Gallery, Projects and General > The Design Shop
3D Printed Quorn Tool & Cutter Grinder
Will_D:
I am watching this with great interest!
When it comes to a motor and spindle the originals will be far too heavy for this printed project. May I suggest you look at some of the electric helicopter motors that are available? Their power to weight ratio is awesome. (These are similiar but cheaper to the CNC Stepper spindle stuff that are available). They also come with speed controllers.
After all its not really the size of the grinding wheel that matters its the surface RPM. So a small motor at 30,000 rpm can drive a quality mounted stone with enough surface speed to equate to a 75 mm cup wheel!
[I think :scratch:]
Joules:
Shucks Will_D, I've been busted.... I was keeping that detail back that the spindle will most likely be a combination of Dremel and Foredom flex drive. NO, I won't be printing the spindle.... In the meantime whats the smallest cup wheel you can get, how hard is it to make grinding tools by reworking existing small stones.
I did sort of hint early on about using a brushless motor to power a spindle.... :D
Your spot on Norman, I have looked at the Quorns using threaded rod to jack the spindle up and down, rack and pinion not really an option for printing as the part size would be too weak. I fancy making the tool to do the spirals as you never know what the next small printed machine might be ? This isn't going to be the last.
Joules:
After getting bugged about how to cut the spiral on the vertical column. I started doing some more doodling and so far have this idea bubbling.
The column will be between centres and the large gear will clamp onto the column. Since I have a good quantity of 30mm bar left over I will print clamps to attach centres and supports for the bar. Loading will be light as I intend to mill a 3mm slot on a 0.500" pitch hence the gear ratio 10:1 on the Taig mills 0.500" x 20tpi leadscrew. Gears will be printed, but shafts turned and supported in bushes. Still developing this one, so it could all change.
I have to give credit for the 3D Taig mill to Richard Crook, very useful model.
Joules:
Here's an example of going beyond the limit of a 0.4mm nozzle.
I printed both these scales at 0.1mm layers, I had tried looking to see if 0.05mm layer would improve resolution, but in this case I am up against the 0.45 blob resolution. Scale on the left was printed first, due to the size of the graticules and characters printed, even gentle rub down soon showed problems like paint creeping along the grain between layers, and the dark line is a rounding adjustment as the printer goes to the next layer. I increased the font size and picked something with thinner proportions. Not much I could do with the graticules, they could have been added after, making them deeper would have been problematic in printing as the surface would start to ripple.
My next printer I hope to improve on things here by being able to use a 0.25mm nozzle, the simulation I ran showed very crisp detail if I could have printed it (<0.3mm blob)
Other than that, the scale is a good fit, so if I don't weld it in I have the option to reprint at a later date in higher resolution. The workhead turntable is really giving me headaches, partly due to the scale around it and also making it as stiff a structure as I can. I found a 16mm reamer in my tool draws, with hindsight I should have adjusted the fit of parts to accommodate a 16mm spindle, but as things are now I break through on to the pivot. Maybe remodel after we see how things work out.
Joules:
This afternoon in the workshop saw me completing the micrometer adjuster. However as I finished milling the grooves in the threaded insert I had made, I realised I had got the splines in the wrong orientation. :palm: I might be OK as it took some force to press the insert in, so it may stay put as is, but a drawing revision is in order and a spare part printing.
This is the underside of the print, so not very pretty. I could have added a little more material and given it a quick skim in the lathe to give a pretty surface but it's not visible.
The Perspex threaded parts look like they are going to work, and can take quite a good load being 27mm of thread engaged.
Final assemble shot and a bit of furniture wax added to the threads. If you want to learn how to screw cut, you can't beat using Perspex. Easy to see the thread forming, tooling can be incredibly basic, even mild steel tools can be used. For the internal threading my threading tool was made from s/steel tig wire. Perspex is unforgiving of tight fits though, so you need to be accurate, but the material is so cheap you can try over and over again till you get it right.
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