Ah, thanks. I appreciate the helpful info!
I did this for laser, worked great! I bought enough magnet strips to also do CNC too! Will aim to get that tried soon.
That does sound like a great idea, i am concerned about the CNC but then again i dont use it yet. and we could always add extra clamping to the cnc table anyhow.
Thank you for sharing this idea.
@hoachter
One idea would be to stick the magnets oo thst all holes on the underside of tbe wasteboard are covered. Then you cannot damage the bed as the screw will meet the magnet and stop.
Good idea. I started this topic, and I’ll say I’ve used the magnetic strips for multiple CNC and laser jobs. Of course laser is no problem since the only force is bed movement. But, at least for me, CNC is fine also. Put enough strips on, the lateral hold force is good. You’re not going to get much lateral force from the small cut depths the head will do.
You obviously haven’t done much cnc. Reliefs are one thing where the bit is only contacting the surface. The force on deep cuts (12mm) against the grain in hardwoods like oak is significant even with smaller bits, let alone when using 1/4". I’ve had things clamped down where I thought the inserts were just about to pull out and still have had the piece shift.
Definitely would need a locking mechanism for me. Guess it all depends on what type of work you’re doing.
-S
I 'm amazed the spindle on the snapmaker can cut that deep. I’ve been cutting 4mm ply with no problem at all but using multiple passes. Oak? That’s a different story. It’s a pain to work even with ‘real’ tools, hard and splintery. Magnetic mounting works for me. If you don’t like it, don’t use it.
I have done something similar for the laser bed only so far.
I used an old “damaged” magnetic bed, laid down painters blue tape on it, then did the same to the back of the laser bed aluminium rails and then I glued them using wood glue and left them overnight. Now I have a super-fast removable bed and it’s rock steady. Plus it’s easily reversible as I only need to remove the tape - there is no glue on the actual plates! The Snapmaker team should have opted for this in the original design as it really adds a LOT of VALUE to the process.
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Maybe you could make (3D Print) some corner clamps that screw together to give it some more holding power.
I bought the above magnetic tape and tried various layouts for it under the CNC bed, but while it held OK for lateral forces, the board still rotated easily.
I decided to print some clamps to attach the CNC board to the 3D print board. I added some duct take to the bottom of the CNC board to give it some grip. With that they work. Can’t even get bed to budge.
Here is the CAD file (in OnShape)
https://cad.onshape.com/documents/e7333554f40d3843248586d8/w/256d71e853ae4efc27915f70/e/f55334c1772b0bd9c57317b4?renderMode=0&uiState=61c02bc49e532060e10495bf
Will make some clamps for attaching Laser plates to 3D print bed next.
I’m just getting started and glad I read your post rather than starting a duplicate. I love the simplicity of your solution & have ordered the magnets.
This close to Christmas they may not arrive until sometime next week but intend to implement solution as soon as they arrive.
Thank you for your work.
I was actually just searching for whether there’s a problem with leaving the 3D bed on all the time, and just bolting the others on top of it.
The holes on the various beds obviously line up, so just using longer (M4?) bolts should do it. A magnet or a steel trip wouldn’t hurt, of course. I’m not thinking of a quick-change solution here - just trying to find a way of not having to unplug that d@mn heated bed every time I want to do laser or CNC. Speaking of, why is one of the two cables that is expected to be unplugged every time you change modes HARD-WIRED at one end? Let’s not get into the cable pinches and all that loveliness - why tf isn’t the heated-bed end of the cable a connector?
Anyways, the main worry I have for just leaving the 3D bed on is damage to the bed: either bending (due to CNC forces) or wear exposing the heating contacts (which seems to happen just by removing the magnetic sheet a bit). So maybe a bit of hardboard (aka Masonite) mounted between the 3D bed and the others?
The magnets do not work… Use 3D printed clamps
Maybe long M4 screws in four corners, then magnets to prevent movement for the rest of the bed? Fine for laser no doubt (except it doesn’t use the corner mounts points!), not sure about the CNC. Might make for wobble in the center.
Yeah experimented a bit with the heated bed magnets tonight. Not as powerful as one might hope.
It’s good to aim to have the CNC bed left on the machine as the ‘base’ level and the other beds ‘attached’ by whatever means when required.
My question.
Is there a heat transfer issue if the 3D printer heated bed when in direct contact with the CNC base if the CNC base is mounted permenantly as the lowest base?
Regards
Graeme
This can also be helpful:
It’s been designed to hold a glass bed in place but works also wonderfully to held the printing surface ( when using high accelerations and speed ) or to keep any other plates to slip horizontally. And they just snap-on.
I’ve doing it for a while. Haven’t had any real issues. Over time the mdf does deform a bit because of the temperature making it a bit less flat. (in my case the corners going up or the center going up.) Depends on the temperatures used as well. the higher the temp, the sooner you’ll see this effect.
That being said, you are attaching a heater to a piece of wood and glue, which are by definition flammable. (Although it shouldn’t combust into flames at those temperatures).
Do note you should cut a small recessed area in the center where the temperature sensor of the heated bed is.
I’ve been working on version of this for my A350. I want to leave the heated bed on all the time (basically because it unplugs at the controller, not at the bed, and I find that too inconvenient), but of course it has to be protected from the abuse of CNC.
What I’m thinking of doing is an MDF intermediate plate, either 1/4" or 1/2", that protects the heated bed and which the other beds bolt to (or through). No magnets: I found they move just when you need them not to. So the process of moving from 3D to non-3D would be: remove the glass print surface (by unbolting the fixture that holds it in place on the heated bed), bolt the intermediate plate to the 10 holes which correspond to the large square of the platform under the heated bed, then bolt CNC wateboard through the intermediate board to the remaining holes (i.e., the innermost and outermost ring of holes on the underlying platform). The corners of the platform are a point of contention, as the linear rail mounts require those: there’s 3/16" of M4 female thread available, though, and 3/32 should be enough for the first 3-4 threads of M4, which should be sufficient.
This won’t work with the laser plates, of course, because they use the mounting holes intended for the intermediate plate. But I’m not a bit fan of those, and will either glue them onto 1/8" hardboard and drill new holes. or just build a better laser worktable. I saw a pictures of a vacuum table in MDF that I might take a stab at implementing; that would deal with the smoke as well as the workholding.
Looking forward to see the results of what you come up with.
For me they have been working very well so far. Also for cnc work. But I am using 4 pretty strong ones (if I remember correctly they can hold more than 20kg each). And I have printed “cups” for them and the metal counter plate so they automatically align perfectly and can’t shift sideways (which takes a lot less force)
Yeah, a pocket or shoulder of some sort would have prevented the lateral movement. I won’t lie: it was an entirely half-assed attempt to hold the 300x300 glass print plate in place using a steel frame with neodesium magnets to supplement the not-really-strong heated bed. I used screws instead, and will probably use screws again in the final verson. Good, honest screws. Well, not those grade-2 ones at the hardware store that shear when you attempt to loosen them: those are less than honest.
Realized last night I can buttress the single-m4-mount-screw for the linear rail mounts by drilling a hole and bandsawing a triangle in some 1/8" or so aluminum plate. The same idea as those printed monuts you guys use in another thread, only it won’t take 4 days to print and won’t require putting this whole thing back together and calibrating it 