some sort of adjustment you are planing on programing. Building a circuit to turn a stepper motor signal into an on off signal is also going to be a challenge. You will have to compensate for retracts and possibly design some sort of logic circuit. Then you will have to power the selenoid that controls the valve somehow. That is all a lot of work when you can just change your pins to turn on and off with gcode.

FYI printers don't have any feedback.

You might want to look into something like this

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You probably want an older printer that used a DC motor to drive the extruder. The wires can be attached to a relay that controls the valve. I know older Cupcakes used them and are very hackable.

Have a talk with the guys making laser cutters.
[forums.reprap.org]
The signal for turning on and off the laser is probably what you want for your spray.
The rest is just a simple CNC table (3D printers are just that with a few added features)
Sounds like a pretty simple system to make yourself, nothing complicated or expensive about it.

Edited 1 time(s). Last edit at 02/06/2014 12:50AM by regpye.

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