Hello Genesis,

I think you should be aware that it is not useful a 3D printer + CNC on the same machine. First you should define better your problem and your target, please else it is very difficult to help you. In a general vision with the information you provided I can confirm the following:

• Arduino is a board that can be used to control CNC and/or 3D printers. Most of the DIY 3D printers uses an Arduino.
• Ardui can just execute the code - g-code - sent by a more advanced software that can generate it starting from the 3D model; SLT file (usually) for the 3D printing and a 3D CAD source in the CNC case.
• 3D printing works with the exactly opposite logid of the CNC: the first add material (filament) to a base creating a solid 3D object layer by layer while the second to exactly the opposite: remove material creating 3D objects.

Take in account that the g-code is a standard. If you explain better what kind of Arduino board you have or you plan to have I can give you more information.

Important note: as the stepper motors needs different power the Arduino board should be interfaced with a number of motor controllers to manage the movements.

Then consider that the 3D printer also has an Extruder that is a mix of heating system (the filament extrusion block with the nozzle) and the stepper motor to drive the filament. So to the motor controllers Arduino in this case will control also a temperature thermocouple to keep the nozzle heating constant at the correct value depending by the kind of filament you are using.

With this scenario in mind, I suggest you depict better what do you need exactly. I think that your best - and cheaper solution is NOT to buy a bare Arduino but at a similar price one of those Arduino board clones adapted to manage stepper motors and extruder (in the case of the 3D printer) or the stepper motors and the shaft in the case of a CNC machine.

Enrico

Hello Genesis,

I think you should be aware that it is not useful a 3D printer + CNC on the same machine. First you should define better your problem and your target, please else it is very difficult to help you. In a general vision with the information you provided I can confirm the following:

• Arduino is a board that can be used to control CNC and/or 3D printers. Most of the DIY 3D printers uses an Arduino.
• Ardui can just execute the code - g-code - sent by a more advanced software that can generate it starting from the 3D model; SLT file (usually) for the 3D printing and a 3D CAD source in the CNC case.
• 3D printing works with the exactly opposite logid of the CNC: the first add material (filament) to a base creating a solid 3D object layer by layer while the second to exactly the opposite: remove material creating 3D objects.

Take in account that the g-code is a standard. If you explain better what kind of Arduino board you have or you plan to have I can give you more information.

Important note: as the stepper motors needs different power the Arduino board should be interfaced with a number of motor controllers to manage the movements.

Then consider that the 3D printer also has an Extruder that is a mix of heating system (the filament extrusion block with the nozzle) and the stepper motor to drive the filament. So to the motor controllers Arduino in this case will control also a temperature thermocouple to keep the nozzle heating constant at the correct value depending by the kind of filament you are using.

With this scenario in mind, I suggest you depict better what do you need exactly. I think that your best - and cheaper solution is NOT to buy a bare Arduino but at a similar price one of those Arduino board clones adapted to manage stepper motors and extruder (in the case of the 3D printer) or the stepper motors and the shaft in the case of a CNC machine.

Enrico

currently it is just a 3 axis table that uses dc motors with attached encoders.

the motors are 24v DC

the encoders are 5v, optical, three channel units with a resolution of 1024 counts per revolution at up to 30,000rpm

I have a PSU that will provide both

I also have L298N and A4988 drivers on hand.

For control I have Mega and Uno arduinos.

I want to be able to send the arduino a g-code file and have the table follow the path, once I get to that point, I can decide on what form I want the machine to take.

I'm pretty good with electronics and mechanics, if it were a stepper system I could figure it out, but I'm not very knowledgeable with the programing side of things.

also I don't know if it is important, but the small pcb next to each motor shunts the motor and acts like a braking mechanism. 

encoder:

http://www.farnell.com/datasheets/79134.pdf?_ga=2.158234874.1556239968.1496190497-1997083092.1494048542

HEDL-5540#A13 - BROADCOM LIMITED - ENCODER, ROTARY, 500PPR, 3CH | Newark element14

Hello,

to be honest I think using a DC and not a stepper motor for driving axes is not a great solution at all. There are lot of reasons including the stability of the motor in every step and the fact that steppers have a specific torque no matter of the speed. Last but not least intuitively I can't imagine that arduino has sufficient processing power to manage the entire logic and feedback via the encoders. The steppers instead, uses the half-bridges but when you send just the number of steps they rotate at the decided frequency and stop exactly in a certain angular position that is easy to translate in linear distance.

Enrico

Basically I have a very nice bare machine, it was in the medical industry so high precision parts all around, one of the heads had a needle attachment that touched various areas of a tiny glass microplate, so as far as accuracy and repeatability, i'm not worried.

all i'm asking for is to be pointed in the right direction.

the original controller (not working and proprietary)  was a Marvell ARMADA 162, it ran at 400mhz but also had to deal with at least 10 servos, along with 3 or 4 stepper motors solenoids and a bunch of temp and pH sensors.

like I initially said, i'm just wanting a push in the right direction, not reasons why it can't be done.

So ok. so far, the general idea is an arduino running at 16mhz controlling 2+ pwm channels and reading 6+ digital position channels will run into resource issues.

How about breaking it into smaller pieces, Use something like an Attiny85 for each encoder, basically set up a simple protocol where it only receives 2 digital signals and translates those into a specific distance and direction, that way existing arduino stepper motor CNC sketches will be usable.

Generally speaking the processors you are talking about are not the first (or second or third) choice for linear motor control.

TI make suitable processors and low cost dev  boards and also publish a lot of good information about motor control. You might do well to look at this and it would at least give you some ideas.

Enrico is right in pointing out that it will be more difficult to control a 3 axis machine based on servo motors.

Of course there are advantages as well - all the commercial CNC metal cutting machines I know of use linear or BLDC servo motors.

MK

To answer you and Add to Enrico

CNC Router and 3D printer have probably 80% or more the same parts (Perhaps more powerful drivers in the case of the CNC Router but the same nonetheless)

X, Y, Z control, mostly driven by steppers that offer 200 Steps per revolution, the torque chosen to suit the loads being moved.and often with 2 steppers on the axis driving the largest load (Y in the case of a lot of CNC Routers, Z in the case of most 3D printers)

A Spindle speed / Filament Feed control, in the case of a CNC Router this is controlling the speed of the cutter in RPM along with speed of movement to result in "Material removal rate", in the case of a 3D printer this is material adding rate , the same but opposite if you like as it is still a combination of motion speed and filament feed rate. For the CNC Machine this is often a 0-10V or PWM signal tot he motor control board, in the case of the 3D printer this is a Stepper control (But does not have to be)

In addition to the above a 3D printer will have another control for the temperature of the Hot End where the plastic is melted prior to squeezing through the nozzle. this is usually many amps at 12 or 24 Volts.

Optionally there is also a heated bed on the 3D printer to aid in print quality and can inhibit curling of the printed product if tuned correctly (An Art into itself )

Can you build a 3D printer / CNC Router combo, of course you can but it will need to be built with the heavier load in mind and that is NOT the 3D printer. for instance my CNC Router has to move over 11KG including the X Gantry and Z along with a bosch Colt router, a Nema 11 or 17 motor wont do for that so I use Nema 23 motors, you could go bigger if you use a bigger router or platform.

A 3D printer often only needs to move the hot end and the gantry and can easily do this with a NEMA11 or 17 motor. I am using Nema 17's in my builds, one with 200 Steps per revolution and one with 400 Steps per revolution (Hopefully giving better accuracy)

Both these machines will easily support a small Dremel style rotary cutter if I want and or even a Laser Diode cutter for cardboard or Foam machining.

What makes the real difference here is the controller will almost certainly use GCode and the CAD Cam software needs to be able to know the difference converting the model from say a Fusion 360 3D model to 3D printer GCode and so there may be a need for a pre-processor like CURA or SLI3CER to convert a STL to compatable 3D printable GCode working from the bottom up and adding material as opposed to the top down and removing material

of course it is a little more complex than that but not much and by the time im done with my videos I will be showing all of this. If I can get someone to send me suitable servos then these will also be shown for 3D printing, perhaps over kill for a 3D printer but perfectly viable nonetheless

Hi Peter, you are perfectly true with a very clear and detailed explanation.

Making a hybrid CNC & 3D Printer is an idea I have already though, but always discarded as the cost to make a similar tool the consts vs benefits analysis is loosing. Not only we should consider that there are some components not fully compatible in one case than the other. This means that every time moving from a 3D print job to a CNC milled part the result is at least:

1. Replace the milling tool with the extruder (need calibration and other delicate operations)
2. clean the area from milling for 3D printing
3. remove the metallic CNC base and replace the bed
4. Managing a lot of connections some excluding the other

There are other intuitive aspects that are complementary and very different that needs to have a a bigger machine (at least) and more space and a relatively complex electronic architecture and a powering system to make the final result just an academic challenge and not a really useful cheap tool.

Enrico

All very good points

To add to this

You can't build either cheaper that one or the other or even the same price. The cost will be more than the more expensive but should not be double. With proper planning you can build it as a hybrid but you need to select the right software to drive it. Also you need to build it to the strength needed for the CNC Router and therefor need to know the load of the cutter, so are you going to just use a dremel style cutter or something much bigger like a Bosch Colt woodworking router. or are you just planning on doing wood / plastic and perhaps a little PCB milling ?

As Enrico pointed out, there are considerations needed when considering a hybrid, calibration being the most critical, the heated bed should be removable and or protected when CNC Routing, the head will need to be switched between the extruder and the cutter, this is where alignment dowels may come in handy to help accurate assembly and therefor easier calibration, the router is not so critical but the printer is, it need a flat bed or software to compensate for an uneven one.

You need a controller that is a superset of one or the other (So the 3D printer style but more power for when doing CNC Work)

I have one of the ST Micro 3D printer reference boards coming so I will see how well it can meet the needs, it runs Marlin and supports 3 extruders, 6 stepper motors etc but only upto 3 Amp per winding (Enough for small CNC router and pretty much any 3D printer or laser cutter), as it has 6 stepper drivers it will handle a 4th axis in CNC mode too. STEVAL-3DP001V1 STMICROELECTRONICS, REF DESIGN BRD, 3D PRINTER DRIVER, Newark element14 Canada

The price of the only board you mention is about 9 times the single controllers price

Enrico

yes but look at its specifications

32Bit vs 8 bit

6 steppers vs4 or 5

3 hot ends at 8Ams each (Not total)

3 heat zones at 20A each, not total and support for 24V heaters here

WIFI Enabled

now find one with similar specifications at 9 times less ??

Pretty much everything is built in

peter

Peter agree and if I would try building an hybrid this is the right one IMHO. The point is about the pricing in general. I am almost sure that the total price maybe heigher than the two tools separate

Enrico