New Toy
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Thanks for the link!
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Well, my first bit of milling for about 48 years didn't turn out too bad.
6 (3 pairs) of new aluminium motor mounts (XYUVAW axes) to replace the plastic printed ones.
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@deckingman ha ha couldn't resist a pythonesk reply, you left the gate wide open!
Cheers though, I shall bare that in mind. I've a few ideas maturing but need to gather thoughts a bit more.
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@deckingman said in New Toy:
Well, my first bit of milling for about 48 years didn't turn out too bad.
6 (3 pairs) of new aluminium motor mounts (XYUVAW axes) to replace the plastic printed ones.
Those parts are looking good Ian. Fly over here to the states and I'll get you a job working here in the machine shop where I work
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@timcurtis67 Thanks Tim but sorry - wrong part of the world. Now if you were in Australia where my daughter lives, I might have been tempted
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Fantastic,
I have a Charter Oaks automation. Physically similar.
Also, I made the same decision: DRO, not full CNC. It's been VERY productive...
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@danal Thanks. Coming from you, I'm reassured that my decision not to eventually turn it into a full CNC machine is justified.
The only thing that I'm finding is a bit of a PITA, is that I need to produce some sort of dimensioned drawings to work from, and as up until now I've designed everything exclusively using OpenScad, this isn't as easy as it could be. I need to look into that. -
You can make cut in OpenSCAD, then export them as DXF, and load them in LibreCAD (very good software)...
Or switch to something much more powerfull, like Onshape/Fusion360 (not open).
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@fma Thanks, I'll give that a try. My current method is to import the OpenScad file into Freecad, then use an add on to make dimensioned drawings. It works reasonably well but I think what I need to do is just get to grips with some other Cad package and cut out the OpenScad step.
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If you don't mind the cloud part of Fusion360 its hard to beat the value to feature ratio of integrated CAD/CAM.
It is a bit tedious to export openscad -> freecad -> fusion just because there are no common formats between openscad and fusion though.
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@bearer Yes I've tried Fusion. It's a big learning curve for someone like me who has never used anything other than OpenScad. But then, so is FreeCad and probably all other CAD packages.
For the motor mounts, I just exported an image from OpenScad, printed it, looked though the OpenScad code to get the dimensions, then just scribbled them onto the printed image. Slightly better than the back of an envelope sketch, but not much........ -
I think that when you learn the basics, Fusion workflow is much easier.
For those mounts, did you just use the same thickness as for plastic ones? -
I think that when you learn the basics, Fusion workflow is much easier.
For those mounts, did you just use the same thickness as for plastic ones?Ref, Fusion - you could be right but I've got a lot going on at the moment so finding the time the time even to learn the basics is not easy.
I did use the same thickness aluminium for those motor mounts as the plastic version. They are 5mm thick and I realise that I could have got away with using say 3mm thick aluminium, but then I'd have had to change many dimensions to get the motor position in exactly the same place in all 3 planes. And I'd likely have needed to get all new bolts because the current ones would bottom out, both in the motor and in the extrusion Tee nuts using a thinner plate. (Edit - and that's 8 bolts per mount x 6 = 48 new bolts).
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I was actually guessing that you kept the same thickness. Because of all of the reasons that you mentioned, that is the simplest way.
And I am curious about the stiffness gains. OK, on your printer it is going to matter, but on smaller ones? I have a feeling that plastic could be good enough. -
I was actually guessing that you kept the same thickness. Because of all of the reasons that you mentioned, that is the simplest way.
And I am curious about the stiffness gains. OK, on your printer it is going to matter, but on smaller ones? I have a feeling that plastic could be good enough.Oh plastic is fine as far as rigidity is concerned. Stiffness isn't an issue, nor is it the reason why I wanted to make metal mounts. Up until now, I've always tried to adhere the the RepRap philosophy and use as many printed parts as possible. Of course, that was partly driven by the fact that I had no means to make anything out of metal so I had no choice. All my carriages and idler pulley mounts are printed parts and I have to plans to change them, even though I could now do so.
The reason why I wanted metal motor mounts was purely to do with heat. I've had problems in the past with very long prints (30 hrs+) and motors getting hot (as is normal) but the heat was causing the plastic mounts to soften slightly. Then the tension of the belts acting on the motor shaft caused the mounts to deform. I re-made the mounts using PET-G and also fitted fans and heat sinks to the motors which was 90% successful but not 100%. I'm still getting some deformation after very long prints - nothing like as bad but it's still an issue. Hence the need to use metal mounts - no other reason than that.
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I wonder if vibration dampening mounts could have gotten you the last 10%? I removed mine when I got alu motor mounts to help dissipate heat from motors.
Moot point at this time though, but maybe someone else who stumble onto the thread will find it usefull.
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@bearer said in New Toy:
I wonder if vibration dampening mounts could have gotten you the last 10%? I removed mine when I got alu motor mounts to help dissipate heat from motors.
Moot point at this time though, but maybe someone else who stumble onto the thread will find it usefull.
Maybe. But I hate the thought of using them on a printer. How can one guarantee positional accuracy if the motor itself can float about? I know they are quite popular but using them where positional accuracy is important, just goes against all my gut instincts.
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Pretty sure they would have less flex than toasty plastic, they're surprisingly rigid. Anyways, relics from an era before silky smooth interpolated microstepping from Trinamic
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To block heat transfert, you could use a square sheet of cork between motor and mount (you can use a decent thickness). And use stainless steel screws. I'm pretty sure it's enough.
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@fma Again, a bit too spongy for my liking.
Also, metal mounts make it bit easier to earth the motors which I'm told is what we should all be doing to prevent static build up. Plastic mounts mean you have to run a separate cable.
