If you can afford it, a part like this can be 3D printed in stainless steel. I think SpaceX 3D prints the injectors used on their Raptor rocket engines in some exotic material like Inconel. Printer that can do that are expensive but you can use a service.
But I think the point of this handle is an exercise, not to make a handle. Given that you have a CNC mill how to you best make an exact replica? Think of this as a homework assignment. Here is what I would do... Take the CAD file and orient it so the two drill holes are on the vertical axis. (I think? the crank and handle holes are parallel) The in the CAD system add a metal pedestal The elevates the crank. On the bottom of the pedestal are two blind threaded holes, perhaps M5 or M6 size. Start by making the hole on the backside of the billet. Fip the billet and screw it to the table from the bottom. Mill the crank top and sides and drill the holes. Flip the crank and use the two holes you just drilled to screw the part to the table, pedestal facing up. You need spacers under the crank to make the drilled holes vertical Using an end mill finish the side of the crank that is now facing up. This will turn the entire pedestal into chips. For both cuts the top surface is flat but horizontal, so maybe a ball mill is required, at least for finishing A second method is to design the part with bridges to the billet. You cut the part, flip the billet and cutfrom the other side and then there is a crank suspended inside the scrap and connected to it by maybe three bridges. then you cut them with a saw and the part falls out. Finally, you smooth over the saw cuts. THis is like casting where you have to saw off some parts. On Wed, Oct 13, 2021 at 8:17 AM Bruce Layne <linux...@thinkingdevices.com> wrote: > > > On 10/13/21 12:02 AM, John Dammeyer wrote: > > Chrome plated pot metal and if that can crack and break a 3D printed > handle would definitely. > > An FDM 3D printed crank arm would almost certainly break, regardless of > the material used. > > An MSLA (resin) 3D printed crank arm almost certainly would not break. > I would fix this problem by creating the part in FreeCAD and printing it > on a resin 3D printer using an "ABS-like" structural resin. > > A part's strength can be measured in many ways, but in general, MSLA > resin printed 3D parts created using a structural polyurethane resin are > stronger than aluminum but not as strong as steel. The polyurethane is > as durable as a hockey puck and polyurethane is very resistant to > cracking, unlike aluminum or the pot metal original part. > > Even for home gamers, 3D printers are not just filament based. Resin goo > MSLA 3D printers are now fairly cheap, and the resolution is almost as > good as injection molding. The parts are very strong and the material > cost is around US$.03 per gram. Part strength is isotropic so layer > delamination isn't a problem when designing parts as it is with FDM 3D > printing. The biggest MSLA downside is the isopropyl alcohol part > cleaning and UV post curing, but it's not that bad. > > Someone needs to make an upgraded MSLA printer that automates the post > processing operations. > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
