Turn By Wire Is A Machinist’s Sixth Sense

It’s hard not to be a little intimidated by the squeaks and whirs that come with your first journey into a machine shop. Here, skilled machinists pilot giant hunks of cast iron that turn metals into piles of chips to yield beautiful parts. But what if machine tools themselves didn’t have to seem so scary. What if using them could feel a bit more intuitive, even, dare we say, natural from the get-go?

Enter Turn by Wire, a unique set of force feedback and machine control concepts applied to a lathe brought to you by researchers [Rundong Tian], [Vedant Saran], [Mareike Kritzler], [Florian Michahelles], and [Eric Paulos] at Berkelely.

Turn by Wire vastly reimagines the relationship between a user’s control inputs and the machine outputs in two ways: (1) by changing the mapping between the hand cranks and machine movements and (2) by changing the haptic feedback felt by the machinist. Since both of these interactions can be defined programmatically, the researchers created three unique ways of interacting with the lathe. First, by defining a tool path in the graphic user interface (GUI), the machinist can use a single hand crank to step forward and back in time along that toolpath. Second, by applying virtual guidelines in the GUI, both the machine and the hand cranks will physically snap to the guide lines when they are sufficiently close. Finally, the hand cranks can be used to teach the machinist a technique by adding resistive forces into the hand cranks depending on movement while a machinist is stepping through a process like peck drilling.

This is a great example of [Tom Knight’s] “just wrap a computer around it!” as mentioned by [Bunnie Huang] when we featured the IQ Motor Modules. It’s a powerful example of how putting a computer between the controls and the machine can correct for real world imperfections, be they in the mechanics of the machine of the operator. For the curious, have a look at [Rundong’s] paper published at UIST and [Vedant’s] master’s thesis.

 

14 thoughts on “Turn By Wire Is A Machinist’s Sixth Sense

  1. the physical disconnect between machine and operator is sort of like advanced surgery machines(dual 3d maneuvering hand grips), large motorized construction equipment(cat/backhoe, hydraulic actuated digging arm), or even “just” the automobile(power steering, accelerator-by-wire); which separate the user from one or more physical senses. this sensory disconnect can cause other senses to become more acute and useful in operating the machine.

    1. There’s a bit of difference. A “power steering” style of operation still relays information – just filtered by the mechanism. A computer in the middle means the computer has to know what should be going on in order to “guide” the operator – but if the computer already knows what’s going on then why do you need the operator?

  2. My business is one granted a waiver by governor in PA, and last night I had to drill and hard turn a mystery material that was the single worst material I’ve ever worked with. I *think* it was an overhardened batch of Viscount 44, it felt like low 50’s Rockwell. It melted 2 drills- melted – at any feed and speed in the right range I tried. High cobalt split points too. Destroyed normal carbide drills. I finally found something special that worked.

    There was an extremely sensitive line in feel between cutting, rubbing, and melting tooling with this stuff a bit more than normal hard turning and drilling. Even my boss and our lead machinist didn’t know what the stuff was.

    Things like this project would really help beginners tune in what proper cutting “feel” on different metals, types of cutters, and tools feel like on equipment, and I think it’s a pretty cool and interesting experiment and concept.

    Serious materials like whatever this was require a lot of skill to manually machine- others like VascoMax and such too.

    1. I should add- the melting was due to instant deep work hardening on the material. Viscount 44 actually turns nicely with a small nose radius of 0.015″ to 0.007″ or so, but work hardens on drilling very quickly. Incolnel does too.

      Feel with materials that work harden is essential, especially when you have to drill out forged titanium in no so nice grades as forgiving as 6AL 4V seized in incolnel dies

    1. a skilled manual machinist can read and act on a set of engineering drawings for a one- or two-off part with much less time invested than a technician machinist turning those same drawings into tool paths. CNC CAM has its big value in repetition of non-castable or cast-then-machine components – the operator time amortizes rapidly by the number of duplicate parts required. There is a place for both, and the break-even point seems to be about 3-off parts when using ‘fresh’ stock.
      another big value in manual machining is in using scrap-stock which may have collision risks from Part Past Life

  3. However, there is the caveat that even a skilled machinist cannot make up for the difference in rigidity between machines, and mostly won’t use the same level of coolant, or allow the same sort of chip throwing I found fine in a CNC machine.

    Most shops that have both, have a much more rigid CNC machine, due to slant bed lathes being so much more compact for a given size of work area, and being able to put more material in where the operator isn’t having to reach over it. Additionally, for mills, a large amount of the manual mills are bridgeports and other knee mills, which while incredibly useful are less rigid thanks to all those articulations.

    Plus, a good CAM package will let you template out operations, and for similar parts, you can apply a batch of templates and get a pretty OK tool path. Not perfect, but it doesn’t need the same sort of tweaking if you’re not running production. I say this as someone who used to do short run production almost exclusively, with my largest quantity ever being 100 of the same turned part, and most of my parts being 1-4 pieces. I also used scrap stock, although most of that was with manually programmed parts, and inefficient air cutting.

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