Newbie Question

[tomdoyle1948]

I have ordered an M2 and am waiting to hear when they be able to ship it.
I created files for a part I hope to make with the M2.
It is a very simple part. If anyone could take a look at my files and let me
know how they look I would appreciate it.

The zip file includes files for the part that includes threads in the hole and
a part that does not include the threads. Other than that the parts are identical.

There are .gcode, .stl, .igs and .f3d (Fusion 360) files for both parts, with and without
threads in the hole.

I have checked it with Autodesk Print Studio and it did not find any problems. It also
looks ok on the preview slices in Print Studio but I still wonder if it is ok.

http://www.tomdoyle.org/MakerGear/Sproc ... dapter.zip

Also interested in hearing from anyone with experience tapping and/or threading parts using different filament materials.

thanks,
tom...

[ednisley]

a part I hope to make with the M2.

Perhaps you've designed them in inches and run into the inch-to-millimeter scaling issue (*). If they're really 25.4 times larger than the 2 mm pins I see, then they're fine, although the screw holes will still be pretty near the minimum practical size and there's no point to the threads.

In round numbers, you can expect 0.8 mm resolution in the XY plane and 0.2 mm (0.1 mm with extra care) along the Z axis: fused-filament printers (not just the M2) simply cannot produce features smaller than that. Holes and columns under 5 mm require tweaking to make them come out right, so you're on the edge of that.

You'll want to print the pins standing on their base, probably with a brim to provide better platform adhesion, and with attention to cooling.

Other than that, they'll work fine... and get you very well acquainted with 3D printing in the process. [grin]

Welcome to the club!

(*) STL files do not include a "unit of measure", so when you create them with a program using 1 unit = 1 inch, then read them with a program using 1 unit = 1 mm, they shrink by a factor of 25.4. Everybody makes that mistake at least once; don't ask how I know.

[jsc]

I've printed M5 thread screws which successfully threaded onto an M5 nut (viewtopic.php?f=6&t=1936). I think that's very near the practical limit. I see you are using #8-32 screws. G-code preview indicates that it will resolve into something that looks thread-like, but I'm not sure it will work. I've done much larger threads, those are no problem: PCO-1881 standard bottle cap (http://www.thingiverse.com/thing:499261) and a Dremel collar (http://www.thingiverse.com/thing:930863; 3/4" 12 TPI).

You may be able to print your internal threads, but if you have a tap just tap it. Make sure you leave enough solid plastic around the hole, though. Because your threaded holes will be printing in a horizontal orientation if you follow Ed's suggestion (and I concur), that will be some combination of using enough solid top/bottom layers and perimeters. Also, I noticed from your model that you made the threadless version the OD of the screw. It should be the ID if you're planning to tap.

In general, with PLA, you don't need to worry too much about support for small holes. Face the hole towards the front, to get maximum cooling from the fan.