Hand Ergometer

[FatFreddie]

Ok, some progress. I've now got a set of gears that mesh reasonably well but I'm not happy with the print quality so I'm going to try a different slicer - the one I'm using at the moment is Sli3er and it's fast and easy to use but it doesn't seem to be the best quality. I was using Skeinforge before which is better quality output but not very friendly - I'll have another go with that over the next couple of days.

[irving2008]

Ok, some progress. I've now got a set of gears that mesh reasonably well but I'm not happy with the print quality so I'm going to try a different slicer - the one I'm using at the moment is Sli3er and it's fast and easy to use but it doesn't seem to be the best quality. I was using Skeinforge before which is better quality output but not very friendly - I'll have another go with that over the next couple of days.

Thanks for your efforts on this. I'm in the process of drawing up slightly modified gears, the main difference being improvements to better support/locate the bearings and space the sun gear off the rotor boss - I may increase the thickness of the gears slightly. I'm also redrawing the supports, the rotor bosses and the planet carrier. I was thinking of 3D printing the carrier but I don't think the boss would be strong enough to take a grub screw to fix it to the axle (but what if the boss was thicker and had a slot for a nut to be inserted?). The other thought I had was 3D printing other components, the rotor bosses for example. I'm not sure about the cranks or the handles from a strength perspective, need to run the numbers. Also do you have any way to calculate the cost of a printed component?

[FatFreddie]

No problem, I'm enjoying having something constructive to do with the machine. Work is a bit binary at the moment so apologies if I go missing occasionally.

I had thought of printing some of the other parts - once I get something that can be strength tested we'll know better what's possible. I have had some unexpected breakages in the past but that was with mounting brackets where I think I underestimated the shock loads. One thing to bear in mind is that things like splines which would normally be difficult are relatively easy with 3D printing. The main problems are fine tolerances and overhangs so a spline would be best if it was tapered or with pinch bolt.

I haven't bought any filament for a while but I think it's around £30 a kilo. Partially hollow parts are the norm so material usage is quite efficient.

[irving2008]

No problem, I'm enjoying having something constructive to do with the machine. Work is a bit binary at the moment so apologies if I go missing occasionally.

I had thought of printing some of the other parts - once I get something that can be strength tested we'll know better what's possible. I have had some unexpected breakages in the past but that was with mounting brackets where I think I underestimated the shock loads. One thing to bear in mind is that things like splines which would normally be difficult are relatively easy with 3D printing. The main problems are fine tolerances and overhangs so a spline would be best if it was tapered or with pinch bolt.

I haven't bought any filament for a while but I think it's around £30 a kilo. Partially hollow parts are the norm so material usage is quite efficient.

OK. Attached are image and DXF file for the 3D printable modded sun gear and rotor boss which now include a seat for a 15 x 10 x 4 magneto bearing. these go either side of the rotor and are joined by 25mm M3 cap headed bolts and captive nyloc nuts. Are these printable?

Crudely each contains 1.25e-5 cubic metres of material, which means 0.02kg of PLA

[FatFreddie]

Shouldn't be a problem to print those.

The new slicer is better, both finish and sizing.

I'm trying to put something together for some destructive testing now :-)

Don't worry about the plastic usage, I've got loads in (as long as you're not too bothered about the colour).