Before few months I asked here for advice for a 3D printing design with Bosh Rexroth linear modules that I bought as bargain. Many of you advised me that with this modules I should try to make machine that could mill and print. So far I manage to make it mill now I need to make it print as well. The biggest challenge was a machine that could mill and print as no matter same movement both operation are a bit different. Printing is requiring fast speed/fast acceleration low inertia movements. Mill require rigid and high mass mechanics that is capable to accept the forces of milling without bending and flexing too much. So I decide at the end to choose top Gantry crane design and to try to address both requirements with some success. So here is the result:
Speed: 100mm/s
Acceleration: 200mm/s2
Max movement x/y/z: 370/370/250mm
Price so far: 3500$+
And again I am asking for your opinion on the result.3d printing is still under development and I am wondering should I try to convert Mach3 to also print or to make separate controller for this task and switch between both operations.
I really don’t see any advantage with having one machine that can do both for the same reasons as you write yourself.
Especially since you’ve got what looks to be a vey capable mill. (Unless you don’t have the space for 2 machines that is)
For a printer you might want a heated bed, for a mill you might want flood cooling. Combining all that in one machine would be impractical and probably expressive.
I can see some neat applications to machine a components then 3d print over the top of it. Say to imbed strain gauges into a thin metal section and then cover that with 3d print material as a protective covering. Also perhaps to machine non-metalic pieces and then add to them with 3d print material.
Also, perhaps, you could create some really nice surface finishes with the milling head after printing the rough shape with the printing head.
These are certainly edges cases, but cases none-the-less…and with them as the premise for a combined machine you would need the software and hardware to be integrated into one system to make it easy on a user to swap between the two uses.
There is only one valuable idea of Mill and printer at one machine. For making molds. The ultimate target but I don’t know if I will be able to achieve it will be to make a mold from PC for example and than to make surface finish with the mill without pre-positioning the detail. Also it will save space but considering the complexity and all the compromises this should be ignored if it is not must.
If you first want to print and then mill the same part it’d have to stick really well to the print surface but is it enough to mill it? When milling the part is usually held down firm in a vice, vacuum table et.c.
Perhaps a heated bed would be enought, but would you want to mill on that? Screw up the z-height with your mill and you’ve ruined your print surface. Or worse you plunge the drill in to the heat element.
Have you tried milling a 3dprinted part to improve surface finish? I’d guess you’ll have to have a thick shell of the 3d printed part? If you have, what was the end result?
(Btw, nice poster behind the mill! =)
No I haven’t try it, I manage to finish the mechanic yesterday. This is in my wishlist. Smoothie and few close source controllers support Mill and print but I will need to deep dive in them. At the moment I use parallel port controller. I know that some guys manage to make Match3 also to print. For the bed I am thinking to make it mount in the channels for the clamps. For the z-height I am thinking for touch sensor that will calibrate the mill tool and the nozzle and this will allow me to keep same offset. But this is something that I am starting to think and research now. Basically I was pushing for the mill cos it will enable me to produce the parts required by myself. I already got 3D printer that helped me a lot for the mill as I manage to print all motor mounts, switch supports and other parts that could be produced from Poly-carbonate by myself.
Just for your info, Printrbot has always been interested in both 3D printing and cnc… we used the tinyg board (v9) for cnc, and now use our tinyg based “Printrboard G2” for 3D printing. It took the authors of the firmware months and months of paid contract work to come up with new additions in the firmware to support 3D printing… all non-motion commands are handled in json in order to tame all the non-standard 3D printing gcode that has wormed its way in to use. If you really want a board that does both and does both very very well, look at our Printrboard G2. I recently made some 24V compatible boards to test as retrofits on our cnc equipment ;).
Brook
Hi Brook thanks for the hint. I was waiting long time to upgrade my Plus board. I don’t need at all motor drivers as I use much more advance drivers currently. Is there board without drivers just pulse,dir and enable control? I want to feed the motors externally. My base PSU is 2000W 12V and for the motors I use DC to DC step up converters in order to have regulated voltage up to 80V in order to choose best amp/volt motor configuration. I believe that smooth voltage regulation is a must also for the printers as this give the ability to choose the optimal configuration for heat, noise and speed.
We haven’t exposed pins for step and direction (yet). I actually regret this now that I have need for it. I would expect it in future releases but it could be months out.
What drivers are you using? The interesting thing about tinyg is their true 6th order acceleration motion planning, even on the extruder.
You gotta read their post since I’m not a mathematician.
We are considering the trinamic drivers in future releases but it has some overlap. They use a chip to produce results similar to the true sign wave the tinyg g2core firmware uses but hard coded to the chip. I’ve met w trinamic guys and discussed in person at my shop- really smart dudes!
Since all the processing happens in the CPU, Alden and I have talked about jumping to the fastest arm chip that we can find. He’s appropriately cost sensitive but I’d rather have more ceiling for $3 more 
Since our development cycle was so long on this first major bit and the heavy lifting is over now, we can look forward to faster cycles and better hardware ahead!
Brook
I could imagine a 3D printed inlay being made on that, but I do not understand the high Z stage that looks like it could make the bit much higher than the X gantry.
The drivers are the only china thing that I use in this build. One of my main goal was no china parts in the mechanics as you always get for what you paid for. So I sit in ebay and start searching for bargain deals of what I need. This is the reason Z is bigger than I need with 10cm. I didn’t manage to find 50cm PSK 60 linear module with two carriages and new one from Bosch would cost me around 1000+ euro. Bought all four for 380$ per piece as new. All linear modules are 600mm long but because they are double carriages this limit the possible stroke to 370mm but stabilize the construction in order to be used as mill. If I went for a just printer and remove second carriage I would achieve 520mm stroke in every direction.
Drivers: RATTM DM556 5.6A/50V digital full sine drivers
Motors:
X:Sanyo Step-Syn 1.8A/200steps/0.8NM,
Y:2xVextra 1.6A/200steps/0.8NM
Z:Vextra 1.5A/200 + Ondrive 30:1 wormdrive (it is must as ball screw will unwind itself because of the Z wight and require either worm-drive or brake)
I am using 1/5 micro step per axis delivering 200steps/1mm for X and Y and no micro stepping for Z that deliver 1200 steps/1mm.
BTW I also made a mistake. I should fill the alu profiles with Epoxy-cement in order to damp the vibrations further but it is too late now. I am also using Vextra Dampeners for Y as it utilize two motors and resonance was really annoying. So far the machine is really quiet it move smoother than my PrintrBot Plus. For Y I also you use sync belt in order to block the motors if one stop unexpectedly or loose step.
