Would it be possible to mount two cores on a single gantry and operate two tools like those “IDEX” printers?
You could offset the X belts and have separate X belts, or you would it be enough to drive both cores off the same X belt? If only one is moving at a time, the tension from acceleration shouldn’t be any higher. Obviously this would eat up some of the capacity in X.
The wiring might get messy with two X and two Y and two Z, and you would need a minimum of six drivers. Most likely you would want two SSRs to power down the tool that’s not being used. Not sure how much of the IDEX firmware can be stolen, or if we would need to write more firmware for homing each core to +X or -X as appropriate.
I’m not thinking of any mechanical reason that two cores couldn’t be mounted. There is a second endstop and wiring and vacuum hoses and firmware and CAM that are by no means trivial, but the mechanical parts of the machine should support it, right?
For what purpose? I’d imagine swapping out the router for a spindle with pneumatic automatic tool changer capabilities might be a better fit here if the intention here was to have two different bits for usage in the same job.
I could see you maybe go this route if you had two totally different types of tool heads such as a router and laser, needle cutter, or 3D printer extruder. My gut reaction would be to focus on just making the toolhead easily swappable over the added complexity of the belt routing, dual cable chains to accommodate the two X positions, and loss of X travel with two toolheads.
Yes, you’re completely correct, the intent does overlap with a tool changer, or is completely covered by a tool changer if you’re not changing to a different category of tool. But a tool changer has a relatively high entry cost. The ones I’ve seen easily cost significantly more than the rest of the machine.
A cheaper DIY version of a tool changer is probably possible but more difficult than adding a second core. Even then, a second core is probably harder than it sounds, after factoring in all the wiring and firmware, but those are all cheap and someone only has to figure it out once.
I like the idea. The biggest problem I see is homing the second to the first.
A 5 pole double throw switch to change over the X stop and X motor, and a parking clamp for the cores at each end.
While a tool changer can do all that, it’s a spendy solution. This costs a stepper motor and a handful of skate bearings. I would just run it on the same X belt rather than remix all of the belt holders and core. Even if you wanted to move both at the same time for some reason, I think it would be stable enough so long as you avoided a collision.
A swappable core sounds good if you have a quick release for the motor, switch and DC, but the X belt will always be problematic, I think, since it will need the thread into the X drive every time and be retensioned… unless you can wangle a quick release for the X drive as well… Hmmm…
I hadn’t thought of a double throw switch style approach. Then the firmware can be oblivious, which is much, much easier than integrating a true IDEX style control. This is my new favorite approach to the double-core idea.
The X offset you could handle with CAM or some G92 commands. Depending on the tool, there could also be a Y and Z offset too by the way.
For homing, maybe the strut plate can have a magnet attached and a reed switch replaces the endstop. Then the second core is not be subject to the accuracy of the position of the first core. You would want both endstops to be the same polarity, either NC or NO, so maybe a reed switch implies the other core has to operate normally open. Other options might be possible but a reed switch is nice and small and is sure to fit.
If you used relays for switching the motors, maybe a sequence of M84 + M42 can switch safely and protect against user error cooking the X driver.
I want to find a reason this would be super useful. Something where you want to change tools as fast as colors in a 3D printer. I can’t think of one. Maybe those metal “printers” that laid down a bead of new material with a welder and then cut the excess off with an emd mill?
I also wonder if you would benefit from redesigning the 2nd core to have the inverse shape. Just to get back a few inches of travel.
Like this?
I found “dual x carriage” in marlin’s cinfiguration_adv the other night when I was setting up my archim, so I liked up some videos.
Home one to the left, the other to the right, both at the same end of the table?
Maybe you have a second setup for cam, where the in its just in the second corner.
Exactly, this was my original thought. I know it’s been done, but I don’t know how much code can be used as-is in Marlin and how much would potentially conflict with dual Y and dual Z. Now I like Dan’s idea for a hard switch, with both homing in the same direction, although if the firmware is easier than I thought, then the dual X carriage is a strong contender. I was assuming the worst for firmware, but I really should look into it.
I think for a 2D flat cut or a roughing + finishing job, with only one change, the value is not huge, because the cost of changing and resetting Z is not that high. With some of the cutting board inlay, I find myself switching back and forth between the V-bit carving and flattening quite a lot. The labor is not really excessive, but it’s annoying to me and it’s worse knowing I’m going to have to change back before long. I think it would be cool to make a cutting board with two or three different inlay colors, but the thought of all that changing starts to drain my motivation.
Now one step further, I am struggling to think of a compelling case for three or more tools in one job, so the dual-core option might just kill any plans for an automatic tool changer that scales to a lot of tools. There’s still value in a (manual) quick-change tool mount that maintains good stiffness, so that’s still on the table, and probably a good thing to prioritize that over a DIY ATC.
There is another mystery that I don’t have the answer to, and that is why am I so interested in tool mounts?? It is a weird feeling, like I can’t help it.
The motors have an inductive load, so you will have arcs if you switch the motor while they are energized. A flyback diode won’t work, because the current could be going either way. So you should disable the motors before hitting the switch.
I typed up a big reply as to why you’d have two different tools at the same time, then I reread your comment… Yea, having both tools on a larger Z would be better, but working with what we have is what jamie is talking about. You would lose a bunch of X cutting space though.
No, they would share the same Y and Z. What I meant by Dual Y and Dual Z is there are two motors and two motor drivers for auto-squaring Y and Z (right?). Maybe the firmware gets complicated (and you need 6 drivers). Or maybe it’s okay in the firmware.
Ah, i gotcha. I didn’t dig any deeper than the config files, but I think the slicer just says “hey, use this stepper for extruding instead” and the firmware sends it, using the offset.
I can’t think of how you would do that through estlcam or fusion, because x is x, then i remembered the mentioned of a switch above and it occured to me just HOW far behind you guys I am.
