Accuracy of parts made by Pocket NC V2

[likl...@gmail.com]

Anyone know the accuracy of Pocket NC V2?  I want to make some small size RC model part, the size will be within 50mm cube with 6061 aluminum, I want to know the accuracy of final part I can achieve if I machine it with 3+2 approach with Pocket NC.  I am quite worry about the geometry error of the machine as my target is +- 0.05mm of final part.

[Jonathan]

Hi,

The specified repeatability of each of the linear axes on the machine is 0.002. This means that a part could be off by that much in each axis. Typically the machines are better than that when we build them, but that is the "worst case" possible while still being within spec. 

I think that you might have trouble holding your parts to +/- 0.05 mm. I think it would be possible to make good parts but that you would have more success in the +/- 1mm range. A lot of it will depend on the part you are trying to make as well and what materials you are using as well. If you have any models that you want to share, I could take a look at them and provide more specific feedback. 

Jonathan

[freder...@gmail.com]

Hey Jonathan,

I have developed a robotic hummingbird. One that flies by flapping it's wings. The development took 8 years :) and now we finaly have one that flies and is reliable. However before we go to production, we would like to mill them in the final material.

The most demanding parts are some gears. Do you think the V2 can mill modulus 0.3 gears? (we use a 0.2mm milling bit for it)

We have tried it on Roland machines, but the result was not good enough.

If you want I can send you (privately) a CAD file of one of our gears.

[Jonathan]

This sounds like a really neat project! 

I would probably need to see a file to give you a definite answer on this one. 

The smallest diameter tool we have used on our machine is 1/64 inch (0.4 mm). With tools that small the amount of runnout on the spindle is critical. depending on which tool holder you use you could have up to 0.002 inches of runnout on the tool, typically I see about .001 runnout on the extended tool holder and less on the standard. So my gut feeling is that this wouldn't be a good fit, but it might be worth checking to make sure. 

If you want me to take a look at the file, pleas send it to me in a private message. 

Regards,

Jonathan

[Logan Rose]

   When I was an engineer at EOS (Metal laser sintering)    we made some pretty small gears. ;)

https://all3dp.com/3d-microprint-laser-sintering-technology-3d-print-tiny-metal-parts/