Precise linear motion output from rotary input

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Discussion Overview

The discussion revolves around achieving precise linear oscillatory motion from a rotary input, specifically for a compact carving tool. Participants explore various mechanisms and methods to control displacement, including the need for adjustments in stroke length and the feasibility of different designs.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant initially questions the feasibility of achieving linear oscillatory motion, suggesting that the terms used are mutually exclusive and requesting clarification on the required motion range.
  • Another participant clarifies that they meant reciprocating motion, specifying a range of 1mm to 3mm.
  • Several participants propose using a multibody system with adjustable holes to modify linear travel distance.
  • Another suggestion involves employing a camshaft with variable lobes to adjust travel distance, allowing for a parallel motor configuration to the reciprocating point.
  • A participant mentions researching slider-crank mechanisms and expresses difficulty in finding practical solutions for real-life adjustments.
  • It is noted that drilling various holes on the crank can change the stroke, but real-time updates may require more complex solutions.

Areas of Agreement / Disagreement

Participants express differing views on the terminology and feasibility of achieving the desired motion, with no consensus on the best approach or mechanism for implementation. Multiple competing ideas are presented without resolution.

Contextual Notes

Participants have not fully defined the constraints of the required motion, and there are unresolved practical considerations regarding the implementation of suggested mechanisms.

Who May Find This Useful

Individuals interested in mechanical design, particularly those working on compact tools or mechanisms requiring precise motion control.

JJ21
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Hi,

I need to get a precise linear oscillatory motion from a rotary input? Its for a compact carving tool. Any ideas on how to control the displacement? Thnks
 
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JJ21 said:
Hi,

I need to get a precise linear oscillatory motion from a rotary input? Its for a compact carving tool. Any ideas on how to control the displacement? Thnks

Strictly speaking the bolded words are mutually exclusive. You simply cannot have linear oscillatory motion. You need to place some constraints on your needs. For example over what range do you need approximately linear motion.
 
Sorry, by linear oscillatory motion i meant reciprocating motion. It would be over several fixed ranges from 1mm to 3mm for example.
 
It would also be possible to use some form of a camshaft which has varibly sized lobes for adjutsing the travel. This would also make it possible to have the motor located parallel to the reciprocacting point, rather than perpandicular to it.
 
Thanks for the ideas! I've been researching how to vary the stroke length of a slider-crank mechanism and have found a few methods but no "practical" solution of how the slider-crank could be adjusted in real life for example the slider-crank mechanism attached below.

Any ideas?

Thanks
 

Attachments

  • slider crank.jpg
    slider crank.jpg
    7.1 KB · Views: 708
As Fred mentioned, you can have various holes drilled on the crank (i.e. the radius of the rotating arm). That will change the stroke.

If you need this updated in real-time, then a more complex solution might be needed.
 

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