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Topic: automated drilling of alcohol stoves (Read 1 time) previous topic - next topic

Jul 10, 2013, 08:31 pm Last Edit: Jul 12, 2013, 11:23 pm by SeaCucumber Reason: 1
I have a company where I manufacture small alcohol stoves for hikers.  I would like to automate the drilling of these stoves.  I'm new to robotics.

I'm attaching pictures of my auto driller design.

Problems I need to solve:

I need to move a dremel drill press up and down a distance of ~1 cm.  I have a lot of control over the spring force that keeps the drill press head up because I can modify the coil spring that does this.  I want to press the drill down at a certain speed.  Pressing it too fast might break bits, and pressing it too slow would create burrs.  What is the best actuator to do this?

I need to move a sliding board to 2 positions (under the loader, and accurately under the drill).  I was thinking of using a regular motor and 2 electromagnets to do this.  When the board gets to one side, an electromagnet will pull it to a stop.  What actuator do you recommend to move the board?

Drew Davis

Lets start with how you will get the can to turn. If it was my project I would use a dc motor with an encoder. On the end of the motor shaft I would put a circular piece of wood so that you can slide the can over the wood. Then when the motor turn it will turn the can. 

What moves the press up and down? Is it that knob on  on the right? If it is I would take it off and try to attach a servo wear the metal lever is screwed in.

Best of luck!

Jack Christensen


Should I use a solenoid or servo motor? If a solenoid, should it be a pulse solenoid?


Stepper motor.
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

the other 2 pics

Chagrin

For the drill press you would want to replace the handle with a timing pulley or sprocket and then connect it to a pulley/sprocket on a stepper motor. Steppers don't have a lot of torque so you want about as big of a sprocket on the drill press as you can fit and then a correspondingly small sprocket on the stepper. Your press needs a limit switch (a lever microswitch) so you can detect when it has been fully lifted/retracted. So long as the stepper is strong enough that you reasonably don't need to worry about losing steps (you'd want a medium length NEMA 23 size) then there should be no need for an encoder.

Instead of a sliding platform to load cans under your drill press what you want to use is a "star wheel". Not really a great example but take a look at: http://www.filtec.co.za/BottleFilling_SemiAutomaticBottleRinsers.aspx. In your case you would want the wheel positioned vertically so the cans would fall into the wheel slots from a chute and correspondingly drop out just as easily. A star wheel like this would again be turned using a stepper motor. To ensure the wheel has rotated to the proper position you should use an indexing hole and photointerrupter or perhaps another lever microswitch that would trip against pegs in the wheel.

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