Beveled bottom wades large gear on Thingiverse.

Hi all,
After printing the wades large gear I'd always have to spend ages filing the bottom edge to the same size as each tooth so it would mesh properly across the entire surface of the tooth so I've remodelled the gear to include a 0.5mm bevel on the bottom edge. This removes the elephants foot situation and the need to sand the gears.

The gear is of course not of my design, I've simply modded it to make it easier to print. Credit (I presume) goes to Wade/Nophead for the original design.

I've included my .rsdoc file on Thingiverse in case anyone wants to play about with the design. I use Designspark Mechanical which is free from RS. It's a very good CAD program for the neuronally challenged like myself....

If I've done anything dumb, breached any etiquet or caused any offence either by making this mod or posting on thingiverse or posting here, please let me know and I'll hope to fix it.

Files can be found here:
[www.thingiverse.com]

Cheers
D

Hi,

That seems, to me, a case of treating the symptom not the cause.

If your first layer differs from the rest then it should be investigated and fixed. Is your first layer too low? Is your heated bed temperature too high? Both of these can be addressed and you can drop the temperature of the heated bed after the first layer (much like you turn on the fan after the first layer for PLA).

I have printed the Wades gear set without this issue (I posted some photographs in an earlier thread). I would treat this problem as one of the challenges to be met in tuning your printer for best results.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Hi Neil,
It absolutley is, a bit of time further fine tuning the setup could get better results but from the point of view of someone who is relatively new to 3d printing, the bevel is a quick and easy way of saving quite a bit of time and having an item that is useable hot (or cold I should say!) off the bed.
Looking around the internet the elephants foot situation seems a common issue for many noobs and presumably as the effect is lessened by reducing squish or lower temps, so is first layer adhesion? Not that its a big issue on this particular part due to its large surface area.
The M90 does take a bit of settling in and adjusting and beveling the edges out is just another tool in the box to make life a bit easier until my tiny brain is capable of setting it up correctly!
Cheers
D

To be honest all my ABS prints exhibit this effect to a lesser extent. The gear with sharp teeth is probably the worst case in this respect but never enough to need filing.

There are two effects. If the first layer is too low then it will leave a ridge, but that is easy to avoid. I always aim to print with the first layer at the correct height. If you want more adhesion then use a higher W/T ratio to squish the plastic more without printing it lower than it it should be. Or print the first layer lower but reduce the flow rate to keep the dimension correct.

The second effect is that first layer is the correct dimensions but subsequent layers taper in slightly but then taper out again very gradually. Having the bed too hot makes this worse but it also happened before I used a heated bed.

I can understand why it would taper in but not why it eventually tapers out again.

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[www.hydraraptor.blogspot.com]